Publications

Publications | Selected Conference Proceedings

Document titles link to PDFs, where available. All articles, book chapters, and drafts are the sole copyright of the respective authors and/or publishers, and may be downloaded for educational and personal use only.

Publications

In Press


Walker, C. & Lombrozo, T. (forthcoming). Explaining the moral of the story. Cognition.

view abstract
Although storybooks are often used as pedagogical tools for conveying moral lessons to children, the ability to spontaneously extract “the moral” of a story develops relatively late. Instead, children tend to represent stories at a concrete level – one that highlights surface features and understates more abstract themes. Here we examine the role of explanation in 5- and 6-year-old children’s developing ability to learn the moral of a story. Two experiments demonstrate that, relative to a control condition, prompts to explain aspects of a story facilitate children’s ability to override salient surface features, abstract the underlying moral, and generalize that moral to novel contexts. In some cases, generating an explanation is more effective than being explicitly told the moral of the story, as in a more traditional pedagogical exchange. These findings have implications for moral comprehension, the role of explanation in learning, and the development of abstract reasoning in early childhood.

Ruggeri, A., Lombrozo, T., Griffiths, T. L., & Xu, F. (forthcoming). Sources of developmental change in the efficiency of information searchDevelopmental Psychology.

view abstract
Children are active learners: they learn not only from the information people offer and the evidence they happen to observe, but by actively seeking information. However, children’s information search strategies are typically less efficient than those of adults. In two studies, we isolate potential sources of developmental change in how children (7- and 10-year-olds) and adults search for information. To do so, we develop a hierarchical version of the 20-questions game, in which participants either ask questions (Study 1) or test individual objects (Study 2) to discover which category of objects within a nested structure (e.g., animals, birds, or owls) has a novel property. We also develop a computational model of the task, which allows us to evaluate performance in quantitative terms. As expected, we find developmental improvement in the efficiency of information search. In addition, we show that participants’ performance exceeds random search, but falls short of optimal performance. We find mixed support for the idea that children’s inefficiency stems from difficulty thinking beyond the level of individual objects or hypotheses. Instead, we reveal a previously undocumented source of developmental change: Children are significantly more likely than adults to continue their search for information beyond the point at which a single hypothesis remains, and thus to ask questions and select objects associated with zero information gain. This suggests that one crucial source of developmental change in information search efficiency lies in children’s “stopping rules.”

Walker, C., Bonawitz, E., & Lombrozo, T. (forthcoming). Effects of explaining on children’s preference for simpler hypothesesPsychonomic Bulletin and Review

view abstract
Research suggests that the process of explaining influences causal reasoning by prompting learners to favor hypotheses that offer “good” explanations. One feature of a good explanation is its simplicity. Here we investigate whether prompting children to generate explanations for observed effects increases the extent to which they favor causal hypotheses that offer simpler explanations, and whether this changes over the course of development. Children aged 4, 5, and 6 years observed several outcomes that could be explained by appeal to a common cause (the simple hypothesis) or two independent causes (the complex hypothesis). We varied whether children were prompted to explain each observation or, in a control condition, to report it. Children were then asked to make additional inferences for which the competing hypotheses generated different predictions. The results revealed developmental differences in the extent to which children favored simpler hypotheses as a basis for further inference in this task: 4-year- olds did not favor the simpler hypothesis in either condition; 5-year-olds favored the simpler hypothesis only when prompted to explain; and 6-year-olds favored the simpler hypothesis whether or not they explained.

Lombrozo, T. (forthcoming) ‘Learning by thinking’ in science and in everyday life. P. Godfrey-Smith & A. Levy (Eds.), The Scientific Imagination, Oxford University Press.


Gottlieb, S. & Lombrozo, T. (forthcoming). Folk theories in the moral domain. In K. Gray and J. Graham (Eds.), The Atlas of Moral Psychology, Guilford Publications.

view abstract
Is morality intuitive or deliberative? This distinction can obscure the role of folk moral theories in moral judgment; judgments may arise “intuitively” yet result from abstract theoretical and philosophical commitments that participate in “deliberative” reasoning.

Lombrozo, T., & Vasilyeva, N. (forthcoming). Causal explanation. In M. Waldmann (Ed.), Oxford Handbook of Causal Reasoning. Oxford, UK: Oxford University Press.

view abstract
Explanation and causation are intimately related. Explanations often appeal to causes, and causal claims are often answers to implicit or explicit questions about why or how something occurred. In this chapter we consider what research on explanation can tell us about causal reasoning. In particular, we review an emerging body of work suggesting that explanatory considerations – such as the simplicity or scope of a causal hypothesis – can systematically influence causal inference and learning. We also discuss proposed distinctions among types of explanations and review their differential effects on causal reasoning and representation. Finally, we consider the relationship between explanations and causal mechanisms and raise important questions for future research.

2017


Walker, C., Lombrozo, T., Williams, J.J., Rafferty, A., & Gopnik, A. (2017). Explaining constrains causal learning in childhood. Child Development, 88(1), 229-246. doi: 10.1111/cdev.12590

view abstract
Three experiments investigate how self-generated explanation influences children’s causal learning. Five-year-olds (N=114) observed data consistent with two hypotheses and were prompted to explain or to report each observation. In Study 1, when making novel generalizations, explainers were more likely to favor the hypothesis that accounted for more observations. In Study 2, explainers favored a hypothesis that was consistent with prior knowledge. Study 3 pitted a hypothesis that accounted for more observations against a hypothesis consistent with prior knowledge. Explainers were more likely to base generalizations on prior knowledge. Findings suggest that attempts to explain drive children to evaluate hypotheses using features of “good” explanations, or those supporting generalizations with broad scope, as informed by children’s prior knowledge and observations.

 2016


Giffin, C. & Lombrozo, T. (2016).Wrong or Merely Prohibited: Special Treatment of Strict Liability in Intuitive Moral Judgment.. Law and Human Behavior, 40(6), 707-720.

view abstract
Most crimes in America require that the defendant have “mens rea,” Latin for “guilty mind.”  However, mens rea is not legally required for strict liability crimes, such as speeding, for which someone is guilty even if ignorant or deceived about her speed. In three experiments involving participants responding to descriptive vignettes, we investigated whether the division of strict liability crimes in the law reflects an aspect of laypeople’s intuitive moral cognition. Experiment 1 (N = 396; 236 male, 159 female, 1 other; mean age = 30) found evidence that it does: ignorance and deception were less mitigating for strict liability crimes than for “mens rea” crimes. Experiments 2 (N = 413; 257 male, 154 female, 2 other; mean age = 31) and 3 (N = 404; 183 male, 221 female, mean age 35) revealed that strict liability crimes are not treated as pure moral violations, but additionally as violations of convention. We found that for strict liability crimes, ratings of moral wrongness and punishment were influenced to a greater extent by the fact that a rule had been violated, even when harm was kept constant, mirroring the legal distinction of malum prohibitum (wrong as prohibited) versus malum in se (wrong in itself). Further, we found that rules prohibiting strict liability crimes were judged more arbitrary than corresponding rules for “mens rea” crimes, and that this judgment was related to the role of mental states. Jointly, the findings suggest a surprising correspondence between the law and laypeople’s intuitive judgments.

Wilkenfeld, D., Plunkett, D., & Lombrozo, T. (2016). Folk attributions of understanding: Is there a role for epistemic luck? Episteme, 1-26. doi: 10.1017/epi.2016.38

view abstract
As a strategy for exploring the relationship between understanding and knowledge, we consider whether epistemic luck – which is typically thought to undermine knowledge – undermines understanding. Questions about the etiology of understanding have also been at the heart of recent theoretical debates within epistemology. Kvanvig (2003) put forward the argument that there could be lucky understanding and produced an example that he deemed persuasive. Grimm (2006) responded with a case that, he argued, demonstrated that there could not be lucky understanding. In this paper, we empirically examine how participants’ patterns of understanding attributions line up with the predictions of Kvanvig and Grimm. We argue that the data challenge Kvanvig’s position. People do not differentiate between knowing-why and understanding-why on the basis of proper etiology: attributions of knowledge and understanding involve comparable (and minimal) roles for epistemic luck. We thus posit that folk knowledge and understanding are etiologically symmetrical.

Lombrozo, T. (2016). Explanatory preferences shape learning and inferenceTrends in Cognitive Sciences, 20, 748-759. doi: 10.1016/j.tics.2016.08.001


Shtulman, A., & Lombrozo, T. (2016). Bundles of contradiction: A coexistence view of conceptual change. In D. Barner & A. S. Baron (Eds.), Core knowledge and conceptual change. (pp. 53-71). Oxford, UK: Oxford University Press.

view abstract
Natural phenomena, such as illness or adaptation, can be explained in many ways. Typically, this many-to-one mapping between explanations and the phenomena they explain is construed as a source of tension between scientific and religious explanations (e.g., creationism vs. evolution) or between different forms of scientific explanation (e.g., Lamarck’s vs. Darwin’s theory of evolution). However, recent research suggests that competing explanations exist not only across individuals within the same community, but also within individuals themselves, who maintain competing explanations. Here, we explore this phenomenon of “explanatory coexistence” and analyze its implications for conceptual change, or knowledge restructuring at the level of individual concepts. We argue that conceptual change is often better construed as a process of augmentation, in which early-developing concepts coexist with later-developing concepts because both types of concepts remain useful for predicting and explaining the natural world, albeit in different circumstances or for different purposes.

Walker, C., Lombrozo, T., Williams, J.J., Rafferty, A., & Gopnik, A. (2016). Explaining constrains causal learning in childhood. Child Development. doi: 10.1111/cdev.12590

view abstract
Three experiments investigate how self-generated explanation influences children’s causal learning. Five-year-olds (N=114) observed data consistent with two hypotheses and were prompted to explain or to report each observation. In Study 1, when making novel generalizations, explainers were more likely to favor the hypothesis that accounted for more observations. In Study 2, explainers favored a hypothesis that was consistent with prior knowledge. Study 3 pitted a hypothesis that accounted for more observations against a hypothesis consistent with prior knowledge. Explainers were more likely to base generalizations on prior knowledge. Findings suggest that attempts to explain drive children to evaluate hypotheses using features of “good” explanations, or those supporting generalizations with broad scope, as informed by children’s prior knowledge and observations.

Lombrozo, T. (2016). Explanation. In J. Sytsma & W. Buckwalter (Eds.), Blackwell Companion to Experimental Philosophy (pp. 491-503). Blackwell. doi: 10.1002/9781118661666.ch34

view abstract
Explanation has been an important topic of study in philosophy of science, in epistemology, and in other areas of philosophy. In parallel, psychologists have been studying children’s and adults’ explanations, including their role in inference and in learning. This entry reviews recent work that begins to bridge the philosophy and psychology of explanation, with sections introducing recent empirical work on explanation by philosophers, formal and functional accounts of explanation, inference to the best explanation, the role of explanation in discovery, and the implications of empirical work on explanation for the “negative program” in experimental philosophy.

Murray, D., & Lombrozo, T. (2016). Effects of manipulation on attributions of causation, free will, and moral responsibility. Cognitive Science. doi: 10.1111/cogs.12338 (Supplementary Materials: AB)

view abstract
If someone brings about an outcome without intending to, is she causally and morally responsible for it? What if she acts intentionally, but as the result of manipulation by another agent? Previous research has shown that an agent’s mental states can affect attributions of causal and moral responsibility to that agent, but little is known about what effect one agent’s mental states can have on attributions to another agent. In Experiment 1, we replicate findings that manipulation lowers attributions of responsibility to manipulated agents.  Experiments 2-7 isolate which features of manipulation drive this effect, a crucial issue for both philosophical debates about free will and attributions of responsibility in situations involving social influence more generally.  Our results suggest that ‘bypassing’ a manipulated agent’s mental states generates the greatest reduction in responsibility, and we explain our results in terms of the effects that one agent’s mental states can have on the counterfactual relations between another agent and an outcome.

Wilkenfeld, D. A., Plunkett, D., & Lombrozo, T. (2016). Depth and deference: When and why we attribute understanding. Philosophical Studies, 173(2), 373-393. doi: 10.1007/s11098-015-0497-y

view abstract
Four experiments investigate the folk concept of ‘‘understanding,’’ in particular when and why it is deployed differently from the concept of knowledge. We argue for the positions that (1) people have higher demands with respect to explanatory depth when it comes to attributing understanding, and (2) that this is true, in part, because understanding attributions play a functional role in identifying experts who should be heeded with respect to the general field in question. These claims are supported by our findings that people differentially withhold attributions of understanding (rather than knowledge) when the object of attribution has minimal explanatory information. We also show that this tendency significantly correlates with people’s willingness to defer to others as potential experts. This work bears on a pressing issue in epistemology concerning the place and value of understanding. Our results also provide reason against positing a simple equation of knowledge(- why) and understanding(-why). We contend that, because deference plays a crucial role in many aspects of everyday reasoning, the fact that we use understanding attributions to demarcate experts reveals a potential mechanism for achieving our epistemic aims in many domains.

2015


Wilkenfeld, D. A. & Lombrozo, T. (2015). Inference to the best explanation (IBE) versus explaining for the best inference (EBI)Science and Education. 1-19. doi: 10.1007/s11191-015-9784-4

view abstract
In pedagogical contexts and in everyday life, we often come to believe something because it would best explain the data. What is it about the explanatory endeavor that makes it essential to everyday learning and to scientific progress? There are at least two plausible answers. On one view, there is something special about having true explanations. This view is highly intuitive: it’s clear why true explanations might improve one’s epistemic position. However, there is another possibility—it could be that the process of seeking, generating, or evaluating explanations itself puts one in a better epistemic position, even when the outcome of the process is not a true explanation. In other words, it could be that accurate explanations are beneficial, or it could be that high-quality explaining is beneficial, where there is something about the activity of looking for an explanation that improves our epistemic standing. The main goal of this paper is to tease apart these two possibilities, both theoretically and empirically, which we align with ‘‘Inference to the Best Explanation’’ (IBE) and ‘‘Explaining for the Best Inference’’ (EBI), respectively. We also provide some initial support for EBI and identify promising directions for future research.

Ruggeri, A. & Lombrozo, T. (2015). Children adapt their questions to achieve efficient search. Cognition, 143, 203-216. doi:10.1016/j.cognition.2015.07.004

view abstract
One way to learn about the world is by asking questions. We investigate how younger children (7- to 8-year-olds), older children (9- to 11-year-olds), and young adults (17- to 18-year-olds) ask questions to identify the cause of an event. We find a developmental shift in children’s reliance on hypothesis-scanning questions (which test hypotheses directly) versus constraint-seeking questions (which reduce the space of hypotheses), but also that all age groups ask more constraint-seeking questions when hypothesis-scanning questions are least likely to pay off: When the solution is one among equally likely alternatives (Study 1) or when the problem is difficult (Studies 1 and 2). These findings are the first to demonstrate that even young children dynamically adapt their strategies for inquiry to increase the efficiency of information search.

 


Lombrozo, T., Knobe, J., & Nichols, S. (Eds.). (2015). Oxford Studies in Experimental Philosophy: Volume 1. Oxford: Oxford University Press.


 

2014


Lombrozo, T. & Gwynne, N. Z. (2014). Explanation and inference: Mechanistic and functional explanations guide property generalizationFrontiers in Human Neuroscience, 8. doi:10.3389/fnhum.2014.00700

view abstract
The ability to generalize from the known to the unknown is central to learning and inference. Two experiments explore the relationship between how a property is explained and how that property is generalized to novel species and artifacts. The experiments contrast the consequences of explaining a property mechanistically, by appeal to parts and processes, with the consequences of explaining the property functionally, by appeal to functions and goals. The findings suggest that properties that are explained functionally are more likely to be generalized on the basis of shared functions, with a weaker relationship between mechanistic explanations and generalization on the basis of shared parts and processes. The influence of explanation type on generalization holds even though all participants are provided with the same mechanistic and functional information, and whether an explanation type is freely generated (Experiment 1), experimentally provided (Experiment 2), or experimentally induced (Experiment 2). The experiments also demonstrate that explanations and generalizations of a particular type (mechanistic or functional) can be experimentally induced by providing sample explanations of that type, with a comparable effect when the sample explanations come from the same domain or from a different domains. These results suggest that explanations serve as a guide to generalization, and contribute to a growing body of work supporting the value of distinguishing mechanistic and functional explanations.

Walker, C.M., Lombrozo, T., Legare, C., & Gopnik, A. (2014). Explaining prompts children to privilege inductively rich propertiesCognition, 133, 343-357. doi:10.1016/j.cognition.2014.07.008

view abstract
Two studies examined the specificity of effects of explanation on learning by prompting 3- to 6-year-old children to explain a mechanical toy and comparing what they learned about the toy’s causal and non-causal properties to children who only observed the toy, both with and without accompanying verbalization. In Study 1, children were experimentally assigned to either explain or observe the mechanical toy. In Study 2, children were classified according to whether the content of their response to an undirected prompt involved explanation. Dependent measures included whether children understood the toy’s functional-mechanical relationships, remembered perceptual features of the toy, effectively reconstructed the toy, and (for Study 2) generalized the function of the toy when constructing a new one. Results demonstrate that across age groups, explanation promotes causal learning and generalization, but does not improve (and in younger children, can even impair) memory for causally-irrelevant perceptual details.

Legare, C. H. & Lombrozo, T. (2014). Selective effects of explanation on learning during early childhoodJournal of Experimental Child Psychology, 126, 198-212. doi:10.1016/j.jecp.2014.03.001

view abstract
Two studies examined the specificity of effects of explanation on learning by prompting 3- to 6-year-old children to explain a mechanical toy and comparing what they learned about the toy’s causal and non-causal properties to children who only observed the toy, both with and without accompanying verbalization. In Study 1, children were experimentally assigned to either explain or observe the mechanical toy. In Study 2, children were classified according to whether the content of their response to an undirected prompt involved explanation. Dependent measures included whether children understood the toy’s functional-mechanical relationships, remembered perceptual features of the toy, effectively reconstructed the toy, and (for Study 2) generalized the function of the toy when constructing a new one. Results demonstrate that across age groups, explanation promotes causal learning and generalization, but does not improve (and in younger children, can even impair) memory for causally-irrelevant perceptual details.

Uttich, K., Tsai, G., & Lombrozo, T. (2014). Exploring metaethical commitments: Moral objectivity and moral progress. In H. Sarkissian & J. C. Wright (Eds.), Advances in experimental moral psychology (pp. 188-208). London: Bloomsbury Publishing.


 

2013


Harvey, A.G., Soehner, A., Lombrozo, T., Bélanger, L., Rifkin, J. & Morin, C.M. (2013). ‘Folk theories’ about the causes and treatment of insomnia. Cognitive Research and Therapy, 37, 1048-1057. doi:10.1007/s10608-013-9543-2

view abstract
The present study investigates ‘folk theories’ about the causes of insomnia. Participants with insomnia (n = 69) completed a qualitative and quantitative assessment of their folk theories. The qualitative assessment was to speak aloud for 1 min in response to: ‘What do you think causes your insomnia?’. The quantitative assessment involved completing the ‘Causal Attributions of My Insomnia Questionnaire’ (CAM-I), developed for this study. The three most common folk theories for both the causes of one’s own insomnia as well as insomnia in others were ’emotions’, ‘thinking patterns’ and ‘sleep-related emotions’. Interventions targeting these factors were also perceived as most likely to be viable treatments. Seventy-five percent of the folk theories of insomnia investigated with the CAM-I were rated as more likely to be alleviated by a psychological versus a biological treatment. The results are consistent with research highlighting that folk theories are generally coherent and inform a range of judgments. Future research should focus on congruence of ‘folk theories’ between treatment providers and patients, and the role of folk theories in treatment choice, engagement, compliance and outcome.

Williams, J.J., Lombrozo, T., & Rehder, B. (2013). The hazards of explanation: Overgeneralization in the face of exceptions. Journal of Experimental Psychology: General, 142, 1006-1014. doi:10.1037/a0030996

view abstract
Seeking explanations is central to science, education, and everyday thinking, and prompting learners to explain is often beneficial. Nonetheless, in 2 category learning experiments across artifact and social domains, we demonstrate that the very properties of explanation that support learning can impair learning by fostering overgeneralizations. We find that explaining encourages learners to seek broad patterns, hindering learning when patterns involve exceptions. By revealing how effects of explanation depend on the structure of what is being learned, these experiments simultaneously demonstrate the hazards of explaining and provide evidence for why explaining is so often beneficial. For better or for worse, explaining recruits the remarkable human capacity to seek underlying patterns that go beyond individual observations.

Lombrozo, T. (2013). Review: Evolution Challenges – Integrating Research and Practice in Teaching and Learning about Evolution. Reports of the National Center for Science Education, 33, 5.


Williams, J.J., & Lombrozo, T. (2013). Explanation and prior knowledge interact to guide learning. Cognitive Psychology, 66, 55-84. doi: 10.1016/j.cogpsych.2012.09.002

view abstract
How do explaining and prior knowledge contribute to learning? Four experiments explored the relationship between explanation and prior knowledge in category learning. The experiments independently manipulated whether participants were prompted to explain the category membership of study observations and whether category labels were informative in allowing participants to relate prior knowledge to patterns underlying category membership. The experiments revealed a superadditive interaction between explanation and informative labels, with explainers who received informative labels most likely to discover (Experiments 1 & 2) and generalize (Experiments 3 & 4) a pattern consistent with prior knowledge. However, explainers were no more likely than controls to discover multiple patterns (Experiments 1 & 2), indicating that effects of explanation are relatively targeted. We suggest that explanation recruits prior knowledge to assess whether candidate patterns are likely to have broad scope (i.e., to generalize within and beyond study observations). This interpretation is supported by the finding that effects of explanation on prior knowledge were attenuated when learners believed prior knowledge was irrelevant to generalizing category membership (Experiment 4). This research provides evidence that explanation can serve as a mechanism for deploying prior knowledge to assess the scope of observed patterns.

 

2012


Lombrozo, T. & Rehder, B. (2012). Functions in biological kind classification. Cognitive Psychology, 65, 457-485. doi:10.1016/j.cogpsych.2012.06.002

view abstract
Biological trais that serve functions, such as zebra’s coloration (for camouflage) or a kangaroo’s tail (for balance), seem to have a special role in conceptual representations for biological kinds. In five experiments, we investigate whether and why functional features are privileged in biological kind classification. Experiment 1 experimentally manipulates whether a feature serves a function and finds that functional features are judged more diagnostic of category membership as well as more likely to have a deep evolutionary history, be frequent in the current population, and persist in future populations. Experiments 2-5 reveal that these inferences about history, frequency, and persistence account for nearly all the effect of function on classification. We conclude that functional features are privileged because their relationship with the kind is viewed as stable over time and thus as especially well suited for establishing category membership, with implications for theories of classification and folk biological understanding.

Lombrozo, T. (2012). Explanation and abductive inference. In K.J. Holyoak and R.G. Morrison (Eds.), Oxford Handbook of Thinking and Reasoning (pp. 260-276), Oxford, UK: Oxford University Press. doi:10.1093/oxfordhb/9780199734689.013.0014

view abstract
Everyday cognition reveals a sophisticated capacity to seek, generate, and evaluate explanations for the social and physical worlds around us. Why are we so driven to explain, and what accounts for our systematic explanatory preferences? This chapter reviews evidence from cognitive psychology and cognitive development concerning the structure and function of explanations, with a focus on the role of explanations in learning and inference. The findings highlight the value of understanding explanation and abductive inference both as phenomena in their own right and for the insights they provide concerning foundational aspects of human cognition, such as representation, learning, and inference.

Genone, J. & Lombrozo, T. (2012). Concept possession, experimental semantics, and hybrid theories of reference. Philosophical Psychology, 25, 717-742. doi: 10.1080/09515089.2011.627538

view abstract
Contemporary debates about the nature of semantic reference have tended to focus on two competing approaches: theories which emphasize the importance of descriptive information associated with a referring term, and those which emphasize causal facts about the conditions under which the use of the term originated and was passed on. Recent empirical work by Machery and colleagues suggests that both causal and descriptive information can play a role in judgments about the reference of proper names, with findings of cross-cultural variation in judgments that imply differences between individuals with respect to whether they favor causal or descriptive information in making reference judgments. We extend this theoretical and empirical line of inquiry to views of the reference of natural and nominal kind concepts, which face similar challenges to those concerning the reference of proper names. In two experiments, we find evidence that both descriptive and causal factors contribute to judgments of concept reference, with no reliable differences between natural and nominal kinds. Moreover, we find evidence that the same individuals’ judgments can rely on both descriptive and causal information, such that variation between individuals cannot be explained by appeal to a mixed population of “pure descriptive theorists” and “pure causal theorists.” These findings suggest that the contrast between descriptive and causal theories of reference may be inappropriate; intuitions may instead support a hybrid theory of reference that includes both causal and descriptive factors. We propose that future research should focus on the relationship between these factors, and describe several possible frameworks for pursuing these issues. Our findings have implications for theories of semantic reference, as well as for theories of conceptual structure.

Bonawitz, E.B. & Lombrozo, T. (2012). Occam’s rattle: children’s use of simplicity and probability to constrain inference. Developmental Psychology, 48, 1156-1164. doi: 10.1037/a0026471

view abstract
A growing literature suggests that generating and evaluating explanations is a key mechanism for learning and inference, but little is known about how children generate and select competing explanations. This study investigates whether young children prefer explanations that are simple, where simplicity is quantified as the number of causes invoked in an explanation, and how this preference is reconciled with probability information. Both preschool-aged children and adults were asked to explain an event that could be generated by 1 or 2 causes, where the probabilities of the causes varied across conditions. In 2 experiments, it was found that children preferred explanations involving 1 cause over 2 but were also sensitive to the probability of competing explanations. Adults, in contrast, responded on the basis of probability alone. These data suggest that children employ a principle of parsimony like Occam’s razor as an inductive constraint and that this constraint is employed when more reliable bases for inference are unavailable.

2011


Lombrozo, T. (2011). The instrumental value of explanations. Philosophy Compass, 6, 539-551. doi:10.1111/j.1747-9991.2011.00413.x

view abstract
Scientific and ‘intuitive’ or ‘folk’ theories are typically characterized as serving three critical functions: prediction, explanation, and control. While prediction and control have clear instrumental value, the value of explanation is less transparent. This paper reviews an emerging body of research from the cognitive sciences suggesting that the process of seeking, generating, and evaluating explanations in fact contributes to future prediction and control, albeit indirectly by facilitating the discovery and confirmation of instrumentally valuable theories. Theoretical and empirical considerations also suggest why explanations may nonetheless feel intrinsically valuable. The paper concludes by considering some implications of the psychology of explanation for a naturalized philosophy of explanation.

Lombrozo, T. (2011). The campaign for concepts. Dialogue: Canadian Philosophical Review, 50, 165-177. doi:10.1017/S0012217311000175 [Written for book symposium on Machery’s Doing Without Concepts]

view abstract
In his book Doing Without Concepts, Edouard Machery argues that cognitive scientists should reject the concept of “concept” as a natural, psychological kind. I review and critique several of Machery’s arguments, focusing on his definition of “concept” and on claims against the possibility and utility of a unified account of concepts. In particular, I suggest ways in which prototype, exemplar, and theory-theory approaches to concepts might be integrated.

 2010


Knobe, J., Lombrozo, T., & Machery, E. (2010). Editorial: Dimensions of experimental philosophy. Review of Philosophy and Psychology, 1, 315-318. doi: 10.1007/s13164-010-0037-9


Lombrozo, T. & Uttich, K. (2010). Putting normativity in its proper place [Peer commentary on the paper “Person as scientist, person as moralist” by J. Knobe]. Behavioral and Brain Sciences, 33, 344-345. doi:10.1017/S0140525X10001810

view abstract
Knobe considers two explanations for the influence of moral considerations on “non-moral” cognitive systems: the “person as moralist” position, and the “person as [biased] scientist” position. We suggest that this dichotomy conflates questions at computational and algorithmic levels, and suggest that distinguishing the issues at these levels reveals a third, viable option, which we call the “rational scientist” position.

Lombrozo, T. (2010). Causal-explanatory pluralism: how intentions, functions, and mechanisms influence causal ascriptions. Cognitive Psychology, 61, 303-332. doi: 10.1016/j.cogpsych.2010.05.002

view abstract
Both philosophers and psychologists have argued for the existence of distinct kinds of explanations, including teleological explanations that cite functions or goals, and mechanistic explanations that cite causal mechanisms. Theories of causation, in contrast, have generally been unitary, with dominant theories focusing either on counterfactual dependence or on physical connections. This paper argues that both approaches to causation are psychologically real, with different modes of explanation promoting judgments more or less consistent with each approach. Two sets of experiments isolate the contributions of counterfactual dependence and physical connections in causal ascriptions involving events with people, artifacts, or biological traits, and manipulate whether the events are construed teleologically or mechanistically. The findings suggest that when events are construed teleologically, causal ascriptions are sensitive to counterfactual dependence and relatively insensitive to the presence of physical connections, but when events are construed mechanistically, causal ascriptions are sensitive to both counterfactual dependence and physical connections. The conclusion introduces an account of causation, an “exportable dependence theory,” that provides a way to understand the contributions of physical connections and teleology in terms of the functions of causal ascriptions.

Williams, J.J. & Lombrozo, T. (2010). The role of explanation in discovery and generalization: evidence from category learning. Cognitive Science, 34, 776-806. doi: 10.1111/j.1551-6709.2010.01113.x

view abstract
Research in education and cognitive development suggests that explaining plays a key role in learning and generalization: When learners provide explanations-even to themselves-they learn more effectively and generalize more readily to novel situations. This paper proposes and tests a subsumptive constraints account of this effect. Motivated by philosophical theories of explanation, this account predicts that explaining guides learners to interpret what they are learning in terms of unifying patterns or regularities, which promotes the discovery of broad generalizations. Three experiments provide evidence for the subsumptive constraints account: prompting participants to explain while learning artificial categories promotes the induction of a broad generalization underlying category membership, relative to describing items (Exp. 1), thinking aloud (Exp. 2), or free study (Exp. 3). Although explaining facilitates discovery, Experiment 1 finds that description is more beneficial for learning item details. Experiment 2 additionally suggests that explaining anomalous observations may play a special role in belief revision. The findings provide insight into explanation’s role in discovery and generalization.

Uttich, K. & Lombrozo, T. (2010). Norms inform mental state ascriptions: a rational explanation for the side-effect effect. Cognition, 116, 87-100. doi: 10.1016/j.cognition.2010.04.003

view abstract
Theory of mind, the capacity to understand and ascribe mental states, has traditionally been conceptualized as analogous to a scientific theory. However, recent work in philosophy and psychology has documented a “side-effect effect” suggesting that moral evaluations influence mental state ascriptions, and in particular whether a behavior is described as having been performed ‘intentionally.’ This evidence challenges the idea that theory of mind is analogous to scientific psychology in serving the function of predicting and explaining, rather than evaluating, behavior. In three experiments, we demonstrate that moral evaluations do inform ascriptions of intentional action, but that this relationship arises because behavior that conforms to norms (moral or otherwise) is less informative about underlying mental states than is behavior that violates norms. This analysis preserves the traditional understanding of theory of mind as a tool for predicting and explaining behavior, but also suggests the importance of normative considerations in social cognition.

Knobe, J., Lombrozo, T., & Machery, E. (2010). Editorial: Psychology and experimental philosophy. Review of Philosophy and Psychology, 1, 157-160. doi: 10.1007/s13164-009-0012-5


Lombrozo, T. (2010). From conceptual representations to explanatory relations [Peer commentary on the paper “Précis of Doing without concepts” by E. Machery]. Behavioral and Brain Sciences, 33, 218-219. doi:10.1017/S0140525X10000415

view abstract
Machery emphasizes the centrality of explanation for theory-based approaches to concepts. I endorse Machery’s emphasis on explanation and consider recent advances in psychology that point to the “heterogeneity” of explanation, with consequences for Machery’s heterogeneity hypothesis about concepts.

 

2009


Lombrozo, T. (2009). Why Why Darwin matters matters [Review of the book Why Darwin matters: the case against intelligent design, by M. Shermer]. Evolution: Education & Outreach, 2, 141-143. doi:10.1007/s12052-008-0109-9


Lombrozo, T. (2009). The role of moral commitments in moral judgment. Cognitive Science, 33, 273-286. doi:10.1111/j.1551-6709.2009.01013.x

view abstract
Traditional approaches to moral psychology assumed that moral judgments resulted from the application of explicit commitments, such as those embodied in consequentialist or deontological philosophies. In contrast, recent work suggests that moral judgments often result from unconscious or emotional processes, with explicit commitments generated post hoc. This paper explores the intermediate position that moral commitments mediate moral judgments, but not through their explicit and consistent application in the course of judgment. An experiment with 336 participants finds that individuals vary in the extent to which their moral commitments are consequentialist or deontological, and that this variation is systematically but imperfectly related to the moral judgments elicited by trolley car problems. Consequentialist participants find action in trolley car scenarios more permissible than do deontologists, and only consequentialists moderate their judgments when scenarios that typically elicit different intuitions are presented side by side. The findings emphasize the need for a theory of moral reasoning that can accommodate both the associations and dissociations between moral commitments and moral judgments.

Lombrozo, T. (2009). Explanation and categorization: how ”why?” informs ”what?”. Cognition, 110, 248-253. doi: 10.1016/j.cognition.2008.10.007

view abstract
Recent theoretical and empirical work suggests that explanation and categorization are intimately related. This paper explores the hypothesis that explanations can help structure conceptual representations, and thereby influence the relative importance of features in categorization decisions. In particular, features may be differentially important depending on the role they play in explaining other features or aspects of category membership. Two experiments manipulate whether a feature is explained mechanistically, by appeal to proximate causes, or functionally, by appeal to a function or goal. Explanation type has a significant impact on the relative importance of features in subsequent categorization judgments, with functional explanations reversing previously documented effects of “causal status”. The findings suggest that a feature’s explanatory importance can impact categorization, and that explanatory relationships, in addition to causal relationships, are critical to understanding conceptual representation.

 

2008


Lombrozo, T., Thanukos, A., & Weisberg, M. (2008). The importance of understanding the nature of science for accepting evolution. Evolution: Education & Outreach, 1, 290-298. doi: 10.1007/s12052-008-0061-8

view abstract
Many students reject evolutionary theory, whether or not they adequately understand basic evolutionary concepts. We explore the hypothesis that accepting evolution is related to understanding the nature of science. In particular, students may be more likely to accept evolution if they understand that a scientific theory is provisional but reliable, that scientists employ diverse methods for testing scientific claims, and that relating data to theory can require inference and interpretation. In a study with university undergraduates, we find that accepting evolution is significantly correlated with understanding the nature of science, even when controlling for the effects of general interest in science and past science education. These results highlight the importance of understanding the nature of science for accepting evolution. We conclude with a discussion of key characteristics of science that challenge a simple portrayal of the scientific method and that we believe should be emphasized in classrooms.

 

2007


Sloman, S., Lombrozo, T., & Malt, B. (2007). Ontological commitments and domain-specific categorisation. In M.J. Roberts (Ed.), Integrating the Mind. Hove, UK: Psychology Press.


Lombrozo, T. (2007). Simplicity and probability in causal explanation. Cognitive Psychology, 55, 232-257. doi:10.1016/j.cogpsych.2006.09.006

view abstract
What makes some explanations better than others? This paper explores the roles of simplicity and probability in evaluating competing causal explanations. Four experiments investigate the hypothesis that simpler explanations are judged both better and more likely to be true. In all experiments, simplicity is quantified as the number of causes invoked in an explanation, with fewer causes corresponding to a simpler explanation. Experiment 1 confirms that all else being equal, both simpler and more probable explanations are preferred. Experiments 2 and 3 examine how explanations are evaluated when simplicity and probability compete. The data suggest that simpler explanations are assigned a higher prior probability, with the consequence that disproportionate probabilistic evidence is required before a complex explanation will be favored over a simpler alternative. Moreover, committing to a simple but unlikely explanation can lead to systematic overestimation of the prevalence of the cause invoked in the simple explanation. Finally, Experiment 4 finds that the preference for simpler explanations can be overcome when probability information unambiguously supports a complex explanation over a simpler alternative. Collectively, these findings suggest that simplicity is used as a basis for evaluating explanations and for assigning prior probabilities when unambiguous probability information is absent. More broadly, evaluating explanations may operate as a mechanism for generating estimates of subjective probability.

Lombrozo, T., Kelemen, D., Zaitchik, D. (2007). Inferring design: evidence of a preference for teleological explanations in patients with Alzheimer’s Disease. Psychological Science, 18, 999-1006. doi: 10.1111/j.1467-9280.2007.02015.x

view abstract
Unlike educated adults, young children demonstrate a “promiscuous” tendency to explain objects and phenomena by reference to functions, endorsing what are called teleological explanations. This tendency becomes more selective as children acquire increasingly coherent beliefs about causal mechanisms, but it is unknown whether a widespread preference for teleology is ever truly outgrown. The study reported here investigated this question by examining explanatory judgments in patients with Alzheimer’s disease (AD), whose dementia affects the rich causal beliefs adults typically consult in evaluating explanations. The results indicate that unlike healthy adults, AD patients systematically and promiscuously prefer teleological explanations, suggesting that an underlying tendency to construe the world in terms of functions persists throughout life. This finding has broad relevance not only to understanding conceptual impairments in AD, but also to theories of development, learning, and conceptual change. Moreover, this finding sheds light on the intuitive appeal of creationism.

 

2006


Lombrozo, T. (2006). The structure and function of explanations. Trends in Cognitive Sciences, 10, 464-470. doi: 10.1016/j.tics.2006.08.004

view abstract
Generating and evaluating explanations is spontaneous, ubiquitous and fundamental to our sense of understanding. Recent evidence suggests that in the course of an individual’s reasoning, engaging in explanation can have profound effects on the probability assigned to causal claims, on how properties are generalized and on learning. These effects follow from two properties of the structure of explanations: explanations accommodate novel information in the context of prior beliefs, and do so in a way that fosters generalization. The study of explanation thus promises to shed light on core cognitive issues, such as learning, induction and conceptual representation. Moreover, the influence of explanation on learning and inference presents a challenge to theories that neglect the roles of prior knowledge and explanation-based reasoning.

Lombrozo, T., Shtulman, A., & Weisberg, M. (2006) The Intelligent Design controversy: lessons from psychology and education. Trends in Cognitive Sciences, 10, 56-57. doi: 10.1016/j.tics.2005.12.001

view abstract
The current debate over whether to teach Intelligent Design creationism in American public schools provides the rare opportunity to watch the interaction between scientific knowledge and intuitive beliefs play out in courts rather than cortex. Although it is tempting to think the controversy stems only from ignorance about evolution, a closer look reinforces what decades of research in cognitive and social psychology have already taught us: that the relationship between understanding a claim and believing a claim is far from simple. Research in education and psychology confirms that a majority of college students fail to understand evolutionary theory, but also finds no support for a relationship between understanding evolutionary theory and accepting it as true [1,2]. We believe the intuitive appeal of Intelligent Design owes as much to misconceptions about science and morality as it does to misconceptions about evolution. To support this position we present a brief tour of misconceptions: evolutionary, scientific and moral.

Lombrozo, T. & Carey, S. (2006). Functional explanation and the function of explanation. Cognition, 99, 167-204. doi: 10.1016/j.cognition.2004.12.009

view abstract
Teleological explanations (TEs) account for the existence or properties of an entity in terms of a function: we have hearts because they pump blood, and telephones for communication. While many teleological explanations seem appropriate, others are clearly not warranted-for example, that rain exists for plants to grow. Five experiments explore the theoretical commitments that underlie teleological explanations. With the analysis of [Wright, L. (1976). Teleological Explanations. Berkeley, CA: University of California Press] from philosophy as a point of departure, we examine in Experiment 1 whether teleological explanations are interpreted causally, and confirm that TEs are only accepted when the function invoked in the explanation played a causal role in bringing about what is being explained. However, we also find that playing a causal role is not sufficient for all participants to accept TEs. Experiment 2 shows that this is not because participants fail to appreciate the causal structure of the scenarios used as stimuli. In Experiments 3-5 we show that the additional requirement for TE acceptance is that the process by which the function played a causal role must be general in the sense of conforming to a predictable pattern. These findings motivate a proposal, Explanation for Export, which suggests that a psychological function of explanation is to highlight information likely to subserve future prediction and intervention. We relate our proposal to normative accounts of explanation from philosophy of science, as well as to claims from psychology and artificial intelligence.

 

Before 2006


Lombrozo, T., Judson, J., & MacLeod, D.I.A. (2005). Flexibility of spatial averaging in visual perception. Proceedings of the Royal Society B: Biological Sciences, 272, 725-732. doi: 10.1098/rspb.2004.3007

view abstract
The classical receptive field (RF) concept – the idea that a visual neuron responds to fixed parts and properties of a stimulus – has been challenged by a series of recent physiological results. Here, we extend these findings to human vision, demonstrating that the extent of spatial averaging in contrast perception is also flexible, depending strongly on stimulus contrast and uniformity. At low contrast, spatial averaging is greatest (about 11 min of arc) within uniform regions such as edges, as expected if the relevant neurons have orientation-selective RFs. At high contrast, spatial averaging is minimal. These results can be understood if the visual system is balancing a trade-off between noise reduction, which favours large areas of averaging, and detail preser vation, which favours minimal averaging. Two distinct populations of neurons with hard-wired RFs could account for our results, as could the more intriguing possibility of dynamic, contrast-dependent RFs.

Federmeier, K.D, Segal, J.B., Lombrozo, T., Kutas, M. (2000). Brain responses to nouns, verbs, and class-ambiguous words in context. Brain, 123, 2552-2566. doi: 10.1093/brain/123.12.2552

view abstract
Recent neuropsychological and imaging data have implicated different brain networks in the processing of different word classes, nouns being linked primarily to posterior, visual object-processing regions and verbs to frontal, motor-processing areas. However, as most of these studies have examined words in isolation, the consequences of such anatomically based representational differences, if any, for the processing of these items in sentences remains unclear. Additionally, in some languages many words (e.g. `drink’) are class-ambiguous, i.e. they can play either role depending on context, and it is not yet known how the brain stores and uses information associated with such lexical items in context. We examined these issues by recording event-related potentials (ERPs) in response to unambiguous nouns (e.g. `beer’), unambiguous verbs (e.g. `eat’), class-ambiguous words and pseudowords used as nouns or verbs within two types of minimally contrastive sentence contexts: noun-predicting (e.g. `John wanted THE [target] but …’) and verb-predicting (`John wanted TO [target] but …’). Our results indicate that the nature of neural processing for nouns and verbs is a function of both the type of stimulus and the role it is playing. Even when the context completely specifies their role, word class-ambiguous items differ from unambiguous ones over frontal regions by ~150 ms. Moreover, whereas pseudowords elicit larger N400s when used as verbs than when used as nouns, unambiguous nouns and ambiguous words used as nouns elicit more frontocentral negativity than unambiguous verbs and ambiguous words used as verbs, respectively. Additionally, unambiguous verbs elicit a left-lateralized, anterior positivity (~200 ms) not observed for any other stimulus type, though only when these items are used appropriately as verbs (i.e. in verb-predicting contexts). In summary, the pattern of neural activity observed in response to lexical items depends on their general probability of being a verb or a noun and on the particular role they are playing in any given sentence. This implicates more than a simple two-way distinction of the brain networks involved in their storage and processing. Experience, as well as context during on-line language processing, clearly shapes the neural representations of nouns and verbs, such that there is no single neural marker of word class. Our results further suggest that the presence and nature of the word class-based dissociations observed after brain damage are similarly likely to be a function of both the type of stimulus and the context in which it occurs, and thus must be assessed accordingly.

Selected Conference Proceedings


Giffin, C. & Lombrozo, T. (2015). Mental states are more important in evaluating moral than conventional violations. In Noelle, D. C., Dale, R., Warlaumont, A. S., Yoshimi, J., Matlock, T., Jennings, C. D., & Maglio, P. P. (Eds.) Proceedings of the 37th Annual Meeting of the Cognitive Science Society. (p. 800-805).

view abstract
A perpetrator’s mental state – whether she had mens rea or a “guilty mind” – typically plays an important role in evaluating wrongness and assigning punishment. In two experiments, we find that this role for mental states is weaker in evaluating conventional violations relative to moral violations. We also find that this diminished role for mental states may be associated with the fact that conventional violations are wrong by virtue of having violated a (potentially arbitrary) rule, whereas moral violations are also wrong inherently.

Ruggeri, A., Lombrozo T., Griffiths, T. L., & Xu, F. (2015) Children search for information as efficiently as adults, but seek additional confirmatory evidence. In Noelle, D. C., Dale, R., Warlaumont, A. S., Yoshimi, J., Matlock, T., Jennings, C. D., & Maglio, P. P. (Eds.) Proceedings of the 37th Annual Meeting of the Cognitive Science Society. (p. 2039-2044).

view abstract
Like scientists, children and adults learn by asking questions and making interventions. How does this ability develop? We investigate how children (7- and 10-year-olds) and adults search for information to learn which kinds of objects share a novel causal property. In particular, we consider whether children ask questions and select interventions that are as informative as those of adults, and whether they recognize when to stop searching for information to provide a solution. We find an anticipated developmental improvement in information search efficiency. We also present a formal analysis that allows us to identify the basis for children’s inefficiency. In our 20-questions-style task, children initially ask questions and make interventions no less efficiently than adults do, but continue to search for information past the point at which they have narrowed their hypothesis space to a single option. In other words, the performance change from age seven to adulthood is due largely to a change in implementing a “stopping rule”; when considering only the minimum number of queries participants would have needed to identify the correct hypothesis, age differences disappear.

Vasilyeva, N., Wilkenfeld, D., & Lombrozo, T. (2015) Goals Affect the Perceived Quality of Explanations. In Noelle, D. C., Dale, R., Warlaumont, A. S., Yoshimi, J., Matlock, T., Jennings, C. D., & Maglio, P. P. (Eds.) Proceedings of the 37th Annual Meeting of the Cognitive Science Society. (p. 2469-2474).

view abstract
Do people evaluate the quality of explanations differently depending on their goals? In particular, are explanations of different kinds (formal, mechanistic, teleological) judged differently depending on the future judgments the evaluator anticipates making? We report two studies demonstrating that the perceived “goodness” of explanations depends on the evaluator’s current goals, with explanations receiving a relative boost when they are based on relationships that support anticipated judgments. These findings shed light on the functions of explanation and support pragmatic and pluralist approaches to explanation.

Vasilyeva, N.,  & Lombrozo, T. (2015) Explanations and Causal Judgments are Differentially Sensitive to Covariation and Mechanism Information . In Noelle, D. C., Dale, R., Warlaumont, A. S., Yoshimi, J., Matlock, T., Jennings, C. D., & Maglio, P. P. (Eds.) Proceedings of the 37th Annual Meeting of the Cognitive Science Society. (p. 2475-2480).

view abstract
We report four experiments demonstrating that judgments of explanatory goodness are sensitive both to covariation evidence and to mechanism information. Compared to judgments of causal strength, explanatory judgments tend to be more sensitive to mechanism and less sensitive to covariation. Judgments of understanding tracked covariation least closely. We discuss implications of our findings for theories of explanation, understanding and causal attribution.

Edwards, B. J., Williams, J. J., Gentner, D., & Lombrozo, T. (2014). Effects of comparison and explanation on analogical transfer. In P. Bello, M. Guarini, M. McShane, & B. Scassellati (Eds.), Proceedings of the 36th Annual Conference of the Cognitive Science Society (pp. 445-450). Austin, TX: Cognitive Science Society.

view abstract
Although comparison and explanation have typically been studied independently, recent work suggests connections between these processes. Three experiments investigated effects of comparison and explanation on analogical problem solving. In Experiment 1, explaining the solutions to two analogous stories increased spontaneous transfer to an analogical problem. In Experiment 2, explaining a single story promoted analogical transfer, but only after receiving a hint that may have facilitated comparison. In Experiment 3, irrelevant stories were interspersed among the two story analogs to block unprompted comparison; prompts to compare were effective, but prompts to explain were not. This pattern suggests that effects of explanation on analogical transfer may be greatest when combined with comparison.

Ruggeri, A. & Lombrozo, T. (2014). Learning by asking: How children ask questions to achieve efficient search. In P. Bello, M. Guarini, M. McShane, & B. Scassellati (Eds.), Proceedings of the 36th Annual Conference of the Cognitive Science Society (pp. 1335-1340). Austin, TX: Cognitive Science Society.

view abstract
One way to learn about the world is by asking questions. We investigate how children (n= 287, 7- to 11-year olds) and young adults (n=160 17- to 18-year olds) ask questions to identify the cause of an event. We find a developmental shift in children’s reliance on hypothesis-scanning questions (which test hypotheses directly) versus constraint-seeking questions (which reduce the space of hypotheses), but also that all age groups ask more constraint-seeking questions when hypothesis-scanning questions are unlikely to pay off: when the problem is difficult (Studies 1 and 2) or the solution is one among equally likely alternatives (Study 2). These findings are the first to demonstrate that even young children adapt their strategies for inquiry to increase the efficiency of information search.

Plunkett, D., Lombrozo, T., & Buchak, L. (2014). Because the brain agrees: The impact of neuroscientific explanations for belief. In P. Bello, M. Guarini, M. McShane, & B. Scassellati (Eds.), Proceedings of the 36th Annual Conference of the Cognitive Science Society (pp. 1180-1185). Austin, TX: Cognitive Science Society.

view abstract
Three experiments investigate whether neuroscientific explanations for belief in some proposition (e.g., that God exists) are judged to reinforce, undermine, or have no effect on confidence that the corresponding proposition is true. Participants learned that an individual’s religious, moral, or scientific belief activated a (fictional) brain region and indicated how this information would and should influence the individual’s confidence. When the region was associated with true or false beliefs (Experiment 1), the predicted and endorsed responses were an increase or decrease in confidence, respectively. However, we found that epistemically-neutral but “normal” neural function was taken to reinforce belief, and “abnormal” function to have no effect or to undermine it, whether the (ab)normality was explicitly stated (Experiment 2) or implied (Experiment 3), suggesting that proper functioning is treated as a proxy for epistemic reliability. These findings have implications for science communication, philosophy, and our understanding of belief revision and folk epistemology.

Williams, J.J., Kovacs, G., Walker, C., Maldonado, S.G., & Lombrozo, T. (2014). Learning online via prompts to explain. 32nd Annual ACM Conference Extended Abstracts on Human Factors in Computing Systems (pp. 2269-2274). New York, NY: ACM.

view abstract
Prompting learners to explain their beliefs can help them correct misconceptions upon encountering anomalies — facts and observations that conflict with learners’ current understanding. We have developed a way to augment online interfaces for learning by adding prompts for users to explain a fact or observation. We conducted two experiments testing the effects of these explanation prompts, finding that they increase learners’ self-correction of misconceptions, though these benefits of explaining depend on: (1) How many anomalies the prompts require people to explain, and (2) Whether anomalies are distributed so that individual observations guide learners to correct ideas by conflicting with multiple misconceptions at once.

Walker, C.M., Lombrozo, T., Legare, C.H., & Gopnik, A. (2013). Explaining to others prompts children to favor inductively rich properties. In M. Knauff, M. Pauen, N. Sebanz, & I. Wachsmuth (Eds.), Proceedings of the 35th Annual Conference of the Cognitive Science Society (pp. 1558-1563). Austin, TX: Cognitive Science Society.

view abstract
Three experiments test the hypothesis that engaging in explanation prompts children to favor inductively rich properties when generalizing to novel cases. In Experiment 1, preschoolers prompted to explain during a causal learning task were more likely to override a tendency to generalize according to perceptual similarity and instead extend an internal feature to an object that shared a causal property. In Experiment 2, we replicated this effect of explanation in a case of label extension. Experiment 3 demonstrated that explanation improves memory for internal features and labels, but impairs memory for superficial features. We conclude that explaining can influence learning by prompting children to favor inductively rich properties over surface similarity.

Edwards, B.J., Williams, J.J., & Lombrozo, T. (2013). Effects of explanation and comparison on category learning In M. Knauff, M. Pauen, N. Sebanz, & I. Wachsmuth (Eds.), Proceedings of the 35th Annual Conference of the Cognitive Science Society (pp. 406-411). Austin, TX: Cognitive Science Society.

view abstract
Generating explanations and making comparisons have both been shown to improve learning. While each process has been studied individually, the relationship between explanation and comparison is not well understood. Three experiments evaluated the effectiveness of explanation and comparison prompts in learning novel categories. In Experiment 1, participants explained items’ category membership, performed pairwise comparisons between items (listed similarities and differences), did both, or did a control task. The explanation task increased the discovery of rules underlying category membership; however, the comparison task decreased rule discovery. Experiments 2 and 3 showed that (1) comparing all four category exemplars was more effective than either within-category or between-category pairwise comparisons, and that (2) “explain” participants reported higher levels of both spontaneous explanation and comparison than “compare” participants. This work provides insights into when explanation and comparison are most effective, and how these processes can work together to maximize learning.

Pacer, M., Williams, J., Xi, C., Lombrozo, T., & Griffiths, T. L. (2013). Evaluating computational models of explanation using human judgments. Proceedings of the Twenty-Ninth Conference on Uncertainty in Artificial Intelligence.

view abstract
We evaluate four computational models of explanation in Bayesian networks by comparing model predictions to human judgments. In two experiments, we present human participants with causal structures for which the models make divergent predictions and either solicit the best explanation for an observed event (Experiment 1) or have participants rate provided explanations for an observed event (Experiment 2). Across two versions of two causal structures and across both experiments we find that the Causal Explanation Tree and Most Relevant Explanation models provide better fits to human data than either Most Probable Explanation or Explanation Tree models. We identify strengths and shortcomings of these models and what they can reveal about human explanation. We conclude by suggesting the value of pursuing computational and psychological investigations of explanation in parallel.

Williams, J.J., Walker, C., Maldonado, S.G., & Lombrozo, T. (2013). Effects of explaining anomalies on the generation and evaluation of hypotheses. In M. Knauff, M. Pauen, N. Sebanz, & I. Wachsmuth (Eds.), Proceedings of the 35th Annual Conference of the Cognitive Science Society (pp. 3777-3782). Austin, TX: Cognitive Science Society.

view abstract
We investigate the effects of explaining anomalies (i.e., observations that conflict with current beliefs) on belief revision, and in particular how explaining contributes to the rejection of incorrect hypotheses, the generation of alternative hypotheses, and the selection of a hypothesis that can account for anomalous observations. Participants learned how to rank students across courses using statistical concepts of deviation, and did so while either explaining sample rankings or writing their thoughts during study. We additionally varied whether or not candidate hypotheses about the basis for ranking were presented to participants prior to learning, and the number of sample rankings that violated intuitive misconceptions about ranking. Measures of learning and coded responses suggest that prompting people to explain can increase the rate at which they entertain both correct and incorrect hypotheses, but that explaining promotes the selection of a hypothesis that can account for anomalous observations.

Williams, J.J., Walker, C., & Lombrozo, T. (2012). Explaining increases belief revision in the face of (many) anomalies. Proceedings of the 34th Annual Conference of the Cognitive Science Society. Austin, TX: Cognitive Science Society.

view abstract
How does explaining novel observations influence the extent to which learners revise beliefs in the face of anomalies — observations inconsistent with their beliefs? On one hand, explaining could recruit prior beliefs and reduce belief revision if learners “explain away” or discount anomalies. On the other hand, explaining could promote belief revision by encouraging learners to modify beliefs to better accommodate anomalies. We explore these possibilities in a statistical judgment task in which participants learned to rank students’ performance across courses by observing sample rankings. We manipulated whether participants were prompted to explain the rankings or to share their thoughts about them during study, and also the proportion of observations that were anomalous with respect to intuitive statistical misconceptions. Explaining promoted greater belief revision when anomalies were common, but had no effect when rare. In contrast, increasing the number of anomalies had no effect on belief revision without prompts to explain.

Walker, C., Williams, J.J., Lombrozo, T., & Gopnik, A. (2012). Explaining influences children’s reliance on evidence and prior knowledge in causal induction. Proceedings of the 34th Annual Conference of the Cognitive Science Society. Austin, TX: Cognitive Science Society.

view abstract
In two studies, we examine how prompting 5- and 6-year-olds to explain observed outcomes influences causal learning. In Study 1, children were presented with data consistent with two causal regularities. Explainers outperformed controls in generalizing the regularity that accounted for more observations. In Study 2, this regularity was pitted against an alternative that accounted for fewer observations but was consistent with prior knowledge. Explainers were less likely than controls to generalize the regularity that accounted for more observations. These findings suggest that explaining drives children to favor causal regularities that they expect to generalize, where current observations and prior knowledge both provide cues.

Williams, J.J., Lombrozo, T., & Rehder, B. (2011). Explaining drives the discovery of real and illusory patterns. In L. Carlson, C. Hoelscher, & T.F. Shipley (Eds.), Proceedings of the 33rd Annual Conference of the Cognitive Science Society (pp. 1352-1357). Austin, TX: Cognitive Science Society.

view abstract
Children’s and adults’ attempts to explain the world around them plays a key role in promoting learning and understanding, but little is known about how and why explaining has this effect. An experiment investigated explaining in the social context of learning to predict and explain individuals’ behavior, examining if explaining observations exerts a selective constraint to seek patterns or regularities underlying the observations, regardless of whether such patterns are harmful or helpful for learning. When there were reliable patterns- such as personality types that predict charitable behavior- explaining promoted learning. But when these patterns were misleading, explaining produced an impairment whereby participants exhibited less accurate learning and prediction of individuals’ behavior. This novel approach of contrasting explanation’s positive and negative effects suggests that explanation’s benefits are not merely due to increased motivation, attention or time, and that explaining may undermine learning in domains where regularities are absent, spurious, or unreliable.

Gwynne, N.Z. & Lombrozo, T. (2010). The cultural transmission of explanations: evidence that teleological explanations are preferentially remembered. In S. Ohlsson & R. Catrambone (Eds.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society (pp. 1301-1306). Austin, TX: Cognitive Science Society.

view abstract
Teleological explanations – explanations in terms of functions, purposes, or goals – are pervasive in religion and feature prominently in intuitive theories about the world, such as theory of mind and folk biology. Previous findings suggest that such explanations reflect a deep, explanatory preference. Here we explore the mechanisms underlying the prevalence and persistence of such explanations, following a method developed by Boyer and Ramble (2001) to examine which religious concepts are likely to survive processes of cultural transmission. Specifically, we test the prediction that novel teleological explanations are remembered better than mechanistic explanations, even when effects of an explanation’s quality are taken into account. Two experiments support this prediction for artifact and biological trait explanations, but find the opposite pattern for explanations of non-living natural entities.

Williams, J.J. & Lombrozo, T. (2010). Explanation constrains learning, and prior knowledge constrains explanation. In S. Ohlsson & R. Catrambone (Eds.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society (pp. 2912-2917). Austin, TX: Cognitive Science Society.

view abstract
A great deal of research has demonstrated that learning is influenced by the learner’s prior background knowledge (e.g. Murphy, 2002; Keil, 1990), but little is known about the processes by which prior knowledge is deployed. We explore the role of explanation in deploying prior knowledge by examining the joint effects of eliciting explanations and providing prior knowledge in a task where each should aid learning. Three hypotheses are considered: that explanation and prior knowledge have independent and additive effects on learning, that their joint effects on learning are subadditive, and that their effects are superadditive. A category learning experiment finds evidence for a superadditive effect: explaining drives the discovery of regularities, while prior knowledge constrains which regularities learners discover. This is consistent with an account of explanation’s effects on learning proposed in Williams & Lombrozo (in press).

Williams, J.J., Lombrozo, T., & Rehder, B. (2010). Why does explaining help learning? Insight from an explanation impairment effect. In S. Ohlsson & R. Catrambone (Eds.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society (pp. 2906-2911). Austin, TX: Cognitive Science Society.

view abstract
Engaging in explanation, even to oneself, can enhance learning. What underlies this effect? Williams & Lombrozo (in press) propose that explanation exerts subsumptive constraints on processing, driving learners to discover underlying patterns. A category-learning experiment demonstrates that explanation can enhance or impair learning depending on whether these constraints match the structure of the material being learned. Explaining can help learning when reliable patterns are present, but actually impairs learning when patterns are misleading. This explanation impairment effect is predicted by the subsumptive constraints account, but challenges alternative hypotheses according to which explaining helps learning by increasing task engagement through motivation, attention, or processing time. The findings have both theoretical and practical implications for learning and education.

Williams, J.J. & Lombrozo, T. (2009). Explaining promotes discovery: Evidence from category learning. Proceedings of the 35th annual conference of the Society for Philosophy and Psychology.


Uttich, K. & Lombrozo, T. (2009). Moral norms inform mental state ascriptions: an alternative explanation for the side-effect effect. In N.A. Taatgen & H. van Rijn (Eds.), Proceedings of the 31st Annual Conference of the Cognitive Science Society (pp. 1096-1101). Austin, TX: Cognitive Science Society.

view abstract
Theory of mind, the capacity to understand and ascribe mental states, has traditionally been conceptualized as analogous to a scientific theory. However, recent work in philosophy and psychology has documented a “side-effect effect” suggesting that moral evaluations influence mental state ascriptions, and in particular whether a behavior is described as having been performed ‘intentionally.’ This evidence challenges the idea that theory of mind is analogous to scientific psychology in serving the function of predicting and explaining, rather than evaluating, behavior. In three experiments, we demonstrate that moral evaluations do inform ascriptions of intentional action, but that this relationship arises because behavior that conforms to norms (moral or otherwise) is less informative about underlying mental states than is behavior that violates norms. This analysis preserves the traditional understanding of theory of mind as a tool for predicting and explaining behavior, but also suggests the importance of normative considerations in social cognition. to accomplish the function of predicting and explaining behavior.

Williams, J.J. & Lombrozo, T. (2009). Explaining promotes discovery: evidence from category learning. In N.A. Taatgen & H. van Rijn (Eds.), Proceedings of the 31st Annual Conference of the Cognitive Science Society (pp. 1186-1191). Austin, TX: Cognitive Science Society.

view abstract
Research in education and cognitive development suggests that explaining plays a key role in learning and generalization: when learners provide explanations – even to themselves – they learn more effectively and generalize more readily to novel situations. This paper explores a potential mechanism underlying this effect, motivated by philosophical accounts of the structure of explanations: that explaining guides learners to interpret observations in terms of unifying patterns or regularities, which in turn promotes the discovery of broad generalizations. Experiment 1 finds that prompting participants to explain while learning artificial categories promotes the induction of a broad generalization underlying category membership. Experiment 2 suggests that explanation most readily prompts discovery in the presence of anomalies: observations inconsistent with current beliefs. Experiment 1 additionally suggests that explaining might result in reduced memory for details. These findings provide evidence for the proposed mechanism and insight into the potential role of explanation in discovery and generalization.

Uttich, K. & Lombrozo, T. (2009). Moral norms inform mental state ascriptions: an alternative explanation for the side-effect effect. Proceedings of the 35th Annual Conference of the Society for Philosophy and Psychology.


Bonawitz, E.B. & Lombrozo, T. (2008). Ockham’s razor as inductive bias in preschoolers causal explanations. Proceedings of the 7th International IEEE Conference on Development and Learning.


Lombrozo, T. (2008). The role of moral theories in moral judgment. Proceedings of the 34th Annual Conference of the Society for Philosophy and Psychology.


Lombrozo, T. (2007). Mechanisms and functions: empirical evidence for distinct modes of understanding. Proceedings of the 33rd Annual Conference of the Society for Philosophy and Psychology.


Lombrozo, T. (2006). Two routes to moral consideration: a psychological investigation of moral intuitions. Proceedings of the 32nd Annual Conference of the Society for Philosophy and Psychology.


Lombrozo, T. & Rutstein, J.J. (2004). Simplicity in explanation. Proceedings of the 26th Annual Conference of the Cognitive Science Society. 837-842.


Lombrozo, T. (2004). Causal constraints and regularities. Proceedings of the 30th Annual Conference of the Society for Philosophy and Psychology.