# Publications

2012
Lombrozo, T., & Rehder, B. (2012). Functions in biological kind classification. Cognitive Psychology , 65 (4), 457-485. https://doi.org/10.1016/j.cogpsych.2012.06.002Abstract
Biological traits that serve functions, such as a 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 & R. G. Morrison (Ed.), Oxford handbook of thinking and reasoning (pp. 260–276). https://doi.org/10.1093/oxfordhb/9780199734689.013.0014Abstract
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.
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.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., 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.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.

2011
Lombrozo, T. (2011). The instrumental value of explanations. Philosophy Compass , 6 (8), 539–551. https://doi.org/10.1111/j.1747-9991.2011.00413.xAbstract
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/Revue canadienne de philosophie , 50 (1), 165–177. https://doi.org/10.1017/S0012217311000175Abstract
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.
Williams, J. J., Lombrozo, T., & Rehder, B. (2011). Explaining drives the discovery of real and illusory patterns. L. Carlson, C. Hoelscher, & T. F. Shipley (Ed.), Proceedings of the 33rd Annual Conference of the Cognitive Science Society.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.
2010
Knobe, J., Lombrozo, T., & Machery, E. (2010). Dimensions of experimental philosophy. Review of Philosophy and Psychology , 1 (3), 315–318. https://doi.org/10.1007/s13164-010-0037-9
Knobe, J., Lombrozo, T., & Machery, E. (2010). Editorial: Psychology and experimental philosophy. Review of Philosophy and Psychology , 1 (2), 157–160. https://doi.org/10.1007/s13164-009-0012-5
Lombrozo, T. (2010). Causal-explanatory pluralism: How intentions, functions, and mechanisms influence causal ascriptions. Cognitive Psychology , 61 (4), 303-32. https://doi.org/10.1016/j.cogpsych.2010.05.002Abstract
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.
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 (4), 344–345. https://doi.org/10.1017/S0140525X10001810Abstract
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). From conceptual representations to explanatory relations [Peer commentary on the paper "Précis of Doing without Concepts" by E. Machery]. Behavioral and Brain Sciences , 33 (2-3), 218-219. https://doi.org/10.1017/S0140525X10000415Abstract
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.
Uttich, K., & Lombrozo, T. (2010). Norms inform mental state ascriptions: A rational explanation for the side-effect effect. Cognition , 116 (1), 87-100. https://doi.org/10.1016/j.cognition.2010.04.003Abstract
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.
Williams, J. J., & Lombrozo, T. (2010). The role of explanation in discovery and generalization: evidence from category learning. Cognitive Science , 34 (5), 776-806. https://doi.org/10.1111/j.1551-6709.2010.01113.xAbstract
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.
Gwynne, N. Z., & Lombrozo, T. (2010). The cultural transmission of explanations: Evidence that teleological explanations are preferentially remembered. S. Ohlsson & R. Catrambone (Ed.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society.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. S. Ohlsson & R. Catrambone (Ed.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society.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. S. Ohlsson & R. Catrambone (Ed.), Proceedings of the 32nd Annual Conference of the Cognitive Science Society.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.
2009
Lombrozo, T. (2009). The role of moral commitments in moral judgment. Cognitive Science , 33 (2), 273-86. https://doi.org/10.1111/j.1551-6709.2009.01013.xAbstract
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 (2), 248-53. https://doi.org/10.1016/j.cognition.2008.10.007Abstract
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.
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. https://doi.org/10.1007/s12052-008-0109-9
Uttich, K., & Lombrozo, T. (2009). Moral norms inform mental state ascriptions: An alternative explanation for the side-effect effect. N. A. Taatgen & H. van Rijn (Ed.), Proceedings of the 31st Annual Conference of the Cognitive Science Society.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. N. A. Taatgen & H. van Rijn (Ed.), Proceedings of the 35th Annual Conference of the Cognitive Science Society.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.
2008
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., Thanukos, A., & Weisberg, M. (2008). The importance of understanding the nature of science for accepting evolution. Evolution: Education and Outreach , 1 (3), 290. https://doi.org/10.1007/s12052-008-0061-8Abstract
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.
Lombrozo, T. (2008). The role of moral theories in moral judgment. Proceedings of the 34th Annual Conference of the Society for Philosophy and Psychology.
2007
Lombrozo, T. (2007). Simplicity and probability in causal explanation. Cognitive Psychology , 55 (3), 232-57. https://doi.org/10.1016/j.cogpsych.2006.09.006Abstract
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 (11), 999-1006. https://doi.org/10.1111/j.1467-9280.2007.02015.xAbstract
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.
Sloman, S., Lombrozo, T., & Malt, B. (2007). Ontological commitments and domain specific categorisation. In M. J. Roberts (Ed.), Integrating the Mind (pp. 105–129) . Hove, UK: Psychology Press.
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.
2006
Lombrozo, T., & Carey, S. (2006). Functional explanation and the function of explanation. Cognition , 99 (2), 167-204. https://doi.org/10.1016/j.cognition.2004.12.009Abstract
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.
Lombrozo, T. (2006). The structure and function of explanations. Trends in Cognitive Sciences , 10 (10), 464-70. https://doi.org/10.1016/j.tics.2006.08.004Abstract
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 (2), 56-7. https://doi.org/10.1016/j.tics.2005.12.001Abstract
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. 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. (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.
2005
Lombrozo, T., Judson, J., & MacLeod, D. I. A. (2005). Flexibility of spatial averaging in visual perception. Proceedings of the Royal Society of London B: Biological Sciences , 272 (1564), 725-32. https://doi.org 10.1098/rspb.2004.3007Abstract
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 preservation, 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.
2004
Lombrozo, T. (2004). Causal constraints and regularities.Abstract
Proceedings of the 30th 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.
2000
Federmeier, K. D., Segal, J. B., Lombrozo, T., & Kutas, M. (2000). Brain responses to nouns, verbs and class-ambiguous words in context. Brain , 123 (12), 2552–2566. https://doi.org/10.1093/brain/123.12.2552Abstract
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.