The relation between essentialist beliefs and evolutionary reasoning

How generic language shapes the development of social thought

Generic language, that is, language that refers to a category as an abstract whole (e.g., 'Girls like pink') rather than specific individuals (e.g., 'This girl likes pink'), is a common means by which children learn about social kinds. Here, we propose that children interpret generics as signaling that their referenced categories are natural, objective, and have distinctive features, and, thus, in the social domain, that such language affects children's beliefs about the social world in ways that extend far beyond the content they explicitly communicate. On this account, even generics expressing uncontentious content (e.g., 'Girls are great at math') can lead children to think of categories as defining fundamentally distinct kinds of people and contribute to the development of stereotypes and other problematic social phenomena.

Deterministic or probabilistic: U.S. children's beliefs about genetic inheritance

Do children think of genetic inheritance as deterministic or probabilistic? In two novel tasks, children viewed the eye colors of animal parents and judged and selected possible phenotypes of offspring. Across three studies (N = 353, 162 girls, 172 boys, 2 non-binary; 17 did not report gender) with predominantly White U.S. participants collected in 2019-2021, 4- to 12-year-old children showed a probabilistic understanding of genetic inheritance, and they accepted and expected variability in the genetic inheritance of eye color. Children did not show a mother bias but they did show two novel biases: perceptual similarity and sex-matching. These results held for unfamiliar animals and several physical traits (e.g., eye color, ear size, and fin type), and persisted after a lesson.

Essential shape: The role of essentialist beliefs in preferences for misshapen produce

Understanding the reasons behind consumer rejection of misshapen produce is important because of its dramatic consequences on food waste. Drawing on psychological essentialism, we conduct seven studies to investigate the role of produce shape-related essentialist beliefs (i.e., the belief that produce shape is determined by an underlying and unobservable essence) in consumers' evaluations of misshapen produce. Our findings show that essentialist beliefs about produce shape are divided into four distinct dimensions (i.e., biological basis, discreteness, informativeness, and immutability). We find that endorsing discreteness beliefs decreases preferences for misshapen produce. Immutability beliefs produce the opposite effect, whereas informativeness and biological basis have little to no effect. These effects operate through typicality judgments. These findings suggest that considering essentialist beliefs have the potential to help enhance the acceptance of edible albeit misshapen produce.

Students explain evolution by natural selection differently for humans versus nonhuman animals

Evolution is foundational to understanding biology, yet learners at all stages have incomplete and incorrect ideas that persist beyond graduation. Contextual features of prompts (e.g., taxon of organism, acquisition vs. loss of traits, etc.) have been shown to influence both the learning process and the ideas students express in explanations of evolutionary processes. In this study, we compare students' explanations of natural selection for humans versus a nonhuman animal (cheetah) at different times during biology instruction. We found "taxon" to be a significant predictor of the content of students' explanations. Responses to "cheetah" prompts contained a larger number and diversity of key concepts (e.g., variation, heritability, differential reproduction) and fewer naïve ideas (e.g., need, adapt) when compared with responses to an isomorphic prompt containing "human" as the organism. Overall, instruction increased the prevalence of key concepts, reduced naïve ideas, and caused a modest reduction in differences due to taxon. Our findings suggest that the students are reasoning differently about evolutionary processes in humans as compared with nonhuman animals, and that targeted instruction may both increase students' facility with key concepts while reducing their susceptibility to contextual influences.

Same people, different group: Social structures are a central component of group concepts

We examine whether people conceptualize organized groups as having at least two parts: In addition to members (e.g., Alice), they also have social structures (i.e., roles and relations). If groups have members and social structures, then numerically distinct groups can have the same members if they differ in their structures. In Studies 1-4, participants numerically distinguished groups that had the same members when they had different structures. Participants numerically distinguished even when groups had the same function-the same people playing chess together Monday and Tuesday can be numerically distinct groups. In Study 4, we compare clubs to tables, and find that participants numerically distinguish tables by their structures too (i.e., the configuration of their parts) even when they have the same parts (which can be disassembled and then reassembled with ease). In Study 5, we find that participants rate groups as existing in space and time like concrete objects, suggesting that participants represent groups as at least partially concrete, such that groups have at least two parts (their structures and their members). Finally, in Study 6, we show that people will judge the same person as exemplary with respect to one group but condemnable with respect to another-even when those groups have the same members.

Thinking Structurally: A Cognitive Framework for Understanding How People Attribute Inequality to Structural Causes

To make accurate causal inferences about social-group inequalities, people must consider structural causes. Structural causes are a distinct type of extrinsic cause-they are stable, interconnected societal forces that systematically advantage some social groups and disadvantage others. We propose a new cognitive framework to specify how people attribute inequality to structural causes. This framework is rooted in counterfactual theories of causal judgment and suggests that people will recognize structural factors as causal when they are perceived as "difference-making" for inequality above and beyond any intrinsic causes. Building on this foundation, our framework makes the following contributions. First, we propose specific types of evidence that support difference-making inferences about structural factors: within-group change (i.e., observing that disadvantaged groups' outcomes improve under better societal conditions) and well-matched between-group comparisons (i.e., observing that advantaged group members, who have similar baseline traits to the disadvantaged group, experience more favorable societal conditions and life outcomes). Second, we consider contextual, cognitive, and motivational barriers that may complicate the availability and acceptance of this evidence. We conclude by exploring how the framework might be applied in future research examining people's causal inferences about inequality.

Speaking of Kinds: How Correcting Generic Statements can Shape Children's Concepts

Generic language (e.g., "tigers have stripes") leads children to assume that the referenced category (e.g., tigers) is inductively informative and provides a causal explanation for the behavior of individual members. In two preregistered studies with 4- to 7-year-old children (N = 497), we considered the mechanisms underlying these effects by testing how correcting generics might affect the development of these beliefs about novel social and animal kinds (Study 1) and about gender (Study 2). Correcting generics by narrowing their scope to a single individual limited beliefs that the referenced categories could explain what their members would be like while broadening the scope to a superordinate category (Study 2) uniquely limited endorsement of gender norms. Across both studies, correcting generics did not alter beliefs about feature heritability and had mixed effects on inductive inferences, suggesting that additional mechanisms (e.g., causal reasoning about shared features) contribute to the development of full-blown essentialist beliefs. These results help illuminate the mechanisms by which generics lead children to view categories as having rich inductive and causal potential; in particular, they suggest that children interpret generics as signals that speakers in their community view the referenced categories as meaningful kinds that support generalization. The findings also point the way to concrete suggestions for how adults can effectively correct problematic generics (e.g., gender stereotypes) that children may hear in daily life.

The influence of linguistic form and causal explanations on the development of social essentialism

Generic descriptions of social categories (e.g., boys play baseball; girls have long hair) lead children and adults to think of the referenced categories (i.e., boys and girls) in essentialist terms-as natural ways of dividing up the world. Yet, key questions remain unanswered about how, why, and when generic language shapes the development of essentialist beliefs. The present experiment examined the scope of these effects by testing the extent to which generics elicit essentialist beliefs because of their linguistic form or because of the causal information they convey. Generic language led children (N = 199, M_age = 6.07 years, range = 4.5-7.95) to essentialize a novel social category, regardless of the causal information used to describe category-property relations (either biological or cultural). In contrast, both linguistic form and causal information influenced adults' (N = 234) beliefs. These findings reveal a unique role of linguistic form in the development and communication of essentialist beliefs in young children.

Intuitive biological thinking in Chinese 8th graders

People spontaneously engage in systematic ways of thinking about biology such as human exceptionalism (the tendency of viewing human species as separate from nonhuman species), essentialism (the tendency of assuming category membership as determined by an underlying essence), and teleology (the tendency of seeing purpose as the cause). However, with the majority of past research drawn on Western samples, little is known about whether various types of intuitive biological thinking apply to non-Western contexts. To better understand the nature and cultural prevalence of intuitive biological thinking, we measured essentialist, teleological, and human exceptionalist thinking in a group of Chinese 8th graders. Results demonstrated the presence of all three types of intuitive biological thinking in Chinese middle schoolers, and comparisons with previously published data on U.S. 8th graders showed consistently less human exceptionalism and slightly higher essentialist thinking in China. As such, the current results highlight the prevalence of intuitive biological thinking in an East Asian sample while addressing the potential role of cultural inputs in shaping the way such thinking manifests.

Darwin’s tales–A content analysis of how evolution is presented in children’s books

In science, certain theories led to a paradigm shift in human being’s approach to explain nature, such as the theory of relativity, the quantum theory, and the theory of evolution. The latter explains the emergence of biodiversity on Earth and all living beings’ relatedness, including humans. Accordingly, evolutionary theory is a central part of scientific literacy. However, scholars have demonstrated that misconceptions emerging in childhood hinder learners from grasping evolutionary processes. Implementing evolution in early science education could enhance scientific ideas as a basis for subsequent learning at school. Currently, children’s literature that deals with evolution is increasing and may enable more children to encounter evolutionary theory before entering school. This explorative study aimed to analyze how children’s books about evolution approach explaining this complex topic to young children in terms of covered contents, underlying concepts and use of language. We conducted (1) a text-based qualitative content analysis of 31 children’s books in the categories of organismal context, evolutionary principles, and misconceptions, and (2) a computer-supported content analysis of 33 word labels concerning (a) scientific terms and (b) verbs expressing evolutionary change. Although evolution is a universal concept, children’s books seem to promote specific contexts such as animal and human evolution. Even though the principle of selection requires an understanding of complex interactions between individuals and environmental factors, this principle was more frequent than the principles variation and inheritance. Phylogenetic history was covered more often than basic evolutionary processes, and evolutionary change was mainly mentioned at the species level over long periods. Besides, most books conveyed misconceptions such as transformationist, teleological or anthropomorphic reasoning. Consequently, books covering evolution may bias children’s first ideas concerning this topic or introduce unscientific ideas. Based on our results, we propose implications for early evolution educators and education researchers.

Effects of Reading Interventions on Student Understanding of and Misconceptions about Antibiotic Resistance

Students possess informal, intuitive ways of reasoning about the world, including biological phenomena. Although useful in some cases, intuitive reasoning can also lead to the development of scientifically inaccurate ideas that conflict with central concepts taught in formal biology education settings, including evolution. Using antibiotic resistance as an example of evolution, we developed a set of reading interventions and an assessment tool to examine the extent to which differences in instructional language affect undergraduate student misconceptions and intuitive reasoning. We find that readings that confront intuitive misconceptions can be more effective in reducing those misconceptions than factual explanations of antibiotic resistance that fail to confront misconceptions. Overall, our findings build upon investigations of intuitive reasoning in biology, examine possible instructional interventions, and raise questions about effective implementation of reading interventions in addressing persistent misconceptions about biology.

Improving Students' Understanding of Biological Variation in Experimental Design and Analysis through a Short Model-Based Curricular Intervention

When conducting biological investigations, experts constantly integrate their conceptual and quantitative understanding of variation with the design and analysis of the investigation. This process is difficult for students, because curricula often treat these concepts as separate components. This study describes the effect of a curricular intervention aimed at improving students' conceptual and quantitative understanding of variation in the context of experimental design and analysis. A model-based intervention curriculum consisting of five short modules was implemented in an introductory biology laboratory course. All students received the regular laboratory curriculum, and half of the students also received the Intervention curriculum. Students' understanding of variation was assessed using a published 16-question multiple-choice instrument designed and validated by the research team. Students were assessed before and after the intervention was implemented, and normalized gain scores were calculated. Students who received the intervention showed significantly higher normalized gains than students who did not receive the intervention. This effect was not influenced by students' gender or exposure to prior statistics courses and persisted into and through the following semester's laboratory course. These results provide support for the use of model-based approaches to improve students' understanding of biological variation in experimental design and analysis.

Ending genetic essentialism through genetics education

Genetic concepts are regularly used in arguments about racial inequality. This review summarizes research about the relationship between genetics education and a particular form of racial prejudice known as genetic essentialism. Genetic essentialism is a cognitive form of prejudice that is used to rationalize inequality. Studies suggest that belief in genetic essentialism among genetics students can be increased or decreased based on what students learn about human genetics and why they learn it. Research suggests that genetics education does little to prevent the development of genetic essentialism, and it may even exacerbate belief in it. However, some forms of genetics education can avert this problem. In particular, if instructors teach genetics to help students understand the flaws in genetic essentialist arguments, then it is possible to reduce belief in genetic essentialism among biology students. This review outlines our knowledge about how to accomplish this goal and the research that needs to be done to end genetic essentialism through genetics education.

A comparison study of human examples vs. non-human examples in an evolution lesson leads to differential impacts on student learning experiences in an introductory biology course

Background

Instructors can teach evolution using any number of species contexts. However, not all species contexts are equal, and taxa choice can alter both cognitive and affective elements of learning. This is particularly true when teaching evolution using human examples, a promising method for evolution instruction that nevertheless comes with unique challenges. In this study, we tested how an evolution lesson focused on a human example may impact students’ engagement, perceived content relevance, learning gains, and level of discomfort, when compared to the same lesson using a non-human mammal example. We use this isomorphic lesson and a pre-post study design administered in a split-section introductory biology classroom to isolate the importance of the species context.

Results

For two of the four measurements of interest, the effect of using human examples could not be understood without accounting for student background. For learning gains, students with greater pre-class content knowledge benefited more from the human examples, while those with low levels of knowledge benefited from the non-human example. For perceived relevance, students who were more accepting of human evolution indicated greater content relevance from the human example. Regardless of condition, students with lower evolution acceptance reported greater levels of discomfort with the lesson.

Conclusions

Our results illustrate the complexities of using human examples to teach evolution. While these examples were beneficial for many students, they resulted in worse outcomes for students that were less accepting of evolution and those who entered the course with less content knowledge. These findings demonstrate the need to consider diverse student backgrounds when establishing best practices for using human examples to teach evolution.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12052-021-00148-w.

Can we get human nature right?

Few questions in science are as controversial as human nature. At stake is whether our basic concepts and emotions are all learned from experience, or whether some are innate. Here, I demonstrate that reasoning about innateness is biased by the basic workings of the human mind. Psychological science suggests that newborns possess core concepts of "object" and "number." Laypeople, however, believe that newborns are devoid of such notions but that they can recognize emotions. Moreover, people presume that concepts are learned, whereas emotions (along with sensations and actions) are innate. I trace these beliefs to two tacit psychological principles: intuitive dualism and essentialism. Essentialism guides tacit reasoning about biological inheritance and suggests that innate traits reside in the body; per intuitive dualism, however, the mind seems ethereal, distinct from the body. It thus follows that, in our intuitive psychology, concepts (which people falsely consider as disembodied) must be learned, whereas emotions, sensations, and emotions (which are considered embodied) are likely innate; these predictions are in line with the experimental results. These conclusions do not speak to the question of whether concepts and emotions are innate, but they suggest caution in its scientific evaluation.

Evidence for multiple sources of inductive potential: Occupations and their relations to social institutions

Several current theories have essences as primary drivers of inductive potential: e.g., people infer dogs share properties because they share essences. We investigated the possibility that people take occupational roles as having robust inductive potential because of a different source: their position in stable social institutions. In Studies 1-4, participants learned a novel property about a target, and then decided whether two new individuals had the property (one with the same occupation, one without). Participants used occupational roles to robustly generalize rights and obligations, functional behaviors, personality traits, and skills. In Studies 5-6, we contrasted occupational roles (via label) with race/gender (via visual face cues). Participants reliably favored occupational roles over race/gender for generalizing rights and obligations, functional behaviors, personality traits, and skills (they favored race/gender for inferring leisure behaviors and physiological properties). Occupational roles supported inferences to the same extent as animal categories (Studies 4 and 6). In Study 7, we examined why members of occupational roles share properties. Participants did not attribute the inductive potential of occupational roles to essences, they attributed it to social institutions. In combination, these seven studies demonstrate that any theory of inductive potential must pluralistically allow for both essences and social institutions to form the basis of inductive potential.

Learning Evolution by Collaboration

Collaboration can be an effective means of learning, but is it effective in domains where collaborators rely on conceptually distinct forms of reasoning? We explored this question in the domain of evolution, where many students construe evolution as the uniform transformation of all members of a population rather than the selective survival and reproduction of a subset. College undergraduates (n = 174) completed an assessment of their evolutionary reasoning by themselves (pretest) and with a partner (dyad test); some (n = 44) also completed an assessment several months later (posttest). Higher-scoring partners pulled up lower-scoring partners to achieve a dyad score equivalent to the higher-scoring partner's pretest score. Lower-scoring partners retained a score boost when working alone at posttest. These findings indicate that students who hold different views of evolution are able to collaborate effectively, and such collaboration yields long-term learning gains for partners with lower levels of understanding.

Categories convey prescriptive information across domains and development

Young children display a pervasive bias to assume that what they observe in the world reflects how things are supposed to be. The current studies examined the nature of this bias by testing whether it reflects a particular form of reasoning about human social behaviors or a more general feature of category representations. Children aged 4 to 9 years and adults (N = 747) evaluated instances of nonconformity among members of novel biological and human social kinds. Children held prescriptive expectations for both animal and human categories; in both cases, they said it was wrong for a category member to engage in category-atypical behavior. These prescriptive judgments about categories depended on the extent to which people saw the pictured individual examples as representative of coherent categories. Thus, early prescriptive judgments appear to rely on the interplay between general conceptual biases and domain-specific beliefs about category structure.

Illusory Essences: A Bias Holding Back Theorizing in Psychological Science

The reliance in psychology on verbal definitions means that psychological research is unusually moored to how humans think and communicate about categories. Psychological concepts (e.g., intelligence, attention) are easily assumed to represent objective, definable categories with an underlying essence. Like the “vital forces” previously thought to animate life, these assumed essences can create an illusion of understanding. By synthesizing a wide range of research lines from cognitive, clinical, and biological psychology and neuroscience, we describe a pervasive tendency across psychological science to assume that essences explain phenomena. Labeling a complex phenomenon can appear as theoretical progress before there is sufficient evidence that the described category has a definable essence or known boundary conditions. Category labels can further undermine progress by masking contingent and contextual relationships and obscuring the need to specify mechanisms. Finally, we highlight examples of promising methods that circumvent the lure of essences and suggest four concrete strategies for identifying and avoiding essentialist intuitions in theory development.

Designing Exhibits to Support Relational Learning in a Science Museum

Science museums aim to provide educational experiences for both children and adults. To achieve this goal, museum displays must convey scientifically-relevant relationships, such as the similarities that unite members of a natural category, and the connections between scientific models and observable objects and events. In this paper, we explore how research on comparison could be leveraged to support learning about such relationships. We describe how museum displays could promote educationally-relevant comparisons involving natural specimens and scientific models. We also discuss how these comparisons could be supported through the design of a display—in particular, by using similarity, space, and language to facilitate relational thinking for children and their adult companions. Such supports may be pivotal given the informal nature of learning in museums.

Inhibiting intuition: Scaffolding children's theory construction about species evolution in the face of competing explanations

Acquiring the counterintuitive logic of how the mechanism of natural selection (NS) leads to the evolution of new species (speciation) represents a paradigm case of conceptual change. Given this, we examined children's intuitive preconceptions about speciation and their ability to construct, generalize, and retain an accurate understanding of the theory. We did so by conducting two multi-age, multi-session, and multi-measure intervention studies that assessed children's understanding of natural selection 4 times over three months using extended interviews. We also examined the role of Executive Function skills (EF) in these conceptual change processes. Distinctively, we explored whether-consistent with conceptual co-existence accounts-EF not only supports children's initial construction of a counterintuitive theory but also plays an ongoing role in the online reasoning of successful learners. Across two studies, North American children in Grades 2 (N = 34) and 3 (N = 34) were provided with coherent mechanistic explanations of NS through a two-storybook intervention sequence. The first storybook described the logic of NS to explain how a specialized body part evolved within a fictional species (adaptation). The second storybook extended the logic to explain how this same species evolved into a new, distinct species (speciation). Findings revealed that many second and third graders were able to learn and generalize the logic of speciation. This is a remarkable feat given that speciation conflicts with early developing essentialist and teleological intuitions, and defeats most adults. Our analyses also confirmed that constructing this counterintuitive theory draws heavily on children's EF capacities. They additionally reveal that once the theory is constructed, EF plays a continuing role in reasoning by inhibiting competing intuitive explanations that co-exist rather than being replaced during the process of conceptual change.

Does It Matter How We Speak About Social Kinds? A Large, Preregistered, Online Experimental Study of How Language Shapes the Development of Essentialist Beliefs

A problematic way to think about social categories is to essentialize them-to treat particular differences between people as marking fundamentally distinct social kinds. From where do these beliefs arise? Language that expresses generic claims about categories elicits some aspects of essentialism, but the scope of these effects remains unclear. This study (N = 204, ages 4.5-8 years, 73% White; recruited predominantly from the United States and the United Kingdom to participate online in 2019) found that generic language increases two critical aspects of essentialist thought: Beliefs that (a) category-related properties arise from intrinsic causal mechanisms and (b) category boundaries are inflexible. These findings have implications for understanding the spread of essentialist beliefs across communities and the development of intergroup behavior.

Developing an Understanding of Science

Young children are adept at several types of scientific reasoning, yet older children and adults have difficulty mastering formal scientific ideas and practices. Why do “little scientists” often become scientifically illiterate adults? We address this question by examining the role of intuition in learning science, both as a body of knowledge and as a method of inquiry. Intuition supports children's understanding of everyday phenomena but conflicts with their ability to learn physical and biological concepts that defy firsthand observation, such as molecules, forces, genes, and germs. Likewise, intuition supports children's causal learning but provides little guidance on how to navigate higher-order constraints on scientific induction, such as the control of variables or the coordination of theory and data. We characterize the foundations of children's intuitive understanding of the natural world, as well as the conceptual scaffolds needed to bridge these intuitions with formal science.

Representing Variability: The Case of Life Cycle Diagrams

Two foundational concepts in biology education are 1) offspring are not identical to their parents, and 2) organisms undergo changes throughout their lives. These concepts are included in both international and U.S. curricular standards. Research in psychology has shown that children often have difficulty understanding these concepts, as they are inconsistent with their intuitive theories of the biological world. Additionally, prior research suggests that diagrams are commonly used in instruction and that their features influence student learning. Given this prior work, we explored the characteristics of life cycle diagrams and discuss possible implications for student learning. We examined 75 life cycle diagrams from books, including five biology or general science textbooks and 25 specialized trade books focusing on biology for children. We also examined 633 life cycle diagrams from a publicly available online database of science diagrams. Most diagrams failed to show any within-species variability. Additionally, many diagrams had perceptually rich backgrounds, which prior research suggests might hinder learning. We discuss how the design characteristics of diagrams may reinforce students' intuitive theories of biology, which might make it difficult for students to understand key biological concepts in the future.

Development of the Biological Variation In Experimental Design And Analysis (BioVEDA) assessment

Variation is an important concept that underlies experimental design and data analysis. Incomplete understanding of variation can preclude students from designing experiments that adequately manage organismal and experimental variation, and from accurately conducting and interpreting statistical analyses of data. Because of the lack of assessment instruments that measure students' ideas about variation in the context of biological investigations, we developed the Biological Variation in Experimental Design and Analysis (BioVEDA) assessment. Psychometric analyses indicate that BioVEDA assessment scores are reliable/precise. We provide evidence that the BioVEDA instrument can be used to evaluate students' understanding of biological variation in the context of experimental design and analysis relative to other students and to their prior scores.

Structural thinking about social categories: Evidence from formal explanations, generics, and generalization

Many theories of kind representation suggest that people posit internal, essence-like factors that underlie kind membership and explain properties of category members. Across three studies (N = 281), we document the characteristics of an alternative form of construal according to which the properties of social kinds are seen as products of structural factors: stable, external constraints that obtain due to the kind's social position. Internalist and structural construals are similar in that both support formal explanations (i.e., "category member has property P due to category membership C"), generic claims ("Cs have P"), and the generalization of category properties to individual category members when kind membership and social position are confounded. Our findings thus challenge these phenomena as signatures of internalist thinking. However, once category membership and structural position are unconfounded, different patterns of generalization emerge across internalist and structural construals, as do different judgments concerning category definitions and the dispensability of properties for category membership. We discuss the broader implications of these findings for accounts of formal explanation, generic language, and kind representation.

Does essentialism lead to racial prejudice? It is not so Black and White

Over half a century ago, psychologists hypothesized that social essentialism, an intuitive theory comprising the beliefs that social categories reflect naturally occurring distinctions and that category members share an underlying and fundamental essence, lays the foundation for prejudice. In the intervening decades, research has shown that although essentialism sometimes leads to prejudicial beliefs, attitudes, and behaviors, it does not always, sometimes even leading to decreased prejudice toward stigmatized groups. The relation between essentialism and prejudice is clearly complex, but this review proposes four questions that will help clarify how and when essentialism leads to prejudice: (1) What precisely is essentialism and how might a more nuanced understanding of its components and structure shed light on the mechanisms by which essentialist beliefs contribute to prejudice?; (2) Do essentialist beliefs orient group-based prejudice toward out-groups or toward stigmatized groups, and what are the consequences of essentialist beliefs among those with minoritized identities?; (3) Do essentialist beliefs engender group-based prejudice directly, or must essentialist beliefs interact with additional information or belief systems to lead to negative consequences?; and (4) Do essentialist beliefs lay a foundation for group-based prejudice to develop, or is essentialism strategically invoked to justify existing prejudice? By posing these questions, describing what is currently known about each, and proposing future lines of inquiry that focus on the importance of including participants from a diverse set of backgrounds and across developmental periods, this review aims to stimulate research studies best designed to fill the gaps in our knowledge. By understanding how and when essentialism contributes to prejudice, we will be better equipped to use this early-emerging, but malleable, aspect of cognition to decrease prejudice and create a more equitable society.

Intuitive biology, moral reasoning, and engineering life: Essentialist thinking and moral purity concerns shape risk assessments of synthetic biology technologies

The field of synthetic biology heralds a new era in our relationship with nature, as organisms are engineered to meet human goals. But little attention has been paid to potential cognitive constraints on reasoning about such technologies. Across four studies with American adults (N = 649), the present research investigates the proposal that essentialist reasoning and moral purity concerns conspire to shape risk assessments of engineered organisms. Moral purity concerns but not moral harm concerns predict moral wrongness judgments of adding a foreign gene to a plant (Studies 1, 2 & 4), as well as assessments of risk (Studies 1 and 2), and risk of harm from eating (Study 4). Adding a gene from a taxonomically distant organism is considered more morally wrong (Studies 2, 3 and 4), more risky (Studies 2 & 3), and more risky to eat (Study 4), than adding either a gene from a similar organism or a new-to-nature gene. Assessments of the risk of gene spread follow a different pattern, with the new-to-nature gene considered safest (Study 4). The findings support the proposal that gene change is reasoned about as essence change that threatens notions of moral purity, with direct implications for certain types of risk perceptions (eating), but not others (gene spread). The findings elucidate cognitive constraints on risk perceptions of synthetic biology, shed fresh light on essentialist and moral reasoning in a novel biological context, and demonstrate the need to differentiate between both risk context and risk type in cognitive accounts of risk perception.

Developmental Changes in Strategies for Gathering Evidence About Biological Kinds

How do people gather samples of evidence to learn about the world? Adults often prefer to sample evidence from diverse sources-for example, choosing to test a robin and a turkey to find out if something is true of birds in general. Children below age 9, however, often do not consider sample diversity, instead treating non-diverse samples (e.g., two robins) and diverse samples as equivalently informative. The current study (N = 247) found that this discontinuity stems from developmental changes in standards for evaluating evidence-younger children chose to learn from samples that best approximate idealized views of what category members are supposed to be like (e.g., the fastest cheetahs), with a gradual shift across age toward samples that cover more within-category variation (e.g., cheetahs of varying speeds). These findings have implications for the relation between conceptual structure and inductive reasoning, and for the mechanisms underlying inductive reasoning more generally.

Evolutionary Mismatch in Mating

Evolutionary mismatch concepts are being fruitfully employed in a number of research domains, including medicine, health, and human cognition and behavior to generate novel hypotheses and better understand existing findings. We contend that research on human mating will benefit from explicitly addressing both the evolutionary mismatch of the people we study and the evolutionary mismatch of people conducting the research. We identified nine mismatch characteristics important to the study of human mating and reviewed the literature related to each of these characteristics. Many of the people we study are: exposed to social media, in temporary relationships, relocatable, autonomous in their mating decisions, nulliparous, in groups that are socially segmented, in an educational setting, confronted with lots of options, and young. We applied mismatch concepts to each characteristic to illustrate the importance of incorporating mismatch into this research area. Our aim in this paper is not to identify all potential mismatch effects in mating research, nor to challenge or disqualify existing data. Rather, we demonstrate principled ways of thinking about evolutionary mismatch in order to propel progress in mating research. We show how attending to the potential effects of mismatch can help us refine our theoretical and methodological approaches and deepen our understanding of existing patterns in the empirical record. We conclude with specific recommendations about how to include consideration of evolutionary mismatch into research on human mating.

Cognitive Construal-Consistent Instructor Language in the Undergraduate Biology Classroom

Researchers have identified patterns of intuitive thinking that are commonly used to understand and reason about the biological world. These cognitive construals (anthropic, teleological, and essentialist thinking), while useful in everyday life, have also been associated with misconceptions about biological science. Although construal-based thinking is pervasive among students, we know little about the prevalence of construal-consistent language in the university science classroom. In the current research, we characterized the degree to which construal-consistent language is present in biology students' learning environments. To do so, we coded transcripts of instructor's speech in 90 undergraduate biology classes for the presence of construal-consistent language. Classes were drawn from two universities with very different student demographic profiles and represented 18 different courses aimed at nonmajors and lower- and upper-division biology majors. Results revealed construal-consistent language in all 90 sampled classes. Anthropic language was more frequent than teleological or essentialist language, and frequency of construal-consistent language was surprisingly consistent across instructor and course level. Moreover, results were surprisingly consistent across the two universities. These findings suggest that construal-consistent language is pervasive in the undergraduate classroom and highlight the need to understand how such language may facilitate and/or interfere with students learning biological science.

Biological Variation as a Threshold Concept: Can We Measure Threshold Crossing?

Threshold concepts are fundamental to a discipline and, once understood, transform students' understanding and perception of the subject. Despite the value of threshold concepts as a learning "portal" for heuristic purposes, there is limited empirical evidence of threshold crossing or achieving mastery. As a threshold concept, biological variation within species is fundamental to understanding evolution and provides a target for analyzing threshold crossing. We aimed to 1) examine student understanding of variation using four dimensions of a threshold concept (discursive, troublesome, liminal, and integrative), 2) measure "threshold crossing," and 3) investigate the utility of the threshold concept framework to curriculum design. We conducted semistructured interviews of 29 students affiliated with a "variation-enriched" curriculum in a cross-sectional design with precurriculum, current, and postcurriculum groups (Pre, Current, and Post) and an outgroup of three postbaccalaureate advanced learners (Outgroup). Interview transcripts revealed that Current students expand their "variation discourse," while the Post group and Outgroup displayed conformity in word choice about variation. The Post and Current groups displayed less troublesome and more integrative responses. Pre, Post, and Outgroup explanations' revealed liminality, with discomfort and uncertainty regardless of accuracy. When we combined all four threshold concept dimensions for each respondent, patterns indicative of threshold crossing emerged along with new insight regarding curricular design.

Cognitive constraints influence an understanding of life-cycle change

We investigated children's (n = 120; 3- to 11-year-olds) and adults' (n = 18) reasoning about life-cycle changes in biological organisms by examining their endorsements of four different patterns of life-span changes. Participants were presented with two separate tasks: (a) judging possible adult versions of a juvenile animal and (b) judging possible juvenile versions of an adult animal. The stimuli enabled us to examine the endorsement of four different patterns of change: identical growth, natural growth, dramatic change, and speciation. The results suggest that endorsement of the different patterns is influenced by age and familiarity. Young children and individuals confronted with unfamiliar organisms often endorsed an identical growth that emphasizes the stability of features over the life span and between parents and offspring. The results are interpreted as supporting the idea that cognitive constraints influence individuals' reasoning about biological change and that the influence of these constraints is most notable when individuals are young or are presented with unfamiliar biological organisms.

The state of evolutionary medicine in undergraduate education

Background and objectives

Undergraduate courses that include evolutionary medicine (EM) are increasingly available, but quantified data about such courses are lacking. In this article, we describe relevant course offerings by institution and department type, in conjunction with information on the backgrounds and experiences of associated instructors.

Methodology

We searched course catalogs from 196 American universities to find courses that include EM, and sent a survey to 101 EM instructors to ask about their backgrounds and teaching experiences.

Results

Research-focused universities (R1) were much more likely to offer at least one course that covers evolutionary applications to health and disease than universities that granted only bachelor's or master's degrees. A survey course on EM was offered in 56% of 116 R1 universities, but only 2% of the 80 non-R1 universities we searched. Most EM instructors have backgrounds in anthropology or biology; each instructor's area of expertise provides clues as to how continued growth of EM may occur differently by discipline.

Conclusions and implications

Undergraduates are most likely to learn about EM in research-intensive universities from an anthropological or biological perspective. Responses from anthropology and biology instructors, including whom they share course materials with, highlight that courses may differ depending on the discipline in which they are taught.

LAY SUMMARY

Recognition of evolution's relevance to understanding health and disease is growing, but documentation of coverage in undergraduate education is lacking. This study explores where evolutionary medicine (EM) content is taught across 196 undergraduate institutions and how 53 instructors describe their experiences teaching EM.

Is the most representative skunk the average or the stinkiest? Developmental changes in representations of biological categories

People often think of categories in terms of their most representative examples (e.g., robin for BIRD). Thus, determining which exemplars are most representative is a fundamental cognitive process that shapes how people use concepts to navigate the world. The present studies (N = 669; ages 5 years - adulthood) revealed developmental change in this important component of cognition. Studies 1-2 found that young children view exemplars with extreme values of characteristic features (e.g., the very fastest cheetah) as most representative of familiar biological categories; the tendency to view average exemplars in this manner (e.g., the average-speeded cheetah) emerged slowly across age. Study 3 examined the mechanisms underlying these judgments, and found that participants of all ages viewed extreme exemplars as representative of novel animal categories when they learned that the variable features fulfilled category-specific adaptive needs, but not otherwise. Implications for developmental changes in conceptual structure and biological reasoning are discussed.

The Magic of Mechanism: Explanation-Based Instruction on Counterintuitive Concepts in Early Childhood

Common-sense intuitions can be useful guides in everyday life and problem solving. However, they can also impede formal science learning and provide the basis for robust scientific misconceptions. Addressing such misconceptions has generally been viewed as the province of secondary schooling. However, in this article, I argue that for a set of foundational but highly counterintuitive ideas (e.g., evolution by natural selection), coherent causal-explanatory instruction-instruction that emphasizes the multifaceted mechanisms underpinning natural phenomena-should be initiated much sooner, in early elementary school. This proposal is motivated by various findings from research in the cognitive, developmental, and learning sciences. For example, it has been shown that explanatory biases that render students susceptible to intuitively based scientific misconceptions emerge early in development. Furthermore, findings also reveal that once developed, such misconceptions are not revised and replaced by subsequently learned scientific theories but competitively coexist alongside them. Taken together, this research, along with studies revealing the viability of early coherent explanation-based instruction on counterintuitive theories, have significant implications for the timing, structure, and scope of early science education.

Cognitive Constraints Shape Public Debate on the Risks of Synthetic Biology

We consider efforts to understand public perceptions of synthetic biology, describing a novel cognitive science approach indicating that cognitive biases constrain risk perceptions of synthetic biology. We discuss the implications of these findings and outline how they may be harnessed to improve the quality of public debate.

Undergraduate Biology Students’ Teleological and Essentialist Misconceptions

Research in developmental psychology has shown that deeply-rooted, intuitive ways of thinking, such as design teleology and psychological essentialism, impact children’s scientific explanations about natural phenomena. Similarly, biology education researchers have found that students often hold inaccurate conceptions about natural phenomena, which often relate to these intuitions. In order to further investigate the relation between students’ conceptions and intuitions, we conducted a study with 93 first year undergraduate students in biology. They were asked to express their level of agreement or disagreement with six misconception statements and to explain their choices in a two-tier test. Results showed a tendency for students to agree with teleological and essentialist misconceptions. However, no association was found between students’ teleological and essentialist conceptions as expressed in their agreement or disagreement with the various misconception statements. Moreover, we found evidence of a variable consistency across students’ answers depending on the misconception considered, which indicates that item features and contexts may have an effect on students’ answers. All together, these findings provide evidence for considerable persistence of teleological and essentialist misconceptions among students. We suggest future directions for thinking, studying, and analyzing students’ conceptions about biological phenomena.

Challenging Cognitive Construals: A Dynamic Alternative to Stable Misconceptions

In biology education research, it has been common to model cognition in terms of relatively stable knowledge structures (e.g., mental models, alternative frameworks, deeply held misconceptions). For example, John D. Coley and Kimberley D. Tanner recently proposed that many student difficulties in biology stem from underlying cognitive frameworks called cognitive construals ( CBE-Life Sciences Education, 11[3], 209-215 [2012]; CBE-Life Sciences Education, 14[1], ar8 [2015]). They argued that three such frameworks-teleology, anthropocentrism, and essentialism-cause undergraduate students to hold a range of misconceptions about the biological world. Our purpose in this article is to present an alternative perspective that considers student thinking to be dynamic and context sensitive. Using the example of cognitive construals, we argue that a dynamic perspective creates a burden of proof for claims of cognitive stability-to demonstrate that patterns of thinking are indeed stable across contexts. To illustrate our argument, we report on the results of a study designed to explore the stability of students' apparent teleological, anthropocentric, and essentialist thinking. Our results are inconsistent with framework models. We propose instead that response patterns stem from students' context-specific interpretations of the statements, consistent with dynamic models of cognition. Building on these preliminary findings, we discuss the implications of a dynamic view of cognition for biology education research and biology instruction.

A field guide for teaching evolution in the social sciences

The theory of evolution by natural selection has begun to revolutionize our understanding of perception, cognition, language, social behavior, and cultural practices. Despite the centrality of evolutionary theory to the social sciences, many students, teachers, and even scientists struggle to understand how natural selection works. Our goal is to provide a field guide for social scientists on teaching evolution, based on research in cognitive psychology, developmental psychology, and education. We synthesize what is known about the psychological obstacles to understanding evolution, methods for assessing evolution understanding, and pedagogical strategies for improving evolution understanding. We review what is known about teaching evolution about nonhuman species and then explore implications of these findings for the teaching of evolution about humans. By leveraging our knowledge of how to teach evolution in general, we hope to motivate and equip social scientists to begin teaching evolution in the context of their own field.

How language shapes the cultural inheritance of categories

It is widely recognized that language plays a key role in the transmission of human culture, but relatively little is known about the mechanisms by which language simultaneously encourages both cultural stability and cultural innovation. This paper examines this issue by focusing on the use of language to transmit categories, focusing on two universal devices: labels (e.g., shark, woman) and generics (e.g., "sharks attack swimmers"; "women are nurturing"). We propose that labels and generics each assume two key principles: norms and essentialism. The normative assumption permits transmission of category information with great fidelity, whereas essentialism invites innovation by means of an open-ended, placeholder structure. Additionally, we sketch out how labels and generics aid in conceptual alignment and the progressive "looping" between categories and cultural practices. In this way, human language is a technology that enhances and expands the categorization capacities that we share with other animals.

How does social essentialism affect the development of inter-group relations?

Psychological essentialism is a pervasive conceptual bias to view categories as reflecting something deep, stable, and informative about their members. Scholars from diverse disciplines have long theorized that psychological essentialism has negative ramifications for inter-group relations, yet little previous empirical work has experimentally tested the social implications of essentialist beliefs. Three studies (N = 127, ages 4.5-6) found that experimentally inducing essentialist beliefs about a novel social category led children to share fewer resources with category members, but did not lead to the out-group dislike that defines social prejudice. These findings indicate that essentialism negatively influences some key components of inter-group relations, but does not lead directly to the development of prejudice.