Elizabeth B. Lynch

Categorization and Reasoning among Tree Experts: Do All Roads Lead to Rome?☆

To what degree do conceptual systems reflect universal patterns of featural covariation in the world (similarity) or universal organizing principles of mind, and to what degree do they reflect specific goals, theories, and beliefs of the categorizer? This question was addressed in experiments concerned with categorization and reasoning among different types of tree experts (e.g., taxonomists, landscape workers, parks maintenance personnel). The results show an intriguing pattern of similarities and differences. Differences in sorting between taxonomists and maintenance workers reflect differences in weighting of morphological features. Landscape workers, in contrast, sort trees into goal-derived categories based on utilitarian concerns. These sorting patterns carry over into category-based reasoning for the taxonomists and maintenance personnel but not the landscape workers. These generalizations interact with taxonomic rank and suggest that the genus (or folk generic) level is relatively and in some cases absolutely privileged. Implications of these findings for theories of categorization are discussed.

Tall is typical: central tendency, ideal dimensions, and graded category structure among tree experts and novices.

Many accounts of categorization equate goodness-of-example with central tendency for common taxonomic categories; the best examples of a category are average members#x2014;those that are most similar to most other category members. In the present study, we asked 24 tree experts and 20 novices to rate goodness-of-example for a sample of 48 trees and found (1) that the internal structure of the categorytree differed between novices and experts and (2) that central tendency did not determine goodnessof-example ratings for either group. For novices, familiarity determined goodness-of-example ratings. For experts, the “ideal” dimensions of height and weediness, rather than average similarity to other trees, were the primary predictors of goodness-of-example ratings for experts. The best examples oftree were not species of average height, but of extreme height. The worst examples were the weediest trees. We also found systematic differences in predictors of goodness-of-example as a function of type of expertise. We argue that the internal structure of taxonomic categories can be shaped by goal-related experience and is not necessarily a reflection of the attributional structure of the environment. Implications for models of category structure and category learning are discussed.

Concepts do more than categorize

Concepts underlie all higher-level cognitive processes. Until recently, the study of concepts has largely been the study of categorization. But categorization is only one conceptual function among several. We argue that concepts cannot be understood sufficiently through the study of categorization, or any other function, in isolation, for two important reasons. First, concepts serve multiple functions which interact to affect conceptual structure and processing. Second, studying a single function in isolation encourages one to see cognitive processes that are particular to each function, but discourages the discovery of processes that are common to multiple functions. For these two reasons, we suggest that concepts should instead be studied in the context of a system of interrelated functions.

FOLKBIOLOGY DOESN'T COME FROM FOLKPSYCHOLOGY: EVIDENCE FROM YUKATEK MAYA IN CROSS-CULTURAL PERSPECTIVE

Nearly all psychological research on basic cognitive processes of category formation and reasoning uses sample populations associated with large research institutions in technologically-advanced societies. Lopsided attention to a select participant pool risks biasing interpretation, no matter how large the sample or how statistically reliable the results. The experiments in this article address this limitation. Earlier research with urban-USA children suggests that biological concepts are (1) thoroughly enmeshed with their notions of naive psychology, and (2) strikingly human-centered. Thus, if children are to develop a causally appropriate model of biology, in which humans are seen as simply one animal among many, they must undergo fundamental conceptual change. Such change supposedly occurs between 7 and 10 years of age, when the human-centered view is discarded. The experiments reported here with Yukatek Maya speakers challenge the empirical generality and theoretical importance of these claims. Part 1 shows that young Maya children do not anthropocentrically interpret the biological world. The anthropocentric bias of American children appears to owe to a lack of cultural familiarity with non-human biological kinds, not to initial causal understanding of folkbiology as such. Part 2 shows that by age of 4-5 (the earliest age tested in this regard) Yukatek Maya children employ a concept of innate species potential or underlying essence much as urban American children seem to, namely, as an inferential framework for understanding the affiliation of an organism to a biological species, and for projecting known and unknown biological properties to organisms in the face of uncertainty. Together, these experiments indicate that folkpsychology cannot be the initial source of folkbiology. They also underscore the possibility of a species-wide and domain-specific basis for acquiring knowledge about the living world that is constrained and modified but not caused or created by prior non-biological thinking and subsequent cultural experience.

The Relation Between Body Size Perception and Change in Body Mass Index Over 13 Years The Coronary Artery Risk Development in Young Adults (CARDIA) Study

The authors assessed associations of body size perception and weight change over 13 years in black men and women and white men and women from the Coronary Artery Risk Development in Young Adults (CARDIA) Study (1992-2005). The perceptions of self and ideal body size were measured by using the Stunkard 9-figure scale at the year 7 examination (1992-1993). Figures were classified into underweight, normal weight, overweight, and obese. Self-ideal discrepancy yielded 4 body size satisfaction categories. Body mass index (BMI) (measured at years 7, 10, 15, and 20) was the dependent variable in gender-specific adjusted multiple regression models stratified by year 7 BMI. Obese women who perceived themselves as obese lost 0.09 BMI units annually, while those who perceived themselves as normal weight gained 0.31 units annually (P = 0.0005); obese women who considered their body size much too large had less annual weight gain than did those who considered their body size a bit too large (0.21 vs. 0.38 BMI units; P = 0.009). Obese women with overweight ideal body size gained less weight annually than did those with normal weight ideal body size (0.12 vs. 0.27 BMI units; P = 0.04). Results for men showed fewer and weaker associations. When obese women perceive themselves as obese and feel that their body size is too large, they gain less weight over time.

Delay discounting and intake of ready-to-eat and away-from-home foods in overweight and obese women

A shift from home-prepared to away-from-home and ready-to-eat foods has occurred in recent decades, which has implications for obesity and health. This study tested whether delay discounting, a facet of impulsivity reflecting sensitivity to immediate reward, is associated with the frequency of consumption and typical amount consumed of home-prepared, away-from-home, and ready-to-eat foods among overweight and obese women. Seventy-eight participants completed a binary choice task assessing discounting of delayed monetary rewards. Nutrient analysis of weighed food records characterized dietary intake over seven consecutive days. Foods were categorized as home-prepared, away-from-home, or ready-to-eat by a registered dietitian from information provided by participants. Delay discounting was not associated with the frequency of consuming home-prepared, away-from-home, and ready-to-eat foods as reflected in the percentages of recorded foods or total energy intake from each category. However, once consuming away-from-home and ready-to-eat foods (but not home-prepared foods), impulsive women consumed more energy than less impulsive women. Exploratory analyses indicated that more impulsive women chose away-from-home foods with a higher energy density (kcal/g). Impulsivity was associated with the quantity of away-from-home and ready-to-eat foods consumed, but not the frequency of their consumption. Home food preparation may be critical to weight control for impulsive individuals.

Setters and samoyeds: the emergence of subordinate level categories as a basis for inductive inference in preschool-age children.

Basic level categories are a rich source of inductive inference for children and adults. These 3 experiments examine how preschool-age children partition their inductively rich basic level categories to form subordinate level categories and whether these have inductive potential. Children were taught a novel property about an individual member of a familiar basic level category (e.g., a collie). Then, childrens extensions of that property to other objects from the same subordinate (e.g., other collies), basic (e.g., other dogs), and superordinate (e.g., other animals) level categories were examined. The results suggest (a) that contrastive information promotes the emergence of subordinate categories as a basis of inductive inference and (b) that newly established subordinate categories can retain their inductive potential in subsequent reasoning over a weeks time.

Explanatory models of illness: A study of within-culture variation

The current studies explore causal models of heart attack and depression generated from American healers whom use distinct explanatory frameworks. Causal chains leading to two illnesses, heart attack and depression, were elicited from participant groups: registered nurses (RNs), energy healers, RN energy healers, and undergraduates. The domain-specificity hypothesis predicted that psycho-social and physical causes would not interact in illness models. Across illnesses, RNs and undergraduates rarely cited interactions between mental and physical causes, consistent with the domain specificity hypothesis. In contrast, energy healers frequently mentioned interactions. Study 2 showed that these differences were not due to salience. These results suggest that domain-specificity theory is supported for groups with extensive exposure to western medicine but does not explain energy models of illness. Implications for other cultural models of illness are discussed.

Body size perception among African American women.

OBJECTIVE To assess body size perception among African American women using cultural definitions of body size terms. METHODS Sixty-nine African American women classified Body Image Scale figures as overweight, obese, and too fat, and independently selected the figure they considered closest to their current body size. RESULTS Body size classifications of figures did not vary by participant weight status. Overweight figures were not considered too fat. For 86% of overweight (body mass index [BMI], 25-29.9) women and 40% of obese (BMI > 30) women, the self figure was not defined as overweight, obese, or too fat. Among participants with BMI ≥ 35, 65% did not classify their self figure as obese and 29% did not classify their self figure as overweight. CONCLUSIONS AND IMPLICATIONS The difference between cultural (folk) and medical definitions of body size terms may serve as a barrier to effective communication between patients and providers about health effects of excess adiposity.

A Self-Management Intervention for African Americans With Comorbid Diabetes and Hypertension: A Pilot Randomized Controlled Trial

Introduction The objective of this pilot 6-month randomized controlled trial was to determine the effectiveness of an intensive, community-based, group intervention that focused on diet, physical activity, and peer support for reducing weight among urban-dwelling African Americans with comorbid type 2 diabetes and hypertension. Methods Sixty-one participants were randomized into an intervention or control group. The 6-month intervention consisted of 18 group sessions led by a dietitian in a community setting and weekly telephone calls from a peer supporter. The intervention featured culturally tailored nutrition education, behavioral skills training, and social support focused on changes to diet and physical activity. The control group consisted of two 3-hour group sessions of diabetes self-management education taught by a community health worker. Outcome measures were assessed at baseline and 6 months. The primary outcome was achievement of a 5% weight reduction at 6 months. A secondary outcome was achievement of a 0.5 percentage-point reduction in hemoglobin A1c (HbA1c). Results Groups did not differ in achievement of the weight-loss goal. Intervention participants lost a mean of 2.8 kg (P = .01); control participants did not lose a significant amount of weight. A greater proportion of intervention (50.0%) than control (21.4%) participants reduced HbA1c by 0.5 percentage points or more at 6 months (P = .03). Conclusion The intervention was more effective than usual care (short-term diabetes education) at improving glycemic control, but not weight, in low-income African Americans with comorbid diabetes and hypertension. A community-based 6-month group class with culturally tailored education, behavioral skills training, and peer support can lead to a clinically significant reduction in HbA1c.