The effect of context on the structure of categories

Three experiments examined the effect of context on the representativeness ordering of exemplars of a category. Experiments 1 and 2 employed an online reading time paradigm to examine the effect of context on the time it takes to establish an anaphoric reference between an exemplar and a category term. Experiment 1 demonstrated that context can change the relation between a category term and an exemplar at the time of comprehension. Experiment 2 showed that category terms presented in context generate graded goodness-of-example distributions of exemplars that are different from the distributions generated in the absence of explicit context. These distributions cannot be derived by assuming that the exemplar most strongly suggested by the context serves as the category representation. Experiment 3 employed a membership verification paradigm. Response time was found to be a function of degree of relatedness to the contextdependent category representation. Typicality, as determined in the absence of explicit context, had no effect on decision time. Several models, including some extensions of current semantic memory theories, are developed to account for the results of these experiments.     

On the adequacy of prototype theory as a theory of concepts

Prototype theory construes membership in a concept's extension as graded, determined by similarity to the concept's “best” exemplar (or by some other measure of central tendency). The present paper is concerned with the compatibility of this view of concept membership with two criteria of adequacy for theories of concepts. The first criterion concerns the relationship between complex concepts and their conceptual constituents. The second concerns the truth conditions for thoughts corresponding to simple inclusions.     

Comprehension of gerundive constructions by Broca's aphasics

Eleven diagnosed Broca's aphasics were tested for comprehension of sentences containing gerundive constructions. Results showed that, as a group, these patients were sensitive to grammatical distinctions signaled by “function” words, contrary to the predictions of some current theories about the specific deficits exhibited in this syndrome. Further analysis showed that the patients fell into two subgroups, one which exhibited sensitivity to the distinctions in normal grammar, and another which exhibited no sensitivity to such distinctions. This suggests that the syndrome may have different manifestations in different populations—patient age is suggested as a possible means for distinguishing the two groups. Suggestions for further research into the nature of the comprehension deficits exhibited by Broca's aphasics are made.     

Evolutionary Ethics: What Can We Learn From from the Past?

In this paper I look at the question of the derivation of ethics from evolutionary biology, and I do so by considering both historical attempts to make such a derivation and contemporary work.     

The nature of curiosity in children

This study examined several behaviors claimed to reflect curiosity in order to determine whether there are one or more types of curiosity. A secondary purpose was to examine the relations between the one or more types of curiosity and sex, social class, intelligence, achievement level, and ratings of personality traits. In two individual sessions 84 American first-grade boys and girls were administered five tasks which measured observation of complex and simple stimuli, preference of complex and simple stimuli, preference for the unknown, structure of meaning, and object exploration. A normalized Varimax factor analysis allowed the extraction of five factors: manipulatory curiosity, perceptual curiosity, conceptual curiosity, curiosity about the complex, and adjustive-reactive curiosity. Only the first factor was related to a demographic variable, sex. The nature of the factors and their theoretical and practical significance are discussed.     

Resolution of complex decisional conflicts as a function of degree of avoidance

The relationship between difficulty of conflict resolution and degree of avoidance was investigated in three experiments using imaginary conflicts consisting of choosing to have more or less of certain personal characteristics. Double forms of conflict were used to control for complexity of choice. In the first experiment, it was found that double approach-approach conflicts were resolved more quickly than double approach-avoidance which in turn were faster than double avoidance-avoidance. The second experiment showed a similar result using scaled judgments of subjective difficulty. In the third experiment, the basic finding was shown to be independent of situational pressure by permitting an undecided choice. The basic finding was also shown to be independent of individual differences in social desirability.     

Effects of self-awareness on antinormative behavior

Based on Zimbardo's (1970) theory of deindividuation and Duval and Wicklund's (1972) theory of “objective self-awareness” it was predicted that self-awareness would lead to a decrease in transgressive behavior. Subjects were either made self-aware (seated in front of a mirror listening to their own tape-recorded voice) or nonself-aware (seated to the side of the mirror listening to another's voice) and were given an opportunity to cheat on an anagrams test. Significantly more cheated in the nonself-aware condition (71%) than in the self-aware condition (7%). The results support the basic premise of deindividuation theory that self-awareness influences impulsive, counternormative behavior and suggest that an integration of the theories of deindividuation and objective self-awareness is possible.     

Size-distance perception in preschool children.

Children between three and six years of age matched the “apparent” and “real” size of familiar and unfamiliar objects 3, 6, or 9 feet away. Prior to the experimental sessions, the children were divided into two groups: (a) those who could distinguish the phenomenal from the real sizes of the arcs in the Jastrow illusion (the “Realists”) and (b) those who could not (the “Phenomenalists”). The results suggest that all children perceived size constancy up to distances of 9 feet solely on the basis of visual information.