Acquisition of basic object categories

Two implications of best-example theory for category acquisition were considered. The first is that categories which people acquire based on initial exposure to good exemplars should be learned more easily and (at first) more accurately than categories based on initial exposure to poor exemplars. The second is that people should generally learn that the best exemplars are category members, before learning that the poor exemplars are category members. These implications are based on the premise that people generalize based on similarity, and that the best example has maximal within-category similarity and minimal extra-category similarity, while the poor examples have minimal within-category similarity and relatively high extra-category similarity. Both implications were strongly supported by the present research. It was also found that when pressure to communicate was removed, comprehension and production of category names were virtually identical. The predictions of best-example theory concerning the conceptual structures underlying the words used by children who are just beginning to talk were discussed briefly. This research also allowed the replication of several important categorization results which had previously been found with real-world categories, with a set of artificial concrete object categories.     

Attention and automaticity in Stroop and priming tasks: Theory and data

Three major variables identified with attention and automaticity in the priming paradigm are shown to have parallel effects in the Stroop paradigm. A model is developed to explain the effects in both paradigms in terms of a single decision process that combines evidence from several sources (e.g., habitual associations and temporary contingencies between the prime and the target or between the unreported and reported dimensions). The model is applied to two Stroop experiments in which the faster two of three stimulus dimensions relate associatively and cue through a frequency manipulation the third, which must be reported. Depending on the direction of the cueing relation, attentional effects enhanced or counteracted automatic (associative) effects, and the attentional effects were stronger with the faster unreported dimension than with the slower one. These results corroborate findings in the priming paradigm and confirm the model. Implications of the results and the model for broader issues are discussed.     

Identifying the speech codes

Models of speech processing typically assume that speech is represented by a succession of codes. In this paper we argue for the psychological validity of a prelexical (phonetic) code and for a postlexical (phonological) code. Whereas phonetic codes are computed directly from an analysis of input acoustic information, phonological codes are derived from information made available subsequent to the perception of higher order (word) units. The results of four experiments described here indicate that listeners can gain access to, or identify, entities at both of these levels. In these studies listeners were presented with sentences and were asked to respond when a particular word-initial target phoneme was detected (phoneme monitoring). In the first three experiments speed of lexical access was manipulated by varying the lexical status (word/nonword) or frequency (high/low) of a word in the critical sentences. Reaction times (RTs) to target phonemes were unaffected by these variables when the target phoneme was on the manipulated word. On the other hand, RTs were substantially affected when the target-bearing word was immediately after the manipulated word. These studies demonstrate that listeners can respond to the prelexical phonetic code. Experiment IV manipulated the transitional probability (high/low) of the target-bearing word and the comprehension test administered to subjects. The results suggest that listeners are more likely to respond to the postlexical phonological code when contextual constraints are present. The comprehension tests did not appear to affect the code to which listeners responded. A “Dual Code” hypothesis is presented to account for the reported findings. According to this hypothesis, listeners can respond to either the phonetic or the phonological code, and various factors (e.g., contextual constraints, memory load, clarity of the input speech signal) influence in predictable ways the code that will be responded to. The Dual Code hypothesis is also used to account for and integrate data gathered with other experimental tasks and to make predictions about the outcome of further studies.     

The demonstration of capacity limitation

The study of divided attention has produced many apparent demonstrations of “capacity limitation.” Possible ambiguities in such demonstrations are considered for three major types of experimental situation: simultaneous inputs with separate responses; choice; and classification. Two issues emerge. First, demonstrations always rest on assumptions about process set, i.e., the set of internal processes by which the task actually is performed. Alternative process sets are considered for situations of each type. Second, a demonstration of capacity limitation is made either by increasing the number of simultaneous processes, or by changing the bias between them. In either case effects unrelated to capacity limitation may influence the results. If several processes contribute to a single response, some performance decrement must accompany an increase in their number, simply through the increased overall chance for error. If the subject is biased toward one alternative in a choice or classification situation, the benefits enjoyed by this alternative may reflect not a preferential allocation of attentional capacity, but simply a willingness to decide in favor of this alternative with relatively little evidence.     

Patterns of desynchrony in agoraphobia: A preliminary report

Changes in heart rate in three moderate to severe agoraphobic women were monitored by a Holter Recorder, used for obtaining portable EKGs. These data were collected before, half-way through, and at the end of a 12 session, group therapy program consisting of exposure and cognitive restructuring while subjects walked, or in one case, were driven along a standard 1.2 km course leading away from the treatment setting. Self-reports of anxiety were collected simultaneously. Despite substantial behavioral improvement in all cases, markedly different patterns of synchrony or desynchrony were noted between heart rate and self-reports of anxiety and substantial increases in heart rate were noted in one subject.     

Anxiety management and applied relaxation in reducing general anxiety

Sixty-three generally anxious subjects were assigned to anxiety management training, applied relaxation training, relaxation-only, placebo and untreated control conditions. After 6 weeks of treatment, anxiety management training led to reductions on a variety of self-report measures of state and trait anxiety and decreases in maladaptive cognitions during a laboratory stress procedure. On several measures, subjects in anxiety management training differed from relaxation-only and placebo subjects as well as untreated controls. However, treatment effects did not extend to performance and physiological measures of anxiety. Applied relaxation training, which in contrast to anxiety management training lacks structured rehearsal involving the recognition and reduction of tension cues during the treatment sessions, resulted in less consistent decreases in measures of general anxiety.     

Some implications of temporal drift in social parameters

Social and political factors often have an effect on the way we perceive and think about particular events. While it is generally acknowledged that these factors are likely to change over time, the implications of such temporal changes for empirical research are not often considered. In this paper, some of these are illustrated by examining data collected from a sequence of studies conducted over a 3-year period (1973–1976). Subjects viewed the same videotaped mock (rape) trial and, prior to experimental manipulations, gave their own personal verdict. An examination of the proportion of mock jurors preferring guilty in each of the studies revealed a drift of 16% (.53 to .69) from 1973–1976. This trend toward harsher judgments was observed for both sexes, with females uniformly more likely than males to favor conviction. Ancillary evidence suggests that the upward drift reflected changes in the perception of rape during that period. The implications of temporal drift in parameter values for empirical research were illustrated by simulating jury size effects using social decision scheme theory (J. H. Davis, Psychological Review, 1973,80, 97–125). The results indicate that the magnitude of theoretical differences due to jury size must have decreased as the probability of an individual guilty vote increased over time. Thus, failures to replicate findings may not be due entirely to sampling error, methodological imprecision, or the like, but to temporal changes in the social phenomenon under investigation.     

A note on the analysis of designs in which subjects receive each stimulus only once

In social psychological experiments, the manipulations of interest are often presented to subjects along with, or as part of, some stimulus. An example would be a manipulation of the verbal label associated with a stimulus photograph, in a person perception study. Ordinarily it is not possible for stimuli to be completely crossed with treatments because subjects cannot be exposed to any stimulus more than once. In such designs it is wise to counterbalance the assignment of stimuli to treatment conditions, but this gives rise to difficulties in the analysis of the experimental data. Data from such designs have frequently been misanalyzed in the published literature. This paper presents a method of constructing a counter-balancing scheme to simplify the analysis, and appropriate methods of analysis for both the simplified and the general case. It is emphasized that stimuli are generally best treated as a random factor in such designs, permitting increased generalizability, but the case where the stimulus factor is fixed is also considered.     

Reducing fears and increasing assertiveness: The role of dissonance reduction

In the research paradigm known as effort justification, people engage in an effortful activity in order to attain a goal. As a result, the goal becomes more attractive. Two experiments were conducted to test the notion that the effort justification sequence can account for the positive changes that result from psychotherapy. In the first experiment, subjects who were afraid to approach a snake underwent one of two types of effortful therapy. One was a modified form of an anxiety-producing therapy known as “implosive therapy”; the other was merely a set of physical exercises. It was reasoned, on the basis of cognitive dissonance theory, that the expenditure of effort would lead to a positive change in the ability to approach the snake but only under conditions of high decision freedom. Half of the subjects in each of the therapy conditions participated with high choice; the other half with low choice. Subjects' improvement in their approach to snakes was assessed. A main effect for decision freedom was predicted and found independently of the type of effort that subjects expended. A second experiment conceptually replicated the findings of the first experiment. Subjects who wanted to become more assertive participated in an effortful, physical exercise therapy or in a modified form of the standard treatment for fear of assertiveness. The results of the 2 × 2 factorial experiment again showed a main effect for decision freedom such that high choice subjects became more assertive. The findings were discussed in terms of dissonance and attribution theories as well as for implications for future consideration of psychotherapy.     

The effects of base rates and individuating information on judgments about another person

Past research suggests that in judging a person's category membership, people largely ignore the population frequency of membership in the category (base rates) in favor of individuating information about the particular person. This study tested the hypothesis that base rates will be utilized to the extent that the usefulness of the individuating information for diagnosing category membership is diminished. Subjects were given problems in which both base rates of membership in each of two categories and individuating information about a target person were presented. Then, in each case, they were asked to assess the probability that the target person belonged to each category. In three sets of problems, the diagnostic usefulness of the individuating information (personality characteristics) was diminished by including individuating information that was either inconsistent or irrelevant, or by increasing the similarity of the two alternative membership categories. In a fourth set of problems, the individualistic information included consistent, relevant personal characteristics and the membership categories were dissimilar. As expected, base rates were used in each of the first three sets of problems but were ignored in the fourth set. The results were interpreted in terms of informational factors that induce a shift away from a habitual, spontaneous reliance on a source of information (e.g., personality traits) for which one has well-developed rules (e.g., intuitive personality theories), and toward a more controlled, deliberate mode of thinking wherein other sources of information (e.g., base rates) are attended to and incorporated into judgment through less frequently used rules (e.g., sampling rules).