Sensitivity in spectral structures

Invariance of matching is shown to be necessary and sufficient for the existence of sensitivity functions that are unique up to multiplication by arbitrary positive real numbers. Examples from auditory and visual psychophysics are discussed.     

A process analysis of the effects of performance-contingent rewards on intrinsic motivation

In this study, the effects of performance-contingent rewards on intrinsic motivation were examined in comparison to no-reward controls receiving identical performance feedback. A path analytic process analysis was conducted to examine the mediation of reward effects on subsequent task interest. It was hypothesized that competence valuation, or the personal importance of doing well, would be an important mediator of interest in situations where performance feedback was available. Rewards were predicted to affect interest by influencing an individual's valuation of competence, and by altering the competence valuation mediation process. In addition, achievement orientation was hypothesized to interact with reward in affecting importance and the mediation process. Prior to performing an interesting puzzle, high school students were offered a performance-contingent reward, and then indicated how personally important it was to do well. After doing three puzzles, all subjects received positive feedback regarding their performance. Multiple regression analyses indicated that importance was affected by the experimental variables, and had a positive causal impact on subsequent intrinsic motivation. It was found that the promise of performance-contingent reward positively affected importance for low achievers relative to high achievers, and that the mediation of subsequent intrinsic interest by importance differed according to reward by achievement combinations. Additionally, a direct effect revealed that performance-contingent rewards significantly enhanced interest, relative to no-reward controls receiving identical performance feedback.     

Intergroup contact: The typical member and the exception to the rule

Three studies examined the role of the perceived typicalness of an out-group member on her effectiveness in improving evaluations of her group. Subjects were students at two adjacent colleges. In the first study they interacted with a member of the out-group college. The interaction was either pleasant or unpleasant, and the contact person either confirmed or disconfirmed several stereotypes of the out-group (typicalness manipulation). Subjects evaluated the out-group most favorably when they interacted with the typical-pleasant member of the out-group. The second study demonstrated that contact with a highly typical member is not beneficial if her typicalness is based on stereotypes that reflect negatively on the subject's in-group. Several explanations of the typicalness findings were considered in a third study. Support was found for the hypothesis that the more typical member is perceived to be more predictive of the personality and actions of other out-group members.     

Semantic and visual memory codes in learning disabled readers

Two experiments investigated whether learning disabled readers' impaired recall is due to multiple coding deficiencies. In Experiment 1, learning disabled and skilled readers viewed nonsense pictures without names or with either relevant or irrelevant names with respect to the distinctive characteristics of the picture. Both types of names improved recall of nondisabled readers, while learning disabled readers exhibited better recall for unnamed pictures. No significant difference in recall was found between name training (relevant, irrelevant) conditions within reading groups. In Experiment 2, both reading groups participated in recall training for complex visual forms labeled with unrelated words, hierarchically related words, or without labels. A subsequent reproduction transfer task showed a facilitation in performance in skilled readers due to labeling, with learning disabled readers exhibiting better reproduction for unnamed pictures. Measures of output organization (clustering) indicated that recall is related to the development of superordinate categories. The results suggest that learning disabled children's reading difficulties are due to an inability to activate a semantic representation that interconnects visual and verbal codes.     

Abnormal and normal obsessions—A replication

A replication of previous work on the incidence and characteristics of intrusive cognitions in non-clinical populations was carried out. The results closely reflected those obtained previously, and further relationships between variables were found. The importance of distinguishing between- and within-S data is stressed.     

Physiological and psychological effects of acute intentional hyperventilation

Research is reviewed which suggests that hyperventilation syndrome is an underdiagnosed disorder for the presentation of many patients experiencing apparent anxiety states. In a test of this hypothesis, 21 normal individuals (9 female) underwent a 2 min period of intentional hyperventilation following a 10 min baseline phase. Hyperventilation was accompanied by increased subjective anxiety and tachycardia, and indications of peripheral vasoconstriction. Following hyperventilation, Ss experienced increased levels of state anxiety and perceived autonomic arousal, as indexed by self-report instruments. These results support the hypothesis that undiagnosed hyperventilatory phenomena may be etiologically implicated in states of pathologic anxiety.     

Delayed reinforcement as an indiscriminable contingency in verbal/nonverbal correspondence training

We investigated the programming of generalization and maintenance of correspondence between verbal and nonverbal behavior in a preschool setting. Four children participated in a series of multiple-baseline designs. In Experiment 1, delayed reinforcement of verbal behavior effectively controlled maintenance of correspondence with previously trained responses and also resulted in generalization of correspondence to one untrained response. As the latter effect was limited, Experiment 2 was a further assessment of the effects of delayed reinforcement of generalization of correspondence to untrained responses, and consistent generalization was shown. Experiment 2 also showed that generalization, if lost, could be recovered through use of "booster training," in which the original contingencies were reinstated for a brief period. Experiment 3 provided replications, with two additional children, of the effects of delayed reinforcement on maintenance of correspondence. Results are discussed in terms of using delayed reinforcement as an indiscriminable contingency.     

Infant sensitivity to figural coherence in biomechanical motions

Two experiments assessed infant sensitivity to figural coherence in point-light displays moving as if attached to the major joints of a walking person. Experiment 1 tested whether 3- and 5-month-old infants could discriminate between upright and inverted versions of the walker in both moving and static displays. Using an infant-control habituation paradigm, it was found that both ages discriminated the moving but not the static displays. Experiment 2 was designed to clarify whether or not structural invariants were extracted from these displays. The results revealed that (1) moving point-light displays with equivalent motions but different topographic relations were discriminated while (2) static versions were not, and (3) arrays that varied in the amount of motion present in different portions of the display were also not discriminated. These results are interpreted as indicating that young infants are sensitive to figural coherence in displays of biomechanical motion.