Facilitation and suppression of human loss-avoidance by signaled, unavoidable loss

A 15-sec stimulus followed by unavoidable monetary loss was presented to human subjects who were avoiding loss on a free-operant schedule. As has been observed in studies where shock is the aversive event, initial reactions to the pre-loss stimulus were transient increases in overall and stimulus rates. Unlike shock studies, continued training produced decreased rates, in the presence of the 15-sec stimulus, which were maintained in two of three subjects. Subsequent observations indicated that lowered rates were a function of the subject's rate of avoidance responding, the duration of the stimulus, and the scheduling of avoidable losses. Increasing the duration of the stimulus eliminated lowered rates in the presence of the stimulus and subsequent exposures to conditions which previously produced lowered rates did not result in recovery of the phenomenon. Introduction of the pre-loss stimulus on an extinction baseline (avoidable losses were omitted), however, reinstituted lowered rates. It is proposed that the pre-loss stimulus assumed discriminative control over low rates because responding in the presence of the stimulus was ineffective in avoiding the unavoidable loss. Recovery from lowered rates is attributed to the occurrence of avoidable losses during the stimulus period, and maintenance of lowered rates on the extinction schedule to the omission of such avoidable losses.     

Self-concept in educable mentally retarded and emotionally handicapped children

A total of 48 educable mentally retarded (EMR) and emotionally handicapped (EH) children ( \(\overline {CA} \) =137.7 months) were pretested on Coopersmith's Self-Esteem Inventory (SEI), Nowicki-Strickland's Locus of Control Scale for Children (LCSC), and 3 behavioral measures: (1) risk-taking, (2) a chance/skill task, and (3) delay of gratification. One group of 12 children from each population was then exposed to either a self-confident or a control model. After exposure, Ss were given an opportunity to perform successfully on an ambiguous task and answer questions about their success, and were readministered the SEI, LCSC, and 3 behavioral choices. Correlational analyses of pretreatment data revealed significant relationships between defensiveness and LCSC, SEI, and delay of gratification and a near-significant relationship between LCSC and SEI. EMR and EH Ss were both lower on self-esteem than the general population, while EMR Ss were more defensive, more external, and less likely to delay gratification than EH Ss. Both treated groups matched more of the behavioral choices than the control groups, while only treated EH Ss were more likely to attribute their success to internal causes. It was concluded that EMR and EH children differ in self-concept development and that future attempts to modify self-concept should include greater modeling exposure as well as increased opportunity for performance with its resultant feedback.     

The quantitative measure of pattern representation in images using orientation-specific color aftereffects

A quantitative method is developed for assessing the quality of pattern information in imagery, using the magnitude of color aftereffects as an objective index. Subjects were given instructions to project imagined bar patterns of particular width and orientation onto adapting color fields, in such a manner as to simulate standard conditions for establishing the McCollough effect. Our control procedures indicate that the resulting orientation-specific complementary color aftereffects cannot be attributed to the conditioning of particular directions of eye scanning movements to color processing during adaptation, or to other possible sources of experimental bias. Furthermore, subjects who rated themselves prior to the adaptation procedure as having relatively vivid imagery showed significantly larger aftereffects than those who reported having relatively low imagery. These results not only provide an important confirmation of our earlier finding that imagination can replace physical pattern information in the formation of basic color-feature associations in the human visual system, but also demonstrate that these aftereffects can provide a practical measure of the fidelity of pattern representation in visual images.     

Laterally induced impedance effects in vision

A linear integral equation for a system of mutually impeding points is developed and solved explicitly. Particular solutions are shown to be subharmonic functions for a large class of stimuli. Specialized forms of the general equation presented in this paper occur within a number of mathematical models of Mach bands. In addition to these known spatial properties, our results also show that the time course of this basic equation may be useful in developing models of transient neural activity as well as of temporal psychophysical phenomena, such as the Broca-Sulzer effect. Further, a spatial transfer function much like the low-frequency cutoff of empirically derived modulation transfer functions follows directly from our basic integral equation if the additional assumption of spatial homogeneity is imposed.     

The tonic immobility reaction in chickens: Response characteristics and methodology

A total of 379 chickens were run in five studies to assess the effect of different procedures on tonic immobility and to measure some of the response components of the reaction. The optimal period of manual restraint, by way of producing the most durable immobility response, was found to be 15 sec, and pretest holding conditions were shown to exert a significant influence on the reaction in naive birds. Birds who defecated during immobility or shortly after termination, remained immobile longer than comparable nondefecators. Duration of eye closure and latency of vocalization were also found to be good predictors of the duration of an immobility episode.     

Moderating Effects of Mothers' Attribution on the Relationships Between Their Affect and Parenting Behaviors and Children's Aggressive Behaviors

We examined Bugental's (1987) transactional model in the context of the relationships between aggressive children and their mothers. Based on Bugental's model, it was hypothesized that mothers who possessed the attributional style of low self-control and high child-control over hypothetical child care failure were more likely to manifest negative affect and negative parenting behaviors toward their child, only when their child is aggressive. Children's aggressive behavior was assessed via mothers' and teachers' ratings. Sixty-six children and their mothers served as subjects. Our results provided support for mothers' negative affect when using teachers' rating of children's aggressive behaviors only. Possible explanations for the differential results obtained using mothers' and teachers' ratings of children's aggressive behaviors were discussed.     

Task switching and the measurement of “switch costs”

The measurement of “switch costs” is held to be of interest because, as is widely believed, they may reflect the control processes that are engaged when subjects switch between two (or more) competing tasks. [In task-switching experiments, the reaction time (RT) switch cost is typically measured as the difference in RT between switch and non-switch (repeat) trials.] In this report we focus on the RT switch costs that remain even after the subject has had some time to prepare for the shift of task, when the switch cost may be approximately asymptotic (so-called residual switch costs). Three experiments are presented. All three experiments used Stroop colour/word, and neutral stimuli. Participants performed the two tasks of word-reading and colour-naming in a regular, double alternation, using the “alternating runs” paradigm (R. D. Rogers & S. Monsell, 1995). The experiments were designed to test the hypothesis that RT switch costs depend on a form of proactive interference (PI) arising from the performance of a prior, competing task. A. Allport, E. A. Styles and S. Hsieh (1994) suggested that these PI effects resulted from “task-set inertia”, that is, the persisting activation-suppression of competing task-sets, or competing task-processing pathways. The results confirmed the existence of long-lasting PI from the competing task as a major contributor to switch costs. Non-switch trials, used as the baseline in the measurement of switch costs, were also shown to be strongly affected by similar PI effects. However, task-set inertia was not sufficient to account for these results. The results appeared inconsistent also with all other previous models of task switching. A new hypothesis to explain these between-task interference effects was developed, based on the stimulus-triggered retrieval of competing stimulus-response (S-R) associations, acquired (or strengthened) in earlier trials. Consistent with this retrieval hypothesis, switch costs were shown to depend primarily on the S-R characteristics of the preceding task (the task that was switched from) rather than the upcoming task. Further, the effects of the other, competing task were found to persist over many successive switching trials, affecting switch costs long after the stimulus overlap (and hence the principal S-R competition) between the current tasks had been removed. Switch costs were also found to be affected by recent, item-specific experience with a given stimulus, in either the same or the competing task. Finally, the results showed that switch costs were massively affected by the ratio of the number of prior trials, in response to the same stimuli, that had implemented either the currently intended or the competing S-R mappings. None of these effects are predicted by current models of residual switch costs, which appeal to the differences in control processes assumed to be engaged in switch versus non-switch trials. Received: 31 March 1999 / Accepted: 23 July 1999     

Covert and overt rehearsal and elaboration during treatment in the development of assertive behavior

The present investigation examined the effects of covert and overt rehearsal and client elaboration of situations designed to train assertive behavior. Nonassertive clients (n = 61) received one of four treatments resulting from the 2 × 2 factorial combination of Modality of Rehearsal (covert vs overt) and Elaboration (elaboration vs no elaboration of training situations). A delayed-treatment group was included in the design to serve as a no-treatment control condition before subjects were assigned randomly to one of the above treatments. Treatment led to significant improvements on self-report and behavioral measures of assertiveness and self-efficacy. Covert and overt rehearsal were equally effective. However, elaboration of training situations significantly enhanced the effects of covert and overt rehearsal. Treatment effects were maintained up to a 6-month follow-up, transferred to novel role-playing situations, and brought clients within the range of other subjects (n = 45) who regarded themselves as adept in social situations requiring assertive behavior and who had not sought treatment.