Multimodal signal detection: Independent decisions vs. integration

The pooling of information from simultaneous, spatially congruent auditory and visual stimuli is examined in a signal detection task. The paradigm used permits discrimination among a number of models of the decision mechanisms involved in processing multiple component stimuli. Parameter-free predictions are presented for the weighted integration model and for three versions of the independent decisions model. The data support an independent decisions model of the bimodal detection process in which attention is shared equally between modalities.     

Development of strategies for recalling letter sequences

Kindergarten, second-grade, and fourth-grade children (6, 8, and 10 years of age, respectively) were asked to recall letter sequences on a task that required the use of: (a) a verbal strategy; (b) a positional strategy; or (c) either strategy. Additional trials, allowing either strategy, were interspersed among those requiring a verbal or positional strategy; strategy use was determined from performance on these interspersed trials. The results show that children at all grade levels attempted to use a task-appropriate strategy. Performance on the verbal task showed a more marked developmental increase than did performance on the positional task. A second experiment replicated the first with the interspersed trials removed. A third experiment was designed to determine whether letter names interfered with older children's efficient use of a positional strategy. Even with this source of interference removed, the developmental pattern of Experiments 1 and 2 was replicated. There was a Sex by Condition interaction in Experiments 2 and 3 which showed that males do better in the condition requiring a positional strategy, and females do better in the condition requiring a verbal strategy.     

Depression: avoidance learning and physiological correlates in clinical and analog populations

The behavioral and physiological components of depression were investigated in two experiments comparing eight student and seven non-student depressed females with an equal number of students and non-student controls on avoidance tasks and electrodermal responsivity to an aversive audiotape. Avoidance behavior was assessed in both active and passive paradigms where the correct response or response suppression, respectively, function to avoid a noxious buzzer. Physiological activity and reactivity were compared using measurements of skin resistance level and SRR fluctuations during resting and aversive tape periods. It was found that the depressed groups showed inferior active and superior passive avoidance learning as compared to controls. Depressed subjects were also more emotionally responsive (showed a greater number of SRR) during presentation of the audiotape. A passive avoidance model for depression is suggested for the explanation of the phenomena observed. A distinct difference was also found between student and non-student populations. The utility of college student analogs for depression is questioned.     

On the development of communicative understandings: An early strategy for interpreting and responding to messages

Young children's apparently sophisticated understanding of language is explained by a simple heuristic which produces responses fortuitously appropriate to many of the messages directed to them. Specifically, the strategy recruits action responses to language unless some element, either linguistic or nonlinguistic, indicates otherwise. Two experiments tested for the existence of the heuristic by examining the responses of children, 19–34 months of age, to sentences susceptible of more than one interpretation. In the first experiment such sentences were spoken in as neutral a context as possible. In the second, the same sorts of sentences were presented in contexts supporting either action or informing responses. The results of both experiments indicate that young children interpret and respond to language in terms of an action-based strategy. Moreover, the observed effects of context show that even young children engage in a continuous, context-sensitive process of interpretation. The data are discussed with regard to speech act theory and its role in a developmental theory of understanding.     

The verbal helping skills of trained and untrained human service paraprofessionals

The verbal helping skills of human service paraprofessionals in a youth service agency were studied. Workers who had previously completed a 10-week systematic training program in basic helping skills were compared to untrained volunteer staff. Using simulated helping interviews, it was found that training made a significant impact on trainees' verbal helping responses. Skill level was maintained at a 2-month follow-up for certain responses whereas others returned to pretraining levels. Trainees were found to use significantly more "helpful" responses than volunteers. The need for training even carefully selected paraprofessionals is discussed.     

Evidence for acute effects of alcohol and marijuana on color discrimination

Significant dose-related impairments in hue discrimination on the Farnsworth-Munsell 100 hue test were produced by acute doses of alcohol and marijuana. The impairment of color discrimination was predominantly located in the blue region of the color circle and resembles that seen in acquired color vision defects associated with retinal pathology. The transient nature of the reduced color discrimination raises practical problems in tasks which require stable color perception.     

Cognitive processes mediating behavioral change.

The present experiment was designed to test the theory that psychological procedures achieve changes in behavior by altering the level and strength of self-efficacy. In this formulation, perceived self-efficacy. In this formulation, perceived self-efficacy influences level of performance by enhancing intensity and persistence of effort. Adult phobics were administered treatments based upon either performance mastery experiences, vicarious experiences., or they received no treatment. Their efficacy expectations and approach behavior toward threats differing on a similarity dimension were measured before and after treatment. In accord with our prediction, the mastery-based treatment produced higher, stronger, and more generalized expectations of personal efficacy than did the treatment relying solely upon vicarious experiences. Results of a microanalysis further confirm the hypothesized relationship between self-efficacy and behavioral change. Self-efficacy was a uniformly accurate predictor of performance on tasks of varying difficulty with different threats regardless of whether the changes in self-efficacy were produced through enactive mastery or by vicarious experience alone.     

Effect of the length of the runs of repetitions on the simple RT-ISI relationship

In a simple RT task the temporal organization of the preparatory processes during a given trial depends upon the time characteristics of the total experimental situation as well as upon the information gathered during one or more previous trials. The present experiment was run in order to determine whether or not these long and short term effects operate independently or interact. The effects of the preceding ISI durations on the simple RT for an ISI 1 (1.5 s) or an ISI 2 (3.0 s) are analysed in 3 experimental conditions differing in the maximum number of successive repetitions (2, 3 or 7) of trials with the same ISI. The results show that the distribution of the preparatory activity during a given trial depends firstly on the number of successive ISIs of the same duration preceding this trial, and secondly on the maximum number of repetitions. An explanation of the subjects' strategy based upon “cost of preparation” is proposed.