Towards a model of stress and human performance

An outline is presented of a model that aims to relate energetical and structural mechanisms of human information processing and to incorporate an interactionally defined stress notion in performance research. The first section summarizes objections to unidimensional notions of arousal and stress. It is concluded that further progress requires the analysis of joint cognitive-energetical processing structures. In the second section two current performance models - in terms of linear stages and resources - are briefly reviewed. Despite a number of problems and objections, it is decided to base the model upon linear stage notions of information processing. This is further elaborated in the third section. In accord with Pribram and McGuinness (1975) three energetical supply systems are proposed which are selectively related to specific cognitive processing mechanisms. Stress is defined as a state of imbalance in the energetical supply which is difficult to restore or to compensate. The final section is devoted to the discussion of some lines of evidence and to suggestions for future research.     

Focus shift and individual differences in the Sternberg memory-search task

One consistent finding in research using the memory search task developed by Sternberg (1966) is that negative set size has no effect on search reaction time, even when the negative set contains fewer items than the positive set. Such inefficient behavior appears to result from an intense positive focus generated by standard memory search task instructions. The present research was designed to explore the conditions under which a subject will switch focus to a smaller negative set. Two experiments were carried out using standard Sternberg instructions. The first experiment examined the effects of making the contents of the negative set explicit. The result was a shift to negative focus when the negative set was much smaller than the positive set. In the second experiment the size of the positive set was increased systematically to induce a shift to negative focus. The second experiment also examined the relationship between focus shift and measures of intelligence (Raven Progressive Matrices) and information storage capacity (digit span). The results are evidence that negative set size can affect reaction time in the memory search task, and that individual differences in ability to shift focus are related to intelligence.     

Halos vs. stigmas: long-term effects of parent's death or divorce on college students' concepts of the family

College students from families of divorce, of death of a parent, and of intact families rated the meaning of six concepts of the family: mother, father, I myself, marriage, family, and divorce. The Semantic Differential was used to assess four dimensions of meaning of family concepts: evaluation, potency, activity, and general cultural favorability. Children of divorce rated father less favorably than did children of death of a parent or of intact families; however, children of divorce rated divorce more favorably than the remaining two groups. Also, children of divorce evaluated the family concepts that were rated here more negatively than, but equally as potent and active as, children of death of a parent and of intact families. Thus, several long-term stigmas attach to family among children of divorce, but no evidence was found of a halo effect for children of death of a parent.     

Two factors of restraint: concern for dieting and weight fluctuation

Factor analysis of the Restraint Scale produced two replicated factors: Concern for Dieting and Weight Fluctuation. Concern for Dieting reflects heightened attention to and emotional association with eating. Weight Fluctuation reflects extent of previously-experienced weight gain and loss. Weight Fluctuation was more highly positively correlated with indices of overweight status than was Concern for Dieting. Concern for Dieting was positively correlated with Public Self-Consciousness and Social Anxiety while Weight Fluctuation was not. Both versions of Restraint were weakly and inversely correlated with Body Image, although this relationship was mediated by degree of overweight status. The findings indicate that the two factors are sufficiently distinct to preclude combination into a single scale. Furthermore. Weight Fluctuation appears to be the more promising subscale for future research.     

Response selection and initiation in speeded reactions: a pupillometric analysis

Three studies are described in which the task-evoked pupillary response is recorded during simple and disjunctive reactions in order to examine its contribution as a measure of the motoric and cognitive aspects of performance in these tasks. In simple reactions a pupillary dilation began about 1.5 sec before the imperative stimulus and peaked about 1 sec after the stimulus. The rate of dilation was inversely related to the interstimulus interval. In disjunctive reactions, both "Go" and "No-Go" responses elicited significant dilations but the No-Go dilation was smaller than the Go dilation. When the response was delayed 2.5 sec after the discrimination stimulus, the dilation to both Go and No-Go responses was much reduced. The pupillary response related to response selection was estimated at 55% of that associated with motor preparation and execution. The probability of responding was found to affect the amplitude of the dilation to No-Go responses but not that to Go responses. The data point to a significant contribution of preparatory motor processing in No-Go reactions and to an overlap between decisional and motoric processing in disjunctive reactions.     

Children's strategies for controlling affective responses to aversive social experience

It was hypothesized that one mechanism of self-control that children develop is the strategic capacity to select the experiences they encounter. This hypothesis led to the prediction that children would deal with certain aversive social experiences by seeking out or taking advantage of opportunities for nurturant experiences. Young children were exposed to an aversive social experience in which they received less nurturance than a peer, a positive experience in which they received more nurturance, or a neutral experience in which nurturance was equal. Subsequently, an opportunity was provided for children to control the length of time they watched a highly nurturant television program. As predicted, boys experiencing an aversive social encounter increased the length of time they exposed themselves to the nurturant television show, and their level of reduced positive affect was related to how long they watched the nurturant content, further supporting the interpretation that they did so in response to their own affective state. Girls did not adopt the strategy of self-exposure to nurturant television but did appear to engage in self-distraction during the aversive social experience. Despite the apparent use of control strategies, there was no indication that these strategies were effective for the amelioration of reduced positive affect resulting from the aversive social experience. Discussion focuses on the sex differences observed in the adoption of strategic behavior and factors contributing to the ineffectiveness of the control strategies. A general model is proposed for personal and environmental factors requisite for the selection, employment, and effectiveness of strategies to control experiences and their affective consequences.     

The complexity continuum in the radex and hierarchical models of intelligence

The hierarchical and radex models of ability organization are shown to be parallel. Both models suggest a complexity continuum along which cognitive performance tasks can be arrayed. In our revised radex model, the complexity continuum from the center to the periphery is shown to correspond to the general-to-specific dimension in factor analyses, or to test correlations with the general factor; complexity is redefined as apparent processing complexity. Examination of the theoretical and empirical bases for this continuum indicates its central importance for theories of intelligence.     

Cholinergic system in the toad's (Bufo bufo L.) visual system

The brain structures mediating the prey-catching behavior of the toad have been described in earlier studies but none of these studies has identified the transmitter systems in the optic tectum responsible for this behavior. Behavioral tests with different test compounds provide evidence that the cells responsible for the orienting, jumping, and snapping behaviors associated with feeding in toads are normally inhibited by cholinergic synapses.