The roles of stimulus repetition and hemispheric activation in visual half-field asymmetries

Hardyck, Tzeng, and Wang (1978, Brain and Language, 5, 56–71) hypothesized that ample repetition of a small number of stimuli is required in order to obtain VHF differences in tachistoscopic tasks. Four experiments, with varied levels of repetition, were conducted to test this hypothesis. Three experiments utilized the general task of object-picture naming and one utilized a word-naming task. Naming latencies constituted the dependent measure. The results demonstrate that for the object-naming paradigm repetition is required for RVF superiority to emerge. Repetition was found to be unnecessary for RVF superiority in the word-naming paradigm, with repetition actually reducing RVF superiority. Experiment I suggested the possibility that RVF superiority developed for the second half of the trials as a function of practice or hemispheric activation, regardless of repetition level. Subsequent experiments, better designed to assess this possibility, clearly refuted it. It was concluded that the effect of repetition depends on the processing requirements of the task. We propose that, for tasks which can be processed efficiently by one hemisphere, the effect of repetition will be to reduce VHF asymmetries; but tasks requiring substantial processing by both hemispheres will show shifts to RVF superiority as a function of repetition.     

Color discrimination on Mangaia

Bornstein’s hypothesis that there is a loss of color discrimination in tropical areas was not supported in earlier research in the Cook Islands. Using a more sensitive color vision test (the Farnsworth-Munsell 100-Hue Test), a loss of color discrimination in the red-purple and blue-green regions of the spectrum was found. The lack of sex differences in this color discrimination loss supports a physiological rather than a genetic explanation of the observed decrement.     

Context effects in episodic studies of verbal and facial memory: A review

Memory research has in the last fifteen years been marked by a considerable interest in context effects. This review begins by examining experimental manipulations of verbal and environmental context in verbal memory. This is followed by a more extensive review of episodic studies of face recognition that have examined the effects of varying the background in which a face is portrayed, the room of testing, and the presence of guided instructions. The relevance of these findings to eyewitness memory is also considered. Discrepancies in the literature are pinpointed with theoretical discussion centering around encoding specificity theory (Tulving & Thomson, 1973) and Baddeley and Woodhead’s (1982) distinction between “independent” (extrinsic) and “interactive” (intrinsic) context effects. The review ends with an evaluation of some recent models of memory and face recognition in an attempt to provide a framework within which to interpret the context effects in the literature.     

Psychosocial risk factors, natural immunity, and cancer progression: Implications for intervention

One of the more important and emerging fields in which psychologists collaborate with other disciplines is psychoimmunology. Centuries of clinical anecdote and decades of psychosomatic hypotheses have gained credibility in the eyes of the medical establishment—and many patients—by the systematic investigation of mechanisms potentially explaining how events intrapsychic and interpersonal could affect physical disease processes. The central nervous system is connected with the immune system by both neuronal and endocrinological pathways. The immune system has been found to mediate the organism’s response to aberrations of its own normal functions, as well as to invading organisms from without. AIDS, arthritis, asthma, lupus, and herpes are some of the illnesses in which research is demonstrating important relationships among psychosocial and immunological factors and disease course. In this article, we first discuss the immunological apparatus in order to provide a base for subsequent discussions of the effects of stress on immune function. Then we discuss malignant diseases and current evidence that disease course is related to both psychosocial stressors and immune function. We next discuss a model of these interactions, and finally we talk about interventions incorporating psychosocial factors aimed at influencing immune status and, thus, disease course.     

The interaction of stimulus and reinforcer control in complex temporal discrimination.

Six pigeons were trained in a discrete-trials signal-detection procedure to discriminate between a fixed-duration stimulus (5 s or 20 s) and a set of variable durations ranging from 2.5 s to 57.5 s in steps of 5 s. For each fixed-duration stimulus, the ratio of reinforcer frequencies contingent upon reporting the fixed versus the variable stimulus was systematically manipulated. Detection performance was well controlled by both the stimulus value and the reinforcer ratio. Both the discriminability between the fixed duration and the set of variable durations, and the discriminability between the fixed duration and each of the variable durations, were independent of the reinforcer-frequency ratio when discriminability was measured as log d. The sensitivity of response bias to reinforcement-ratio changes was independent of the value of the fixed duration, but was not independent of the discriminability of the variable durations from the fixed durations. Under current models, discriminability measures in complex temporal discrimination may be independent of biasing manipulations, but bias measures are not independent of stimulus values.     

Choice between reliable and unreliable outcomes: mixed percentage-reinforcement in concurrent chains.

Pigeons' choices between alternatives that provided different percentages of reinforcement in mixed schedules were studied using the concurrent-chains procedure. In Experiment 1, the alternatives were terminal-link schedules that were equal in delay and magnitude of reinforcement, but that provided different percentages of reinforcement, with one schedule providing, reinforcement twice as reliably as the other. All pigeons preferred the more reliable schedule, and their level of preference was not systematically affected by variation in the absolute percentage values, or in the magnitude of reinforcement. In Experiment 2, preference for a schedule providing 100% reinforcement over one providing 33% reinforcement increased systematically with increases in the duration of the terminal links. In contrast, preference decreased systematically with increases in the duration of the initial links. Experiment 3 examined choice with equal percentages of reinforcement but unequal delays to reinforcement. Preference for the shorter delay to reinforcement was not systematically affected by variation in the absolute percentage of reinforcement. The overall pattern of results supported predictions based on an extension of the delay-reduction hypothesis to choice procedures involving mixed schedules of percentage reinforcement.     

Effects of delayed conditioned reinforcement in chain schedules.

The contingency between responding and stimulus change on a chain variable-interval 33-s, variable-interval 33-s, variable-interval 33-s schedule was weakened by interposing 3-s delays between either the first and second or the second and third links. No stimulus change signaled the delay interval and responses could occur during it, so the obtained delays were often shorter than the scheduled delay. When the delay occurred after the initial link, initial-link response rates decreased by an average of 77% with no systematic change in response rates in the second or third links. Response rates in the second link decreased an average of 59% when the delay followed that link, again with little effect on response rates in the first or third links. Because the effect of delaying stimulus change was comparable to the effect of delaying primary reinforcement in a simple variable-interval schedule, and the effect of the unsignaled delay was specific to the link in which the delay occurred, the results provide strong evidence for the concept of conditioned reinforcement.     

Measuring gender differences: The expressive dimension and critique of androgyny scales

This paper calls for a new approach to the measurement of gender similarities and differences in personality. Critiques of current measures that are based on the measurement of stereotypical masculinity and femininity are reviewed, and an alternative measure is presented. It avoids many of the problems in the other scales by measuring expressiveness and instrumentality in such a way that they are not confounded with variables such as independence or autonomy. Results with this measure in five different samples are presented. These confirm our theoretical definitions of expressiveness and instrumentality, and suggest that only the expressive or relational dimension consistently differentiates samples of women and men.We thank Mary Rothbart for her insightful and constructive comments on an earlier draft; Leisha Sanders, Marcia DeCaro, Vickie Van Nortwick, and Lyn Cogswell for their clerical assistance; the Center for the Study of Women in Society for financial support; and Liza Kuecker and Patricia Gwartney-Gibbs for providing data used in the analysis. An earlier version of this paper was presented at the 1984 annual meeting of the Pacific Sociological Association.     

Automaticity and the capture of attention by a peripheral display change

The proposal that peripheral visual changes (cues) tend to summon attention automatically was tested by studying the effect of peripheral cueing on simple detection latency. Delay between cue onset and target onset, the contingent relationship between cue location and target location, and instructions to subjects were manipulated. Results showed that a peripheral display change could capture attention even when the target was far more likely to appear at an uncued location. When subjects were explicitly informed that targets were likely to appear away from the cued location they were able to suppress this effect, but were unable completely to reverse it by rapidly orienting attention towards the uncued side. Hence the process appears to be automatic in the sense that it occurs unless there are explicit instructions to the contrary. With explicit instructions the processing operation can be suppressed, but not completely reversed. This work was supported by the U.K. Admiralty Research Establishment (Research Agreement No. 53482).