In defence of a ratio model for movement detection at threshold

Sutherland (1961) proposed that the detection of motion might depend upon the ratios of firings in cells sensitive to movement in opposite directions. Sekuler and his collaborators have argued that the notion of a ratio mechanism at threshold is wrong. The findings and arguments upon which this conclusion was based are challenged, an explicit model is described which provides an account of data previously held to be inconsistent with a ratio model, and an experiment is reported which provides unequivocal support for the ratio model and whose findings are inconsistent with the predictions from Sekuler's “independence” model.     

Isolating the typicality effect in semantic memory

An experiment was conducted to isolate the typicality effect in the overall categorization process. Subjects were required to indicate whether or not a probe word was a member of one of a variable number of categories held in memory. The typicality of the probe word, with respect to its superordinate category, was varied as was the physical quality of the probe. These manipulations were designed to test predictions drawn from Collins and Loftus (1975) and Anderson and Reder (1974), as well as a prediction based on the well-known effect of semantic context on word perception. A fourth prediction was drawn from a proposed model which postulates successive access of categories and locates the typicality effect in a within-category search stage. Typicality proved to be additive with stimulus quality and set size, but interacted with response type. These results were interpreted as support for the successive-access within-category search model while disconfirming the alternative predictions.     

Acquisition and discrimination of appetitively and aversively conditioned heart rate responses in rhesus monkeys

This report describes the acquisition of a conditional heart rate response to both classical aversive and appetitive conditioning in eight rhesus monkeys(Macaca mulatta). The behavioral paradigm consisted of two discrete one minute tones followed by the corresponding unconditional stimuli,i.e., electric shock or Purina monkey chow. A third tone followed by neither food nor shock served as a discriminative stimulus (DS). The conditional heart rate responses developed in two phases. The first phase was characterized by similar responses to both conditional stimuli and the DS. Control heart rate rose during this period. During the second phase, control heart rate decreased (five animals), the DS response disappeared, and different conditional heart rate patterns to food and shock emerged. The existence of distinct conditional response patterns indicates probable differences in the autonomic nervous regulation of the heart during aversive and appetitive conditioning.     

Ethanol’s influence on the stimulus level required to evoke an orienting response in goldfish

In goldfish the heart rate orienting response to periodic photic stimuli was measured by a specially designed computer that also regulated the intensity of the stimuli to maintain the response. When ethanol was administered, the fish then exhibited orienting responses to less intense stimuli; this increased excitability was maintained for the duration of all tests(i.e., a maximum of 26 hours). There also seemed to be a residual increase of excitability lasting as long as 7 days after the ethanol was administered.     

Career stages: A partial test of Levinson's model of life/career stages

This study purports to test a theory of life and career stages developed by Daniel Levinson and his associates. The theory suggests four distinct stages between ages 20 and 45 each with their own developmental tasks and related behaviors and attitudes. Subjects (759 managerial, professional, and technical employees) were selected randomly from levels and departments of a major public sector employer in the midwest United States. The measure of career stage asked respondents to indicate whether they had passed through, were still in, or had not yet reached each stage as operationalized by a short vignette. Attitudinal and behavioral measures were abstracted from previously developed instruments. Only moderate support for the theory was found with little or no evidence to support the age-linked notion of these stages. Stages were found to be discriminable in terms of certain attitudes (upward mobility, career and overall job satisfaction, and job commitment) as predicted. Suggestions are given for improvements in measurement, research design, and theory refinement.     

CULTURAL VARIATION IN PROBABILISTIC THINKING: ALTERNATIVE WAYS OF DEALING WITH UNCERTAINTY*

This study reviews research on cultural differences in “probabilistic thinking” and presents some intra- and inter-cultural findings. Strong differences are shown to exist between people raised under Asian and British cultures on measures of this ability. These differences were found to out-weigh any influence of subculture, religion, occupation, arts/science orientation and sex. Generally, Asians were found to adopt a less finely differentiated view of uncertainty both numerically and verbally than did the British sample. Numerical probabilities assessed by the Asians were more extreme and less realistic than those assessed by the British sample. Possible antecedents of these differences are outlined, and cultural differences in probabilistic thinking are shown to be compatible with decriptions of cultural differences in business decision making. It is argued that there are qualitative cultural differences in ways of dealing with uncertainty.     

Promoting Energy Conservation in Master-Metered Apartments through Group Financial Incentives1

An energy conservation contest among four groups of apartments (44 to 70 units each) in a University of Colorado family housing complex was conducted February-April, 1977. The winning group in each of six 2-week contests won $80 to use however it determined. The program produced a drop of about 10% in use of natural gas during the first contest; energy savings were smaller but still statistically significant throughout the first 8 weeks. Over a 12-week period, savings averaged 6.6%. Some changes in energy-using behaviors were reported by residents surveyed at the contest's end; however, knowledge of contest results by residents was minimal. The results are compared to those of other contest and rebate programs, the practical problems of costs exceeding savings and inaccurate estimates of energy savings are discussed, and implications for future research are suggested.     

A repertory grid study of therapist/couple interaction

A case of marital therapy is described in which the presenting problem, one of non-consummation, is treated by the standard Masters and Johnson's technique. Using repertory grids at the start and finish of treatment the changing perceptions of both partners and the therapist were determined. In spite of an ostensibly behavioural treatment, substantial changes occurred in the couple's understanding of the nature of their problem. The changes undergone in the couple's perceptions, and their differences from the therapist's assessments of change give rise to speculations about the nature of the therapeutic interaction and suggest further lines of exploration.