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.     

Observing behavior in monkeys (Macaca arctoides): Support for the information hypothesis

A single lever, discrete-trials observing procedure was used with stumptailed monkeys (Macaca arctoides). Lever-presses during a trial produced colored key lights (IS⁺ and IS^?) which signaled whether the trial would end with response-independent food or without food. During the baseline period, both IS⁺ and IS^? were produced on a variable-interval (VI) 15-sec schedule which began operating at the onset of the trial. The two experimental conditions involved a combination of this VI schedule and a DRL schedule. In one of these conditions, only a response that both met the VI requirement and was preceded by at least 6 sec of nonresponding could produce IS^? on nonfood trials, while the schedule for IS⁺ on food trials remained VI 15 sec. In the other experimental condition, the schedules for producing the two stimuli were the reverse. All subjects eventually learned to produce either IS⁺ or IS^? on the combined VI-DRL schedule. These data support an information hypothesis of observing in monkeys and contrast with data from pigeons which support a conditioned reinforcement hypothesis.     

Drug effects on repeated acquisition: comparison of cumulative and non-cumulative dosing

Pigeons acquired a different four-response chain each session by responding sequentially on three keys in the presence of a sequence of four colors. The response chain was maintained by food presentation under a fixed-ratio schedule. Errors produced a brief timeout but did not reset the chain. Each day there were four 15-minute sessions, with a 10-minute inter-session interval. Cumulative dose-effect curves for phencyclidine, pentobarbital, and d-amphetamine were obtained by giving an injection before each of the four sessions; successive injections increased the cumulative dose in equally spaced logarithmic steps. For comparison, non-cumulative doses of each drug (i.e., doses not preceded by other doses on the same day) were also tested. As the cumulative dose of each drug increased, the overall response rate decreased, the percent errors increased, and there was less within-session error reduction (acquisition). With phencyclidine and pentobarbital, the rate-decreasing and error-increasing effects tended to be greater with a non-cumulative dose than with the corresponding cumulative dose. In contrast, with d-amphetamine, the effects were considerably greater with the cumulative doses. The results indicate that although the cumulative-dosing procedure saved a substantial amount of time in determining dose-effect curves, there were quantitative differences in effects between cumulative and non-cumulative doses.