On the reduction of choice reaction times with practice

Information theory concepts have been discussed in relation to data from choice reaction time experiments. Specifically, it has been stated that choice reaction time is proportional to the logarithm of the number of randomly appearing alternative stimuli. It is suggested that the reported increase in choice reaction times with an increased number of alternatives is the result of insufficient practice. Data are provided to show that, with sufficient practice, this increase does not occur between two and four choices.     

On becoming a leader: Effects of gender and cultural differences on power distance reduction

The present research focused on power processes in a simulated organizational structure consisting of three hierarchical levels occupied by different numbers of mules and females. Subjects were presented with a chart showing the organizational hierarchy of which they were a member placed at the lowest level, and asked to nominate any person for the leader position vacated by the current incumbent. The results of Experiment I (n = 88 Dutch male and female university students) showed that male subjects strongly overnominated themselves, whereas a majority of the female subjects nominated either self or another female. Of the others that were nominated by both males and females, almost all were occupants of positions immediately below the leader position, indicating the normative influence of a bureaucratic rule of leader succession. Experiment 2 was a replicational study carried out in a different culture (n = lOl Polish male and female university students). Polish subjects adhered to the bureaucratic rule more strongly than their Dutch counterparts, and both females and males nominated mostly males. Results are discussed with reference to gender self-stereotypes and cultural differences.     

Infant characteristics and anger reduction

Konrad Lorenz first suggested in 1943 that certain physical and behavioral characteristics common to infants (babyishness) serve as cues to attract adult attention and care as well as to decrease the likelihood of aggression. The present study was designed to determine whether the visual stimuli of a baby's face alone are sufficient to reduce anger. The subjects were 60 female students between 18 and 30 years of age. Anger was evoked by setting unsolvable tasks and by noise and maintained by adequate instructions and by continuing noise. Three procedures of measurement (heart rate, retrospective self-report, and interpretation of facial affect by two observers) were designed to show the reactions of the subjects viewing photos of babies and adults. We found a slight increase in heart rate to be an expression of happiness and a massive acceleration to be an expression of anger. The self-report measures and interpretation of facial affect supported the hypothesis that there is a more positive response to infants than to adults, and to cute babies also a more positive one than to less attractive infants. We found weak evidence that babyishness reduces anger. As a consequence of the length of the experiment, subjects who should not be aroused became angry. Thus, it was possible to register a reduction of anger as reaction to cute infants.     

Behavioral contrast without response-rate reduction

Behavioral contrast was obtained in two experiments, which both employed a standard free-operant successive discrimination (a multiple variable-interval extinction schedule), without the occurrence of reductions of response rate in the extinction component. In Experiment I, one group of four pigeons was trained on a multiple schedule in which one stimulus was associated with a variable-interval schedule and the second stimulus with response-independent reinforcement on a free variable-interval schedule. Though by the end of this training three pigeons were responding very little to the second stimulus, when this stimulus was associated with extinction all subjects showed a contrast effect. In Experiment II, eight pigeons were trained extensively to respond to a single stimulus on a variable-interval schedule, before a second stimulus associated with extinction was introduced. This second stimulus was dissimilar to the initial stimulus and five pigeons never responded in its presence. Nevertheless, all pigeons showed a contrast effect and there was no evidence that the effect was smaller in errorless subjects or smaller than in a subsequent discrimination where all subjects made many errors. Both experiments indicated that response reduction in one component of a multiple schedule is not a necessary condition for the occurrence of contrast.     

Shape-slant relations under reduction conditions

Two experiments are reported which attempted to test implications of the shape-slant invariance hypothesis. Both experiments employed an apparatus in which variations in the slant and in the width settings of a rectangle were highly ambiguous and subject to instructional sets. In the first experiment, the stimulus was varied in both its width and its slant to achieve matches to four standard angles; the resultant width settings were found to be close to the projected widths of the obtained angles of slant. In the second experiment, width and slant were varied to match four standard widths; the projected widths of the obtained angles of slant did not differ from the obtained width settings.     

The reduction of claustrophobia--I.

The purpose of this study was to investigate the process of change during three interventions for claustrophobia, with particular reference to cognitive changes. Forty-eight participants, recruited from the community through the local media, were randomly assigned to one of four groups: pure exposure, exposure to the sensations of anxiety (interoceptive exposure), modification of negative cognitions, or a control group. All interventions were given over three sessions. The exposure group proved superior to the control on a wide range of measures. In the cognitive group, scores of reported fear and panic, declined significantly. The interoceptive group made some modest gains. An analysis of the timing of fear reduction and of treatment generalization, provides some indications of the mechanism of change.     

Negative reinforcement as shock-frequency reduction

Is a conditioned aversive stimulus necessary in avoidance conditioning? Or is a reduction in the rate of aversive stimulation alone sufficient to generate and maintain an avoidance response? Rats were subjected to an avoidance procedure in which shocks occurred randomly in time, but a response could reduce the overall rate of shock. Fifteen acquisition curves, obtained from 16 animals, showed both immediate and delayed, rapid and gradual increases in response rate; there was no representative acquisition curve. Response rates were directly related to the amount by which the response reduced shock frequency. In extinction, when shock rates were not affected by responding, the response total was inversely related to the amount by which the response had reduced shock frequency during prior conditioning, with as many as 20,000 extinction responses when the shock frequency reduction had been relatively small. Responding on this procedure shows that avoidance conditioning can occur without benefit of either classical exteroceptive stimuli or covert stimuli inferred from the temporal constancies of a procedure. It also shows that reduction in shock rate is alone sufficient to maintain avoidance.     

Negative reinforcement without shock reduction

Stable lever-press responding in rats was reliably produced and maintained by a procedure in which responses could delay shocks without affecting overall shock frequency. Responding was not maintained when the delay-of-shock involved an increase in overall shock frequency.