Recent cohorts lead rejection of sex typing

In samples of the Detroit metropolitan population, four items indicating rejection of sex typing of children's household chores were negatively related to birth year of respondent in 1953, but positively related in 1971 and 1976: Older women were more likely to reject sex typing in 1953, but less likely to do so than younger women in 1971 and 1976. The regression was stronger for three items in 1976 than in 1971, while there was no change for the fourth. But associations between pairs of items in 1971 and 1976 were negatively related or unrelated to birth year. The explanation of these changes as an immediate and direct result of the women's movement is, therefore, discounted. The pattern of changes is congruent with assumptions in a model suggested by Carlsson and Karlsson (1979), which predicts oscillations in aggregate behavior with a period about a generation in length.This research was supported by NSF Grant SOC77-27365. Charles Brody Assisted with computations. Beverly Duncan made valuable suggestions. Howard Schuman generously provided early access to the 1976 data, collected for use in his own research.     

CONTINGENT EXERCISE: A MILD BUT POWERFUL PROCEDURE FOR SUPPRESSING INAPPROPRIATE VERBAL AND AGGRESSIVE BEHAVIOR

Two single-subject experiments were conducted in public school classrooms for severely emotionally disturbed children. Both experiments investigated the effects of a treatment requiring a child to exhibit a simple exercise task after a verbal or aggressive response, using reversal and multiple-baseline designs. The independent variable, contingent exercise, required standing up and sitting on the floor five to ten times contingent on an inappropriate behavior. It was found that contingent exercise was easy to carry out, and following it, the child quickly returned to the learning task that had been interrupted by the inappropriate behavior. The contingent exercise procedure required a minimum of prompting or manual guidance. Although contingent exercise was not topographically related to the inappropriate response, it decreased those responses dramatically. The results suggested that contingent exercise was not only more powerful than DRO but also could be administered independently. It was concluded that contingent exercise may constitute an alternative procedure that can be used by therapists confronted with severely abnormal behaviors. It would appear to be particularly relevant in settings where procedures such as timeout and painful consequences find restricted use. Finally, a number of guidelines have been proposed as a safeguard against the misuse of this mild but powerful procedure.     

The demonstration of capacity limitation

The study of divided attention has produced many apparent demonstrations of “capacity limitation.” Possible ambiguities in such demonstrations are considered for three major types of experimental situation: simultaneous inputs with separate responses; choice; and classification. Two issues emerge. First, demonstrations always rest on assumptions about process set, i.e., the set of internal processes by which the task actually is performed. Alternative process sets are considered for situations of each type. Second, a demonstration of capacity limitation is made either by increasing the number of simultaneous processes, or by changing the bias between them. In either case effects unrelated to capacity limitation may influence the results. If several processes contribute to a single response, some performance decrement must accompany an increase in their number, simply through the increased overall chance for error. If the subject is biased toward one alternative in a choice or classification situation, the benefits enjoyed by this alternative may reflect not a preferential allocation of attentional capacity, but simply a willingness to decide in favor of this alternative with relatively little evidence.     

Two classes of models for magnitude estimation

One class of models assumes that presentation of a signal results in an internal representation as a random variable. Depending on whether the signal is close to or far from the preceding signal, the variance of the representation is smaller or larger. Responses are determined largely by this random variable; however, when the signal is close to the preceding one, the response is generated by modifying the representation multiplicatively by some function of the ratio of the previous response to its representation. Power and linear functions are explored. The form of the random variable is assumed to be that arising from either the timing or the counting model operating on a Poisson process. Detailed analyses are carried out successfully only for the timing model with neural sample sizes independent of intensity; however, the data require the sample to increase with intensity. The linear response function coupled with the constant sample size counting model appears somewhat viable, but detailed calculations are very difficult to carry out. The second class of models postulates a power function relation between magnitude estimates and signals intensity for which the exponent is a Gaussian distributed random variable and the unit is the product of two log normal random variables. Again we assume an attention band such that succesive stimuli that are widely separated in intensity lead to independent samples of the random variables while a variety of assumptions is explored for successive stimuli that are near each other in intensity. Although they each give rise to the qualitative features of the data, estimates of parameters are sufficiently inconsistent that we are led to reject all of the submodels studied.     

Variability and sequential effects in cross-modality matching of area and loudness

Individual subjects' performance was examined for cross-modality matching (CMM) of loudness to visual area, as well as for magnitude estimation (ME) of the component continua. Average exponents of power functions relating response magnitude to stimulus intensity were .73 for area, .20 for loudness, and 2.44 for CMM. Predictions of the CMM exponent based on ME were higher than the empirical values, whereas more accurate predictions were made from magnitude production exponents obtained in a previous study. Sequential dependencies were assessed by comparing the response on trial n to the response on trial n--1. The coefficient of variation of the response ratio Rn/Rn-1 was systematically related to the stimulus ratio Sn/Sn-1 for both area and loudness. The coefficient was lowest for ratios near 1 and increased for larger or smaller values. For CMM, the coefficient of variation appeared to be independent of stimulus ratios. The correlation between log Rn and log Rn-1 was also related to Sn/Sn-1 for both ME and CMM. The correlation was highest when Sn/Sn-1 was 1 and dropped to 0 with increasing stimulus separation, but CMM yielded a shallower function than ME.     

Variability of magnitude estimates: A timing theory analysis

Three procedures for magnitude estimation were investigated, and a sufficient number of responses were obtained to make reasonable estimates of both the mean and variance of the responses. The conventional magnitude estimate procedure, without a standard signal, appeared to produce the most sensible data. The best method of establishing the central tendency of the data appears to be the plot of the mean ratio of successive responses against the intensity ratio of the corresponding signal intensities. When this is done, the average response ratio increases roughly as a power function of the signal ratios. The coefficient of variation, σ/m, varies from about 0.1 for small signal ratios and increases to 0.3 at about 20 dB and greater signal separations. The distribution of response ratios appears to be reasonably well approximated by a beta distribution. The change in σ/m with signal ratio is suggestive of an attention mechanism in which the sample size depends on the location of the attention band. The ratio estimation procedure suffers badly from discrete number tendencies.     

Detection of auditory signals presented at random times: III

Reaction times to a pure tone in noise were measured. Throughout, the time from the warning signal to the reaction signal was exponentially distributed, and the signal was response terminated. Response criterion, signal intensity, and mean foreperiod wait were varied. A model that assumes a Poisson sensory transduction, a pulse-activated decision process, and an additive bounded residual process was tested. It was concluded that the assumed decision process was in error. Among the empirical results, the dependence of mean reaction time on signal waits was shown to depend largely on the average wait, not the actual one, and that this relationship between mean reaction time and average stimulus wait increased for strong signals and decreased for weak ones.     

Induction of a principle

Two experiments are reported in which student subjects attempted to discover a principle obtaining among pairs of numbers and letters. In the first experiment, subjects were more successful when they were free to select whatever number-letter pairs they wished than if they were restricted in whole or in part to pairs specified by the experimenter. In the second experiment, subjects who did discover the principle were compared to those who did not. Successful subjects were shown to be slightly more systematic in their approach to the task, to work at a faster pace, to write down more positive instances, and to have a much stronger tendency to vary only one variable of the task at a time.

Wason (1960) reported a study in which subjects tried to discover a principle applying to instances each of which consisted of three numbers. He discovered that subjects mostly showed enumerative rather than eliminative induction, i.e. they made little use of instances that would have enabled them to eliminate wrong hypotheses. Wetherick (1962) found that by modifying Wason's procedure in certain ways, enumerative behaviour was reduced and the subject's chance of discovering the principle was increased. Elimination of hypotheses remained infrequent.

In the Wason study, the subject was free to write down, for each instance, any three numbers he wished, i.e. his choice of instances was not restricted in any way. This may account in part for the behaviour Wason observed. In the first experiment to be reported here, the subject is restricted, in various degrees, in his choice of instances, to determine whether the principle is discovered more (or less) readily under such restriction.