Concurrent schedules: undermatching and control by previous experimental conditions.

Five pigeons were trained on concurrent variable-interval schedules. A series of conditions in which the ratio of reinforcement rates on two keys was progressively increased and then decreased was arranged twice. The birds were then exposed to an irregular sequence of conditions. Each condition in which reinforcement was available on both keys lasted six sessions. Performance in the first, third, and sixth sessions after a condition change was analyzed. Following a condition change, preference was biased toward the preference in the last condition, but this effect largely disappeared before the sixth session of training. The birds' preferences also appeared less sensitive to reinforcement rates in early sessions after a transition. Preference in a session was a function of both the reinforcements in that session and the reinforcements obtained in as many as four or five previous sessions. The effects of reinforcements in previous sessions could be summarized by the performance in the immediately preceding session, giving a relatively simple relation between present performance and a combination of present reinforcement and prior session performance. While such hysteresis could cause undermatching when only a small number of sessions are arranged in a condition, undermatching in a stable-state performance probably arises elsewhere.     

Personality patterns of adolescent poor and good sleepers

To determine whether poor sleepers have a unique personality constellation significantly different from that of good sleepers, a sample of 162 emotionally disturbed adolescent poor sleepers was compared to a sample of 153 emotionally disturbed adolescent good sleepers on standardized personality instruments. Poor sleepers were found to have a high incidence of neurotic psychopathology with personality patterns characterized by depression, fearfulness, inhibition, anxiety, and rumination. In contrast, good sleepers showed quasi healthy and/or characterological patterns. While this study does not resolve cause and effect relationships, it does establish a highly significant relationship between neuroticism and sleep disturbance for adolescent boys and girls, and also demonstrates a similarity of personality dynamics and patterns between adult and adolescent samples of patients with sleep disturbances.     

Auditory processing and anxiety in stutterers

This study utilized the Synthetic Sentence Identification/Ipsilateral and Contralateral Competing Message subtests and the State-Trait Anxiety Inventory to examine auditory processing deficits, anxiety levels, and the interaction of these two components in 15 adult stutterers and 15 nonstutterers. Results support brainstem auditory processing deficits in stutterers and equalization of cortical functioning between groups. Group differences were not found in anxiety levels. Nonsignificant correlations between anxiety levels and auditory processing were revealed.     

Ratio scaling of taste intensity by a matching procedure

Given the assumptions that the taste sense is analytic and that the total perceived intensity of a complex taste equals the sum of the perceived intensities of the components, a new procedure was devised to scale taste intensity. Subjects matched the intensity of test substances either to the total intensity or to the intensity of one component of two-component mixtures tin which the two components appeared equally intense. Given the above-stated assumptions, such a pair of matches should define a psychological ratio of 2∶1. Scales erected by this procedure agreed well with scales determined by magnitude estimation.     

Data analysis implications of some concepts related to the cuts of a graph

Connections are pointed out between the concept of a cut in a graph and the data analysis problems of hierarchical clustering and seriation encountered in the social and behavioral sciences. An emphasis is placed on hierarchical clustering by the criterion of k-edge connectivity and on the relationship between several criteria for object seriation proposed in the literature and the appropriate graph-theoretical structures.     

Explorations using computer simulation to comprehend thematic apperceptive measurement of motivation

The new theory of motivation by Atkinson and Birch (1970), based on conceptual analysis of a change in activity, has been programmed to allow computer simulation of effects of differences in motivation on the stream of operant behavior. Simulation of conditions that exist when people who differ in strength of achievement motive write imaginative stories in response to a sequence of pictures shows that construct validity does not require internal consistency as traditionally supposed. The theoretically deduced differences in total time spent imagining achieving (instead of something else) can postdict input differences in motive strength (i.e., construct validity) even when there is little or no internal consistency reliability as indicated by Cronbach's (1951) alpha computed from theoretically deduced time spent imagining achievement in response to particular pictures. This general point has already been amply documented in 25 years of productive empirical research using TATn Achievement. Now a definitive theoretical refutation of the repeated psychometric criticism of the method is provided. Those who have been moved to dispel fantasies about fantasy-based measures of achievement motivation (Entwistle, 1972) are invited, instead, to examine the shallow theoretical foudation of our traditional myths of measurement.This paper elaborates a report presented August 30, 1975, at the 83rd annual meeting of the American Psychological Association. The authors gratefully acknowledge early assistance by Mary M. Moffett, and financial support by a Rackham Faculty Research Grant (JWA), a National Science Foundation Fellowship (KB), and a Michigan Student Medical Research Grant (LHP). Intricate detail has been avoided in describing the several simulations for the sake of clarity in this overview of exploratory work.     

Influence of temporal masking on click-pair discriminability

When temporal auditory acuity is estimated using time-reversed click pairs, the asymmetry of temporal masking may influence the results. To investigate this hypothesis, we first established normal-hearing listeners’ psychometric functions for the discrimination of time-reversed click pairs. An attempt to relate listeners’ performances in click-pair discrimination to their performances in forward and backward masking tasks was unsuccessful, probably due to the presence of spectral artifact in the temporal masking paradigms. We then investigated listeners’ abilities to discriminate time-reversed click pairs in which the intensity of the lower level click in one pair was altered. This alteration was introduced at random in order to minimize the influence of spectral artifact. Our results suggest that the course of temporal masking influenced the discriminability of the modified click pairs. Thus, the discrimination of time-reversed click pairs may yield a biased estimate of auditory temporal acuity.