Varying temporal placement during CS of an added stimulus correlated with non-delivery of UCS

This experiment extends Pavlov’s method of contrasts for training a stimulus discrimination to the case of the cardiac conditional response in the rhesus monkey. It explores the parameter of temporal placement of an additional stimulus (“CS₂”) within a 10-sec CS (or “CS₁”), with the appearance of the former stimulus on any trial signalling the absence of UCS (electric shock) on that trial. This experimental paradigm is a parallel to that of the “intruded stimulus” studies in operant conditioning. In both cases, several ways of describing the function of the added stimulus are possible, but all seem reducible to the same operational terms. Data were taken in the present study with respect to the form and latency of the cardiac rate changes produced by intrusion of CS₂ (light), across a range of placements varying from simultaneity with CS₁ (a different light) onset to two sec before UCS would have been delivered. The control of CS₂ over the cardiac rate CR was occasionally exhibited with a latency as short as three beats after stimulus onset. The order of CS₂ temporal placements to which a subject was exposed was a factor in determining the form of the conditioned cardiac rate response to CS₁.     

Effect of stimulus frequency on subjective vibrotactile magnitude functions

Subjective magnitude functions were determined by the method of magnitude estimation at 60 and 250 Hz at the fingertip and thenar eminence, both with and without a rigid surface surrounding the contactor. When the surround was in place, the slopes of the curves were independent of stimulus frequency. The slopes became frequency dependent when the surround was removed—the lower frequency produced a steeper slope at both body sites. An explanation of the effect is suggested. It involves the frequency characteristics and spatial sensitivity of the receptors.

     

Hand-eye coordination: The role of “motor memory”

Ten Ss attempted to track a visual target, which was moved either by hand (test run) or by a tape recording of the same hand movements (control run). On some test runs, movement of the target lagged behind that of the hand by a fixed amount (.18, .36, .72, or 1.44 sec). The number of saccades occurring on a given test run was divided by the number on the matched control run, and the test/control ratio was studied as a function of the hand-to-target lag time. With lag times of .36 sec or less, the test/control ratios were less than 1. indicating that manual control of the target had a significant effect on oculomotor performance. This effect disappeared at a lag close to .72 sec. The results are discussed in terms of a hypothetical “motor memory.”     

Mechanisms of aural encoding: VI. Consonants and vowels are remembered as subsets of distinctive features

An attempt was made to examine the manner in which consonants and vowels are coded in short-term memory. under identical recall conditions. Ss were presented with sequences of consonant-vowel digrams for serial recall. Sequences were composed of randomly presented consonants paired with/a/ or randomly presented vowels paired with /d/. Halle’s distinctive feature system was used to generate predictions concerning the frequency of intrusion errors. among phonemes. These predictions were based on the assumption that phonemes are discriminated in memory in terms of their component distinctive features, so that intrusions should most frequently occur between phonemes sharing similar distinctive features. The analysis of intrusion errors revealed that each consonant and vowel phoneme was coded m short-term memory by a particular combination of distinctive features which differed from one phoneme to another. A given phoneme was coded by the same set of distinctive features regardless of the number of syllables in the sequence. However, distinctive feature theories were not able to predict the frequency of intrusion errors for phonemes presented in the middle serial positions of a sequence with 100% accuracy. The results of the experiment support the notion that consonant and vowel phonemes are coded in a similar manner in STM and that this coding involves the retention of a specific set of distinctive features for each phoneme.     

Child- versus teacher-administered token programs in a psychiatric hospital school

The purpose of this study was to: (a) compare student-administered token programs with similar programs administered by professional teachers, (b) investigate the contribution of feedback to the success of token systems, (c) compare the effectiveness of peer and teacher feedback, and (d) test a sequence of withdrawal from token programs designed to increase generalization. Results indicated that (a) peers could do just as well as teachers in reducing disruptive behavior through a token program, (b) feedback is not solely responsible for the effectiveness of token reinforcement, (c) peer feedback may be more effective than teacher feedback, and (d) withdrawal from token reinforcement to feedback may be a successful method of retarding the increases in disruptive behavior usually found when backup reinforcers are eliminated.The project was supported by Grant OEG 0-71-2872 (607) from the U.S. Department of Education and Department of Health, Education, and Welfare. The opinions expressed herein, however, do not necessarily reflect the position or policy of the U.S. Office of Education, and no official endorsement by that Office should be inferred. The author would like to thank Drs. L. Krasner, A. O. Ross, and K. Feldman for their assistance throughout the study, and Dr. K. D. O'Leary for his invaluable help. Also gratefully acknowledged is the help of R. Spitalnik, R. Kent, M. Hageman. S. Ransom, W. Kaler, S. Golembeski and E. Howard.     

Social Comparison and Bystander Intervention in Emergencies

In a 2 × 2 experimental design, male subjects were exposed to a "lady in distress" in the presence of a confederate who was either similar or dissimilar to the subject and who reacted to the situation with either passive unconcern or with apparent alarm. Consistent with a social comparison interpretation, the confederate's reactions markedly influenced whether subjects intervened. While degree of similarity was unrelated to probability of occurrence of an intervention response, it exerted a strong effect on intervention response latency. It is proposed that social comparison processes not only may influence an observer's interpretation of a situation, but may also contribute to situational ambiguity and affect the observer's degree of confidence in the validity of his interpretation of the situation. Any of these factors may, in turn, determine whether and how quickly an intervention response occurs.