On the role of reduced auditory feedback and kinesic self-stimulation during Stroop Color-Word performance1

Feedback from one's own voice provides important vocal–motor cues for effective cognitive processing. Reduction of such feedback is known to disturb such functioning. Work in our laboratory has shown that kinesic self-stimulation also plays an important role in cognition, and appears to regulate the focusing of attention under conditions of distraction. The present study investigated the effects of both auditory feedback and kinesic self-stimulation in the regulation of cognitive interference during performance of the Stroop Color-Word Task. Twelve subjects were tested on the Stroop task under conditions of normal and occluded hearing. Kinesic self-stimulation and response errors during color-word performance were recorded on video tape. The findings indicated that not only did self-stimulation increase when voice feedback was reduced, but that this increase was associated with a reduction in specific types of color-word performance errors. Individual differences revealed that high kinesic responders made significantly fewer errors in task performance than did low kinesic responders. Results were interpreted as revealing a kinesic feedback mechanism which has adaptive significance in regard to self-editing when auditory feedback is reduced.     

The availability explanation of excessive plausibility assessments

The assessment of hypotheses in hypothesis generation involves a comparison between those hypotheses that have been generated (specified) and those that are not generated (unspecified). Experiment 1 was an investigation of an “availability explanation” for subjects' overconfidence in the probability of specified hypotheses. The conjecture is that subjects have difficulty retrieving unspecified hypotheses from memory. Therefore, the underpopulated set of unspecified hypotheses is assessed as less probable then it actually is and the specified set is assessed as more probable. Two manipulations to increase the availability of unspecified hypotheses were investigated. One involved explicitly requesting subjects to populate the unspecified set; the other was a computer presentation of candidate unspecified hypotheses. Results of experiment 1 were that assessment overconfidence for both experimental groups was reduced. The results support the conjecture that the availability heuristic is at least partially responsible for subjects' overconfidence. The main result of experiment 2 was that the overconfidence bias persisted with different assessment methods for both subject-generated and experimenter-supplied hypotheses.     

A note on sufficient conditions that a common factor will be determinate in an infinite domain of variables

It is proved for the common factor model withr common factors that under certain condition s which maintain the distinctiveness of each common factor a given common factor will be determinate if there exists an unlimited number of variables in the model each having an absolute correlation with the factor greater than some arbitrarily small positive quantity.The author is indebted to R. P. McDonald for suggesting the proof of Guttman's determinantal equation for the squared multiple correlation in predicting a factor from the observed variables used in the parenthetical note.     

Learning the invariants of a perceptual motor skill

The concept of invariant relative timing has typically been associated with the concept of a generalized motor programme. The present study approaches the phenomenon of invariant relative timing from the perspective of learning. The underlying question of concern for this study was, "What is learned." The specific question was whether relative timing is one of the essential properties of movement that is learned during skill acquisition. In the present experiment, subjects were given extensive practice in learning to track and reproduce a criterion waveform using a joystick control for their response. In order to test whether subjects learn the relative timing of a movement, they were transferred to tracking waveforms that were identical to the criterion in terms of relative timing, but different in terms of absolute timing. Measurements were taken on all waveforms in two conditions: (a) in a pursuit tracking condition where subjects were temporally constrained by the stimulus, and (b) in a reproduction condition where subjects' timing was not constrained. The outcome from both conditions gives support to the idea that humans learn invariant relative timing during the acquisition of a motor skill.     

The influence of positive and negative reinforcement on selective attention in the rat

In Experiments 1 and 2 rats were trained under two multiple schedules of reinforcement. In one, bar pressing during a tone-light compound stimulus was reinforced under a variable-interval food reinforcement schedule. In the other multiple schedule, bar pressing avoided grid shock on a free-operant schedule. In both multiple schedules, a discrimination was maintained by an extinction schedule that was operative during the absence of the tone-light compound. In Experiments 1 and 2 the intensity of the tone-light compound was manipulated over three levels. Subsequent extinction tests revealed that light was attended to, almost exclusively of the tone, when food reinforcement had maintained bar pressing. On the other hand, the tone gained considerable attentional control under the shock avoidance schedule. This stimulus-reinforcer interaction was maintained for all three levels of the compound intensity. In Experiment 3 it was investigated whether this interaction was associative by presenting shock during the absence of the tone-light compound when food reinforcement maintained responding, and food during the absence of the compound when shock avoidance maintained responding. Since both food and shock were presented during a single session for both schedules, nonassociative effects of the reinforcing stimuli were equivalent across the schedules. Nevertheless, the stimulus-reinforcer interaction was maintained, indicating that the interaction was an associative effect.     

Self-image formation in adopted children: The environment within

Adoption of a child is an event in which a number of crises have converged. Both the biologic and adoptive families have contributed their failures and crises, and the subsequent interpretations of these by the adopted child can lead to polarized themes of goodness and badness. The absence of the biologic parents and of a coherent history reinforces the tendency to splitting. This paper explores these operations and raises questions about prevailing adoption practices.Paper presented at Spence-Chapin Symposium on Identity Problems of Children in Non-Nuclear Families, April 11, 1981.     

The relationship between sighting dominance and the fading of a stabilized retinal image

The fading of a stabilized retinal image in the sighting and the nonsighting dominant eye was studied using the Haidinger’s brush target. Reaction time to the complete disappearance of the stabilized image was significantly longer when the target was input to the sighting eye. The greater persistence of stabilized targets in the sighting eye suggests possible differences in the neural channels from the two eyes or processing differences in the two monocular channels that are related behaviorally to eye dominance.     

A truth-conditional formulation of Karttunen's account of presupposition

Karttunen's seminal 1973 article Presuppositions of compound sentences, lays the groundwork for the elegant and fruitful theory of this subject which he subsequently presented in (1974). In (1973, pp. 185–8), however, he fallaciously argued that the regularities he discovered concerning the behavior of and, or, and if ... then in English cannot be embodied in any three-valued logic giving a truth-functional interpretation to these connectives. The present paper refutes Karttunen's argument by exhibiting an interpretation with the desired properties, and shows further how the full articulation of his 1974 system can be developed naturally within a truth-conditional semantics for English if bivalence is abandoned — contrary to what Karttunen expected.