Dichotic ear preferences of stuttering children and adults.

39 stutterers and 39 normal speakers indicated their ear preferences for dichotically presented words and digits. A single response mode for both dichotic words and digits was selected to study speech perception. Stutterers showed significantly less of the normal right-ear preference for dichotic words and digits than non-stutterers. The proportion of stutterers who failed to demonstrate a right-ear preference for dichotic words was significantly greater than for non-stutterers. 18% of the stutterers and none of the non-stutterers showed reversed or a left-ear preference for dichotic digits. Although non-stuttering children and adults performed alike on the dichotic tasks, the right-ear dichotic-words scores of stuttering children were significantly smaller than those of adult stutterers. The results are related to an early notion that stuttering may be related to mixed dominance and recent evidence showing that large percentages of older stuttering children show spontaneous remission of stuttering.     

Voluntary attention and the spacing effect

Three experiments were done to test the hypothesis that the spacing effect results from a voluntary decision by the subject to pay little attention to the second presentation (P₂) of an item when it occurs shortly after the first (P¹)- In all three experiments, the spacing of repetitions was varied. In Experiment I, allocation of attention was manipulated by pairing P₂ of some pictures with a signal that indicated high payoff for later retention. In Experiment II, attention was controlled more directly by requiring the subject, in one condition, to recite words aloud. In both experiments, the dependent variable was judged frequency. In neither experiment did the effect of the attention manipulation interact with that of the spacing of repetitions. In Experiment III, the number of eye fixations given a picture was taken to be a measure of attention. The number of fixations dropped from P₁ to P₂ to P₃, but was unaffected by the spacing of repetitions. The experiments provide no support for a voluntary attention explanation of the spacing effect.     

The interference of various word parts on color naming in the Stroop test

This study compared the interfering effects of various word parts on performance of the Stroop task. In different conditions, the first, middle, and last two letters of a color word formed color patches. In other conditions, random letters were attached to these word parts. In a control condition, entire words formed the color patches. While no condition produced as much interference as the control condition, the first part of a color word interfered with color naming more than other word parts. The addition of unrelated letters had little or no effect on the interference produced by the first part of a word. The results are consistent with suggestions that word perception often involves the activation of an articulatory motor program which is initiated by the first part of the word.     

Vigilance and the reinforcing properties of shock

There have been some observations to indicate that waiting for a shock is stressful, that the coining of an anticipated shock can serve as a tension reliever, and that failure to obtain an anticipated shock is more stressful than being shocked. Based on these observations, the following hypotheses were tested. If it is true that failure to receive shock is more stressful than the shock itself, it should be possible to train an animal to bring on a shock that had failed to come when anticipated. If a period of anticipating shock is stressful, and shock serves as a reliever of the stress, it should be possible to train an animal to perform a response instrumental to bringing on the shock sooner. Results indicated that shock does seem to serve as a reliever, that waiting for shock is stressful, but that failure to receive an anticipated shock under these circumstances is not more stressful than the shock itself. In addition, it was found that subjects learned to produce shock instrumentally if the shock was inevitable and could thus be brought about sooner. Results were inconclusive, though generally negative, on the issue of whether S’s would produce an avoidable shock that had failed to come when anticipated.