Temporal sequence effects in auditory oddity discrimination

The oddity method was used in assessing pitch, loudness, simultaneous tone, successive tone, and speech sound discrimination in 35 normal children and 15 children with learning problems. With this method three auditory stimuli are presented, two of which are identical, and the S is required to indicate the temporal position of the odd stimulus. For both groups, discrimination was most accurate when the odd stimulus was in the third position. These results could be explained by assuming that the oddity response was based upon successive Same-Different judgments of the first and second stimuli and the second and third stimuli, since a correct response to third-position oddity would require only a Same judgment of the first and second stimuli. Other findings were not as easily explained by this simple model, and alternative hypotheses are discussed.     

d-Amphetamine-chlorpromazine antagonism in a food reinforced operant

Dose effect curves for d-amphetamine and chlorpromazine were obtained with rats on a milk reinforced FR 10 schedule. A dose of d-amphetamine (2.5 mg/kg, i.p.) which completely suppressed all responding for 60 min was administered simultaneously (concomitant with the pretreatment times) with various doses of chlorpromazine. The d-amphetamine-induced cessation of responding was removed by several of the doses of chlorpromazine with maximal antagonism occurring at a dose of 1.5 mg/kg i.p. This dose of chlorpromazine, when administered independently, produced no observable side effects and showed no effect on the FR 10 schedule. One animal appeared to develop tolerance to the repeated dosages of d-amphetamine.     

Laboratory control of thumbsucking by withdrawal and re-presentation of reinforcement

A 5-year-old boy was shown cartoons, and punished for thumbsucking during alternate cartoons by turning off the cartoons for as long as his thumb remained in his mouth. Thumbsucking weakened during such periods. During alternate periods of uninterrupted cartoons, thumbsucking promptly recovered, suggesting a quick discrimination process. Two other 5-year-old boys were shown the same cartoons; withdrawal of the cartoons was made contingent upon thumbsucking for one, and randomly yoked for the other. Then their roles were reversed. Contingent withdrawal and re-presentation of the cartoons controlled thumbsucking rate; yoked withdrawal and re-presentation did not.     

The effect of prior recall on multiple response recognition

Certain investigators have found that recognition is impaired when a recall test is interpolated during the retention interval. One possible explanation of this finding is that interpolated recall leads subjects to employ a more stringent recognition criterion. In the two experiments reported here, the influence of the recognition criterion was eliminated by using a multiple-response test requiring subjects to rank a recognition list consisting of old and new items. Nevertheless recall impaired subsequent recognition in both experiments, the effect being most marked for lowly ranked items. The recognition test in the first experiment was carried out in two stages. This made possible a direct examination of whether recall has an effect on the recognition criterion. No evidence for such an effect was obtained. Other ways in which recall may affect the recognition criterion are discussed.     

In search of ambiguity

A study of the time required for Ss to perceive the two meanings of ambiguous sentences, supports the following conclusions: (I) Perception time (PT) is a function of the type of ambiguity, three of which are defined in this study. (2) A similar relative function was obtained for thePT in sentences with more than one ambiguity and for sentences with only a single ambiguity. (3) ThePT for finding a single ambiguity in such multiply ambiguous sentences was significantly longer than in singly ambiguous sentences. (4) When one of the interpretations of certain types of ambiguous sentences is less likely than the other (where likeliness is defined in terms of the number of Ss perceiving that inter-pretation first)PT is high. (5) Complexity of the surface and underlying structures (which are defined in transformational grammar) is an important determinant of thePT for surface and underlying structure ambiguities, respectively.