Errorless establishment of visual discrimination using fading procedures

A visual discrimination task involved presenting a triangle briefly as a sample. When it was withdrawn, this triangle and two others differing slightly in degree of rotation were presented in different positions, with S required to locate the sample that had been presented. Discrimination proved difficult for preschool children. When only the correct triangle was illuminated, discrimination was readily established. The brightness difference between correct and incorrect matches was gradually faded out by increasing the intensity of the incorrect matches, until they were equal in brightness to the correct match. The discrimination established by brightness difference was maintained in its absence, thereby transferring stimulus control from brightness to form, in an almost errorless sequence.     

Alcoholism and the Force of Education

Education in regard to alcoholism has not been a noted success. This problem is examined by approaching the situation from a psychoanalytic view, as well as through the review of the history of the use, abuse, and prohibition of alcohol in this country. Attitudes toward alcohol share much in common with the attitudes to the other instinctual gratifications. Because of the many repressions involved, the problems of transference make their appearance in the performance of the alcoholism educator, as well as the student. The conscious avoidance of patronizing, prohibitionist, and similar attitudes might allow the teacher to present both the advantages and the dangers in the use of alcohol, and thus open the subject to more wholesome consideration.     

The Edinburgh Masker: A clinical analog study

This article will describe the effects of instructions and practice on the vocal intensities of normal speakers and stutterers while reading in the presence of masking moise generated by the Edinburgh Masker. Both the normal speakers and the stutterers reacted in similar ways: They increased vocal intensity with the introduction of the noise, reduced vocal intensity in the presence of the noise, given instructions and practice, but failed to reduce vocal intensity to pre-noise reference levels. While these results are hardly reflective of long-term change in clinical behavior, a recommendation is made for a reexamination of the role of the increased vocal intensity as at least one factor, of perhaps many, responsible for whatever the long-term clinical effectiveness of the Masker.     

Contribution of nesting experience to progesterone-induced incubation in ring doves (Streptopelia risoria)

Injections of progesterone induce incubation behavior in gonadally intact ring doves only if the doves have had previous experience with at least the nest-building phase of a breeding cycle. The present study was designed to determine whether exposure to progesterone during the nest-building phase is sufficient to account for the ability of progesterone to induce incubation at a later time or whether some other factor provided by experience with this phase of the cycle is needed. Six groups of 10 pairs of doves each were provided with different combinations of experience and progesterone priming. Progesterone priming combined with social isolation or with courtship experience had no significant effect on subsequent progesterone-induced incubation. However, doves that participated in the nesting phase of the cycle during progesterone priming later incubated in response to progesterone treatment. Nesting activity, which may or may not include building the nest, seemed to be the relevant experience.     

Lick-trading by rats: on the substitutability of dry, water, and saccharin tubes.

Thirsty rats licked two metal tubes: a water tube paired with another water tube, with saccharin, or with a dry tube. For each pair, a multipoint baseline function was measured by offering free access to one tube throughout each session, and free or restricted access to the other. The three resulting baseline functions showed the members of each pair to be mutual substitutes: When access to either tube was restricted, the rats made more licks at the other. A linear function identified the two water tubes as perfect substitutes. Convex functions identified the members of the saccharin-water and the dry-water pair as imperfect substitutes. Each pair was also tested under several reciprocal fixed-ratio schedules that required instrumental licking of either tube for contingent access to the other. The resulting schedule functions showed the members of each pair to be perfect substitutes: Water licks decreased linearly as licks at the other water tube, the saccharin, or the dry tube increased, in agreement with a conservation model of instrumental performance. Baseline and schedule functions, indistinguishable in the water-water pair, indicated a schedule facilitation of dry-tube licking in the dry-water pair and of water-tube licking in the saccharin-water pair.