Reinforcement duration and the peak shift in post-discrimination gradients

Pigeons were trained to key-peck for food, first with single-stimulus training and then with successive discrimination (multiple schedule) training. In the multiple schedule, two different wavelengths were each correlated with equally frequent variable-interval reinforcement but different durations (6 sec vs. 2 sec) of access to grain. For some birds, the different durations of feeding cycle were cued by different intensities of the food hopper light. For some of these “cued” birds, single-stimulus training had been carried out with 6-sec feedings and when multiple-schedule training was introduced, the novel stimulus was correlated with 2-sec feedings. For the others, 2-sec feedings were originally used, and the novel stimulus was then present during the 6-sec reinforcement duration. The cueing procedure enhanced discrimination performance, and was necessary for the consistent production of a peak shift. In addition, the condition in which original training had been carried out with 6-sec feedings, and thus reinforcement duration was reduced in the presence of the novel stimulus, led to the best performance.     

Syntactic structure modifies attention during speech perception and recognition

The present paper demonstrates the interaction of syntactic structure and speech perception with a response task which minimizes the effects of memory: reaction time (RT) to clicks during sentences. (1) In 12-word unfamiliar sentences each with two clauses, RT is relatively slow overall to clicks located at the end of the first clause but decreases as a function of clause length. Clicks at the beginning of the second clause are not affected by length of the preceding clause. (2) In familiar sentences, RT is relatively fast to clicks located at the end of a clause while RT to clicks at the beginning of clauses is relatively unaffected by familiarity. (3) RT is not fastest overall to clicks located between clauses either in novel or familiar sentences. (4) As in previous studies, the subject's subsequent judegment of the location of the click tone are towards the clause break. (5) We could find no systematic interaction between RT and subjective click location. Findings (1) to (3) are consistent with the view that perceptual processing alternates between attending to all external stimuli and developing an internal representation of the stimuli. Finding (3) is in conflict with an “information channel” view of immediate attention to speech, which would predict high sensory attention to non-speech stimuli between clauses. However, findings (4) and (5) indicate that the channel view of perception may be correct for that perceptual processing which occurs after the immediate organization of the speech stimulus into major segments.     

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.     

Investigations of a mirror-image transfer effect in pigeons

In two separate experiments, pigeons trained binocularly to peck a key on which an oblique line (e.g., 60 degrees counter-clockwise rotation from horizontal) was projected yielded bi-modal angularity generalization gradients in extinction, with peaks of responding at both the training stimulus and its mirror image (in this case 120 degrees ). This mirror-image transfer effect may be analogous to an "octave effect" in auditory generalization, but Mello's finding of a mirror-image reversal transfer effect following monocular training in pigeons suggests an alternative interpretation.     

Wistful Wish: Evaluation Without Values

Two recommendations from a recent statement of standards for counselor education are examined for underlying philosophical assumptions. The first recommendation, that counselors should possess ability for and conduct scientific research, assumes that the counseling process is lawful and orderly, that theoretical concepts can be operationally defined and that empirically testable predictions can be derived from counseling theories. A second recommendation suggests that counselors-in-training be selectively admitted and retained. Underlying this recommendation is the assumption that counseling is a process of influence that can be evaluated. Such evaluation must be based on conditions outside the counseling relationship, in the social context of the life of the client. The serious implications of these assumptions are illustrated and discussed.     

The active use of grammar in speech perception

Judgments of the location of short bursts of noise in sentences were used to reveal perceptual segmentation of sentences. It was assumed that segmentation would correspond to major constituent boundaries. In order to control for correlated variables of pitch and intonation, identical acoustic material was provided with alternate constituent structures. It was found that differences in response to identical strings were predicted by the points of variation in constituent structure.     

Source variability and recall of auditory material 1

Recall of auditory narrative material was measured under three conditions of presentation. These were a single source condition with material from one speaker, a four source fixed sequence condition with material from four speakers in a fixed sequence of 3-sec. lengths, and a four source random condition with material from four speakers in a random sequence of 3-sec. lengths. Recall was better for the single source condition than for the four source conditions. No significant difference was found between the fixed and random sequential presentations. Results are discussed in terms of the attentional behaviors involved in the tasks.     

Binocular summation in the perception of form at brief durations

Visual form identification at brief durations was studied under: (a) monocular presentation; (b) dichopic presentation where the same form was presented successively on noncorresponding areas; and (c) dichopic presentation where the same form was presented on corresponding areas simultaneously and successively. Form identification for noncorresponding area dichopic presentation was at the level to be expected from 2independent chances to perceive. Both simultaneous and successive dichopic presentation on corresponding areas gave identification accuracy significantly above the level predicted by the assumption of independence. However, the binocular summation was not complete. When the same amount of energy entering the visual system in a binocular presentation was given in a monocular stimulation, the latter condition gave significantly better identification.