Successive vs simultaneous processing of superimposed visual stimuli

A visual analogue of Savin’s (1967) auditory task was used to examine preferred order of recall and order of recall accuracy for two pairs of visually superimposed digits. Savin (1967) and Rollins, Everson, and Schurman (1972) found that Ss preferred to recall simultaneous auditory information in successive order, even though the information was presented over a single channel. In the present experiments, Ss were found to prefer strongly to recall visual information in simultaneous order. On the other hand, the results of Rollins et al (1972), that Ss are equally accurate when forced to recall simultaneous auditory information in either the preferred or nonpreferred mode, were replicated for this visual task. The results of these experiments, together with the experiment reported by Rollins et al (1972), indicate that verbal information is processed differently by these two sensory systems.     

Schedule control of the vocal behavior of Cebus monkeys

The vocal behavior of three Cebus monkeys was maintained by fixed-ratio schedules of response dependent reinforcement at values between fixed-ratio 1 and fixed-ratio 15. In one monkey that was exposed to variable-interval, fixed-interval, and conjunctive fixed-ratio fixed-interval schedules of reinforcement, vocal responding occurred at a low rate, but schedule-appropriate patterns were maintained. The rates and patterns of responding engendered indicated that the vocal operant can be brought under schedule control in the monkey by the use of response-dependent reinforcement.     

Positive interaction (induction) in multiple variable-interval, differential-reinforcement-of-high-rate schedules

The effect of increases in the rate of responding in one component of a multiple schedule upon the rate of responding in a second component was investigated. Pigeons were exposed to a multiple schedule where both components were initially variable-interval schedules having the same parameter value. After rate of key pecking stabilized, one component was changed to a schedule that differentially reinforced high rates of responding. Rate of reinforcement in this varied component was adjusted to remain equal to rate of reinforcement in the constant (variable-interval) component. Four of five pigeons showed a maintained increase in rate of responding during both the constant and varied components, even though rates of reinforcement did not change.     

Fixed-interval limited-hold avoidance with and without signalled reinforcement

Rats trained to lever press on a fixed-interval limited-hold avoidance schedule maintained a pattern of responding similar to that maintained by fixed-interval limited-hold schedules of positive reinforcement. But this positively accelerated pattern of behavior was maintained only when the occurrence of reinforcement was signalled by the presentation of a brief flash of light. This result suggests that the discriminative function of the reinforcer in avoidance is less pronounced than the discriminative function of the reinforcer in escape or positive reinforcement. It also suggests that the distinction between positive reinforcement and avoidance is not superfluous. Although the schedule of reinforcement is an important variable in determining the pattern of behavior, other variables, such as the nature (i.e., stimulus presentation, termination, or omission) of the reinforcer, are also potent determinants of behavior.     

Social validation of an objective measure of dominance in captive monkeys

The validity of a primate dominance hierarchy was examined in terms of its relationship to social interactions. Twelve social behaviors associated with dominance and aggression were recorded during 61 h of observation of six pigtail macaques (Macaca nemestrina). Of the 1,462 interactions recorded, 94.7% were oriented in the water dominance hierarchy in the direction that would be predicted on the basis of their ascribed functions.     

Short-term visual memory and pattern masking

The results of two experiments involving the matching of unfamiliar, nameless shapes (Gibson forms) indicated that a visual representation of a brief (30-100 ms) stimulus survives in a Short-Term Visual Memory (STVM) for 6 s or more after the onset of a pattern mask. On the basis of these results a possible alternative to Sperling's (1967) model for short-term memory for visual stimuli was presented. In this model it is assumed that recognition processes occupy several hundred milliseconds and continue after the arrival of the mask using the information available in STVM.     

An apparatus for apparent conditioning ofOctopus cyaneus Gray

An ann-out-of-water response was conditioned as an operant inOctopus cyaneus Gray. The response was limited to a vertical tube, 2.54 em i.d, Photoresistive sensors, illuminated with modulated light arranged around the tube above the waterline, detect the presence of an opaque object in the tube. The signal from this response detector is amplified and used to initiate a commercial motor-driven universal feeder according to the reinforcement schedule maintained by the logic control circuit. A sample cumulative record for perfonnance on a CRF schedule is given.