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.     

“Backward masking” of simple detection latencies

Simple detection latencies were determined with stimuli that comprised two successive flashes. The second flash either equaled or exceeded the first in luminance, duration, or both. When a low-luminance flash preceded either a low-or a high-luminance flash, the flashes summated, yielding latencies that were shorter than the latency for the first flash alone. In the limit, when the second flash was intense and followed the first by a short time, the latency for the paired flashes behaved as if it was determined by the second flash alone. This limit was analogous to the retroactive interference in studies of the neurophysiological concomitants of backward masking. However, the S in masking studies detects the first flash despite interference by the second, whereas the present S detected the onset of the stimulus light. The need for an analysis of the S’s response under masking is thus indicated.     

CULTURAL DIFFERENCES IN REACTION TO FAILURE1

Les Occidentaux admettent qu'on critique leur performance; ils réagissent en général à la critique en essayant de faire mieux. En Extrême-Orient, il n'est pas convenable de dire à quelqu'un qu'il a échoué en quelque chose; le faisant, on a toute chance de le voir renoncer ou faire plus mal encore. Cette différence de comportement dans les deux civilisations s'explique par des différences d'organisation cognitive. Les AA. ont comparé, dans trois groupes d'étudiants de culture différente (Américains; Extrême-orientaux suivant les cours d'universités américaines; Thais de Thaïlande), les individus qui ont réussi et ceux qui ont échoué dans leurs études. Les sujets américains réagissent à l'échec en réduisant les relations entre toutes les variables étudiées, ce qui constitue un mode de défense en profondeur par le biais d'une organisation plus souple. Les sujets des deux autres groupes réagissent à l'échec par une réduction des contacts personnels et une rigidité accrue de l'organisation personnelle interne. Ces résultats ont une grande importance pratique relativement aux effets sociaux du développement économique en Extrême-Orient.     

An extinction-induced increase in an aggressive response with humans

Nine subjects, 14 to 18 yr old, pulled a knob on a schedule of monetary reinforcement. Concurrently, they escaped or avoided periodic presentations of a tone by pressing a button that required 1.5 lb (6.67 N) of force or by punching a padded cushion that required 20 lb (88.96 N) of force. The punching response was designated as an aggressive response because the force of this response together with its topography was comparable to responses of humans that deface objects and produce escape or counter aggression from other humans. It was found that button pressing was the preferred concurrent avoidance response and there were few punches. However, when the monetary reinforcer was discontinued (extinction) punching increased for seven of the nine subjects, but there was no consistent change in the rate of button pressing. When the punching response was replaced by another non-preferred but non-aggressive response, neither this response nor button pressing increased during extinction. Hence, the increase in punching during extinction cannot be attributed solely to the fact that it was a concurrent response or a non-preferred response.     

Punishment of shock-induced aggression

Squirrel monkeys were restrained in a chair equipped with a tail-shock apparatus and a pneumatic bite hose located in front of the subject's face. An aggressive response was recorded when the monkey bit the hose. Initial sessions in which no shocks were delivered produced some biting. When biting during these sessions stabilized at a near-zero level, regularly scheduled shocks were delivered to the monkey's tail, causing a consistently higher rate of biting. After several sessions under these conditions, a punishment phase was introduced in which the previous shock conditions were maintained, and every bite was followed immediately by another, more intense shock. Biting under these conditions was suppressed to a near-zero level. When the punishment contingency was removed, biting increased. With one subject, two additional bite-contingent stimuli were examined: (1) a milder shock that, when made contingent upon hose biting, also suppressed that response, and (2) a contingent tone that had no obvious suppressing or facilitating effect. Individual differences among subjects were extreme, but the effect of bite-contingent shock was consistent. Observations of the subjects during the punishment sessions indicated the existence of certain side effects that resulted from the use of punishment to suppress shock-induced aggression.     

Disruption of a temporal discrimination under response-independent shock

The responding of rats was reinforced on one key after a 1-sec auditory stimulus and on a second key after a 5-sec stimulus. With errors punished by a short timeout, all subjects achieved a high level of accuracy. A chain of responses during the stimuli mediated the performance so that when the auditory signals were omitted accuracy decreased only slightly. Response-independent aversive stimulation superimposed upon this procedure both suppressed the total amount of behavior and reduced the accuracy of the discriminative performance, the intensity of the stimulus determining the error rate. The increase in errors under these conditions may have depended in part upon differential suppression of members of the response chain, but such suppression was not necessary, since error rate increased even in its absence. Furthermore, the locus of response disruption within the chain was not consistent from day to day either for any individual animal or across animals.     

Effects of pentobarbital on fixed-ratio reinforcement,

Certain doses of pentobarbital consistently increased the rate of pecking engendered by a fixed-ratio schedule of 30 responses in a group of 13 pigeons, and still higher doses produced decrements in rate of responding. For individual subjects, the dose-effect functions were qualitatively similar, but differed with respect to the doses producing the maximum increase and subsequent decrease in rate. In general, the maximum occurred at lower doses and the decrement was greater at the highest dose in the birds with the highest control rates. It was also possible to distinguish between the effects of pentobarbital and several other drugs on the behavior maintained by FR 30. The results indicate that changes in rate of responding on FR 30 after drug administration are dose-dependent, drug-specific effects.