Springer Science and Business Media LLC

The present study analyzes dissonance and incentive responses to being under-or overpaid for performance. A U-shaped curve of performance as a function of amount of payment was hypothesized. It was also hypothesized that Ss who commit themselves to the importance of a task perform better than those who do not, and that they are more affected by both underpayment and overpayment conditions than uncommitted Ss. For the first and third hypotheses, trends were in the expected direction; the second hypothesis received clear support.

Punishment (shock) administered during or after reward (interesting pictures) produced greater suppression of a human response than did punishment administered prior to reward. These results indicate that the degree of response-suppression depends upon the temporal arrangement of reward and punishment.

The total night-time activity-wheel running by two sympatric species of mice, P. californicus and P. eremicus, was compared under the same simulated sun and moon cycles. Total running by P. californicus correlated negatively with the nightly duration of moonlight, while that of P. eremicus correlated positively. The results were discussed in terms of a temporal dimension of competitive exclusion.

This study was designed to determine whether ducklings would show evidence of attachment to a previously “imprinted” object when they were placed in an open field at 14 days of age. It was found that they did show attachment, spending considerably more time in the center of the field when the object was there than when it was absent. It was also found that when a fear object was placed in the field, half the ducklings stayed close to the imprinted object despite the fact that it meant being closer to the fear object than any duckling would tolerate in the absence of the imprinted object.

Rats were permitted to ingest both a novel and a familiar substance prior to injection with apomorphine hydrochloride (a nausea-producing drug) or isotonic saline. Subsequent 2-choice preference tests showed that apomorphine produced a conditioned aversion to the novel substance, but only with the more palatable of the two novel substances employed.

Four species of testwise monkeys with extensive ablations of posterior neocortex (including inferotemporal tissue) were impaired in a size discrimination problem. The deficit, which was persistent after 1200 trials and two testing procedures may be attributed to a loss in ability to classify visual information.

To determine if S’s ability to perceive and to recognize a letter would increase with well spaced repetitions, even if the position and I or the typeface changed from flash to flash, four Ss were shown six flashes of single letters and were asked to guess the letter and to indicate whether or not they saw it clearly. Recognition (measured by both forced-choice guesses and by perceptual reports) increased at a constant rate whether an identical test letter was flashed on each trial or the form and/or position of the letter was varied (over four levels each) between flashes. The mean level of recognition was also unimpaired by variations in typeface and I or position, when measured by forced-choice guesses. With a perceptual report, recognition was lowered by variation of the test stimulus, apparently through a change in report criterion. These data suggest that the perceptual repetition effect must operate through arousal of the letter name or some other representation of the stimulus rather than by a simple sensory facilitation.

Free recall and clustering performance were studied in children of ages 4 and 9–10 years. Nine different lists were presented, each for three trials, with three lists presented per day. The lists were composed of conceptually related or unrelated items. Each list type was presented consistently with all the items randomized, with conceptually related items grouped together, or with unrelated items arbitrarily grouped together. Performance was generally higher for the older children, but no evidence was found in either age group of learning-to-learn effects of recall or category clustering.