Knowledge that Transforms

Auditory memory of 2 rhesus monkeys was tested in a serial probe recognition task. Lists of four environmental or natural sounds were followed by a retention interval and a test. The test matched one of the list items on half of the trials. The retention interval was varied across sessions. Six experiments showed similar results and changes in the serial position function. At short retention intervals, there was good memory for first list items (primacy effect) and poor memory for last list items. At intermediate retention intervals, memory improved for last list items (recency effect). At long retention intervals (20 s and 30 s), the recency effect was strong, and the primacy effect had dissipated. These auditory primacy and recency effects and their changes with retention interval were opposite to those for visual memory. Implications for processes and mechanisms of memory are discussed.

Infants watched an experimenter hide a toy in one of three wells and then attempted to retrieve it after a brief delay. Seven-month-olds performed at chance. Nine-month-olds reached correctly on 43% of trials, which is significantly better than chance. After an incorrect reach, infants were allowed to choose between the two remaining locations. Seven-month-olds responded at a chance level on their second reach, but 9-month-olds chose correctly more often than would be expected by chance despite a 10- to 20-s delay between hiding and search. One cause of error on the initial reach was a profound bias toward the center well. In Experiment 2, the wells were covered simultaneously, and the infant's spatial orientation was disrupted during the delay; this procedure eliminated the centripetal bias. Nine-month-olds still responded correctly more often than would be expected by chance on their second reach. These findings suggest that 9-month-olds sometimes have a more durable working memory for location than is generally reported for that age group.

We examined posthypnotic suggestion away from the laboratory. In Experiment 1, high-hypnotizable subjects were given a post-hypnotic suggestion (of limited or unlimited duration) or a social request (of unlimited duration) to mail one postcard every day to the experimenter. Subjects given a social request rather than a posthypnotic suggestion sent more postcards, and those given a limited-duration suggestion responded differently from those given an unlimited-duration suggestion. In Experiment 2, real, hypnotized and simulating, unhypnotized subjects were given a posthypnotic suggestion, and nonhypnotic control subjects were given a social request, to mail one postcard every day; the suggestion or request was of either limited or unlimited duration. Real, hypnotized subjects sent more postcards than simulators; control subjects sent as many postcards as real, hypnotized subjects; and subjects given a suggestion or request of limited duration sent more than those given one of unlimited duration. The findings highlight the interaction of individual differences and the social context of the suggestion or request. They underscore important aspects of experience and behavior associated with posthypnotic responding away from the hypnotic setting.

The Yu et al. (1997) study on correlates of mean score on the Examination for Professional Practice in Psychology (EPPP) contained some clerical errors that are corrected here. The findings and associated inferences are basically the same after making these corrections as they were before. Academically stronger clinical psychology programs have graduates who tend to score higher on the EPPP. An additional analysis using only professional schools revealed that programs approved by the American Psychological Association and those that are not freestanding tend to produce graduates with higher scores.

Previously unacquainted undergraduates (15 men, 15 women) interacted briefly in randomly assigned pairs, and subsequently attempted to infer the self-evaluations of their partners in terms of both personal constructs elicited from the latter and a set of supplied constructs. Inferences based on elicited constructs were significantly more accurate (p < .005) than were those based on supplied ones. Also, the self-evaluations of participants with relatively less differentiated personal-construct systems, as assessed by the repertorygrid procedure, were inferred by their partners significantly more accurately (p < .01) in terms of elicited constructs than were those of participants with relatively more differentiated personal-construct systems. These findings are interpreted within the framework of personal-construct theory.

Successful navigation in the world requires differentiating an obstacle in one's path from an aperture through which one could pass. An approaching obstacle is specified by texture expansion within the obstacle's contour and the deletion of background texture outside the object. In contrast, an approaching aperture contains texture expansion within the aperture's frame and accretion of background texture within the aperture's contour. This study investigated 3- to 5-month-old infants' discrimination of obstacles from apertures, examining eyeblink responses to the movement of both kinds of objects against backgrounds varying in salience. Obstacles produced stronger looming reactions than apertures, and the salience of the background influenced responses to apertures but not obstacles. These findings imply that infants differentiate obstacles from apertures based on their relative patterns of accretion versus deletion of background texture, and suggest that infants recognize the functional consequences of contact with these objects.