Effects of ontogeny on performance of rats in a novel object-recognition task

The current experiment investigated ontogenetic forgetting on a novel object-recognition task similar to that of Besheer and Bevins. 18-day-old pups (n = 49) and adult (n = 29) rats were tested at two retention intervals (1 min. or 120 min.). By employing exclusion criteria which demanded minimum amounts of object exploration at training and test, the performance of 18-day-old pups but not that of adults was significantly impaired at 120 min. relative to 1 min. Analysis indicated that the ontogeny of the learning and memory measured in novel object recognition follows a developmental trend similar to that of other forms of learning, with older animals remembering more and thus performing better than younger animals. Unfortunately, given the extreme variability inherent to the task and large N necessary to achieve significance, the use of this task in studies of learning, memory, and development is discouraged.     

A role for CS-US contingency in Pavlovian conditioning

Two experiments evaluated the role of conditioned stimulus-unconditioned stimulus (CS-US) contingency in appetitive Pavlovian conditioning in rats. In both experiments, some groups received a positively contingent CS signaling an increased likelihood of the US relative to the absence of the CS. These groups were compared with control treatments in which the likelihood of the US was the same in the presence and absence of the CS. A trial marker served as a trial context. Experiment 1 found contingency sensitivity. There was a reciprocal relationship between responding to the CS and the trial marker. Experiment 2 showed that this result was not stimulus or response specific. These results are consistent with associative explanations and the idea that rats are sensitive to CS-US contingency.     

Verbal mediation of number knowledge: evidence from semantic dementia and corticobasal degeneration

Patients with corticobasal degeneration (CBD) appear to have impaired number knowledge. We examined the nature of their number deficit while we tested the hypothesis that comprehension of larger numbers depends in part on verbal mediation. We evaluated magnitude judgments and performance on number conservation measures rooted in Piagetian theory in nonaphasic patients with CBD (n=13) and patients with a fluent form of progressive aphasia known as semantic dementia (SD; n=15). We manipulated the numbers of the arrays and the visual-spatial properties of the stimuli being compared during magnitude judgments and Piagetian conservation measures. CBD patients were consistently impaired judging the magnitudes of larger numbers (4-9), while they had minimal difficulty with smaller numbers (magnitudes < or = 3). By comparison, SD patients performed all measures of number knowledge at a ceiling level regardless of number magnitude. Neither patient group was significantly impacted by manipulations of the spatial properties of the stimuli. CBD patients' impairment with larger numbers despite minimal aphasia, and SD patients' intact performance despite an aphasia, challenge the proposal that understanding larger numbers depends on verbal mediation.     

The impact of rock videos and music with suicidal content on thoughts and attitudes about suicide

In Experiment 1, 133 college student volunteers watched a rock music video with or without suicidal content and then completed written measures assessing mood, priming of suicide-related thoughts, perceptions of personal risk, sensitivity to suicidality in others, and attitudes/beliefs about suicide. In Experiment 2, 104 college student volunteers listened to rock music with either suicidal or neutral content and then completed measures similar to Experiment 1, with the addition of a hopelessness measure. In both experiments, participants exposed to suicidal content wrote more scenarios with suicide-related themes in a projective storytelling task than those exposed to nonsuicidal content. However, there were virtually no group differences on explicit measures of affect, attitudes, and perceptions. Music and videos with suicide content appeared to prime implicit cognitions related to suicide but did not affect variables associated with increased suicide risk.     

Interpersonal problems,personality pathology,and social adjustment after cognitive therapy for depression

The authors examined the level and structure of the Inventory of Interpersonal Problems-Circumplex version (IIP-C; L. M. Horowitz, L. E. Alden, J. S. Wiggins, & A. L. Pincus, 2000) before and after 20 sessions of acute-phase cognitive therapy for depression (N = 118), as well as associations with the Schedule for Nonadaptive and Adaptive Personality (L. A. Clark, 1993b) and the Social Adjustment Scale--Self-Report version (M. M. Weissman & S. Bothwell, 1976). Interpersonal problems had a 3-factor structure (Interpersonal Distress, Love, and Dominance), with the latter 2 factors approximating a circumplex, both before and after therapy. Interpersonal Distress decreased and social adjustment increased with therapy, but the Love and Dominance dimensions were relatively stable, similar to personality constructs. Social adjustment related negatively to Interpersonal Distress but not to Love or Dominance. Personality pathology related broadly to Interpersonal Distress and discriminantly to Love and Dominance. These findings support the reliability and validity of the IIP-C and are discussed in the context of personality theory and measurement.