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.     

Another evaluation of touch and helping behavior

Although positive effect of touch on compliance has been widely reported, new evaluation was made with an unusual request. 80 male bus drivers were solicited by a male or a female confederate to take the bus despite having too little money for the fare. Bus drivers were briefly touched by the confederate during solicitation. Analysis showed that bus drivers who were touched accepted the request more favorably but only when made by a female.     

Time-to-contact estimation of accelerated stimuli is based on first-order information

The goal of this study was to test whether 1st-order information, which does not account for acceleration, is used (a) to estimate the time to contact (TTC) of an accelerated stimulus after the occlusion of a final part of its trajectory and (b) to indirectly intercept an accelerated stimulus with a thrown projectile. Both tasks require the production of an action on the basis of predictive information acquired before the arrival of the stimulus at the target and allow the experimenter to make quantitative predictions about the participants' use (or nonuse) of 1st-order information. The results show that participants do not use information about acceleration and that they commit errors that rely quantitatively on 1st-order information even when acceleration is psychophysically detectable. In the indirect interceptive task, action is planned about 200 ms before the initiation of the movement, at which time the 1st-order TTC attains a critical value.     

On discontinuities in motor learning: a longitudinal study of complex skill acquisition on a ski-simulator

The qualitative behavioral reorganizations that occurred during the acquisition of a complex motor skill were examined. Five novice participants practiced for 39 sessions of ten 1-min trials on a modified version of the ski-simulator. Analyses focused on the motion of the apparatus platform, modeled as a self-sustained oscillator. At the beginning of the experiment, all participants adopted a behavior that could be modeled with a highly nonlinear stiffness function and a Rayleigh damping function. The behavior in the final part of the experiment was captured by a qualitatively different model, with a linear stiffness function and a van der Pol damping behavior. The transition from the initial to the final model was gradual and was marked in most cases by an abrupt increase of oscillation frequency. During the transition stage, the 2 damping behaviors seemed alternately exploited within each trial. The results are discussed in the framework of the dynamical systems approach to motor coordination and learning, considering motor skill acquisition as a phase transition.     

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.