Age-related deficits in prospective memory: the influence of task complexity.

Younger and older subjects were asked to perform an action whenever target words occurred during a short-term memory task. The difficulty of this prospective memory task was manipulated by varying the delay preceding the occurrence of a target event and by varying the number of different target events. Age-related performance differences emerged when there were several different target events but not when there was one target event presented several times. Age-related performance differences, when they occurred, were associated with poorer retrospective memory for the target events. The results were interpreted in terms of a componential analysis of prospective memory, which assumes both similarities and differences between prospective and retrospective memory.     

Predicting cognitive recovery from closed head-injury in children and adolescents

Longitudinal data from 84 head-injured children and adolescents, who were tested at three points in the first year postinjury, were analyzed to determine the best combination of demographic, injury-related, and behavioral factors predicting cognitive performance. Dependent variables were language, memory, visuomotor, and speeded performance factor scores obtained through confirmatory factor analyses of an extensive test battery. Multiple regression analyses indicated that injury severity and the existence of previous psychological, physical, or cognitive disorders were primary for predicting acute (1 month post-hospital discharge) performance for older subjects. For younger subjects, however, parental marital status was the most important correlate of acute cognitive performance. Those residing in homes with both parents fared better than children in one-parent families. At 6 months and 1 year postinjury, the older subjects who performed most poorly initially remained the most impaired. For younger children, acute cognitive standing was also an important predictor of later performance, but parental marital status remained a crucial influence on their longer-term recovery of cognitive skills.     

The role of a guessing strategy in the Bransford-Franks paradigm

Within the framework of the Bransford-Franks paradigm, variations of two memory models and a guessing strategy hypothesis were evaluated using concepts that differed in the number of atomic units each contained (‘concept size’). Results showed that, though the precise patterns of recognition for concept size were not completely consistent with any of the explanations, the changes in the patterns across concept size agreed with the guessing strategy hypothesis. It was argued that the subject's interpretation of the guessing strategy is likely to be a similar but simpler version of the experimenter-theorist's formal model, with the consequence that, while less sensitive to the finer details of the formal model, it will still reflect coarser differences.     

BEHAVIORISM: PART OF THE PROBLEM OR PART OF THE SOLUTION?1

The form frequently taken by behavior-modification programs is analyzed in terms of the parent science, Behaviorism. Whereas Behaviorism assumes that behavior is the result of contingencies, and that lasting behavior change involves changing the contingencies that give rise to and support the behavior, most behavior-modification programs merely arrange special contingencies in a special environment to eliminate the “problem” behavior. Even when the problem behavior is as widespread as alcoholism and crime, behavior modifiers focus on “fixing” the alcoholic and the criminal, not on changing the societal contingencies that prevail outside the therapeutic environment and continue to produce alcoholics and criminals. The contingencies that shape this method of dealing with behavioral problems are also analyzed, and this analysis leads to a criticism of the current social structure as a behavior control system. Although applied behaviorists have frequently focused on fixing individuals, the science of Behaviorism provides the means to analyze the structures, the system, and the forms of societal control that produce the “problems”.     

Transfer of inhibition after serial and simultaneous feature negative discrimination training

Three experiments examined the nature of inhibitory learning in Pavlovian simultaneous (A+, XA-) and serial (A+, X → A-) feature negative discrimination prodecures in a conditioned suppression situation with rat subjects. The feature (X) trained with simultaneous procedures readily inhibited suppression conditioned to another excitor (B) that was not involved in the feature negative discrimination with X. But the feature trained with serial procedures showed little or no ability to inhibit suppression conditioned to other excitors. These results were obtained with both between- and within-subjects designs, with a variety of test procedures, and after extinction of the A excitor used to establish the inhibition to X. They suggest that nature of the inhibition learned in feature negative discriminations depends on the temporal arrangement of stimuli. We favored the possibility that inhibitors established using simultaneous stimulus arrangements modulate behavior by acting on a representation of the unconditioned stimulus, but inhibitors established with serial procedures act on particular conditioned stimulus-unconditioned stimulus associations.     

Associations in Pavlovian conditioned inhibition

Two experiments with rat subjects used a variety of transfer tests to examine the associations learned when Pavlovian inhibition is established by an A+, AX− paradigm. Experiment 1 found in a conditioned suppression situation that inhibition conditioned to X with one exciter (A) readily transferred to another exciter (B) which had been paired with the same shock US. Transfer occurred even when the response to A had been extinguished prior to testing with B. However, X did not inhibit a general activity response produced by a B which had been subsequently paired with a food US. Experiment 2 employed a Pavlovian conditioning situation in which A and B, when separately paired with the same food US, evoked dissimilar responses. Nevertheless, an inhibitor trained in an A+, AX− paradigm successfully inhibited the different response evoked by B. However, such an X did not inhibit the behaviors acquired by A or B when they were subsequently paired with a shock US. The transfer of Pavlovian inhibition across conditioned stimuli and responses but not across unconditioned stimuli is consistent with the notion that a conditioned inhibitor acts to prevent activation of a US representation which would normally be activated by conditioned exciters.     

The effect of the blackout method on acquisition and generalization

In discrimination training with the Lyons' blackout method, pecks to the negative stimulus are prevented by darkening the chamber each time the subject approaches the negative stimulus. Stimulus generalization along a stimulus dimension was measured after training with this method. For comparison, generalization was also measured after reinforced responding to the positive stimulus without discrimination training, and after discrimination training by extinction of pecks to the negative stimulus. The blackout procedure and the extinction of pecks to the negative stimulus both produced a peak shift in the generalization gradients. The results suggest that after discrimination training in which the positive and negative stimulus are on the same continuum, the blackout method produces extinction-like effects on generalization tests.