Dissociating uncertainty responses and reinforcement signals in the comparative study of uncertainty monitoring

Although researchers are exploring animals' capacity for monitoring their states of uncertainty, the use of some paradigms allows the criticism that animals map avoidance responses to error-causing stimuli not because of uncertainty monitored but because of feedback signals and stimulus aversion. The authors addressed this criticism with an uncertainty-monitoring task in which participants completed blocks of trials with feedback deferred so that they could not associate reinforcement signals to particular stimuli or stimulus-response pairs. Humans and 1 of 2 monkeys were able to make cognitive, decisional uncertainty responses that were independent of feedback or reinforcement history within a task. This finding unifies the comparative literature on uncertainty monitoring. The dissociation of performance from reinforcement has theoretical implications, and the deferred-feedback technique has many applications.     

Developmental patterns in priming and familiarity in explicit recollection

Developmental trajectories of two classes of human memory, implicit and explicit memory, appear to diverge. We examined how developmental differences in perceptual and conceptual priming, two types of implicit memory, coincide with differences between familiarity and recollective responses on explicit memory tests that employ the Remember/Know paradigm ( Tulving, 1985 ). Both types of priming were characterized by developmental invariance in 52 children and adolescents ages 8-19 years. Contrary to Komatsu, Naito, and Fuke (1996) results, few age-group differences in perceptual priming were observed following a levels-of-processing encoding manipulation. In contrast, age group differences were found for "Remember" but not "Know" responses. Neither levels of awareness nor strategies influenced priming. Adult levels of performance appear earlier in development on perceptual and conceptual priming tests compared to explicit memory tests. Similar developmental dissociations exist between explicit and implicit memory performance as between "Remember" and "Know" recollective responses.     

Prospective and retrospective memory in normal aging and dementia: an experimental study

Two experiments investigated the effects of normal aging and dementia on laboratory-based prospective memory (PM) tasks. Participants viewed a film for a later recognition memory task. In Experiment 1, they were also required either to say "animal" when an animal appeared in the film (event-based PM task) or to stop a clock every 3 min (time-based PM task). In both tasks, young participants were more successful than older participants, who were, in turn, more successful than patients with Alzheimer's disease (AD). For successful remembering in the time-based task, older participants and AD patients checked the clock more often than did young participants. In Experiment 2, participants were asked to reset a clock either when an animal appeared in the film (unrelated cue-action) or when a clock appeared in the film (related cue-action). Responses were faster in the related condition than in the unrelated condition. Again, there were differences in PM performance between young and older participants, and between older participants and AD patients. The observed deficits were not due to the forgetting of the PM task instructions in either experiment. Retrospective memory (RM) tasks (digit span, sentence span, free recall, and recognition) were more impaired by AD than were the PM tasks. Factor analysis revealed separate factors corresponding to RM and PM.     

Psychometric evaluation of the depressive personality disorder inventory

The purpose of this study was to evaluate the psychometric properties of the Depressive Personality Disorder Inventory (DPDI; Huprich, Margrett, Barthelemy, & Fine, 1996). The DPDI was found to have strong internal consistency in both an undergraduate and a veteran, psychiatric outpatient population. The DPDI had significant, positive correlations with other measures of depressive personality, supporting its convergent validity. These relationships remained even after controlling for state-like depression, suggesting that the DPDI has incremental validity. The DPDI also significantly predicted scores on measures of interpersonal loss, even after controlling for state-like depression, suggesting that the DPDI has good construct validity. In support of discriminant validity, the DPDI was more correlated with another measure of depressive personality than it was with measures of other personality disorders. Finally, the DPDI had strong diagnostic efficiency statistics: (a) Sensitivity = .82, (b) Specificity = .80, (c) Positive Predictive Power = .75, (d) Negative Predictive Power = .86, and (e) Overall Diagnostic Power = .81. It appears that the DPDI has good psychometric properties.     

Behavioral consequences of radiation exposure to simulated space radiation in the C57BL/6 mouse: open field,rotorod, and acoustic startle

Two experiments were carried out to investigate the consequences of exposure to proton radiation, such as might occur for astronauts during space flight. C57BL/6 mice were exposed, either with or without 15-g/cm2 aluminum shielding, to 0-, 3-, or 4-Gy proton irradiation mimicking features of a solar particle event. Irradiation produced transient direct deficits in open-field exploratory behavior and acoustic startle habituation. Rotorod performance at 18 rpm was impaired by exposure to proton radiation and was impaired at 26 rpm, but only for mice irradiated with shielding and at the 4-Gy dose. Long-term (>2 weeks) indirect deficits in open-field activity appeared as a result of impaired experiential encoding immediately following exposure. A 2-week recovery prior to testing decreased most of the direct effects of exposure, with only rotorod performance at 26 rpm being impaired. These results suggest that the performance deficits may have been mediated by radiation damage to hippocampal, cerebellar, and possibly, forebrain dopaminergic function.     

Instructions to authors

Instructions for Authors

Instructions to authors