On the relation between indistinguishability of identical particles and (anti)symmetry of the wave function in quantum mechanics

Two different concepts of distinguishability are often mixed up in attempts to derive in quantum mechanics the (anti)symmetry of the wave function from indistinguishability of identical particles. Some of these attempts are analyzed and shown to be defective. It is argued that, although identical particles should be considered as observationally indistinguishable in (anti)symmetric states, they may be considered to be conceptually distinguishable. These two notions of (in)distinguishability have quite different physical origins, the former one being related to observations while the latter has to do with the preparation of the system.     

Substance P facilitation of memory: effects in an appetitively motivated learning task

Food deprived, heterogeneous strain (HS/IBG) mice were trained on two different discrimination tasks for food reinforcement. In one experiment animals were trained to make spatial discriminations in a T maze. Immediately after training they were given subcutaneous injections of either substance P (1 ng/g) or vehicle. Twenty-four hours later the animals were given reversal training in the same maze. The results showed that substance P-treated animals took significantly longer to acquire the reversal habit than did control mice. In a second experiment, animals were trained to make visual discriminations in a T maze. Immediately after reaching acquisition criterion animals were injected with either substance P (1 ng/g) or vehicle. Different groups of mice were retrained on the same task either 1, 2, 3, or 7 days after original learning. Savings scores were calculated and, at every interval, substance P-treated mice retained the task better than control animals. One interpretation of these data is that substance P-treated mice remembered the original task significantly better than vehicle-injected control animals.     

Evidence that fixation digits can contribute to visual field asymmetries in lateralized tachistoscopic tasks

Fixation point digits have been widely used in tachistoscopic laterality studies as a simple and convenient means of ensuring unihemispheric projection of stimulus materials to the hemispheres. Previous findings demonstrate that fixation digits do not influence asymmetries in recognition accuracy studies with adult Ss. Present results, comparing four conditions differing in their use of fixation digits, show that in the naming latency paradigm the requirement to remember and report fixation control digits significantly augments RVF superiority. Implications for other latency tasks are discussed.     

Modification of preschool sex-typed behaviors by participation in adult-structured activities

Earlier studies have shown the girls spend more time than boys in activities that are highly structured by adults. Structured activities may encourage feminine sex-typed behaviors such as compliance to adults; low-structure activities may encourage masculine sex-typed behaviors such as independence and assertiveness. In the present study the effects of high or low levels of adult structuring on children's social behavior during preschool free-play activities were tested in a field experiment carried out during an entire semester in one preschool classroom. For the first 15 minutes of free play, children were assigned to high- or low-structure activities. As predicted, when children were in high-structure activities, they exhibited high rates of bids for recognition and compliance to adults; in low-structure activities, they exhibited peer-directed leadership, bids for recognition, and compliance. There were no generalized effects of these treatments on their subsequent free choice of activities or social behavior. The study demonstrates powerful effects of naturally occurring variations in children's play activities on sex-typed social behaviors.     

Some evidence for correlated separate activation in a simple letter-detection task

This study investigates the separate activation versus coactivation issue for redundant targets in a simple letter-detection paradigm with latency as the dependent variable. The results of a one-response visual-search task are reported. Since, on single-target trials, only the target was presented and no accompanying noise element, no “distraction decrement” caused by irrelevant noise elements (Grice et al., 1984) was to be expected. The data obtained showed a clear redundantsignal effect. Subsequent detailed analysis of the latency data using Miller’s (1982) procedure indicated that the results were consistent with a separate activation model and failed to provide convincing evidence in favor of coactivation models. A further analysis of the data indicated that, in the present study, the separate channels were negatively correlated for a range of fast RTs and positively correlated for intermediate and larger RTs. No evidence in favor of Grice et al.’s (1984) distraction-decrement hypothesis was found. The conclusions of this study are that (1) a separate activation model summarizes the essential features of information processing in this simple visual search task, and (2) no convincing evidence in favor of coactivation in visual search tasks has been reported in the literature up to now.     

Cognitive dysfunction in compulsive checkers: Further explorations

Recent evidence suggests a relationship between certain memory deficits and compulsive-checking behavior. The present study explores this relationship in the context of several additional memory capacities not yet investigated. Using the Maudsley Obsessional-Compulsive Inventory and the Everyday Checking Behavior Scale four groups of Ss were identified: (1) frequent checkers, (2) occasional checkers, (3) infrequent checkers and (4) noncheckers. Consistent with previous research, a memory-for-actions task indicated a deficit among compulsive checkers. Furthermore, checking status was found to be negatively related to memory functioning as measured by the Wechsler Memory Scale (WMS) and the Cognitive Failures Questionnaire (CFQ). This memory deficit was most pronounced on the Logical Memory subtest of the WMS. Checkers appear to have difficulty recalling details of meaningfully linked sequences, either presented in narrative form or engaged in personally. Although the reasons for these checking-related deficits are not clear, a complete understanding of checking phenomena will involve an appreciation of the role played by memory deficits.     

Older men,older women: Are their perceived sex roles similar?

Men and women age 60 or older responded to Bem Sex-Role Inventory “masculinity” and “femininity” scale items on two separate administrations of the test. In the first, they described their own attributes; in the second, they described what others expected them to be like. Item analyses determined that the two sexes were more alike than different in sex-role-related attributes and perceived social expectation that they adopt both M and F attributes. Conflicts between actual and expected attributes were more frequent on “masculine” items. Those conflicted on “feminine” items tended to report depression.