Representation of memory for order of mental operations in cognitive tasks

Recent research shows that people learning a cognitive task acquire a memory for the order of operations applied, independent of the data to which those operations were applied. We designed two experiments to show how this sequence memory is represented. Experiment 1 compared predictions based on 3 possible sequence representation methods: composition, dyad transition, and associative chain. Latency and error results from a simple sequential task supported the associative chain representation. The associative links between operations presumably enhance performance by priming subsequent operations but do not operate in an all-or-none fashion. Experiment 2 explored whether transfer items that matched the first 2 rules and first 3 elements of a training item could bias participants toward executing a composed production learned during training. Latency and undetected error results were consistent with an associative chain representation but not with additional predictions made by the composition representation. These two experiments support the representation of operation sequences in memory as an associative chain.     

The priority of primary process categorizing: experimental evidence supporting a psychoanalytic developmental hypothesis

Earlier work has provided experimental evidence for the existence of the primary and secondary process mental organization posited by Freud and has demonstrated that primary process effects are the more active unconsciously (Brakel et al. 2000). Primary and secondary processes were assessed by a categorization test in which qualitatively different principles could be used. In new experiments using the same stimuli, another significant implication of Freud's model was tested: that primary process mental organization has developmental priority. In these experiments, which studied 559 participants ranging in age from 3 to 80, it was found (1) that primary process mentation predominates in preschoolers; (2) that it is not until around age 7 that primary process organization is supplanted by secondary process organization; and (3) that after age 7 the predominance of secondary process organization remains remarkably stable throughout the life span.     

Perception of the symmetrical patterning of human gait by infants

Two experiments tested 3- and 5-month-old infants' sensitivity to properties of point-light displays of human gait. In Experiment 1, infants were tested for discrimination of point-light displays of a walker and a runner, which, although they differed in many ways, were equivalent with regard to the phasing of limb movements. Results revealed that 3-month-old, but not 5-month-old, infants discriminated these displays. In Experiment 2, the symmetrical phase-patterning of the runner display was perturbed by advancing two of its limbs by 25% of the gait cycle. Both 3- and 5-month-old infants discriminated the walker display from this new phase-shifted runner display. These findings suggest that 3-month-old infants respond to the absolute and relative motions within a single limb, whereas 5-month-old infants respond primarily to the relations between limbs and, in particular, to the bilateral symmetry between the limbs.     

Two-year-olds' search strategies and visual tracking in a hidden displacement task

Children younger than 3 years have difficulty with search tasks that involve hidden displacement. Partial visual information was provided about a ball's path as it moved toward a hiding place. Children (2.0 and 2.5 years old) saw a ball rolling down a ramp placed behind a transparent screen with 4 opaque doors. A wall, placed on the ramp and directly behind 1 of the doors, protruded above the screen and stopped the ball. Children were asked to find the ball. The transparency of the screen permitted visual tracking of the ball between the doors, but its final resting place was obscured. Both age groups were equally proficient at tracking the ball as it rolled behind the screen, but the 2.5-year-olds were more likely to reach to the correct door. Looking behavior was related to errors in the younger group in that tracking that stopped short or continued past the correct door was associated with incorrect choices.     

Depressive symptoms and lymphocyte proliferation in older adults

In an 18-month prospective study, community-dwelling older adults, including both spousal caregivers of dementia patients and noncaregiving controls, were examined. Participants were selected on the basis of the presence or absence of chronic depressive symptoms that exceeded a cutoff score for clinically relevant depressive symptoms on a self-report symptom measure. Compared with nondepressed older adults, those with chronic, mild depressive symptoms had poorer T cell responses to 2 mitogens from baseline to follow-up. Additionally, among individuals with depressive symptoms, older age was associated with the poorest blastogenic response to the mitogens at follow-up. These findings extend the association between depression and immune function to community-dwelling older adults with chronic, mild depressive symptoms.     

Putting the cart before the horse: the benefits of arbitrating before mediating

The authors examined the impact of 2 hybrid dispute resolution procedures (mediation-arbitration [med-arb] and arbitration-mediation [arb-med]) and 3 disputant dyadic structures (individual vs. individual, individual vs. team, and team vs. team) on various dispute outcomes. Consistent with W. H. Ross and D. E. Conlon (2000), the authors found that disputants in the arb-med procedure (a) settled in the mediation phase of their procedure more frequently and (b) achieved settlements of higher joint benefit than did disputants in the med-arb procedure. These results suggest that arb-med may be a dispute resolution procedure with broader applicability than originally imagined.