A Search for the Optimal Stimulus

How do stimulus size and item number relate to the magnitude and direction of error on center estimation and line cancellation tests? How might this relationship inform theories concerning spatial neglect? These questions were addressed by testing twenty patients with right hemisphere lesions, eleven with left hemisphere lesions and eleven normal control subjects on multiple versions of center estimation and line cancellation tests. Patients who made large errors on these tests also demonstrated an optimal or pivotal stimulus value, i.e., a particular size center estimation test or number of lines on cancellation that either minimized error magnitude relative to other size stimuli (optimal) or marked the boundary between normal and abnormal performance (pivotal). Patients with right hemisphere lesions made increasingly greater errors on the center estimation test as stimuli were both larger and smaller than the optimal value, whereas those with left hemisphere lesions made greater errors as stimuli were smaller than a pivotal value. In normal subjects, the direction of errors on center estimation stimuli shifted from the right of true center to the left as stimuli decreased in size (i.e., the crossover effect). Right hemisphere lesions exaggerated this effect, whereas left hemisphere lesions diminished and possibly reversed the direction of crossover. Error direction did not change as a function of stimulus value on cancellation tests. The demonstration of optimal and pivotal stimulus values indicates that performances on center estimation and cancellation tests in neglect are only relative to the stimuli used. In light of other studies, our findings indicate that patients with spatial neglect grossly overestimate the size of small stimuli and underestimate the size of large stimuli, that crossover represents an “apparent” shift in error direction that actually results from normally occurring errors in size perception, and that the left hemisphere is specialized for one aspect of size estimation, whereas the right performs dual roles.     

A study of a bimanual synergy associated with holding an object

The task of supporting an object with one or two hands was used to test the applicability of the notion of synergy. Subjects sat with their dominant forearm supported up to the wrist while holding a cylindrical “cup” between their thumb and fingers. Force transducers recorded the grip force applied normal to the cup's side by the thumb and the force applied normal to the cup bottom. On different series, a supporting force was added to and released from the bottom of the cup by the subject's non-dominant hand or by the experimenter. As predicted, the results indicated feedforward adjustments of the grip force, and of the EMGs, and significant correlations between grip force and supporting force when they were produced by two hands of one person, and the lack of such closely tied changes when the two forces were produced by two different persons. In the latter case, different subjects could demonstrate grip force changes in different directions. The findings suggest that grip force adjustments represented peripheral patterns of a single central process (a single synergy) rather than being separately controlled focal and postural components of the action.PsycINFO classification: 2330     

The analytic initiation: the effect of the archetype of initiation on the personal unconscious

The author proposes the term 'analytic initiation1' to describe a rite of passage from childhood to adult life effected by psychotherapy. He suggests this passage is based upon a personal regression within the embrace of an archetypal symbolic process. Archetypal symbols orientate the analysand towards the transformative potential of a regressive experience. They also contain him as he separates from parental complexes and tolerates their dissolution. The analysand's growth depends on his submitting to an intrapsychic and interpersonal experience of the initiatory process with its attending regression. Correspondingly, it relies on the analyst being available for both the personal and impersonal transference/countertransference interaction. Over time, the analysand's participation in this process brings his ego in greater relationship to the Self.
The most important outcome of a successfully constellated analytic initiation is not the dissolution of a group of complexes. Rather, it is the establishment of a symbolic process that allows the individual to continue to evolve. The author supports his findings with a critical review of Jung's writings on initiation and additional case material.     

A multivariate investigation of the reinforcer structure of occupations

Earlier research based on 81 Occupational Reinforcer Patterns (ORPs) suggested a nine-category classification of occupations. The present research, based on 148 ORPs, investigated the ability of that classificatory system to assimilate new information. Cluster analysis of the 148 ORPs yielded an eight-category classification of occupations in which five of the original occupational clusters appeared virtually unchanged; the other four original clusters were combined into two occupational clusters. One new cluster was identified. Principal factors analysis was employed to study the factor structure of the occupational reinforcers and to highlight the essential nature of the classificatory system. Five reinforcer factors were identified.