Effects of Pointing Rate and Availability of Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed 60 times straight ahead of their nose at a rate of one complete movement every 2 or 3 s, with visual feedback available early in the pointing movement or delayed until the end of the movement. Sagittal pointing was paced such that movement speed covaried with pointing rate. Aftereffect measures (obtained after every 10 pointing trials) showed that when the limb became visible early in a pointing movement, proprioceptive adaptation was greater than visual, but when visual feedback was delayed until the end of the movement, the reverse was true. This effect occurred only with the 3-s pointing rate, however. With the 2-s pointing rate, adaptation was predominately proprioceptive in nature, regardless of feedback availability. Independent of the availability of visual feedback, visual adaptation developed more quickly with 3-s pointing, whereas proprioceptive adaptation developed more rapidly with 2-s pointing. These results are discussed in terms of a model of perceptual-motor organization in which the direction of coordinative (guidance) linkage between eye-head (visual) and hand-head (proprioceptive) systems (and consequently the locus of discordance registration and adaptive recalibration) is determined jointly by pointing rate and feedback availability. An additional effect of pointing rate is to determine the rate of discordant inputs. Maximal adaptive recalibration occurs when the input (pointing) rate matches the time constant of the adaptive encoder in the guided system.     

Factors and Taxa, Traits and Types, Differences of Degree and Differences in Kind

ABSTRACT A taxon is a nonarbitrary class whose existence is conjectured as an empirical question, not a mere semantic convenience. Numerous taxa are known to exist in nature and society (chemical elements, biological species, organic diseases, geological strata, kinds of stars, elementary particles, races, cultures, Mendelizing mental deficiencies, major psychoses, vocations, ideologies, religions). What personality types, if any, occur in the nonpathological population remains to be researched by sophisticated methods, and cannot be settled by fiat or "dimensional" preference. The intuitive concept of taxonicity is to be explicated by a combination of formal-numerical and causal criteria. Taxometric methods should include consistency tests that provide Popperian risk of strong discorroboration. In social science, latent class methods are probably more useful than cluster algorithms.     

MMPI taxonomies of child sexual and nonsexual offenders: a cross-validation and extension.

In a court clinic sample of 107 child sexual and nonsexual offenders, Minnesota Multiphasic Personality Inventory (MMPI) profiles did not differ as a function of arrests for sexual versus nonsexual offending. However, a three-group cluster-analytic solution was generated. Two of these clusters replicated those derived by Hall, Graham, and Shepherd (1991). The first cluster was unelevated, with Scales 4 and 9 as high points. The second cluster had MMPI Scales 4, 8, 2, and 7 as the highest scales. The third cluster was even more elevated than the other two clusters, characterized by extreme elevations on MMPI Scales F, 2, 4, 6, 7, and 8. The somewhat different results of this study versus previous studies (e.g., Hall et al., 1991) may be a function of the different populations sampled. The results provide evidence of within-group heterogeneity among sexual and nonsexual offenders that may be as important as between-group differences.     

Hillel's maxim: Framework for psychological health

Mental health practitioners continually struggle to find a simple framework for describing the characteristics of the psychologically healthy individual. Hillel's often quoted saying provides relevant insight into the healthy personality and a convenient framework against which to examine psychological health.     

The practice of psychotherapy and spiritual direction

The author compares and contrasts insight-oriented psychotherapy, supportive psychotherapy, and spiritual direction in relation to goals and methods; management of resistance, transference, and countertransference; and selection criteria. The enhancement of spiritual formation through insight-oriented psychotherapy and supportive psychotherapy is also discussed.     

Altruism in surgery of AIDS patients

There is usually a long period of time between infection with the AIDS virus and manifestation of symptoms. Asymptomatic patients often would benefit from elective surgery for diseases such as arthritis which are unrelated to their infection. The surgeons' decisions to accept the risks to themselves, their spouses, and their operating teams in order to relieve pain and suffering appear to be based upon two covenants; one concerns their role within the doctor-patient relationship, and the other concerns their relationship to what they see as the ultimate meaning in life.