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.     

Classification of adult attachment: an integrative taxonomy from attachment and psychoanalytic theories.

Developmental and psychoanalytic theorists have focused increasingly on empirically determined early childhood antecedents of adult attachments, with several resulting taxonomic models. This article suggests a theoretically based and clinically based model of attachment consistent with both psychoanalytic and attachment theories, resulting in an integrative taxonomy of four adult attachment styles: dependent, avoidant, hostile, and resistant-ambivalent. These styles reflect behavioral manifestations of dependence and anger, as derived from the interaction of primitive relational drives, defenses, and interpersonal experience. In addition to theoretical construction, brief clinical examples are presented to facilitate discussion of the model.     

Marital processes predictive of later dissolution: behavior, physiology, and health.

Seventy-three married couples were studied in 1983 and 1987. To identify marital processes associated with dissolution, a balance theory of marriage was used to generate 1 variable for dividing couples into regulated and nonregulated groups. For studying the precursors of divorce, a "cascade" model of marital dissolution, which forms a Guttman-like scale, received preliminary support. Compared with regulated couples, nonregulated couples had (a) marital problems rated as more severe (Time 1); (b) lower marital satisfaction (Time 1 and Time 2); (c) poorer health (Time 2); (d) smaller finger pulse amplitudes (wives); (e) more negative ratings for interactions; (f) more negative emotional expression; (g) less positive emotional expression; (h) more stubbornness and withdrawal from interaction; (i) greater defensiveness; and (j) greater risk for marital dissolution (lower marital satisfaction and higher incidence of consideration of dissolution and of actual separation).     

The effect of hypnotically elicited testimony on jurors' judgments of guilt and innocence.

Survey data from several countries indicate that many people believe that hypnosis may increase the accuracy of an eyewitness's memory; most experimental research, however, suggests that this belief is inaccurate. This study examined whether the belief could influence judgments of guilt and innocence in a simulated criminal trial. The results indicated that British undergraduates were more likely to find a male defendant guilty when told that the testimony against him had been elicited under hypnosis. Results concerning a nonhypnotic memory facilitation technique were found to be inconclusive, and the salience of hypnotically elicited testimony was ruled out as a contributory element.     

Predicting Zimbabwean women's ability to tell their partners to use condoms.

The effectiveness of AIDS education may depend on the development of models that predict and explain HIV prevention behavior. In this study, the aim was to test Fishbein and Ajzen's theory of reasoned action model in predicting women's capacity to tell their partner to use condoms. The basic theory pertains to the relationship of 1) attitude toward behavior and 2) the subjective norms to behavior; further refinements reflect factors such as 3) perceived behavioral control or self-efficacy, 4) and perceived barriers. A sample was drawn of 123 female first-year teacher trainees in Harare, Zimbabwe, in late 1990; a self-administered questionnaire was distributed and returned. 72% of the respondents were sexually experienced. The mean age of the entire sample was 24 years. The results of the multiple linear regression indicated that the model was able to predict were F(2,74)=32.81, p.0001. 47% of the variance was explained by this Fishbein model. Attitude toward behavior was significantly associated with the intention to tell one's partner to use condoms (beta = .60, p .05). Subjective norms were not significant (beta = .15, p .05). Perceived behavioral control and perceived barriers were also not significantly associated with the intention to tell one's partner to use condoms. A caveat was that the subjective norm was measured by only one item, and an improved conceptualization and measurement of this construct might have changed the relationship. The suggestion is that health educators should address women's underlying beliefs and attitudes about the benefits of telling their partners to use condoms. Future prospective studies will better delineate the relationship between attitude and behavior.     

Choice with delayed and probabilistic reinforcers: effects of variability, time between trials, and conditioned reinforcers.

In a discrete-trials procedure with pigeons, a response on a green key led to a 4-s delay (during which green houselights were lit) and then a reinforcer might or might not be delivered. A response on a red key led to a delay of adjustable duration (during which red houselights were lit) and then a certain reinforcer. The delay was adjusted so as to estimate an indifference point--a duration for which the two alternatives were equally preferred. Once the green key was chosen, a subject had to continue to respond on the green key until a reinforcer was delivered. Each response on the green key, plus the 4-s delay that followed every response, was called one "link" of the green-key schedule. Subjects showed much greater preference for the green key when the number of links before reinforcement was variable (averaging four) than when it was fixed (always exactly four). These findings are consistent with the view that probabilistic reinforcers are analogous to reinforcers delivered after variable delays. When successive links were separated by 4-s or 8-s "interlink intervals" with white houselights, preference for the probabilistic alternative decreased somewhat for 2 subjects but was unaffected for the other 2 subjects. When the interlink intervals had the same green houselights that were present during the 4-s delays, preference for the green key decreased substantially for all subjects. These results provided mixed support for the view that preference for a probabilistic reinforcer is inversely related to the duration of conditioned reinforcers that precede the delivery of food.     

Molecular contingencies in schedules of intermittent punishment

In two experiments, key pecking of pigeons was maintained by a variable-interval 180-s schedule of food presentation. Conjointly, a second schedule delivered response-dependent electric shock. In the first experiment, shocks were presented according to either a variable-interval or a nondifferential interval-percentile schedule. The variable-interval shock schedule differentially delivered shocks following long interresponse times. Although the nondifferential shock schedules delivered shocks less differentially with respect to interresponse times, the two shock schedules equally reduced the relative frequency of long interresponse times. The second experiment differentially shocked long or short interresponse times in different conditions, with resulting decreases in the relative frequency of the targeted interresponse times. These experiments highlight the importance of selecting the appropriate level of analysis for the interaction of behavior and environment. Orderly relations present at one level of analysis (e.g., interresponse times) may not be revealed at other levels of analysis (e.g., overall response rate).