Updating process of internal model of action as assessed from motor and postural strategies in young adults

Internal models are constantly updated based on the actions and experiences of a person in the world. In the present study, we proposed to assess the updating process of internal models of action by providing new environmental constraints for motor planning, postural control, and execution processes in daily tasks such as STS and BTS. STS and BTS tasks were performed with different inclinations of the support surface on which the participant and the chair were positioned: horizontal support, support tilted 10° to the right, or forward. Twelve healthy adults participated in this experiment. Kinematic characteristics were recorded using an optoelectronic motion analysis system. Movement duration and trunk inclination amplitudes were analyzed for STS and BTS as well as trunk orientation and strategies of head stabilization. Concerning the movement analysis our results showed (1) temporal asymmetry between STS and BTS, attributed mainly to the integration of the mechanical effects of gravity, and (2) a decrease of trunk movements when the support was tilted forward, attesting to an immediate adaptation process. Concerning the postural analysis our study revealed that adults adopted selective head stabilization on space strategy with respect to balance constraints. To conclude, young adults were able to immediately update their internal model of action in order to optimize motor control and vertical body orientation.     

The general causality orientations scale: Self-determination in personality

This paper describes the development and validation of a general causality orientations scale. Causality orientations are conceptualized as relatively enduring aspects of people that characterize the source of initiation and regulation, and thus the degree of self-determination, of their behavior. Three orientations—autonomy, control, and impersonal—are measured by the three subscales of the instrument. Individuals are given a score on each orientation, thus allowing the use of the theoretically appropriate subscale (or, in some cases, a combination of subscales) to predict affects, cognitions, and behaviors. The scale was shown to have internal consistency and temporal stability. The orientations were shown to fit appropriately into a nomological network of constructs and to relate to various behaviors that were hypothesized to be theoretically relevant.     

An evaluation of outcome variables in the systematic desensitization of test anxiety.

This study investigated the effects of group systematic desensitization and group counseling on anxiety and academic performance. Fifty-four undergraduates who requested help for debilitating test anxiety were randomly assigned to Desensitization. Group Counseling, or No-treatment control groups. Measures of test anxiety, trait anxiety, and academic achievement were obtained for all students' pre- and post-treatment. The Desensitization group showed a significant decrease in test anxiety; the Counseling and No-treatment groups showed no changes in these measures. None of the groups showed any change in trait anxiety or academic achievement. The results provided evidence that systematic desensitization was an effective treatment for reducing test anxiety, but not for improving grades.     

Emotional mood and memory in young children

Two experiments examined affect-dependent memory with preschool/kindergarten and third-grade children. A two-list intentional learning procedure was used to assess the effects of the congruent versus incongruent relationship between affect (happy vs sad) during initial list learning and affect (happy vs sad) during a delayed recall test. When induction of emotional mood was preceded by relaxation exercises in Experiment 1, no evidence of affect dependence was observed. When the relaxation procedure was omitted in Experiment 2, the affect-dependent pattern was obtained in both free recall and cued recall for both age groups. The results of Experiment 2 show that affect-dependent memory is a reasonably robust phenomenon in children and that hypnosis is not necessary for its appearance. However, the phenomenon is apparently absent under conditions of relaxation, a result consistent with two-factor theories of emotion.     

Reaction time,evoked brain potentials,and psychometric g in the severely retarded

Measurements derived from reaction time (RT), movement time (MT), and an index of neural adaptability (NA) derived from averaged evoked potentials are significantly related to each other as well as to g factor scores extracted from a battery of 15 psychometric tests in a sample of 54 severely retarded adults. The RT-MT and NA variables show a shrunken multiple R of .64 (p < .001) with psychometric g.     

The concept of development in vocational theory and intervention

One of the major problems in the vocational literature is the absence of theoretical formulations which deal with development in more than a superficial manner. Specific problems are that (1) key constructs are adapted from developmental theory without proper attention to the conceptual, empirical, and methodological problems involved; (2) little recognition has been accorded to significant changes in developmental theory during the past 15 years, changes which stress the multidimensional, plastic, contextual, and life-span features of development; (3) there is a paucity of adequately designed, contextually sensitive, longitudinal research; and (4) well-established empirical findings of developmental research have been misrepresented or ignored by vocational researchers. It is proposed that a theory of life-span vocational role development must meet the conceptual and methodological requirements of a developmental approach, that it must contain a contextual perspective, and that it must be relational in the sense that it provides for the examination of the “goodness of fit” between individual and contextual developments. The consequences of this viewpoint for vocational intervention are described as a more pronounced focus on events, processes, and life periods which are identified as antecedents of major vocational decisions. Finally, it is observed that vocational intervention should be viewed as a succession of procedures designed to assist the individual, throughout his/her life, to adapt vocational functioning to changing personal situations as well as to changing economic and contextual circumstances.     

Semantic processing can facilitate free recall in mildly retarded adolescents

The efficacy of semantic processing in free recall was investigated in two experiments with EMR adolescents. In Experiment 1, they were taught to use one of two semantic strategies for memorizing a 15-word list. Compared with controls, neither strategy helped recall either in original learning or transfer. In Experiment 2, one of the semantic strategies, a story mnemonic, was investigated further. Rather than being taught to construct their own stories as in Experiment 1, subjects in Experiment 2 were provided with experimenter-composed stories. They showed better immediate recall and retention after 2 months than did no-strategy controls. However, about 1 year after original learning, the retention of experimental and control subjects no longer differed. Discussion focused on the story mnemonic's potential utility and the criteria for judging such potential, e.g., amount of facilitation, ease of training and performance of the strategy, and the degree of its generalizability.     

Influence of mechanical factors on movement units in infant reaching

In a number of studies it is assumed that movement units (combinations of an acceleration and a deceleration in the tangential velocity profile) are a reflection of the control process. In this study, we investigated to what extent movement units reflect the oscillatory mechanics of the arm. At the ages of 16 and 20 weeks, the age range in which infants just begin to reach, a toy rattle was presented in three conditions, with varying external forces acting on the arm: sitting, sitting with masses on the forearms, and supine.The tangential velocity profile of the wrist during successful reaching attempts was decomposed to a gravity-dependent (φ_v), and a gravity-independent component (φ_h), and movement units were determined in the total velocity profile and in its components. Significant effects of experimental condition, but not age, were found for movement time, number of movement units and duration ofphi;_hcomponent units. It was shown that these effects can be accounted for by a simple mechanical model, in which the arm is approximated as a harmonic oscillator governed by, gravity, the moment of inertia of the arm, and the stiffness of the shoulder joint. Stiffness values, derived from fitting the model to the data, were in the order of 1 Nm/rad.From these results we conclude that movement units in an infant's initial attempts at reaching are to a large extent a reflection of the mechanical context.     

Memories of Morocco: The influence of age,schooling, and environment on memory

To what extent are models of memory general, in that they may be applied to children or to other cultural groups? In an attempt to answer this question, two experiments were undertaken in Morocco to investigate various cultural and experiential antecedents to memory development. A total of 384 children and young adults, ranging in age from 6 to 22 years, were tested in a design that contrasted schooled and nonschooled children in urban and rural environments. Three additional groups of subjects—Koranic students, Moroccan rug sellers, and University of Michigan students—were also studied because it was hypothesized that each might have particular “culture-specific” memory skills as a function of previous experience.A serial short-term recall task was used in Experiment I. Results showed that the recency effect or short-term store was generally invariant with age or experience. Control processes appeared to be a function of age, but only when coupled with schooling, and, to a lesser extent, urban environment. In Experiment II, a continuous recognition memory task was given with black and white photographs of Oriental rugs as stimuli. Forgetting rates were generally invariant with age and experience, while the acquisition parameter seemed to vary as a function of specific cultural experiences. Data from the three additional groups were useful in supporting the hypothesis of culture-specific memory skills.From Experiments I and II, and previous research, it was hypothesized that structural features of memory (e.g., short-term store and invariant forgetting rates) may be universal, while control processes or mnemonics in memory are probably culture-specific, or a function of a variety of experiential and cultural factors that surround the growing child.