Horizontal Plane Head Stabilization During Locomotor Tasks

Frequency characteristics of head stabilization were examined during locomotor tasks in healthy young adults (N = 8) who performed normal walking and 3 walking tasks designed to produce perturbations primarily in the horizontal plane. In the 3 walking tasks, the arms moved in phase with leg movement, with abnormally large amplitude, and at twice the frequency of leg movement. Head-in-space angular velocity was examined at the predominant frequencies of trunk motion. Head movements in space occurred at low frequencies (< 4.0 Hz) in all conditions and at higher frequencies (> 4.0 Hz) when the arms moved at twice the frequency of the legs. Head stabilization strategies were determined from head-on-trunk with respect to trunk frequency profiles derived from angular velocity data. During natural walking at low frequencies (< 3.0 Hz), head-on-trunk movement was less than trunk movement. At frequencies 3.0 Hz or greater, equal and opposite compensatory movement ensured head stability. When arm swing was altered, compensatory movement guaranteed head stability at all frequencies. Head stabilization was successful for frequencies up to 10.0 Hz during locomotor tasks Maintaining head stability at high frequencies during voluntary tasks suggests that participants used feedforward mechanisms to coordinate head and trunk movements. Maintenance of head stability during dynamic tasks allows optimal conditions for vestibulo-ocular reflex function.     

The Relationship of Impulse to Response Timing Error

This paper examines the relationship between response impulse and timing error in 200 msec discrete timing responses over a range of movement velocities and system masses. The results from two experiments showed that variable timing error decreased as both movement velocity and the mass of the system to be moved increased. The variability of force proportional to force (measured either as impulse or peak force) decreased curvilinearly as force output increased. The correlations between each of these parameters and variable timing errors, calculated on a group mean basis, ranged between .91 and .95. The ability to predict the movement time outcome of each individual trial from impulse-related parameters was considerably reduced, although the relationship between the various kinematic and kinetic parameters did strengthen as the movement velocity approached maximum. Collectively, the findings show that size of impulse is related to movement timing error, although it is premature to argue that impulse variability is a causal agent of timing error.     

Error Detection and Correction in a Structured Movement Task

Error-detection and error-correction experiments were conducted to examine the assumption that organizational processes play an important role in motor learning and control. During the initial phase of each experiment, the sensory aspects of five movements were held constant while the organizational structure (sequential vs. random) of the movements was varied. In the learning phase of both experiments, the effect of organization produced increased reproduction accuracy for the structured movement sequences compared to those that were random. This benefit of organization carried over into the error detection and correction parts of the experiments where it was shown that improved error detection and correction capabilities were assisted by the manner in which the movements were presented. The importance of cognitive processes is discussed in terms of past and contemporary accounts of motor learning and control.     

Category inference as a function of correlational structure, category discriminability, and number of available cues

Two experiments investigated category inference when categories were composed of correlated or uncorrelated dimensions and the categories overlapped minimally or moderately. When the categories minimally overlapped, the dimensions were strongly correlated with the category label. Following a classification learning phase, subsequent transfer required the selection of either a category label or a feature when one, two, or three features were missing. Experiments 1 and 2 differed primarily in the number of learning blocks prior to transfer. In each experiment, the inference of the category label or category feature was influenced by both dimensional and category correlations, as well as their interaction. The number of cues available at test impacted performance more when the dimensional correlations were zero and category overlap was high. However, a minimal number of cues were sufficient to produce high levels of inference when the dimensions were highly correlated; additional cues had a positive but reduced impact, even when overlap was high. Subjects were generally more accurate in inferring the category label than a category feature regardless of dimensional correlation, category overlap, or number of cues available at test. Whether the category label functioned as a special feature or not was critically dependent upon these embedded correlations, with feature inference driven more strongly by dimensional correlations.     

Downsizing in britain and its effects on survivors and their organizations

Abstract

In this paper, we examine the psychological effects of downsizing and redundancy on those remaining within organizations after large-scale redundancy programs. While there have been a number of studies of this type in the recent past, our task is to explore two separate studies which have investigated this phenomena. The first study explores the impact of redundancy in a recently privatized organization in the UK. This, we argue, is a particularly fertile area of study given the radical changes that have affected organizations in the UK that have been subjected to privatization. The results stem from an exploratory and qualitative case study which takes an individual perspective. The second study discussed in this paper explores the results of a survey conducted in the UK that examines the implications of change in both the public and private sector organizations. This survey takes a quantitative look at the implications of redundancy from an organizational perspective. By investigating these two studies, our research explores the impact of redundancy on two levels—the individual level and the organizational level. First, we examine the emotional, attitudinal and behavioral effects of redundancy on survivors and the resultant implications for management: in particular the changing role of line managers where delayering and redundancy has taken place. Second, we explore the impact of redundancy on the organization in terms of organizational morale, motivation, organizational loyalty and job security where redundancy has and has not been used as a method of downsizing.     

The Role of Peers in the Linkages Between Harsh Parenting and Mental Health Outcomes Among Adolescents from Families At-Risk

Harsh parenting is associated with adolescent mental health concerns. Peer relationships also importantly influence adolescent mental health outcomes. Although the direct associations between harsh parenting, peer relationships, and adolescent outcomes have been empirically established, less is known about the extent to which peer relationships mediate the associations between harsh parenting and adolescent outcomes. This study tested the links between harsh parenting, peer relationships, and adolescent outcomes among families at-risk for child maltreatment. With a sample of caregivers and adolescents (n = 218), the results of mediation analyses indicated that peer aggression partially mediated the pathway between harsh parenting and externalizing symptoms of both females and males. Additionally, peer rejection partially mediated the links between harsh parenting and internalizing symptoms of both females and males and peer rejection also was a partial mediator of male externalizing symptoms.     

SELF OR NO-SELF? CONVERGING PERSPECTIVES FROM NEUROPSYCHOLOGY AND MYSTICISM

Abstract. The nature of self is examined in relation to psychological observations which reveal some form of dissociation of knowledge from consciousness. Such dissociations are apparent in cases of blindsight, and amnesic patients displaying implicit memory effects, among others. While amnesic patients, for example, are unable consciously to recall material previously presented, such material does influence subsequent physiological and psychological processes. Thus, it is not the memories themselves that have been lost, but the ability to make conscious connection to them. In attempting to account for such observations, theoreticians generally have posited some kind of "consciousness system" that may become dissociated from brain modules dealing with specific processing.
It is argued here that a view of self along the lines of the Buddhist concepts of no-self and the conditioned nature of "I" introduces a more parsimonious perspective on the neuropsychological data. A theory of the nature of self is presented that constitutes a synthesis between key ideas drawn from Buddhist and other mainly mystical traditions and the scientific observations in psychology. Central to this theory is the role that the left hemisphere's interpreter (Gazzaniga 1985; 1988a; 1988b) plays in constructing a unified "I." This "I" is, in effect, a hypothesis that the mind generates to introduce some coherence into otherwise fragmentary mental elements. Although it appears to be the causal focus of the individual's behavior and experience, it is in fact a retrospective construction and not a true causal structure of the mind. This theoretical view is discussed in relation to various meanings of the term consciousness and also in relation to the relevant neuropsychological cases.     

THE SEMANTIC STRUCTURE OF EVOLUTIONARY BIOLOGY AS AN ARGUMENT AGAINST INTELLIGENT DESIGN

Abstract. This paper examines the impact of two formalizations of evolutionary biology on the antiselectionist critiques of the Intelligent Design (ID) movement. It looks first at attempts to apply the syntactic framework of the physical sciences to biology in the twentieth century, and to their effect upon the ID movement. It then examines the more heuristic account of biological‐theory structure, namely, the semantic model. Finally, it concludes by advocating the semantic conception and emphasizing the problems that the semantic model creates for ID's negative and positive theses.     

Perception-action coupling and anticipatory performance in baseball batting

The authors examined 10 expert and 10 novice baseball batters' ability to distinguish between a fastball and a change-up in a virtual environment. They used 2 different response modes: (a) an uncoupled response in which the batters verbally predicted the type of pitch and (b) a coupled response in which the batters swung a baseball bat to try and hit the virtual ball. The authors manipulated visual information from the pitcher and ball in 6 visual conditions. The batters were more accurate in predicting the type of pitch when the response was uncoupled. In coupled responses, experts were better able to use the first 100 ms of ball flight independently of the pitcher's kinematics. In addition, the skilled batters' stepping patterns were related to the pitcher's kinematics, whereas their swing time was related to ball speed. Those findings suggest that specific task requirements determine whether a highly coupled perception-action environment improves anticipatory performance. The authors also highlight the need for research on interceptive actions to be conducted in the performer's natural environment.     

Fit for persuasion: the effects of nonverbal delivery style,message framing,and gender on message effectiveness

This study examined two experimental variables, delivery style and message framing, that have yet to be examined together in the regulatory fit literature. College students (mean age = 30) watched a video message encouraging regular exercise delivered in an eager or vigilant nonverbal style and framed in terms of gain or loss. Results revealed significant fit effects involving gender, delivery style, and message framing. The eager message was perceived as more effective by men whereas the vigilant message was perceived as more effective by women. A message framing by delivery style fit effect also emerged for perceived message effectiveness. The implications and limitations of these findings are discussed.