Achieving Coordination in Prehension: Joint Freezing and Postural Contributions

The focus of the present study was on the intersegmental relationships that emerge when both task and oganismic constraints are imposed upon the coordination system. Seven right-handed subjects were required to reach and grasp a cup (hand transport phase) and place it on a designated target (cup transport phase), using either their preferred or nonpreferred hand. The kinematics of the movement were examined as a function of task (grasping a full cup versus grasping an empty one) and organismic (preferred or nonpreferred hand) constraints. During the hand transport phase, a task constraint effect was revealed through an increase in the low-velocity phase for the full cup condition. This constraint coexisted with a decrease in angular motion of the shoulder and elbow joints, indicating subjects reduced the number of variables to be independently controlled in the final homing-in stage of the movement. Accompanying this decrease in angular change was an increase in the displacement of the trunk. During the cup transport phase, the trunk was shown to contribute significantly more to the movement in the full cup condition and for the left hand movements, thereby increasing the stability of the movement system. These findings are in agreement with Bernstein's (1967) notion of fixating parts of the body as an initial solution to a movement problem, and they lend support to the concept of a proximodistal organization of coordination.     

Origins of Ruminative Thought: Trauma, Incompleteness, Nondisclosure, and Suppression

The purpose of this paper is to discuss theories of the origin of ruminative thought. We begin by providing a working definition of rumination, separating rumination from other forms of cognitive activity and distinguishing ruminations from ordinary memories. Then, we review what we believe are the major categories of theory that attempt to account for the existence and nature of rumination. These include theories of traumatization, incompleteness, nondisclosure, and thought suppression. Ruminations may originate for a number of reasons, but it seems they may continue because of our attempts to control them. Evidence from studies on thought suppression suggests that the suppression of unwanted thoughts may in fact fuel the very emotions and thoughts we are trying to avoid. Thought suppression may set up a state in which we not only increase the amount we think about an unwanted thought, but potentially also sharpen our emotional reaction to those thoughts.     

Ethnic and Gender Variations in the Sources of Information Used to Evaluate Performance in the Exercise Setting1

The purpose of this study was to identify ethnic and gender differences in the types of information Anglo and Hispanic exercisers use in self-evaluation. University students in exercise classes rated the importance of norm-referenced and self-referenced sources used in self-evaluation of performance. Results showed that males rated norm-referenced sources as more important to self-evaluation, while females rated self-referenced sources as most important. A gender by ethnicity interaction showed that Anglos, especially Anglo males, preferred norm-referenced sources, while Hispanics preferred self-referenced sources. Provided with this information, instructors could more effectively motivate exercise participants.     

Goal Setting by Groups Performing an Additive Task: A Comparison With Individual Goal Setting1

This article compares goal levels and task performance of groups and individuals that are assigned or self-set goals. Groups performed an additive task that allowed for direct comparison with individuals' i]ndependent performance of the task. Consistent with predictions, groups and individuals selected goals that were less difficult than assigned goals which required only a modest increase in performance. Group members and individuals who were assigned goals attained higher levels of performance than self-set or no goal condition subjects. The prediction that group members and individuals who self-set their goals would have more positive affective reactions to the goal-setting situation than participants in assigned condition was supported. The results of this study are consistent with the existing literature on groups and individuals regarding effects of goals, performance, and affective reactions. Analyses also indicate that the group goal decision process involves a compensatory strategy in which an average of group member preferences for the goal was used to reach a group goal decision. Discussion focuses on the similarities and differences between the findings of self-set and assigned goal-setting situations for groups and individuals, with particular reference to goal choice strategies, goal expectancies, and efficacy.     

Variation of Isometric Response Force in the Rat

Hungry, unrestrained rats (N = 7) were rewarded for pressing a response beam in excess of 11 different force requirements. Changes in peak force production as a function of peak force requirement were examined by analyses of the first four moments of distributions of peak response forces: constant error, the within-subject standard deviation, skewness, and kurtosis. Results were similar to those previously obtained with human subjects: Constant error was positive at low and negative at high force requirements, the within-subject standard deviation increased as a negatively accelerating function of force requirement, and skewness and kurtosis were positive at low force requirements and decreased to negative values at the highest increments. Additional analyses of response kinetics indicated that rats, like humans, meet increasing force requirements by altering the rate of rise of force. The performance similarities suggest that common processes are engaged by the human and rat motor control systems to solve the problem of generating forces that are appropriate to the prevailing environmental constraints.     

Behavioral Intentions: Which Ones Predict Fertility Behavior in Married Couples?1

The published literature on the relationship between behavioral intentions and fertility behavior exhibits four major problems: inconsistent and confusing use of theoretical constructs, limited use of different types of intentions, use of nonbehavioral outcomes, and failure to explore adequately the couple aspects of the intentions/behavior relationship. The study reported here addresses these problems by using a theoretical framework that characterizes the psychological/behavioral sequence leading to a planned conception, three different types of fertility intentions, a behavioral outcome variable, and data from 196 married couples with no children and 185 married couples with one child. Data analysis results in a simultaneous equation, constrained regression model which indicates that child-timing intentions are the most important predictors of proceptive behavior over a 3-1/2 year period and that childbearing intentions are next in importance; that behavioral intentions are the final common pathway through which fertility motivations, attitudes, beliefs, and desires affect behavior; that the use of proceptive behavior as an outcome variable improves the explanatory power of our models; and that the interaction of couple intentions do not demonstrate greater husband or wife influence over couple proceptive behavior but do demonstrate that disagreement has a delaying effect on the onset of that behavior.     

Residualanalysis in the polytomous rasch model

Residuals for check of model fit in the polytomous Rasch model are examined. Comparisons are made between using counts for all response pattern and using item totals for score groups for the construction of the residuals. Comparisons are also, for the residuals based on score group totals, made between using as basis the item totals, or using the estimated item parameters. The developed methods are illustrated by two examples, one from a psychiatric rating scale, one from a Danish Welfare Study.     

Reviews

Editor's note: The original edition of the book is (nearly) sold out, but a shortened, updated version will probably be published by Sage Publications, Thousand Oaks CA. Information can be obtained from: T.U.P., P.O. Box 90153, 5000 LE Tilburg, The Netherlands.     

Organizational factors in the effect of irrelevant speech: The role of spatial location and timing

Typically, hearing a repeated syllable produces minimal disruption of serial recall of visual lists, but a sequence of different syllables impairs performance markedly. Two conditions for presenting anidentical sequence of three syllables are compared: one, in which, by means of stereophony, each syllable is assigned to the left, center, or right auditory locus (three streamsnot changing in state), and another, in which the same syllable sequence occurs in one location only (one streamwith changing state). Disruption was significantly less in the stereophonic than in the monophonic condition. There was a joint effect of changing state and location, not an effect of the number of locations alone. In Experiment 2, temporal predictability was used to manipulate changing state. The disruptive effect ofregular presentation of a repeated syllable was markedly increased when it was presentedirregularly. The results are discussed in the context of organizational factors in short-term memory.     

Developing TODAM: Three models for serial-order information

TODAM2, a theory of distributed associative memory, shows how item and associative information can be considered special cases of serial-order information. Consequently, it is important to get the right model for serial-order information. Here, we analyze and compare three distributed-memory models for serial-order information that use TODAM’s convolution-correlation formalism. These models are the chaining model, the chunking model, and a new model, the power-set model. The chaining model associates each item with its predecessor; the chunking model uses multiple convolutions andn-grams to form chunks; and the power-set model interassociates all items in a set in a particular way to form a chunk. The models are compared in terms of their performance on seven basic tests of serial-order information—namely, serial recall, backward recall, recall of missing items, sequential probe tests, positional probe tests, serial-to-paired-associate transfer, and item recognition. The strengths and weaknesses of each model are discussed.