Patterns of Aggression in Parents and their Children

In this research, we examined children's awareness of inconsistencies in messages that are meaningful for children, instructions for games. In the first experiment, kindergarten (n = 25) and second- (n = 25) and fourth-grade (n = 26) children were individually read the instructions for two games, each of which included two inconsistent statements. Chi-square analyses yielded a significant effect for grade for one game (p < .05) and a marginally significant effect for a second game (p < .10). In a second experiment, second- (n = 40), fourth- (n = 40), and sixth-grade (n = 40) children were read the instructions for two games, each of which included two statements that were inconsistent. An analysis of variance demonstrated that with an increase in grade, there was a significant increase (p < .001) in awareness that a message contained an inconsistency. The analysis also indicated that the subjects were more willing (p < .08) to question an adult than they were to question a child about an inconsistency. Moreover, a regression analysis indicated that awareness of inconsistencies in the rules for games was significantly related to memory (p < .001) and to one's ability to note inconsistencies in shorter, simpler messages (p < .001).     

Effect of Age and Gender in the Control of Elbow Flexion Movements

In previous studies of rapid elbow movements in young healthy men, characteristic task-dependent changes in the patterns of muscle activation when movement speed or distance was varied have been reported. In the present study, the authors investigated whether age or gender is associated with changes in the patterns of muscle activity previously reported in young men. Arm movements of 10 healthy older and 10 healthy younger participants (5 men and 5 women in each group) were studied. Surface electromyograms (EMGs) from agonist (biceps) and antagonist (triceps) muscles, kinematic and kinetic parameters, as well as anthropometric and strength measures were recorded. All 4 groups of participants showed similar task- (distance or speed) dependent changes in biphasic EMG activity. Similar modulation of the initial rate of rise of the EMG, integrated agonist and antagonist EMG activity, as well as their relative timing were observed in all 4 groups. Those results suggest that older individuals of both genders retain the control strategies for elbow movements used by young individuals. Despite the qualitative similarities in the patterns of muscle activation, the men moved more quickly than the women, and younger participants moved more quickly than older participants. Those performance differences could not be explained in terms of differences in body size and strength alone.     

Spinal Cord Circuits

Over the past decade, research at three different levels of sensorimotor control has revealed a degree of complexity that challenges traditional hypotheses regarding servocontrol of individual muscles: (a) The connectivity of spinal circuits is much more divergent and convergent than expected. (b) The normal and reflex-induced recruitment of individual muscles and compartments of muscles is more finely controlled than was noted previously. (c) The mechanical interactions among linked skeletal segments and their often multiarticular muscles are neither simple nor intuitively obvious. We have developed a mathematical model of the cat hind limb that permits us to examine the influence of individual muscles on posture and gait. We have used linear quadratic control theory to predict the optimal distribution of feedback from a hypothetical set of proprioceptors, given different assumptions about the behavioral goals of the animal. The changes in these predictions that result from changes in the structure and control objectives of the model may provide insights into the functions actually performed by the various circuits in the spinal cord.     

The Effect of Interpolated Motor Activity on the Short-Term Retention of Movement Distance and End-Location

The effect of an interpolated movement on the recall of a blind, lever-positioning movement was assessed separately for the reproduction cues of distance and end-location. Both cues showed the context effect of assimilation, that is, the end-location of the interpolated movement caused directional biasing of the algebraic or constant error (CE) for location reproduction while the length of the interpolated movement caused similar directional biasing for distance reproduction. Variability about algebraic error (VE) was used to assess forgetting. There was no change in VE for location reproduction, and an increase in VE for distance reproduction was limited to the relatively large movements. Thus, an interpolated movement that does not have to be remembered does not cause interference with the retention of location information, but does cause some interference with the retention of distance information. The findings are discussed in relation to a model of motor short-term memory which incorporates both CE and VE.     

Comment on “Retention Characteristics of Motor Short-Term Memory Cues”

Marteniuk (1973) used negative results, which may be attributed to a lack of power, to question the adequacy of variable error as a measure of forgetting. He also used these negative results, along with constant error results which were consistent with the Laabs (1971, 1973) model of motor memory, to reject parts of the model related to variable error. Caution is advised when interpreting negative results and interchanging dependent measures.     

Power Spectral Density Analysis of Lateral Human Standing Sway

A number of investigators have used power spectral density (PSD) analysis to try to identify and quantify various sensory systems which are involved in upright standing. Using PSD analysis, over a frequency range from 0.02-2.5 Hz, the present study examined two trials of lateral sway in each of 80 men. The results showed that little change occurred in PSD values between the first and second trials. Exponential curves were fit to the averaged trials data of each subject. The values of the parameter estimates obtained from the curve-fitting were regressed on the values of various direct, and derived anthropometric variables to try to explain the variance of the parameter estimates in terms of the anthropometrics. The subject’s center of gravity location accounted for no more than 15.8% of the parameter variance, whereas the remaining anthropometrics explained even less. The overall averaged data suggest that three functions (related to visual, vestibular, and proprioceptive processes) may underlie the sway pattern over this frequency range. PSD curves of individuals with a history of high-level athletic activity clearly differed from those of sedentary subjects.     

Children's Perception of Parental Empathy as a Precursor of Children's Empathy in Middle and Late Childhood

The present study investigated the relationship between children's self-concepts and evaluations of parent figures. The subjects were elementary school children (352 males and 280 females; Grades 5 through 10) who came from intact families, divorced families, or families in which one or both parents had died. Significant relationships were obtained between children's self-concept ratings and their evaluations of their natural father and mother for both intact and divorced families. This relationship was not significant, however, for families in which a parent had died. Furthermore, children's self-ratings were not significantly correlated with their evaluations of stepparents.     

In search of average growth: Describing within-year oral reading fluency growth across Grades 1–8

Measures of oral reading fluency (ORF) are perhaps the most often used assessment to monitor student progress as part of a response to intervention (RTI) model. Rates of growth in research and aim lines in practice are used to characterize student growth; in either case, growth is generally defined as linear, increasing at a constant rate. Recent research suggests ORF growth follows a nonlinear trajectory, but limitations related to the datasets used in such studies, composed of only three testing occasions, curtails their ability to examine the true functional form of ORF growth. The purpose of this study was to model within-year ORF growth using up to eight testing occasions for 1448 students in Grades 1 to 8 to assess (a) the average growth trajectory for within-year ORF growth, (b) whether students vary significantly in within-year ORF growth, and (c) the extent to which findings are consistent across grades. Results demonstrated that for Grades 1 to 7, a quadratic growth model fit better than either linear or cubic growth models, and for Grade 8, there was no substantial, stable growth. Findings suggest that the expectation for linear growth currently used in practice may be unrealistic.     

Explaining the Success of Science: Kuhn and Scientific Realists

In this essay, I critically evaluate the approaches to explaining the success of science in Kuhn and the works of inference-to-the-best-explanation scientific realists. Kuhn’s challenge to realists, who invoke the truth of theories to explain their success, is two-fold. His paradigm-account of success confronts realists with the problem of theory change, and the historical fact of successful theories later rejected as false. Secondly, Kuhn’s account of the success of science has no need to bring truth into the explanation. In turn, I argue that weakness in Kuhn and the prevailing forms of scientific realism motivate a better account of realism which I characterize as ‘best current theory realism’ and defend against the pessimistic meta-induction and the problem of theory-change. This realism argues that the best explanation of the success of current and past scientific theories only requires the simple claim that our best current theories are true. Kuhn’s account can explain how normal science succeeds but cannot account for why its problem solutions work where they do and why they fail for other puzzles.