Development of prehension between 5 and 10 years of age: distance scaling, grip aperture, and sight of the hand

The authors investigated whether 5- to 10-year-old children (N = 75) differ from adults (N = 12) in the developmental course of distance scaling and the adaptations to the inability to see the hand during prehension movements. The children reached under a surface and grasped and lifted an object suspended through it. All children scaled velocity appropriately for movement distance, both with and without sight of the hand. However, 5- to 6-year-old children did not increase grip aperture with increased distance, whereas older children and adults did. The older children and adults spent longer after peak deceleration when they could not see the hand, and maximum grip aperture (MGA) was larger, providing an increased safety margin. Children aged 5 to 6 spent the same amount of time between peak deceleration and grasp, whether or not they could see the hand, and they failed to increase MGA when they could not see the hand. Prehension in the younger children differed from that of older children in two ways: The younger children did not integrate reach and grasp over different distances and did not use visual information about hand position to optimize accuracy.     

Unit price and choice in a token-reinforcement context

Pigeons were exposed to multiple and concurrent second-order schedules of token reinforcement, with stimulus lights serving as token reinforcers. Tokens were produced and exchanged for food according to various fixed-ratio schedules, yielding equal and unequal unit prices (responses per unit food delivery). On one schedule (termed the standard schedule), the unit price was held constant across conditions. On a second schedule (the alternative schedule), the unit price was either the same or different from the standard. Under conditions with unequal unit prices, near-exclusive preference for the lower unit price was obtained. Under conditions with equal unit prices, the direction and degree of preference depended on ratio size (number of responses per exchange period). When this ratio differed, strong preferences for the smaller ratio were observed. When this ratio was equal, preferences were nearer indifference. Response rates on the multiple schedule were generally consistent with the preference data in showing sensitivity to ratio size. Results are discussed in terms of a unit-price model that includes handling and reinforcer immediacy as additional costs. On the whole, results show that preferences were determined primarily by delay to the exchange period.     

Prior knowledge and subtyping effects in children's category learning

Two experiments examined how 5- and 10-year-old children revise their category representations when exposed to exemplars that are congruent or incongruent with existing knowledge. During training children were presented with exemplars containing features that were congruent or incongruent with children's social stereotypes together with a stereotype-neutral feature. In the knowledge-subtyping condition this neutral feature predicted the stereotype-congruence of the other features. In the knowledge-standard condition the neutral feature was uncorrelated with stereotype-congruence. At test children made judgements about feature co-occurrence within the learned category. In each experiment these judgements were influenced by both stereotypical beliefs and exemplar observation. Stereotypical beliefs, however, had a greater influence on co-occurrence judgements in the knowledge-subtyping than in the standard conditions. In Experiment 2 these effects were shown to generalize to judgements about features that were not presented during training. These results challenge current models of knowledge-based categorization by showing that exemplar structure determines whether novel exemplar features are incorporated into category representations.     

The effects of a mentoring program on at-risk youth

This study examined an intensive mentoring program that focuses on youth deemed at-risk for juvenile delinquency or mental illness. Mothers and teachers completed the Child Behavior Checklist, and youth completed the Hopelessness Scale for Children, the Piers-Harris Self-Concept Scale, and the Self-Report Delinquency Scale. The youth (ages 10 to 17) either participated in the mentoring program (intervention, n = 34) or remained on the waiting list (nonintervention, n = 34) for 6 months. Repeated-measures ANOVAs assessed changes from preintervention to postintervention and indicated significant improvement in problematic behaviors for the intervention group. Mentoring appeared to affect African American youth differently than Caucasian and Latino youth. There were no significant interactions involving gender. The findings of this study supported the positive influence of mentoring on at-risk youth.     

Young infants' perception of unity and form in occlusion displays

Young infants have been reported to perceive the unity of a center-occluded object when the visible ends of the object are aligned and undergo common motion but not when the edges of the object are misaligned (Johnson & Aslin, 1996). Using a recognition-based paradigm, the authors investigated the possibility that past research failed to provide sufficiently sensitive assessments of infants' perception of the unity of misaligned edges in partial occlusion displays. Positive evidence was obtained in 4-month-olds for veridical perception of the motion and location of a hidden region but not its orientation, whereas 7-month-olds, in contrast to the younger infants, appeared to respond to the orientation of the hidden region. Overall, the results suggest that habituation designs tapping recognition processes may be particularly efficacious in revealing infants' perceptual organization. In addition, the findings provide corroborative evidence for the importance of both motion and orientation in young infants' object segregation and for the difficulty in achieving percepts of the global form of a partly occluded object.     

Dying to Be Old: A Sociological Analysis of Old Age as Cause of Death

While gerontology and issues of aging are attracting more focus and scholarship, little has been done to examine the social constructions of old age as perception, particularly in historical contexts. We use data from gravestones and burial records (1870s–1950s) of a single, large, midwestern cemetery to examine those who were said to have died of old age or senility for patterned differences in the application of these labels. We then compare this labeled group with all others of the same age range in the cemetery for fundamental demographic differences that would explain the presence or absence of these elder-status labels. Though differences in patterns between and within groups were often small and not statistically significant, they are typically in the direction predicted, and contribute to some historical sense of old age as social construction.     

Estimating Reading Growth Attributable to Accelerated Reader at One American School in the Caribbean

This article provides a statistical analysis of the reading gains observed at one American school in the Caribbean that was using Accelerated Reader. It provides an estimate of the number of hours students needed to read to advance their reading performance an additional year. The authors estimate how much Accelerated Reader contributed to the advancement and determine how many points per grade a student needs to earn to make a year of reading growth. When points are converted to hours of time, the data show that it takes about 800 hours of time each year for students in grade 3 through grade 12 to achieve a year of growth. It is the conclusion then that students who read this much would spend about 9,600 total hours reading during their first 12 years of schooling.     

Now You See Them,Now You Do Not: The Influence of Indicator–Factor Ratio on Support for Assessment Center Dimensions

The inability of assessment center (AC) researchers to find admissible solutions for confirmatory factor analytic (CFA) models that include dimensions has led some to conclude that ACs do not measure dimensions at all. This study investigated whether increasing the indicator–factor ratio facilitates the achievement of convergent and admissible CFA solutions in 2 independent ACs. Results revealed that, when models specify multiple behavioral checklist items as manifest indicators of each latent dimension, all of the AC CFA models tested were identified and returned proper solutions. When armed with the ability to undertake a full set of model comparisons using model fit rather than solution convergence and admissibility as comparative criteria, we found clear evidence for modest dimension effects. These results suggest that the frequent failure to find dimensions in models of the internal structure of ACs is a methodological artifact and that one approach to increase the likelihood for reaching a proper solution is to increase the number of manifest indicators for each dimension factor. In addition, across exercise dimension ratings and the overall assessment rating were both strongly correlated with dimension and exercise factors, indicating that regardless of how an AC is scored, exercise variance will continue to play a key role in the scoring of ACs.     

The role of forget-cue salience in list-method directed forgetting

Research suggests that manipulating the wording of the forget cue in list-method directed forgetting affects the magnitude of directed forgetting both in younger children (Aslan, Staudigl, Samenieh, & Bauml, in press) and in older adults (Sahakyan, Delaney, & Goodmon, 2008). This occurs when the forget cue overemphasises the importance of forgetting in the current context. The present experiment investigated whether de-emphasising forgetting affected the magnitude of list-method directed forgetting in college adults. Some participants received overt forget cues that explicitly instructed them to forget earlier studied items, whereas others received covert forget cues that implied forgetting by emphasising selective remembering (e.g., “you will only need to remember some of the items”). Results indicated equivalent directed forgetting for both types of cues. However, regardless of the type of cue received, participants who reported using specific forgetting strategies in response to the forget cue showed directed forgetting, whereas those that reported doing nothing did not show any effects. The results underscore that successful directed forgetting requires engagement of controlled processes.