Representational masking and the attentional blink

After successful detection of a target item within a stream of rapidly displayed visual stimuli, subsequent detection of an additional target is impaired for roughly 500 ms. This impairment is known as the “attentional blink” (AB). Previous studies have found that if either the first (Tl; Raymond, Shapiro, & Arnell, 1992) or second target (T2; Giesbrecht & Di Lollo, 1998) is not followed by a mask, the AB impairment is significantly reduced. Whereas low-level perceptual factors have been found to influence the efficacy of masking in the AB (e.g., Seiffert & Di Lollo, 1997), the current experiment used a higher level (representational) manipulation, i.e., repetition blindness to reduce the efficacy of target masking in the AB. These findings contribute to the growing literature suggesting that masking plays more than a perceptual role in the AB phenomenon.     

Adult age differences in subjective and objective measures of strategy use on a sequentially cued prediction task

Differences in strategy use are thought to underlie age-related performance deficits on many learning and decision-making tasks. Recently, age-related differences in learning to make predictions were reported on the Triplets Prediction Task (TPT). Notably, deficits appeared early in training and continued with experience. To assess if age differences were due to early strategy use, neural networks were used to objectively assess the strategies implemented by participants during Session 1. Then, the relationship between these strategies and performance was examined. Results revealed that older adults were more likely to implement a disadvantageous strategy early in learning, and this led to poorer task performance. Importantly, the relationship between age and task performance was partially mediated by early strategy use, suggesting that early strategy selection played a role in the lower quality of predictions in older adults.     

Actuarial Criminology: Meeting Current Challenges in Southern Africa

South African prisons were overcrowded by more than sixty-three percent in 2005. Overcrowding and poor prison conditions have enormous implications for rehabilitation efforts made by the South African Department of Correctional Services. The South African White Paper on Corrections (2005) commits the Department of Correctional Services to provide needs-based rehabilitation processes and a framework of continuous evaluation to measure the impact and success of such processes. It also acknowledges that monitoring the rates of recidivism is a critical indicator of the success, the effectiveness of needs-based rehabilitation, and improved service. A reliable system for monitoring recidivism will have to be developed and put in place. In this respect, actuarial criminology can make a vital contribution. This article poses a strategic alternative to the correctional industry in Southern Africa that can be used for the realization of correctional ideals, especially where retribution and overcrowding are still the main features of correctional institutions.     

Time,number and length: Similarities and differences in discrimination in adults and children

The aim of this study was to focus on similarities in the discrimination of three different quantities—time, number, and line length—using a bisection task involving children aged 5 and 8 years and adults, when number and length were presented nonsequentially (Experiment 1) and sequentially (Experiment 2). In the nonsequential condition, for all age groups, although to a greater extent in the younger children, the psychophysical functions were flatter, and the Weber ratio higher for time than for number and length. Number and length yielded similar psychophysical functions. Thus, sensitivity to time was lower than that to the other quantities, whether continuous or not. However, when number and length were presented sequentially (Experiment 2), the differences in discrimination performance between time, number, and length disappeared. Furthermore, the Weber ratio values as well as the bisection points for all quantities presented sequentially appeared to be close to that found for duration in the nonsequential condition. The results are discussed within the framework of recent theories suggesting a common mechanism for all analogical quantities.     

Expertise makes the world slow down: Judgements of duration are influenced by domain knowledge

Experts often appear to perceive time differently from novices. The current study thus examined perceptions of time as a function of domain expertise. Specifically, individuals with high or low levels of knowledge of American football made judgements of duration for briefly presented words that were unrelated to football (e.g., rooster), football specific (e.g., touchdown), or ambiguous (e.g., huddle). Results showed that high-knowledge individuals judged football-specific words as having been presented for a longer duration than unrelated or ambiguous words. In contrast, low-knowledge participants exhibited no systematic differences in judgements of duration based on the type of word presented. These findings are discussed within a fluency attribution framework, which suggests that experts' fluent perception of domain-relevant stimuli leads to the subjective impression that time slows down in one's domain of expertise.     

Timing inter-reward intervals

Rats judged inter-reward intervals (IRIs) in a two-alternative, forced-choice task. The IRI was either short (S) or long (L). At the end of each IRI, two response levers were inserted into the box. A press to the lever designated as correct or incorrect produced a large (3-5 food pellets) or small (1 pellet) reward, respectively. Psychophysical functions were obtained by testing intermediate IRIs, which were followed by the small reward, independent of the response location. S and L intervals were manipulated across groups, as specified (in seconds) by the group name, S-L: 3-12 (n=12), 25-100 (n=12), and 50-200 (n=7). The psychophysical functions (p[L] vs. IRI) were ogival in shape and had bisection points (p[S]=p[L]=0.5) near the geometric mean of S and L intervals. The psychophysical functions did not superimpose in relative time (IRI/L). Instead, 3-12 was timed with greater relative sensitivity than were 25-100 and 50-200.     

Predictor Variables Associated with Positive Fast Track Outcomes at the End of Third Grade

Progress has been made in understanding the outcome effects of preventive interventions and treatments designed to reduce children's conduct problems. However, limited research has explored the factors that may affect the degree to which an intervention is likely to benefit particular individuals. This study examines selected child, family, and community baseline characteristics that may predict proximal outcomes from the Fast Track intervention. The primary goal of this study was to examine predictors of outcomes after 3 years of intervention participation, at the end of 3rd grade. Three types of proximal outcomes were examined: parent-rated aggression, teacher-rated oppositional–aggressive behavior, and special education involvement. The relation between 11 risk factors and these 3 outcomes was examined, with separate regression analyses for the intervention and control groups. Moderate evidence of prediction of outcome effects was found, although none of the baseline variables were found to predict all 3 outcomes, and different patterns of prediction emerged for home versus school outcomes.     

Saving the worst for last: The effect of time horizon on the efficiency of negotiating benefits and burdens

Three experiments explored the effect of outcome delays—longer time horizons for the realization of outcomes—on the efficiency of negotiated agreements. We hypothesized that there would be a positive relationship between a longer temporal distance to the consequences of negotiated agreements and the efficiency of those agreements. Outcome delays did increase the efficiency of the negotiated agreements. In addition, type of resource, burden or benefit, moderated this relationship. Because negotiating for burdens is more difficult than negotiating for benefits in the present, the salutary discounting effects of outcome delays were greater for burdens. The multifaceted effects of time on negotiations are discussed.     

Conditions for factor (in)determinacy in factor analysis

The subject of factor indeterminacy has a vast history in factor analysis (Guttman, 1955; Lederman, 1938; Wilson, 1928). It has lead to strong differences in opinion (Steiger, 1979). The current paper gives necessary and sufficient conditions for observability of factors in terms of the parameter matrices and a finite number of variables. Five conditions are given which rigorously define indeterminacy. It is shown that (un)observable factors are (in)determinate. Specifically, the indeterminacy proof by Guttman is extended to Heywood cases. The results are illustrated by two examples and implications for indeterminacy are discussed.