Suboptimal choice and initial‐link requirement

Pigeons (n = 14) were trained in a concurrent‐chains suboptimal choice procedure that tested the effect of an increased ratio requirement in the initial links. Fixed‐ratio 1 and 25 conditions were manipulated within subjects in a counterbalanced order. In all conditions, distinct terminal‐link stimuli on a suboptimal alternative signaled either primary reinforcement (20% of the time) or extinction (80% of the time). On an optimal alternative, two distinct terminal‐link stimuli each signaled a 50% chance of primary reinforcement. Preference for the suboptimal alternative was significantly attenuated, and in some birds completely reversed, by the larger response requirement irrespective of condition order. This larger response requirement also generated a notable increase in between‐subject variability. A measure of cumulative choice responding is introduced to mitigate the problems associated with traditional session averages. Ordinal predictions of some current theories of suboptimal choice are also considered in light of the results.     

Coordinating between Graphs and Science Concepts: Density and Buoyancy

Graphs illustrating complex scientific relationships require students to integrate multiple concepts and visual features into a coherent understanding. We investigate ways to support students in integrating their understanding of density concepts through a graph that is linked to a simulation depicting the relationship between mass, volume, and density. We randomly assigned 325 8^th-grade students to 1 of 2 graphing activities. In the analyze condition, students plotted a set of data points selected to help clarify the relationship between mass, volume, and buoyancy, and then interacted with a guided simulation to improve their plotting accuracy. In the generate condition, students chose their own data points, and then interacted with a guided simulation to test and revise their choices. We found that, although analyze participants were more likely to construct accurate graphs, generate participants were more likely to develop a coherent understanding of density and buoyancy. Analyses of process data and interviews suggest that generate participants grappled with the mass-volume ratio by deliberately testing points and identifying patterns as they updated their understanding of science concepts. In contrast, analyze participants displayed less deliberate exploration of the graph space. We discuss how activities that integrate graph interpretation and concept refinement can deepen science learning.     

Participant Retention in the Parents Matter! Program: Strategies and Outcome

We present a discussion of the literature addressing retention of ethnic minority samples in longitudinal studies. In addition, we describe the retention procedures implemented in the Parents Matter! Program (PMP), a community-based sexual risk reduction intervention for African American families. Finally, the results of PMP's retention strategies are presented.     

Source monitoring and suggestibility to misinformation: adult age‐related differences

We compared young and older adults' source monitoring performance on an explicit source identification test using the misinformation paradigm. Several age‐related differences in source memory were demonstrated: (a) older adults were more likely than were young adults to say that they saw information that was actually only suggested to them; (b) older adults were more confident in their false memories than were young adults; (c) older adults were less confident in their accurate memory for the source of information than were young adults. Together, the data suggest that older adults either lacked or failed to use helpful diagnostic source information (e.g. perceptual details or temporal information), and that their confidence in their false memories reflected an over‐weighting of semantic information. Copyright © 2002 John Wiley & Sons, Ltd.     

Ecocultural bias in culture-specific intelligence tests in an ecologically diverse culture: The Philippines

In an ecologically diverse society (the Philippines), measurement equivalence across ecological settings was investigated with two culture-specific intelligence tests. Comparative reliability and factor analyses indicated that the tests (one for preschoolers, one for adults) were measuring the same ability dimensions equally reliably within each setting. Across settings, however, delta-plot analyses revealed considerable bias at the item level in tests of crystallized abilities, and the preschool tests tended to favor children from the setting where the tests were developed. The results are interpreted in terms of an ecocultural framework in which group differences in intellectual performance can reflect not only actual ability differences but differences in practice with, and exposure to, particular environmental stimuli and/or cognitive skills. The study demonstrates: (a) the need, particularly in ecologically diverse and segmented societies, to inspect tests for item bias; (b) the difficulty of culturally “equating” cognitive measures, even for very similar cultural subgroups who differ primarily in ecological setting.     

Abstract categorization ability as a predictor of learning disability classification

Based on a theoretical analysis of the type of cognitive processing that should be sensitive to population differences, this study evaluated the diagnostic validity of a task measuring abstract categorization ability in six-, seven-, and eight-year-old learning disabled (LD) and non-LD peers. This research is part of a project, the major goal of which is the development of a cognitive-based preschool screening test for the early detection of children who may subsequently fail in school. Diagnostic validity is being evaluated within the context of the research strategy we have adopted. Data are presented that demonstrate that the component of abstract category knowledge that best discriminates LD children from non-LD peers, is knowledge of how members of abstract categories differ from each other. This is consistent with a priori predictions from theory.