Accessing distant premise information: how memory feeds reasoning

According to current psychological models of deduction, people can draw inferences on the basis of information that they receive from different sources at different times. In 3 reading-comprehension experiments, the authors demonstrated that premises that appear far apart in a text (distant) are not accessed and are therefore not used as a basis for logical inferences (Experiment 1), unless the premises are reinstated by a contextual cue (Experiment 2). In Experiment 3, the authors investigated whether these deductions are then integrated into the reader's situation model of the text. The results are interpreted in terms of a collaboration between memory-based text processing and higher level schema-driven logical reasoning.     

Word frequency and memory: effects on absolute versus relative order memory and on item memory versus order memory

Word frequency can produce opposite effects on recognition and order memory: Low-frequency words produce greater recognition accuracy, whereas high-frequency words produce superior order memory. The present experiments further delineate the relationship between word frequency and order memory. Experiment 1 indicates that low-frequency words produce worse performance on a measure of absolute order memory but not on a test of relative order, which is consistent with the idea that different forms of information underlie different types of order judgments (Greene, Thapar, & Westerman, 1998). Experiment 2 contrasted high-, low-, and very low-frequency words on recognition memory and absolute order memory. In comparison with high-frequency words, low-frequency words enhanced recognition, whereas very low-frequency words did not. Both low- and very low-frequency words, however, produced worse memory for absolute order. Thus, the relationship between frequency and item memory is an inverted U-shaped function, whereas the relationship between frequency and absolute order memory is direct. This implies that the item-enhancing effects of lower word frequency may be dissociated from its order-disrupting effects.     

Generation and hypermnesia

The multifactor account of the generation effect makes detailed predictions about the effects of generation on item-specific and relational encoding, predictions confirmed in four experiments using a multiple-test methodology. In pure-list designs with unrelated study items, generation produced more interest item gains (indexing greater item-specific processing) and more interest item losses (indexing less relational processing) relative to the read condition. In a mixed-list design, generation produced more gains but did not affect losses. With categorically-related study items, generation produced more gains but fewer losses (indicating enhanced relational encoding). Generation consistently produced hypermnesia whereas reading did so only for related study items. Also, a significant generation effect emerged on later tests under conditions (between-subjects design, unrelated study items) which typically yield no generation effect.     

Image processing for improved eye-tracking accuracy

Video cameras provide a simple, noninvasive method for monitoring a subject’s eye movements. An important concept is that of the resolution of the system, which is the smallest eye movement that can be reliably detected. While hardware systems are available that estimate direction of gaze in real time from a video image of the pupil, such systems must limit image processing to attain real-time performance and are limited to a resolution of about 10 arc minutes. Two ways to improve resolution are discussed. The first is to improve the image processing algorithms that are used to derive an estimate. Offline analysis of the data can improve resolution by at least one order of magnitude for images of the pupil. A second avenue by which to improve resolution is to increase the optical gain of the imaging setup (i.e., the amount of image motion produced by a given eye rotation). Ophthalmoscopic imaging of retinal blood vessels provides increased optical gain and improved immunity to small head movements but requires a highly sensitive camera. The large number of images involved in a typical experiment imposes great demands on the storage, handling, and processing of data. A major bottleneck had been the real-time digitization and storage of large amounts of video imagery, but recent developments in video compression hardware have made this problem tractable at a reasonable cost. Images of both the retina and the pupil can be analyzed successfully using a basic toolbox of image-processing routines (filtering, correlation, thresholding, etc.), which are, for the most part, well suited to implementation on vectorizing supercomputers.     

Perceptual interference improves explicit memory but does not enhance data-driven processing.

Nairne (1988) has recently demonstrated that interfering with the perceptual processing of an item at study improves later memory for that item. Nairne hypothesized that interfering with perceptual processes induces a data-driven generation process that enhances the representation of visual information. Using a variant of Nairne's procedure, we both replicated his original findings and tested his hypothesis that enhanced data-driven processing causes the current effect. The results of studies using free recall and perceptual identification tests were inconsistent with Nairne's hypothesis. We consider several alternative interpretations in the General Discussion.     

Attending to simple auditory and visual signals

Rutgers-The State University, New Brunswick, New Jersey 08903 Is the quality of information obtained from simple auditory and visual signals diminished when both modalities must be attended to simultaneously? This question was investigated in an experiment in which subjects made forced-choice judgments of the location of simple light and tone signals presented in focused- and divided-attention conditions. The data are compared with the predictions of a model that describes the largest performance decrement to be expected in the divided-attention condition on the basis of nonattentional factors. The results of this comparison suggest that the difference in performance between focused- and dividedattention conditions is attributable solely to the increased opportunity to confuse signal with noise as the number of modalities is increased. Thus, there appears to be no evidence that dividing attention between modalities affects the quality of the stimulus representations of individual light and tone signals.     

Family factors associated with attention deficit hyperactivity disorder and emotional disorders in children

Few well-controlled studies have identified psychosocial profiles of families of boys with ADHD and boys with emotional disorders compared with normal controls. However, the clinical and theoretical literature pinpoints four domains in which distinctive profiles would be expected to occur. In this study, twenty-two mothers and thirteen fathers of twenty-two boys with ADHD; twenty mothers and fifteen fathers of twenty boys with a mood or anxiety disorder; and twenty-six mothers and sixteen fathers of twenty-seven normal controls were compared on: (1) stress, support and quality of life; (2) current family functioning; (3) parenting style and satisfaction in the family of origin and current family; and (4) current and past parental functioning. The two clinical groups showed higher levels of stress and lower levels of both social support and quality of life than did normal controls. Both clinical groups showed deficits in current family functioning, but contrary to expectations the ADHD and emotional disorder group did not show distinctly different profiles. Parents of ADHD children reported higher levels of authoritarian parenting styles, and parents from both clinical groups reported less parenting satisfaction than did normal controls in both their current families and their families of origin. Parents of children with ADHD and emotional disorders reported greater parenting satisfaction in their families of origin than in their current families. This discrepancy was greatest for parents of ADHD children. Parents of children with ADHD and emotional disorders reported greater psychological health problems and more childhood ADHD symptomatology than did normal controls. Parents of children with ADHD and emotional disorders have significant psychosocial difficulties in family and personal functioning. Family intervention is highly appropriate for families with children who are referred for help with both types of difficulties.