The strategic regulation of children's memory performance and suggestibility

We report two empirical studies that investigated previously reported benefits of a high accuracy motivation, and thus a high threshold, for children's and adults' event recall and for their ability to resist false suggestions. In the studies, 6-, 7-, and 8-year-olds, as well as adults, were shown a brief video about an event and were later asked unbiased and misleading questions about it. In Study 1, participants were either (a) given the typical accuracy instructions (including the option to answer with "I don't know"), (b) reminded of the accuracy instructions during the interview, or (c) immediately given feedback and a token for every correct answer. The results showed that the reminders were ineffective in stimulating strategic control behavior in children, independent of age. In Study 2, the confounding effects of feedback and incentives were disentangled by contrasting (a) free report, (b) feedback only, (c) incentives only, and (d) feedback plus incentives. Analyses on recall performance and suggestibility revealed that both feedback and incentives are necessary to increase children's accurate memory reports.     

Theoretical correlations and measured correlations: relating recognition and recall in four distributed memory models

This article addresses the relation between item recognition and associative (cued) recall. Going beyond measures of performance on each task, the analysis focuses on the degree to which the contingency between successful recognition and successful recall of a studied item reflects the commonality of memory processes underlying the recognition and recall tasks. Specifically, 4 classes of distributed memory models are assessed for their ability to account for the relatively invariant correlation (approximately .5) between successive recognition and recall. Basic versions of each model either under- or overpredict the intertask correlation. Introducing variability in goodness-of-encoding and response criteria, as well as output encoding, enabled all 4 models to reproduce the moderate intertask correlation and the increase in correlation observed in 2 mixed-list experiments. This model-based analysis provides a general theoretical framework for interpreting contingencies between successive memory tests.     

The development of organizational strategies in children: evidence from a microgenetic longitudinal study

The authors examined memory on a sort-recall task in children 8 to 12 years of age. Children were first classified as either strategic or nonstrategic on a sort-recall pretest and then participated in an 11-week microgenetic study involving nine sessions. Strategy use was assessed on each trial. Consistent with past longitudinal research, changes from nonstrategic to strategic behavior occurred suddenly rather than gradually. Once children began using organizational strategies, their recall performance improved immediately. Deliberate strategy use was clearly reflected by sorting behavior during encoding but not in clustering during recall. Conclusions about whether there are children with utilization deficiencies are thus affected by how the concept is defined and whether sorting or clustering is taken as the indicator of spontaneous strategy use.     

Top-down gain control in the auditory system: evidence from identification and discrimination experiments

The influence of intensity range in auditory identification and intensity discrimination experiments is well documented and is usually attributed to nonsensory factors. Recent studies, however, have suggested that the stimulus range effect might be sensory in origin. To test this notion, in one set of experiments, we had listeners identify the individual tones in a set. One baseline condition consisted of identifying four 1-kHz, low-intensity tones; the other consisted of identifying four 1-kHz, high-intensity tones. In the experimental conditions, these baseline tone sets were augmented by adding a fifth tone at either 1 or 5 kHz. Added 5-kHz tones had little effect on identification accuracy for the four baseline tones. When an added 1-kHz tone differed substantially in intensity from the four baseline tones, it adversely affected performance, with the addition of a high-intensity tone to a set of low-intensity tones having a more deleterious effect than the addition of a low-intensity tone to a set of high-intensity tones. These and further results, obtained in an exploration of this asymmetrical range effect in a third identification experiment and in two intensity-discrimination experiments, were consistent with the notion of a nonlinear amplifier under top-down control whose functions include protection against sensory overload from loud sounds. The identification data were well described by a signal-detection model using equal-variance Laplace distributions instead of the usual Gaussian distributions.     

Representational bias does not affect bisection of lines with a pictorially or semantically defined top by patients with left hemispatial neglect

Normal subjects may have both representational and visual-based components determining bias in bisection of horizontal, vertical, and radial lines. The influence of these components is less clear in patients with neglect. We asked 25 patients with right hemisphere stroke and clinical features of neglect to bisect lines oriented horizontally, vertically, and radially above and below eye level. Objects including human silhouette figures, arrowheads, and the words 'TOP' and 'BOTTOM' were placed at either end of each line. These figures were presented either upright or upside down in some orientations, and presented rightward and leftward in other orientations, to pictorially or semantically define a "top" to each line independent of the actual top of the visual field. Patients demonstrated a rightward bias on all horizontal line bisections, with similar bias and greater magnitude than normal subjects. Patients also demonstrated visual-based biases on some of the vertical, radial down, and radial up lines presented. However, patients did not demonstrate a significant representational bias with any of the visual cues presented on any of the line orientations. Patients with acute right hemisphere stroke demonstrate a rightward bias when asked to perform line bisection in the horizontal line orientation, as well as an upward bias in vertical line bisection. The lack of representational bias in patients with neglect may be due to a greater degree of visual-based neglect as compared to representational neglect, or it may be due to an absence of representational bias in patients with right hemisphere stroke.     

Attentional control in the aging brain: insights from an fMRI study of the stroop task

Several recent studies of aging and cognition have attributed decreases in the efficiency of working memory processes to possible declines in attentional control, the mechanism(s) by which the brain attempts to limit its processing to that of task-relevant information. Here we used fMRI measures of neural activity during performance of the color-word Stroop task to compare the neural substrates of attentional control in younger (ages: 21-27 years old) and older participants (ages: 60-75 years old) during conditions of both increased competition (incongruent and congruent neutral) and increased conflict (incongruent and congruent neutral). We found evidence of age-related decreases in the responsiveness of structures thought to support attentional control (e.g., dorsolateral prefrontal and parietal cortices), suggesting possible impairments in the implementation of attentional control in older participants. Consistent with this notion, older participants exhibited more extensive activation of ventral visual processing regions (i.e., temporal cortex) and anterior inferior prefrontal cortices, reflecting a decreased ability to inhibit the processing of task-irrelevant information. Also, the anterior cingulate cortex, a region involved in evaluatory processes at the level of response (e.g., detecting potential for error), showed age-related increases in its sensitivity to the presence of competing color information. These findings are discussed in terms of newly emerging models of attentional control in the human brain.     

The role of accuracy motivation on children's and adults' event recall

To examine the role of accuracy motivation in event recall, 6-, 7-, and 8-year-old children and adults were shown a short video about a conflict between two groups of children. Three weeks later, participants were asked a set of unbiased specific questions about the video. Following A. Koriat and M. Goldsmith's (1994) distinction of quantity- and quality-oriented memory assessments, and based on their model of strategic regulation of memory accuracy (1996), accuracy motivation was manipulated across three conditions. Participants were (a) forced to provide an answer to each question (low accuracy motivation), (b) initially instructed to withhold uncertain answers by saying "I don't know" (medium accuracy motivation), or (c) rewarded for every single correct answer (high accuracy motivation). When motivation for accuracy was high, children as young as 6 were to withhold uncertain answers to the benefit of accuracy. The expected quality-quantity trade-off emerged only for peripheral items but not for the central items. Participants who were forced to provide an answer gave more correct answers but also high numbers of incorrect answers than participants who had the option to answer "I don't know." The results are discussed in terms of the underlying model as well as in terms of forensic interviewing.     

Telling stories: the perils and promise of using verbal reports to study math strategies

The problem size effect in adult arithmetic performance is generally attributed to direct retrieval processes operating on a network representation in long-term memory. J. LeFevre and her colleagues (J. LeFevre, J. Bisanz, et al., 1996; J. LeFevre, G. S. Sadesky, & J. Bisanz, 1996) challenged this explanation using verbal report evidence that adults also use time consuming nonretrieval strategies to solve simple addition and multiplication. The authors replicated J. LeFevre and colleagues' methods, but added instructional biasing and silent control conditions to test these methods. Both reaction time and report results suggest that LeFevre and colleagues' conclusions about nonretrieval frequency may have been influenced by instructions that revealed the experimental hypothesis and affected participants' strategy reports. Obtaining evidence about adult strategy use in simple arithmetic will require understanding instructional demand and appropriate report methodology.     

Monocular unmasking of noise-embedded patterns.

Binocular disparity cues may help an observer "unmask" a target in a background, thereby enhancing its detectability (e.g., Moraglia & Schneider, 1992). Here, we sought to determine whether similar effects could be produced by monocular displacement cues resulting from a two-frame sequential presentation of a Gabor pattern (a sinusoidal modulation of luminance combined with a Gaussian modulation of local contrast) embedded in an unvarying field of two-dimensional Gaussian noise. The Gabor in the second frame was spatially displaced relative to its location in the first frame; the horizontal displacement corresponded to a phase shift of the peak spatial frequency of the Gabor of 0 degree, 90 degrees, 180 degrees, 360 degrees, or 540 degrees. Monocular detection thresholds for the Gabor were appreciably lower for the 90 degrees, 180 degrees, and 540 degrees shift, than for the 0 degree and 360 degrees values. We explain these findings in terms of a model that constitutes the monocular analog of our summation model of binocular unmasking.