Focused attention improves working memory: implications for flexible-resource and discrete-capacity models

Performance in working memory (WM) tasks depends on the capacity for storing objects and on the allocation of attention to these objects. Here, we explored how capacity models need to be augmented to account for the benefit of focusing attention on the target of recall. Participants encoded six colored disks (Experiment 1) or a set of one to eight colored disks (Experiment 2) and were cued to recall the color of a target on a color wheel. In the no-delay condition, the recall-cue was presented after a 1,000-ms retention interval, and participants could report the retrieved color immediately. In the delay condition, the recall-cue was presented at the same time as in the no-delay condition, but the opportunity to report the color was delayed. During this delay, participants could focus attention exclusively on the target. Responses deviated less from the target’s color in the delay than in the no-delay condition. Mixture modeling assigned this benefit to a reduction in guessing (Experiments 1 and 2) and transposition errors (Experiment 2). We tested several computational models implementing flexible or discrete capacity allocation, aiming to explain both the effect of set size, reflecting the limited capacity of WM, and the effect of delay, reflecting the role of attention to WM representations. Both models fit the data better when a spatially graded source of transposition error is added to its assumptions. The benefits of focusing attention could be explained by allocating to this object a higher proportion of the capacity to represent color.     

On P-compatible hybrid identities and hyperidentities

P-compatible identities are built up from terms with a special structure. We investigate a variety defined by a set ofP-compatible hybrid identities and answer the question whether a variety defined by a set ofP-compatible hyperidentities can be solid.Presented byJan Zygmunt;     

Language effects in magnitude comparison: small, but not irrelevant

It is assumed that number magnitude comparison is performed by assessing magnitude representation on a single analog mental number line. However, we have observed a unit-decade-compatibility effect in German which is inconsistent with this assumption (Nuerk, Weger, & Willmes, 2001). Incompatible magnitude comparisons in which decade and unit comparisons lead to different responses (e.g., 37_52 for which 3<5, but 7>2) are slower and less accurately responded to than compatible trials in which decade and unit comparisons lead to the same response (e.g., 42_57, for which 4<5 and 2<7). As overall distance was held constant, a single holistic magnitude representation could not account for this compatibility effect. However, because of the inversion property of the corresponding German two-digit number words ("einundzwanzig" ), the language-generality of the effect is questionable. We have therefore examined the compatibility effect with native English speakers. We were able to replicate the compatibility effect using Arabic notation. Thus, the compatibility effect is not language-specific. However, in cross-linguistic analyses language-specific modulations were observed not only for number words but also for Arabic numbers. The constraints imposed on current models by the verbal mediation of Arabic number comparison are discussed.     

Control of the contents of working memory--a comparison of two paradigms and two age groups

Two experiments investigated whether young and old adults can temporarily remove information from a capacity-limited central component of working memory (WM) into another component, the activated part of long-term memory (LTM). Experiment 1 used a modified Sternberg recognition task (S. Sternberg, 1969); Experiment 2 used an arithmetic memory-updating task. In both paradigms, participants memorized 2 lists, one of which was cued as temporarily irrelevant. Removal of the irrelevant list from capacity-limited WM was indexed by the disappearance of list-length effects of that list on latencies for concurrent processing tasks. Young adults could outsource the irrelevant list within 2-3 s and retrieve it back into the central part of WM later. Old adults showed the same flexibility in the arithmetic updating task but seemed somewhat less able or inclined to temporarily move information into the activated part of LTM in the modified Sternberg task.     

Binding and inhibition in working memory: individual and age differences in short-term recognition

Two studies investigated the relationship between working memory capacity (WMC), adult age, and the resolution of conflict between familiarity and recollection in short-term recognition tasks. Experiment 1 showed a specific deficit of young adults with low WMC in rejecting intrusion probes (i.e., highly familiar probes) in a modified Sternberg task, which was similar to the deficit found in old adults in a parallel experiment (K. Oberauer, 2001). Experiment 2 generalized these results to 3 recognition paradigms (modified Sternberg, local recognition, and n back tasks). Old adults showed disproportional performance deficits on intrusion probes only in terms of reaction times, whereas young adults with low WMC showed them only in terms of errors. The generality of the effect across paradigms is more compatible with a deficit in content-context bindings subserving recollection than with a deficit in inhibition of irrelevant information in working memory. Structural equation models showed that WMC is related to the efficiency of recollection but not of familiarity.     

Evidence of separable spatial representations in a virtual navigation task

Three experiments investigated spatial orientation in a virtual navigation task. Subjects had to adjust a homing vector indicating their end position relative to the origin of the path. It was demonstrated that sparse visual flow was sufficient for accurate path integration. Moreover, subjects were found to prefer a distinct egocentric or allocentric reference frame to solve the task. "Turners" reacted as if they had taken on the new orientation during turns of the path by mentally rotating their sagittal axis (egocentric frame). "Nonturners," by contrast, tracked the new orientation without adopting it (allocentric frame). When instructed to use their nonpreferred reference frame, both groups displayed no decline in response accuracy relative to their preferred frame; even when presented with reaction formats based on either ego or allocentric coordinates, with format unpredictable on a trial, both groups responded highly accurately. These findings support the assumption of coexisting spatial representations during navigation.     

Mood and memory for tightly organized social information

The frequently cited finding that mood-congruent information can be better recalled than mood-incongruent information is tested using categorically organized stimulus material which imposes a systematic structure on the recall process. A target person was described with respect to six categories of social behaviour, with predominantly desirable behaviours in some categories and predominantly undesirable behaviours in others. Participants were induced either an elated mood state or a neutral state using Velten's procedure. Instructions (impression formation versus memory) were also manipulated. Although the mood manipulation apparently worked and did influence the impression judgments of the target person, it did not selectively facilitate the recall of mood-congruent material, neither at the level of specific items nor at the categorical level. However, when only deviating behaviours are considered which do not fit the structural constraints, mood-congruent information is indeed better recalled. To interpret these results, it is argued that the manifestation of mood effects depends on the restrictions of different tasks or response modes. Three other findings were obtained: Superior recall of redundant, structurally consistent information compared with deviating information; an advantage of positive over negative information which is confined to the impression formation condition; and, surprisingly, an incongruency effect for the encoding mood which may reflect the deeper processing of incongruent material.     

Individual differences in components of reaction time distributions and their relations to working memory and intelligence

The authors bring together approaches from cognitive and individual differences psychology to model characteristics of reaction time distributions beyond measures of central tendency. Ex-Gaussian distributions and a diffusion model approach are used to describe individuals' reaction time data. The authors identified common latent factors for each of the 3 ex-Gaussian parameters and for 3 parameters central to the diffusion model using structural equation modeling for a battery of choice reaction tasks. These factors had differential relations to criterion constructs. Parameters reflecting the tail of the distribution (i.e., tau in the ex-Gaussian and drift rate in the diffusion model) were the strongest unique predictors of working memory, reasoning, and psychometric speed. Theories of controlled attention and binding are discussed as potential theoretical explanations.     

Voice quality analysis of American and German speakers

Six phoneticians rated the voices of 26 American and 22 German speakers on nine voice quality parameters which were discussed and illustrated by tape-recorded examples before the rating sessions. A reliability analysis showed highly significant interrater agreement on most parameters. Intercorrelations of the expert ratings and correlations with lay ratings of voice are reported and discussed. In concluding, empirical voice-personality relationships are reported and the role of sociocultural and atributional factors in this area is discussed.     

The hyperactive child at adolescence: Cognitive,emotional, and social functioning

In view of the paucity of detailed followup studies on hyperactive children, the performance of 15 adolescents diagnosed hyperactive 5 years previously was compared to that of a control group of equivalent age, sex, intelligence, and social class. Eleven cognitive tests measuring sustained attention, visual-motor and motor skills, abstraction, and reading ability, as well as three self-assessment tests examining selfesteem, activity level, social functioning, academic status, and career aspirations were administered. The hyperactives performed significantly worse than the controls on the sustained attention, visualmotor, and motor tasks, and on two of the four reading tests. They also gave themselves significantly lower ratings on some of the selfesteem and sociability items. It would appear that the hyperactives at adolescence still have attentional and stimulus-processing difficulties, which affect not only their academic performance but also their social functioning.This study was supported by a Federal-Provincial Mental Health Grant to Dr. G. Weiss. The authors wish to thank Katherine Levine and Margaret Radigan for their assistance with test preparation and scoring. Thanks are also extended to Ken MacRae for his computer-processing advice, particularly his help with several multivariate and principal components analyses from which the present authors have derived their current theoretical position. Klaus Minde and Nancy Cohen are now at the Toronto Hospital for Sick Children, while Elizabeth Hoy is at the Queen's University of Belfast, Northern Ireland.