Perfect visual short-term memory for periodic patterns

Abstract

The short-term memory for spatial frequency information was assessed by measuring the spatial frequency discrimination thresholds for briefly flashed luminance gratings as a function of the time interval between the test and reference gratings, using a computer-controlled two-interval forced-choice procedure. Discrimination thresholds were stable for interstimulus intervals in the range 1–30 sec under all conditions tested. At low contrasts, short exposure times and low spatial frequencies discrimination thresholds increased, but no interactions between stimulus parameters affecting thresholds and interstimulus interval were observed. It is concluded that factors limiting spatial discrimination are associated with the sensory coding stage. Spatial discrimination and visual memory may be based on a common representation, which is perfectly retained in short-term memory. Visual half-field tests revealed no hemispheric differences in the processing and retention of spatial frequency information.     

Surprise-induced blindness: a stimulus-driven attentional limit to conscious perception

The cost of attending to a visual event can be the failure to consciously detect other events. This processing limitation is well illustrated by the attentional blink paradigm, in which searching for and attending to a target presented in a rapid serial visual presentation stream of distractors can impair one's ability to detect a second target presented soon thereafter. The attentional blink critically depends on 'top-down' attentional settings, for it does not occur if participants are asked to ignore the first target. Here we show that 'bottom-up' attention can also lead to a profound but ephemeral deficit in conscious perception: Presentation of a novel, unexpected, and task-irrelevant stimulus virtually abolishes conscious detection of a target presented within half a second after the 'Surprise' stimulus, but only for its earliest occurrences (generally 1 to 2 presentations). This powerful but short-lived deficit contrasts with a milder but more enduring form of attentional capture that accompanies singleton presentations in rapid serial visual presentations. We conclude that the capture of stimulus-driven attention alone can limit explicit perception.     

Both exogenous and endogenous target salience manipulations support resource depletion accounts of the attentional blink: A reply to Olivers, Spalek, Kawahara, and Di Lollo (2009)

Input control theories of the attentional blink (AB) suggest that this deficit results from impaired attentional selection caused by the post-Target 1 (T1) distractor (Di Lollo, Kawahara, Ghorashi, & Enns, 2005; Olivers, van der Stigchel, & Hulleman, 2007). Accordingly, these theories predict that there should be no AB when no distractors intervene between the targets. Contrary to these hypotheses, Dux, Asplund, and Marois (2008) observed an AB (T3 deficit) when three targets, from the same attentional set, were presented successively in a rapid stream of distractors, if subjects increased the resources they devoted to T1 processing. This result is consistent with resource depletion accounts of the AB. However, Olivers, Spalek, Kawahara, and Di Lollo (2009) argue that Dux et al.’s results can be better explained by the relationship between T1 and T2, and by target discriminability effects, rather than by the relationship between T1 and T3. Here, we find that manipulating the resources subjects devote to T1, either exogenously (target perceptual salience) or endogenously (target task relevance), affects T3 performance, even when T2 and target discriminability differences are controlled for. These results support Dux et al.’s conclusion that T1 resource depletion underlies the AB.     

An attentional blink for sequentially presented targets: Evidence in favor of resource depletion accounts

Several accounts of the attentional blink (AB) have postulated that this dual-target deficit occurs because of limited-capacity attentional resources being devoted to processing the first target at the expense of the second (resource depletion accounts; e.g., Chun & Potter, 1995). Recent accounts have challenged this model (e.g., Di Lollo, Kawahara, Ghorashi, & Enns, 2005; Olivers, van der Stigchel, & Hulleman, 2007), proposing instead that the AB occurs because of subjects’ inability to maintain appropriate levels of attentional control when targets are separated by distractors. Accordingly, the AB is eliminated when three targets from the same attentional set are presented sequentially in a rapid serial visual presentation (RSVP) stream. However, under such conditions poorer identification of the first target is typically observed, hinting at a potential trade-off between the first and subsequent target performances. Consistent with this hypothesis, the present study shows that an AB is observed for successive targets from the same attentional set in an RSVP stream when the first target powerfully captures attention. These results suggest that resource depletion contributes significantly to the AB.     

Individually tailored internet-based cognitive behaviour therapy for older adults with anxiety and depression: a randomised controlled trial

Mixed anxiety and depression is common among older adults. The aim of the study was to compare the effects of an eight-week-long tailored internet-supported cognitive behaviour therapy (ICBT) programme and to compare against the provision of weekly general support. A second aim was to investigate if pre-treatment cognitive flexibility and self-reported cognitive problems would predict outcome. We included 66 older adults (aged over 60 years) with mixed anxiety/depression following media recruitment and randomised them into treatment and control groups. We also included a one-year follow-up. As a measure of executive function, we used the Wisconsin Card Sorting Test (perseverative errors) and the Cognitive Failures Questionnaire during the pre-treatment phase. Results showed a moderate between-group effect on the main outcome measure, the Beck Anxiety Inventory (BAI) (d= .50), favouring the treatment group. Nearly half (45.5%) of that group were classified as responders. One person (3%) in the treatment group deteriorated. There were significant correlations between perseverative errors and outcome (on the BAI r = ?.45), but not among self-reported cognitive function. We conclude that guided, tailored ICBT may be effective for some older adults and that the role of cognitive function needs to be investigated further.     

Prereaders’ eye movements during shared storybook reading are language-mediated but not predictive

When viewing a visual scene, eye movements are often language-mediated: people look at objects as those objects are named. Eye movements can even reflect predictive language processing, moving to an object before it is named. Children are also capable of making language-mediated eye movements, even predictive ones, and prediction may be involved in language learning. The present study explored whether eye movements are language-mediated in a more naturalistic task – shared storybook reading. Research has shown that children fixate illustrations during shared storybook reading, ignoring text. The present study used high-precision eye-tracking to replicate this finding. Further, prereader participants showed increased likelihood of fixating relevant storybook illustrations as words were read aloud, indicating that their eye movements were language mediated like the adult participants. Language-mediated eye movements to illustrations were reactive, not predictive, in both participant groups.     

The future of workplace commitment: key questions and directions

This position paper presents the state-of-the art of the field of workplace commitment. Yet, for workplace commitment to stay relevant, it is necessary to look beyond current practice and to extrapolate trends to envision what will be needed in future research. Therefore, the aim of this paper is twofold, first, to consolidate our current understanding of workplace commitment in contemporary work settings and, second, to look into the future by identifying and discussing avenues for future research. Representative of the changing nature of work, we explicitly conceptualize workplace commitment in reference to (A) “Temporary work”, and (B) “Cross-boundary work”. Progressing from these two themes, conceptual, theoretical and methodological advances of the field are discussed. The result is the identification of 10 key paths of research to pursues, a shared agenda for the most promising and needed directions for future research and recommendations for how these will translate into practice.     

Internet-based acceptance and commitment therapy for psychological distress experienced by people with hearing problems: a pilot randomized controlled trial

Psychological distress is common among people with hearing problems, but treatments that specifically target this aspect have been almost non-existent. In this pilot randomized controlled trial, an eight-week long Internet-based treatment, informed by Acceptance and Commitment Therapy, was administered to explore the feasibility and efficacy of such a treatment. Included participants were randomized to either treatment (n = 31) or wait-list control (n = 30) condition. All participants were measured prior to randomization and immediately after treatment ended using standardized self-report instruments measuring hearing-related emotional and social adjustment (Hearing Handicap Inventory for the Elderly – S, HHIE-S), quality of life (Quality of Life Inventory, QOLI), and symptoms of depression and anxiety (Patient health Questionnaire, PHQ-9 and Generalized Anxiety Disorder scale, GAD-7). Linear mixed effects regression analysis using the full intention-to-treat sample demonstrated that the treatment had superior outcomes on the main outcome measure as compared with the control group, Cohen’s d = 0.93, 95% CI [0.24, 1.63]. The benefits of treatment over control were also evident in scores of depression, Cohen’s d = 0.61, 95% CI [0.04, 1.19], and quality of life, Cohen’s d = 0.88, 95% CI [0.14, 1.61]. The results provide preliminary support for Internet-delivered acceptance and commitment therapy as a potentially effective treatment of psychological symptoms associated with hearing problems.     

Visualizations in Mathematics

In this paper we discuss visualizations in mathematics from a historical and didactical perspective. We consider historical debates from the 17th and 19th centuries regarding the role of intuition and visualizations in mathematics. We also consider the problem of what a visualization in mathematical learning can achieve. In an empirical study we investigate what mathematical conclusions university students made on the basis of a visualization. We emphasize that a visualization in mathematics should always be considered in its proper context.

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Coping Strategies in Late Adolescence: Relationships to Parental Attachment and Time Perspective

The authors investigated adolescents' use of coping strategies in relation to attachment to parents and time perspective. Adolescents in Grade 3 upper secondary school (M age = 18.3 years, SD = 0.6 years; n = 160) completed the Inventory of Parent and Peer Attachment, the Zimbardo Time Perspective Inventory, and the Brief COPE. Correlational analyses showed that attachment to parents was associated with a more favorable view of the past (higher past positive and lower past negative), a less fatalistic view of the present, and a more favorable view of the future (higher future positive and lower future negative). Parental attachment accounted for significant variance in composite coping scores (adaptive and maladaptive) when entered before, but not after, time perspective subscales in hierarchical regression analyses. However, time perspective (mainly present hedonistic and positive or negative future) predicted adaptive or maladaptive coping over and beyond attachment. The results are consistent with the hypothesis that most of the relationship between adolescents' attachment to parents and coping is mediated by individual differences in time perspective. By contrast, factors other than attachment to parents (e.g., temperament) must be considered to fully account for the relationship between time perspective and coping.