The modulation of reward priority by top-down knowledge

Reward-associated features capture attention automatically and continue to do so even when the reward contingencies are removed. This profile has led to the hypothesis that rewards belong to a separate class of attentional biases that is neither typically top-down nor bottom-up. The goal of these experiments was to understand the degree to which top-down knowledge can modulate value-driven attentional capture within (a) the timecourse of a single trial and (b) when the reward contingencies change explicitly over trials. The results suggested that top-down knowledge does not affect the size of value-driven attentional capture within a single trial. There were clear top-down modulations in the magnitude of value-driven capture when reward contingencies explicitly changed, but the original reward associations continued to have a persistent bias on attention. These results contribute to a growing body of evidence that reward associations bias attention through mechanisms separate from other top-down and bottom-up attentional biases.     

Affective stimuli capture attention regardless of categorical distinctiveness: An emotion-induced blindness study

Affective stimuli capture attention, whether their affective value stems from emotional content or a history of reward. The uniqueness of such stimuli within their experimental contexts might imbue them with an enhanced categorical distinctiveness that accounts for their impact on attention. Indeed, in emotion-induced blindness, categorically distinctive neutral pictures disrupt target perception, albeit to a lesser degree than do emotional pictures. Here, we manipulated the categorical distinctiveness of distractors in an emotion-induced blindness task. Participants searched within RSVP streams for a target that followed an emotional or a neutral distractor picture. In a categorically homogenous condition, all non-distractor items were exemplars from a uniform category, thus enhancing the distractor's categorical distinctiveness. In a categorically heterogeneous condition, each non-distractor item represented a distinct category. Neutral distractors disrupted target perception only in the homogenous condition, but emotional distractors did so regardless of their categorical distinctiveness.     

Motivational Predictors of Change in Oral Health: An Experimental Test of Self-Determination Theory

We tested the hypothesis that a psychosocial dental intervention formulated in terms of self-determination theory would increase patients’ perceived competence and autonomous motivation for dental care and would decrease their plaque and gingivitis over a seven month period, compared to standard dental treatment. We also tested a process model in which the intervention was expected to increase perceived dental competence and autonomous motivation, that they would be positively associated with oral health behaviors (i.e., brushing and flossing), which was expected to decrease plaque and, in turn, decrease gingivitis. We also examined whether: changes in perceived competence and autonomous motivation would mediate the effect of the intervention on dental-health behaviors; dental-health behaviors would mediate the links from changes in perceived competence and autonomous motivation to change in plaque; and change in plaque would mediate the relation of dental health behaviors to change in gingivitis. Finally, we examined the fit of the overall model with structural equation modelling. Results supported all predictions.

School profiles of at-risk student concentration: Differential growth in oral reading fluency

The present study provides a data-driven approach to identifying groups of schools based on the concentration of at-risk students the school serves. The percentage of English language learners, minority students, and students eligible for free or reduced priced lunch were used as indicators in a latent profile analysis of 569 schools. The goal of the present study was to determine whether school-level average student reading performance varied as a function of the groups identified in the latent profile analysis. To do so, groups extracted by the latent profile analysis were used as school-level predictors of growth in oral reading fluency, which was modeled at the within-student level of a three-level hierarchical growth curve model. Oral reading fluency was measured at four points during the year in a large cross-sectional sample of first-, second-, and third-grade students. Results indicated that schools were able to be classified into four distinct groups based on their concentrations and types of at-risk students. Further, in all three grades, there were significant differences between the four identified groups observed in average reading fluency scores at the beginning of the year, the end of the year, and growth during the year indicating that groups based on school-concentration of at-risk students were significantly related to average student achievement in reading ability.     

In search of average growth: Describing within-year oral reading fluency growth across Grades 1–8

Measures of oral reading fluency (ORF) are perhaps the most often used assessment to monitor student progress as part of a response to intervention (RTI) model. Rates of growth in research and aim lines in practice are used to characterize student growth; in either case, growth is generally defined as linear, increasing at a constant rate. Recent research suggests ORF growth follows a nonlinear trajectory, but limitations related to the datasets used in such studies, composed of only three testing occasions, curtails their ability to examine the true functional form of ORF growth. The purpose of this study was to model within-year ORF growth using up to eight testing occasions for 1448 students in Grades 1 to 8 to assess (a) the average growth trajectory for within-year ORF growth, (b) whether students vary significantly in within-year ORF growth, and (c) the extent to which findings are consistent across grades. Results demonstrated that for Grades 1 to 7, a quadratic growth model fit better than either linear or cubic growth models, and for Grade 8, there was no substantial, stable growth. Findings suggest that the expectation for linear growth currently used in practice may be unrealistic.     

Perceptual grouping based on temporal structure: Impact of subliminal flicker and visual transients

In two experiments we examined the perceived grouping of grids of equidistant dots, which are rapidly modulated over time so that alternate rows or columns are presented out of phase. In Experiment 1, we report that observers were able to group the grids consistent with the temporal modulation reliably, even at contrasts/frequencies for which flicker was not detectable. Moreover, flicker thresholds decreased with stimulus duration, whilst grouping thresholds did not change. In Experiment 2, we examined the impact of visual transients, by measuring performance when, either a mask or a contrast ramp was presented before and after the stimulus. Performance dropped substantially for both conditions, but remained significantly above chance. The results are discussed in relation to the role of temporal correlations in stimulus modulations and visual transients in grouping.     

Relationship between working memory capacity and contingent involuntary orienting

Individual differences in working memory capacity are related to the ability to control attention; where less working memory capacity is associated with less attentional control. A well-known demonstration of attentional control is contingent involuntary orienting (Folk, Remington, & Johnston, 1992), which is the finding that visuospatial attention is captured by a salient peripheral cue, but only if the cue is featurally similar to the target of search and not if the cue is featurally dissimilar. This control of attention and ability to resist shifting attention towards an irrelevant visual cue is believed to be moderated by attentional settings for target-specific features. This study establishes that working memory capacity is related to contingent involuntary orienting of attention. Lower working memory capacity was associated with larger stimulus-driven cueing effects at short cue-to-target onset asynchronies, than at longer asynchronies, suggesting working memory capacity was associated with the ability to control covert orienting of attention at early processing stages.     

When does feature search fail to protect against attentional capture?

ABSTRACT

When participants search for a shape (e.g., a circle) among a set of homogenous shapes (e.g., triangles) they are subject to distraction by colour singletons that are more salient than the target. However, when participants search for a shape among heterogeneous shapes, the presence of a non-target colour singleton does not slow responses to the target. Attempts have been made to explain these results from both bottom-up and top-down perspectives. What both accounts have in common is that they do not predict the occurrence of attentional capture on typical feature search displays. Here, we present a case where manipulating selection history, rather than the displays themselves, leads to attentional capture on feature search trials. The ability to map specific colours to the target and distractor appears to be what enables resistance to capture during feature search.     

Equally attending but still not seeing: An eye-tracking study of change detection in own- and other-race faces

The present study aimed to investigate whether the faster change detection in own-race faces in a change blindness paradigm, reported by Humphreys, Hodsoll, and Campbell (2005) and explained in terms of people's poorer ability to discriminate other-race faces, may be explained by people's preferential attention towards own-race faces. The study by Humphreys et al. was replicated using the same stimuli, while participants’ eye movements were recorded. These revealed that there was no attentional bias towards own-race faces (analysed in terms of fixation order, number, and duration), but people still detected changes in own-race faces faster than in other-race faces. The current results therefore give further support for the original claim that people are less sensitive to changes made in other-race faces, when own and other-race faces are equally attended.     

Saccadic eye movements as indicators of cognitive function in older adults

Older adults appear to have greater difficulty ignoring distractions during day-to-day activities than younger adults. To assess these effects of age, the ability of adults aged between 50 and 80 years to ignore distracting stimuli was measured using the antisaccade and oculomotor capture tasks. In the antisaccade task, observers are instructed to look away from a visual cue, whereas in the oculomotor capture task, observers are instructed to look toward a colored singleton in the presence of a concurrent onset distractor. Index scores of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were compared with capture errors, and with prosaccade errors on the antisaccade task. A higher percentage of capture errors were made on the oculomotor capture tasks by the older members of the cohort compared to the younger members. There was a weak relationship between the attention index and capture errors, but the visuospatial/constructional index was the strongest predictor of prosaccade error rate in the antisaccade task. The saccade reaction times (SRTs) of correct initial saccades in the oculomotor capture task were poorly correlated with age, and with the neurospsychological tests, but prosaccade SRTs in both tasks moderately correlated with antisaccade error rate. These results were interpreted in terms of a competitive integration (or race) model. Any variable that reduces the strength of the top-down neural signal to produce a voluntary saccade, or that increases saccade speed, will enhance the likelihood that a reflexive saccade to a stimulus with an abrupt onset will occur.