Spatially mediated capacity limits in attentive visual perception

Modern theories conceptualize visual selective attention as a competition between objects for the control of cortical receptive fields (RFs). Implicit in this framework is the suggestion that spatially proximal objects, which draw from overlapping pools of RFs, should be more difficult to represent in parallel and with excess capacity than spatially separated objects. The present experiments tested this prediction using analysis of response time distributions in a redundant-targets letter identification task. Data revealed that excess-capacity parallel processing is possible when redundant targets are widely separated within the visual field, but that capacity is near fixed when targets are adjacent. Even at the largest separations tested, however, processing capacity remained strongly limited.     

Competition for representation is mediated by relative attentional salience

The biased competition model of attentional selection proposes that objects compete with one another for neural representation, with the competition rooted in stimulus and attentionally-based salience. Two experiments explore how the salience of a target item relative to flanking items impacts the speed of target identification. The results of two experiments suggest that spatially proximal items compete for shared, spatially dependent processing resources. In both experiments, subjects identified target elements embedded in multi-element displays. In Experiment 1, attentional salience was manipulated by using abrupt onsets (high-salience) and non-onsets (low-salience). Target identifications were slowest when the target was flanked by two high-salience stimuli (abrupt onsets) and fastest when the target was flanked by two low-salience items, (non-onsets). In Experiment 2, the attentional salience of display items was set through a probability manipulation involving the color of the target. The results mirrored those of Experiment 1, consistent with predictions of the biased competition model.     

Attentional capture by abrupt onsets and feature singletons produces inhibitory surrounds

Two experiments found that form discriminations to a target item were inhibited when the target appeared adjacent to an attentionally salient item. Experiment 1 manipulated the attentional salience of an irrelevant color singleton through the attentional set adopted by the subjects. Color singletons captured attention when the target was itself a feature singleton, but not when the target was defined as a conjunction of features. Attentional capture was accompanied by an inhibitory region (i.e., slowed target reaction times), which dissipated with distance from the color singleton. In Experiment 2, the attentional salience of abrupt onsets and color singletons was compared. Irrelevant abrupt onsets captured attention, whereas irrelevant color singletons failed to capture attention. Again, an inhibitory region surrounded the attentionally salient abrupt onsets, but not the color singletons. The results are discussed in the context of current models of visual spatial attention and suggest a distinction between attentional preparation and attentional selection.     

Attentional breadth and trade-offs in spatial and temporal acuity

Various manipulations have been shown to induce trade-offs in spatial and temporal acuity. Two experiments examine the role of the breadth of the attentional focus in such trade-offs. In the first experiment, exogenous attentional cues indicated 1, 2, 3, or 4 possible (contiguous) target locations. Half of the subjects performed a perceptual task on the target requiring spatial acuity – detecting spatial gaps in a ring; the other half of the subjects performed a task requiring temporal acuity – detecting a temporal gap in the presentation of the target ring. The results revealed a trade-off in spatial and temporal acuity: as the cue size increased, performance on the spatial task declined and performance on the temporal task improved. A second experiment replicated this pattern using two different tasks: a temporal order judgment task that assessed temporal acuity, and a task requiring the localization of a thin line that assessed spatial acuity.     

Selective attention to Stroop dimensions: Effects of baseline discriminability,response mode,and practice

The framework of dimensional interaction was used to test the hypothesis that the Stroop effect is partially rooted in mismatches in baseline discriminability, with stimulus differences along the word dimension typically exceeding stimulus differences along the color dimension. Subjects made speeded classifications, with either keypresses or vocalizations, of either words or colors. Stroop congruity and Garner interference were measured under conditions in which discriminabilities were (1) matched (Experiments1 and 4), (2) mismatched in favor of colors (Experiment 2), or (3) mismatched in favor of words (Experiment3). When matched, colors and words appeared separable, with small interactive effects being reduced or eliminated through practice. When mismatched, asymmetric Stroop and Garner effects emerged, with the more discriminable dimension disrupting classification of the less discriminable dimension. Asymmetric effects were obtained in both response modes, and were not alleviated by practice. We conclude that (1) the Stroop effect is an optional effect, and (2) unequal discriminability causes a mandatory failure of selective attention.     

Localized attentional interference reflects competition for reentrant processing

Visual performance is compromised when attention is divided between objects that are near one another in the visual field. It has been postulated that this effect, termed localized attentional interference (LAI), reflects competition between visual-object representations for the control of cortical neural responses. To determine whether LAI arises during feedforward processing or during reentrant processing, the present study examined the influence of poststimulus pattern and four-dot masks on the strength of the effect. Experiment 1 found that pattern masks, which are believed to compromise feedforward processing, do not produce stronger LAI than do four-dot masks, which are believed to leave feedforward processing undisrupted. Experiment 2 found that LAI is weaker when reentrant processing is interrupted shortly after initiation than it is when reentrant processing is allowed to run to completion. The results suggest that LAI emerges from competition between objects during reentrant processing.     

Perceived Parenting Style of Fathers and Iranian Adolescents' Self-efficacy: The Moderating Role of Gender and Education

The authors examined the moderating role of adolescent's gender and father's education on the associations between perceived paternal parenting styles and self-efficacy in a socioeconomical diverse sample of Iranian ado-lescents (n = 382). Results revealed that paternal authoritative parenting was significantly and positively related to self-efficacy. Interestingly, a significant and positive relation was also found between paternal authoritarian parenting and self-efficacy. This finding might have been the result of the fact that this study was conducted as part of a collectivist culture. In addition, the results indicated that boys who perceived their fathers as highly authoritative indicated higher self-efficacy than girls did. Furthermore, the findings demonstrated that higher educational levels attenuate the negative impact of the permissive parenting style on self-efficacy. The present findings underscore the need to focus on the role of gender and father's education when assessing the link between parenting style and adolescents' self-efficacy.     

Why Odd Pricing?1

The practice of setting prices a few pennies or a few dollars below an even (whole) number is referred to as odd pricing. Most attempts to explain odd pricing use an argument that, in part, draws on varying degrees of consumer irrationality. In this note, a justification for odd pricing is provided that assumes rational and informed consumers and businesses. Empirical evidence is offered in support of this view.