Whether or not the capture of visual attention is driven solely by the salience of an attention-capturing stimulus or mediated by top-down control has been a point of contention since Folk, Remington, and Johnston (1992) introduced their contingent involuntary orienting hypothesis, which states that the capture of attention by a salient stimulus depends on its relevance to a feature distinguishing the target from nontargets. Gibson and Kelsey (1998) extended Folk et al.'s (1992) hypothesis by demonstrating that features associated with the appearance of the target display also mediate capture. Although similar to Folk et al. (1992), Gibson and Kelsey's displaywide contingent orienting hypothesis makes it difficult to demonstrate stimulus-driven capture, because an observer must always use some perceptible feature as a signal of the target display's appearance; hence, such features could always be mediating capture. The present article reviews and applies the logic of Gibson and Kelsey's and Folk et al.'s (1992) hypotheses to experiments from the attentional capture literature, and assesses whether previously reported capture effects were mediated by top-down attentional control. It concludes that these capture effects were not stimulus-driven.

BackgroundAdult weight gain and obesity have become worldwide problems. Issues of cost and potential side effects of prescription weight loss drugs have led overweight and obese adults to try nutraceuticals that may aid weight loss. One promising nutraceutical is green coffee extract, which contains high concentrations of chlorogenic acids that are known to have health benefits and to influence glucose and fat metabolism. A 22-week crossover study was conducted to examine the efficacy and safety of a commercial green coffee extract product GCA™ at reducing weight and body mass in 16 overweight adults.MethodsSubjects received high-dose GCA (1050 mg), low-dose GCA (700 mg), or placebo in separate six-week treatment periods followed by two-week washout periods to reduce any influence of preceding treatment. Treatments were counterbalanced between subjects. Primary measurements were body weight, body mass index, and percent body fat. Heart rate and blood pressure were also measured.ResultsSignificant reductions were observed in body weight (−8.04 ± 2.31 kg), body mass index (−2.92 ± 0.85 kg/m2), and percent body fat (−4.44% ± 2.00%), as well as a small decrease in heart rate (−2.56 ± 2.85 beats per minute), but with no significant changes to diet over the course of the study. Importantly, the decreases occurred when subjects were taking GCA. Body mass index for six subjects shifted from preobesity to the normal weight range (<25.00 kg/m2).ConclusionThe results are consistent with human and animal studies and a meta-analysis of the efficacy of green coffee extract in weight loss. The results suggest that GCA may be an effective nutraceutical in reducing weight in preobese adults, and may be an inexpensive means of preventing obesity in overweight adults.

Load theory (Lavie, N., Hirst, A., De Fockert, J. W., & Viding, E. [2004]. Load theory of selective attention and cognitive control. Journal of Experimental Psychology: General, 133, 339-354.) proposes that control of attention depends on the amount and type of load that is imposed by current processing. Specifically, perceptual load should lead to efficient distractor rejection, whereas working memory load (dual-task coordination) should hinder distractor rejection. Studies support load theory's prediction that working memory load will lead to larger distractor effects; however, these studies used secondary tasks that required only verbal working memory and the central executive. The present study examined which other working memory components (visual, spatial, and phonological) influence visual selective attention. Subjects completed an attentional capture task alone (single-task) or while engaged in a working memory task (dual-task). Results showed that along with the central executive, visual and spatial working memory influenced selective attention, but phonological working memory did not. Specifically, attentional capture was larger when visual or spatial working memory was loaded, but phonological working memory load did not affect attentional capture. The results are consistent with load theory and suggest specific components of working memory influence visual selective attention.

C. L. Folk, R. W. Remington, and J. C. Johnston's (1992) contingent involuntary orienting hypothesis states that a salient visual feature will involuntarily capture attention only when the observer's attentional set includes similar features. In four experiments, when the target's relevant feature was its being an abruptly onset singleton, attentional capture occurred for a static discontinuity cue that was the boundary between a group of red Xs contiguously joined to a group of green Os within a single row. Such an attentional capture effect is novel and contrary to Folk et al.'s (1992) hypothesis, because the attentional set for the target should have included abrupt onset but not color discontinuity, which was the feature that captured attention. These capture effects were involuntary because they occurred even when the target never appeared in the same location as the cue, and color could not have been used as a cue to signal the appearance of the target array (cf. B. S. Gibson & E. M. Kelsey, 1998).

Color singletons that are irrelevant to locating a visual target do not typically capture attention if visual search is effortful. In contrast, when search is efficient color singletons are often found to capture attention. Such distraction by a color singleton can be modulated by single-task vs. dual-task manipulations when visual search is efficient. This is due, presumably, to the increased cognitive load in the dual-task condition, which interferes with top-down attentional control. This study investigated whether capture by a color singleton is also modulated by single-task vs. dual-task manipulations when visual search was effortful. The results of three experiments revealed that attentional capture effects were absent in a single-task condition and were present in a dual-task condition, but only when the identity of the color singleton is not associated with the target response-set. When the identity of the color singleton was relevant to the response-set it captured attention in both the single-task and in dual-task conditions.

No abstract

No abstract

The influence of top-down attentional control on the selection of salient visual stimuli has been examined extensively. Some accounts suggest all salient stimuli capture attention in a stimulus-driven manner, while others suggest salient stimuli capture attention contingent on top-down relevance. Evidence consistently shows target templates allow only salient stimuli sharing a target's features to capture attention, while salient stimuli not sharing a target's features do not. A number of hypotheses (e.g., contingent orienting, disengagement, signal suppression) from both sides of this debate have been proposed; however, most predict similar performance in the visual search and spatial cuing tasks. The present study combined a cuing task, in which subjects identified a target defined by its having a unique feature, with a probe identification task developed by Gaspelin, Leonard, and Luck (Psychological Science, 26, 1740-1750, 2015), in which subjects identified letters appearing in potential target locations just after the appearance of a salient cue that matched or did not match the target-defining feature. The probe task provided a measure of where attention was focused just after the cue's appearance. In six experiments, we observed top-down modulation of spatial cuing effects in response times and probe identification: Probes in the cued location were identified more often, but more when preceded by a cue that shared the target-defining feature. Though not unequivocal, the results are explained in terms of the ongoing debate over whether top-down attentional control can prevent bottom-up capture by salient, taskirrelevant stimuli.