Top-down matching singleton cues have no edge over top-down matching nonsingletons in spatial cueing

Swift attenuation of irrelevant features through feature consistency: Evidence from a capture-probe version of the contingent-capture protocol

In the present two experiments, we explore the possibility of swift attenuation of capture by irrelevant features in the contingent-capture protocol. Some prior research suggests that feature attenuation might be most efficient for fixed, anticipated irrelevant features and that varying irrelevant features from trial to trial can undermine their successful attenuation. Here, we exploited this dependence of attenuation on feature certainty to test if attenuation contributed to contingent-capture effects in a capture-probe version of the contingent-capture protocol. In line with the swift attenuation of irrelevant features, salient but target-dissimilar singleton cues that were consistently coloured diminished recall of probes at their locations. This was in comparison to inconsistently coloured target-dissimilar singleton cues. Nonetheless, probe-recall was still better at target-dissimilar cue locations than at non-singleton locations in the cueing display, indicating attenuation of task-irrelevant features rather than their complete suppression.

A revised diffusion model for conflict tasks

The recently developed diffusion model for conflict tasks (DMC) Ulrich et al. (Cognitive Psychology, 78, 148-174, 2015) provides a good account of data from all standard conflict tasks (e.g., Stroop, Simon, and flanker tasks) within a common evidence accumulation framework. A central feature of DMC's processing dynamics is that there is an initial phase of rapid accumulation of distractor evidence that is then selectively withdrawn from the decision mechanism as processing continues. We argue that this assumption is potentially troubling because it could be viewed as implying qualitative changes in the representation of distractor information over the time course of processing. These changes suggest more than simple inhibition or suppression of distractor information, as they involve evidence produced by distractor processing "changing sign" over time. In this article, we (a) develop a revised DMC (RDMC) whose dynamics operate strictly within the limits of inhibition/suppression (i.e., evidence strength can change monotonically, but cannot change sign); (b) demonstrate that RDMC can predict the full range of delta plots observed in the literature (i.e., both positive-going and negative-going); and (c) show that the model provides excellent fits to Simon and flanker data used to benchmark the original DMC at both the individual and group level. Our model provides a novel account of processing differences across Simon and flanker tasks. Specifically, that they differ in how distractor information is processed on congruent trials, rather than incongruent trials: congruent trials in the Simon task show relatively slow attention shifting away from distractor information (i.e., location) while complete and rapid attention shifting occurs in the flanker task. Our new model highlights the importance of considering dynamic interactions between top-down goals and bottom-up stimulus effects in conflict processing.

Testing the role of temporal selection for stimulus-driven capture of attention

Stimulus-driven and top-down dependent capture of attention can be observed under very similar conditions, raising the question of the decisive factors for whether one or the other effect is seen. In the current study, we tested the role of temporal selectivity. Studies showing less evidence of stimulus-driven attention by salient color singletons often used sequences of displays, in which the first display contained an irrelevant color cue that could easily be ignored by timed allocation of attention, as the relevant target was consistently presented in a second display only. In contrast, studies showing more evidence of stimulus-driven attention used distractors presented simultaneously with the targets, making it more difficult to simply ignore additional salient distractors at the point in time where the target was presented. Here, we therefore tested stimulus-driven capture under two conditions: with temporal certainty that the first display could safely be ignored and without temporal certainty that the first display could be ignored. Results showed that this manipulation had no significant influence on stimulus-driven capture of attention by irrelevant but salient cues preceding the targets, although the same participants showed more distractor interference by a target-concomitant and salient color singleton. Thus, temporal selection was seemingly not the decisive factor for the amount of stimulus-driven capture of attention.

Attentional disengagement effect based on relevant features

In visual search tasks, distractors similar to the target can attract our attention and affect the speed of attentional disengagement. The attentional disengagement refers to shifting attention away from stimuli that are not relevant to the task. Previous studies mainly focused on the attentional disengagement of one feature dimension. However, the mechanisms of different feature dimensions on attentional disengagement in single and conjunction visual search remain unclear. In the current study, we adopted the oculomotor disengagement paradigm and used saccade latency as an indicator to explore the effects of different feature dimensions of center stimuli on attentional disengagement. In both single and conjunction feature search tasks, participants began each search by fixating on a center stimulus that appeared simultaneously with search display but would not be the target. Participants were instructed to ensure the first saccade to the target location. In Experiments 1A (single feature search) and 1B (conjunction feature search), we found that the attentional disengagement was significantly delayed or accelerated when center stimuli shared color features with the target or salient distractor, but not in shape feature. Moreover, we found that the difference between the two feature dimensions might be caused by their different search difficulty (Experiment 1C). Therefore, in Experiment 2, we matched the difficulty of searching for color and shape tasks before exploring whether there were differences in the effects of different feature dimensions on attentional disengagement. However, the results in Experiment 2 were similar to those in Experiment 1A, indicating that the different effects of feature dimensions on attentional disengagement were caused by feature asymmetry. Therefore, in Experiment 3, we improved the salient discernibility of shape dimension and matched color search to it. The results showed that although the attentional disengagement was delayed in shape dimension, it was still smaller than that in color dimension. Our results supported that goal-oriented attention sets were the main cause of delayed attentional disengagement. By series of experiments, we found that the utilization of different feature dimensions was associated with task difficulty and the features asymmetry in both single and conjunction visual search.

Does feature intertrial priming guide attention? The jury is still out

Our search performance is strongly influenced by our past experience. In the lab, this influence has been demonstrated by investigating a variety of phenomena, including intertrial priming, statistical learning, and reward history, and collectively referred to as selection history. The resulting findings have led researchers to claim that selection history guides attention, thereby challenging the prevailing dichotomy, according to which top-down and bottom-up factors alone determine attentional priority. Here, we re-examine this claim with regard to one selection-history phenomenon, feature intertrial priming (aka priming of pop-out). We evaluate the evidence that specifically pertains to the role of feature intertrial priming in attentional guidance, rather than in later selective processes occurring after the target is found. We distinguish between the main experimental rationales, while considering the extent to which feature intertrial priming, as studied through different protocols, shares characteristics of top-down attention. We show that there is strong evidence that feature intertrial priming guides attention when the experimental protocol departs from the canonical paradigm and encourages observers to maintain the critical feature in visual working memory or to form expectations about the upcoming target. By contrast, the current evidence regarding the standard feature intertrial priming phenomenon is inconclusive. We propose directions for future research and suggest that applying the methodology used here in order to re-evaluate of the role of other selection history phenomena in attentional guidance should clarify the mechanisms underlying the strong impact of past experience on visual search performance.

Procedural Control Versus Resources as Potential Origins of Human Hyper Selectivity

In the current review, we argue that experimental results usually interpreted as evidence for cognitive resource limitations could also reflect functional necessities of human information processing. First, we point out that selective processing of only specific features, objects, or locations at each moment in time allows humans to monitor the success and failure of their own overt actions and covert cognitive procedures. We then proceed to show how certain instances of selectivity are at odds with commonly assumed resource limitations. Next, we discuss examples of seemingly automatic, resource-free processing that challenge the resource view but can be easily understood from the functional perspective of monitoring cognitive procedures. Finally, we suggest that neurophysiological data supporting resource limitations might actually reflect mechanisms of how procedural control is implemented in the brain.

No identification of abrupt onsets that capture attention: evidence against a unified model of spatial attention

Many studies have reported that spatial attention can be involuntarily captured by salient stimuli such as abrupt onsets. These involuntary shifts are often assumed to have the same effects on feature extraction as voluntary shifts: there are two different ways of moving the same attentional mechanism. According to this unified model of spatial attention, all shifts of attention should enhance the identification of attended objects. We directly tested this assumption using compatibility effects in a series of spatial cueing experiments. Participants searched a display and indicated whether the target number was greater or less than five. The salient precues were also numbers, allowing measurement of compatibility effects between the precue and the target. Precues that reliably predicted the target location produced compatibility effects (e.g., the precue "1" facilitated responding to the target "one"), indicating enhanced identification of the precue. Compatibility effects were also found for precues that were nonpredictive but had the target-finding feature (i.e., contingent capture). Critically, however, four separate experiments failed to find compatibility effects for salient abrupt onsets that were neither predictive nor task-relevant. This is surprising given that these same precues produced enormous cue validity effects (up to 186 ms), suggesting salience-based attention capture. Our findings argue against the unified model: salience-based attention capture recruits different attentional mechanisms than contingent capture or voluntary shifts in attention.

Evidence for early top-down modulation of attention to salient visual cues through probe detection

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 on-going debate over whether top-down attentional control can prevent bottom-up capture by salient, task-irrelevant stimuli.

Testing a priming account of the contingent-capture effect

In the contingent-capture protocol, singleton cues that have a target's searched-for feature capture attention, but cues that do not have the target's searched-for feature do not, a result labeled the contingent-capture effect. The contingent-capture effect is usually regarded as evidence for the observers' ability to establish search settings for certain nonspatial features in a top-down manner. However, in recent years it has become increasingly clear that selection history is also a powerful mediator of attentional capture. In this vein, it has been suggested that contingent-capture effects could emerge as a result of (intertrial) priming: The idea is that features that have been encountered previously in the target are primed, so that cues that have these features automatically capture attention in a subsequent encounter. Here we tested a strong version of the priming account of the contingent-capture effect. We wanted to know whether cues that had target features would capture attention when the corresponding features were not part of the instructions (i.e., when the corresponding features were task-irrelevant). The results suggested that a strong version of the priming account of contingent capture is not supported. In five experiments, we found little evidence that the contingent-capture effect could be explained by (intertrial) priming of task-irrelevant features alone. These results show that processes beyond priming through task-irrelevant features are critical for contingent-capture effects.