Delayed onsets are not necessary for generating distractor quitting thresholds effects in visual search.

Salient distractors lower quitting thresholds in visual search. That is, when searching for the presence of a target among filler items, a large heterogeneously coloured distractor presented at a delayed onset produces quick target-absent judgements and increased target-present errors. The aim of the current study was to explore if the timing of the salient distractor modulates this Quitting Threshold Effect (QTE). In Experiment 1, participants completed a target detection search task in the presence or absence of a salient singleton distractor that either appeared simultaneously with other search items or appeared at a delayed onset (i.e., 100 ms or 250 ms after other array items appeared). In Experiment 2, a similar method was used, except that the salient singleton distractor appeared simultaneously, 100 ms before, or 100 ms after the other array items. Across both experiments, we observed robust distractor QTEs. Regardless of their onset, salient distractors decreased target-absent search speeds and increased target-present error rates. In all, the present findings suggest that delayed onsets are not required for lowered quitting thresholds in visual search.

Imagined object files: Visual imagery produces partial repetition costs where perception does not.

The present study explored whether object (or event) files can be formed that integrate color imagery and perceptual location features. To assess this issue, a cue-target procedure was used whereby color imagery was cued to be generated at a particular location in space, which was then followed by a perceptual color discrimination task. Partial repetition costs (PRCs) were then measured by varying the overlap of the color and location features of the cue and target to evaluate whether an object/event file was formed. Robust PRCs were observed when imagery was generated at a location, supporting the idea that imagery and perception can be incorporated into a common event file. It was also revealed that the PRC effects for perceptual color cues were tenuous-they did not reach significance in the present study. Overall, the present study indicates that imagery can produce stronger binding effects than perception, offering important insights into the role that active engagement plays in the formation of object/event files.

Top-down then automatic: Instructions can continue to influence visual search when no longer actively implemented.

The present study investigated the automaticity of top-down instructions in visual search when the instruction was no longer actively implemented. To do so, we exploited the Priming of Pop-out (PoP) effect, a selection history phenomenon that reflects faster responses when the target and distractor colors are repeated than switched across trials of singleton search. We then had participants perform a color singleton search task where they implemented the instruction of imagining the opposite color of the previous target, which put the target colors underlying PoP and the imagery instruction in opposition. To assess automaticity, on some trials participants were instructed to stop implementing the imagery instruction. When the imagery instruction was implemented, responses were faster when the target and distractor colors switched (i.e., imagery congruent) than repeated (i.e., imagery incongruent) across search displays - a pattern of results opposite to the PoP effect. When participants were to not implement this instruction, the PoP effect was absent, indicating the imagery instruction had a lingering influence on visual search. This remained true even when participants reported successfully not implementing the instruction, and only when the imagery abandonment instruction was supplanted by a different top-down task was the lingering influence removed such that the PoP effect returned. Overall, the present study demonstrates that top-down instructions can continue to influence visual search despite the will of the observer.

It hurts more than it helps: Cuing T1 with imagery can impair T2 identification in an attentional blink task.

The purpose of the present study was to evaluate whether cuing a first target with color imagery could influence second target identification using the two-target attentional blink procedure of MacLellan, Shore, and Milliken (2015, Psychological Research, 79, 556-569.). This method asks participants to identify a first target word interleaved with a distractor word and a second target word that follows the first target after a variable stimulus onset asynchrony. Prior to each trial of the two-target procedure, participants were cued to generate color imagery that was congruent with the color of the first target word, the color of the distractor word, the color of neither the first target or distractor words (Experiment 2), or to withhold generating color imagery (Experiment 3). The results revealed that identification of the second target was impaired when the cue was congruent with the distractor word, and equivalent when the cue was congruent with the first target word, relative to when color imagery was withheld. These results suggest that the attentional resources needed to identify the first target were not reduced by a match between the color of imagery and the first target, but a match between the color of imagery and the distractor increased the attentional resources needed to identify the first target.

The item-specific proportion congruency effect transfers to non-category members based on broad visual similarity.

The item-specific proportion congruency (ISPC) effect-that Stroop effects are reduced for items that are more likely to be incongruent than congruent-indicates that humans have the remarkable capacity to resolve conflict when it is associated with statistical regularities in the environment. It has been demonstrated that an ISPC signal induced by mostly congruent and mostly incongruent inducer items transfers to a set of distinct but visually similar transfer items that are equally likely to be congruent and incongruent; however, it is unclear what the ISPC signal is associated with to allow its transfer. To investigate this issue, an animal Stroop task was used to evaluate whether the ISPC signal would transfer to animal pictures that were different but visually similar same-category members (e.g., retrievers to retrievers, Experiment 1), visually dissimilar same-category members with broadly similar features (e.g., retrievers to bulldogs, Experiment 2), and visually dissimilar different-category members with broadly similar features (e.g., retrievers to house cats, Experiment 3). It was revealed that an ISPC effect was observed for the transfer items of each experiment, suggesting that these conflict signals can be linked based on broad feature similarity.

Is the attentional SNARC effect truly attentional? Using temporal order judgements to differentiate attention from response.

The spatial-numerical association of response codes (SNARC) effect reflects the phenomenon that low digits are responded to faster with the left hand and high digits with the right. Recently, a particular variant of the SNARC effect known as the attentional SNARC (which reflects that attention can be shifted in a similar manner) has had notable replicability issues. However, a potentially useful method for measuring it was revealed by Casarotti et al. using a temporal order judgement (TOJ) task. Accordingly, the present study evaluated whether Casarotti et al.'s results were reproducible by presenting a low (1) or high (9) digit prior to a TOJ task where participants had to indicate which of two peripherally presented targets appeared first (Experiment 1) or second (Experiment 2). In Experiment 1, it was revealed that the findings of Casarotti et al.'s were indeed observable upon replication. In Experiment 2, when attention and response dimensions were put in opposition, the SNARC effect corresponded to the side of response rather than attention. Taken together, the present study confirms the robustness of the attentional SNARC in TOJ tasks, but that it is not likely due to shifts in attention.

The item-specific proportion congruency effect can be contaminated by short-term repetition priming.

The item-specific proportion congruency (ISPC) effect reflects the phenomenon that Stroop congruency effects are larger for Stroop items that are more likely to be congruent (MC) than incongruent (MI). While the ISPC effect is purported to reflect long-term memory associations, the proportion manipulation entails that stimulus repetitions vary as a function of the MC and MI conditions, suggesting that a short-term repetition priming process may also contribute. In the present study, we investigated whether the ISPC effect reflected contributions from separate long-term associative learning and short-term repetition priming processes. To do so, the magnitude of the ISPC effect was compared when stimulus repetitions were present and absent. While the ISPC effect was robust, it was revealed that removing stimulus repetitions significantly attenuated the effect. Overall, the present study indicates the ISPC effect can reflect contributions from both short-term repetition and long-term memory processes.

Comparing imagery and perception: Using eye movements to dissociate mechanisms in search.

It has been demonstrated that color imagery can have a profound impact when generated prior to search, while at the same time, perceptual cues have a somewhat limited influence. Given this discrepancy, the present study evaluated the processes impacted by imagery and perception using a singleton search task where participants had to find an oddball colored target among homogenously colored distractors. Prior to each trial, a perceptual color was displayed or imagery was generated that could match the target, distractors, or neither item in the search array. It was revealed that color imagery led to both a larger benefit when it matched the target and a larger cost when it matched the distractors relative to perceptual cues. By parsing response times into pre-search, search, and response phases based on eye movements, it was revealed that, while imagery and perceptual cues both influenced the search phase, imagery had a significantly greater influence than perceptual cues. Further, imagery influenced pre-search and response phases as well. Overall, the present findings reveal that the influence of imagery is profound as it affects multiple processes in the vision-perception pipeline, while perception only appeared to impact search.

Top-down imagery overrides the influence of selection history effects.

The present study investigated whether color imagery could override the representations of the prevalent selection history effect termed Priming of Pop-out (PoP), which is constituted by faster responding when the target color is repeated rather than switched across trials of color singleton search. Participants imagined a color in the interval between trials of a color singleton search task that could be the same as or different to the previous target color, and they were to rate the vividness of these representations following each imagery event. It was revealed that when highly vivid imagery was reported, the PoP effect was attenuated relative to less vivid forms of it (and absent in two out of three experiments), and that color imagery eliminated the build-up of priming following consecutive target color repeats. Overall, the present findings suggest the representations of the selection history system can be overridden by top-down imagery.

Looking into the mind's eye: Directed and evaluated imagery vividness modulates imagery-perception congruency effects.

While most people have had the experience of seeing a representation in the mind's eye, it is an open question whether we have control over the vividness of these representations. The present study explored this issue by using an imagery-perception interface whereby color imagery was used to prime congruent color targets in visual search. In Experiments 1a and 1b, participants were required to report the vividness of an imagined representation after generating it, and in Experiment 2, participants were directed to create an imagined representation with particular vividness prior to generating it. The analyses revealed that the magnitude of the imagery congruency effect increased with both reported and directed vividness. The findings here strongly support the notion that participants have metacognitive awareness of the mind's eye and willful control over the vividness of its representations.

Context isn't everything: Search performance is influenced by the nature of the task but not the background.

AbstractIt has been demonstrated in the literature that cues in the environment that are predictive of how a task ought to be performed can influence performance. In an extension of this general notion, Cosman and Vecera (Journal of Experimental Psychology: Human Perception and Performance, 39(3), 836-848, 2013) reported that simply performing singleton and feature search tasks when irrelevant scenes were displayed in the background automatically modulated the search strategies adopted by participants when these scenes were reinstated at a later time. While intriguing, this result was also somewhat surprising given that an adaptive system (like the human brain) should disregard irrelevant information so task competencies generalize across environments. To investigate this issue further, we replicated the experimental procedures of Cosman and Vecera, while varying whether the test phase was either a singleton search (Experiments 1 and 3) or a feature search (Experiment 2) task. While it was observed that the nature of the search task varied whether a color singleton distractor influenced performance, there was no evidence that background scenes modulated the search strategies adopted by participants, contrasting the results of Cosman and Vecera. Overall, the findings here support the conclusion that the visual system prioritizes task-relevant information while disregarding irrelevant background information.

Visual imagery influences attentional guidance during visual search: Behavioral and electrophysiological evidence.

Recent behavioral studies have shown that color imagery can benefit visual search when it is congruent with an upcoming target. In the present study we investigated whether this color imagery benefit was due to the processes underlying attentional guidance, as indicated by the electrophysiological marker known as the N2pc component. Participants were instructed to imagine a color prior to each trial of a singleton search task. On some trials, the imagined color was congruent with the target, and on other trials, it was congruent with the distractors. The analyses revealed that the N2pc was present when color imagery was congruent with the search target, and absent when it was congruent with the distractors. Further, there was preliminary evidence that attentional guidance depended on the vividness of color imagery and the frequency at which participants implemented the imagery instruction. Overall, the results of the present study indicate that color imagery can influence the attentional guidance processes underlying visual search.

Re-examining Maljkovic and Nakayama (1994): Conscious expectancy does affect the Priming of Pop-out effect.

Maljkovic and Nakayama (Memory & Cognition, 22(6), 657-672, 1994) observed that color singleton search performance was faster when the target and distractor colors repeated rather than switched across trials - an effect termed Priming of Pop-out (PoP). Two of the key results of this seminal study revealed that the PoP effect was not influenced by the knowledge of the probability of a target color change (Experiment 2), nor was it influenced by anticipating the upcoming target color by subvocalizing it (Experiment 4). Based on these findings they concluded that the PoP effect reflected the automatic priming due to the persistence of the target and distractor colors of the previous trial. Based on recent findings indicating that conscious expectancy may influence the PoP effect, as well as several bygone experimental practices in the original study (i.e., experimenter participants, no inferential statistics, etc.), we felt it worthwhile to evaluate whether their findings were observed when replicated in an empirically rigorous manner. Though the present study revealed that the PoP effect was robust, it was profoundly impacted by the knowledge of the probability of a target color switch (Experiment 1) and vocally anticipating the upcoming target color (Experiment 2). Overall, the results suggest that we should abandon the notion that the PoP effect only reflects the automatic priming of the previous target and distractor colors independent of conscious expectancy.

The representational basis of positive and negative repetition effects.

Repetition of target features in the same spatial location can either benefit or impair performance in perceptual tasks. Moreover, which of these two effects occurs can depend on whether an intervening event is presented temporally between consecutive targets. Here, we explored these effects for color feature repetitions by varying the representational overlap of consecutive targets. The second target on all experimental trials was a simple perceptual color. The task and first target were manipulated to vary the representation produced in response to the first target (perceptual representation of color in Experiment 1; imagined representation of color in Experiments 2 and 5; conceptual representation of color in Experiment 3; color-unrelated representation in Experiment 4). Perceptual and imagined color representations for the first target produced a positive repetition effect when an intervening event did not appear between targets but produced a negative repetition effect when an intervening event did appear between targets. In contrast, conceptual color and color-unrelated representations produced a negative repetition effect both with and without an intervening event. These results suggest that positive repetition effects depend on consecutive targets that share visual representations, whereas negative repetition effects reflect a more complex relationship between stimulus and response features across targets. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Imagined event files: An interplay between imagined and perceived objects.

An important function of attention is to integrate features processed in distinct brain areas into a single coherent object representation. The immediate outcome of this binding process has been termed an event file, a transient memory structure that links features, context, and associated actions. A key result that supports the existence of event files is the partial repetition cost - slowed responses to a current event thought to reflect the updating of event file bindings in simple trial-to-trial repetition methods. In four experiments, using a procedure similar to Hommel (Visual Cognition, 5 (1/2), 183-216, 1998), we explored whether similar event file binding effects occurred when participants imagine rather than perceive a first event prior to responding to a following visual event. The results indicate that this effect does occur, implying that feature binding in imagery and perception may follow similar principles.

Cueing color imagery: A critical analysis of imagery-perception congruency effects.

The relation between mental imagery and visual perception is a long debated topic in experimental psychology. In a recent study, Wantz, Borst, Mast, and Lobmaier (2015) demonstrated that color imagery could benefit color perception in a task that involved generating imagery in response to a cue prior to a forced-choice color discrimination task. Here, we scrutinized whether the method of Wantz et al. warrants strong inferences about the role of color imagery in color perception. In Experiments 1-3, we demonstrate that the imagery effect reported by Wantz et al. does replicate nicely using their method but does not occur when cue-target contingencies and a redundancy between the imagery and response dimensions are removed from their method. In Experiments 4-6, we explored cued imagery effects further using a method in which the cued imagery dimension was orthogonal to the response dimension. The results of these experiments demonstrate that a compelling endogenously cued imagery effect does not occur for lone targets but does occur for singleton color targets embedded amid homogenous color distractors. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Strategic visual imagery and automatic priming effects in pop-out visual search.

Priming of Pop-out (PoP) is defined by faster responses in singleton search when the target repeats across trials than when it switches. In a recent study, it was shown that the PoP effect can be reversed using visual imagery (Cochrane, Nwabuike, Thomson, & Milliken, 2018). The goal of the current study was to pinpoint the procedural constraints necessary to observe the imagery-induced reversal of PoP. Across four experiments the reversal of the PoP effect (i) depended critically on the response-stimulus interval between trials, (ii) was remarkably stable across long experimental sessions, (iii) was observed within trial-pairs when participants engaged in visual imagery, but not between trial-pairs when participants did not, and (iv) appeared to be more robust with self-paced trial-pairs than with a long continuous run of trials. Together, these results offer strong confirmation of the idea that self-generated visual imagery can produce robust reversals of the PoP effect.

An imagery-induced reversal of intertrial priming in visual search.

Maljkovic and Nakayama (1994) found that pop-out search performance is more efficient when a singleton target feature repeats rather than switches from 1 trial to the next-an effect known as priming of pop-out (PoP). They also reported findings indicating that the PoP effect is strongly automatic, as it was unaffected by knowledge of the upcoming target color. In the present study, we examined the impact of visual imagery on the PoP effect. Participants were instructed to imagine a target color that was opposite that of the preceding trial (e.g., if the prior target was red, then imagine green). Under these conditions, responses were faster for targets that matched the imagined color than for targets that matched the previous target color, reversing the typical PoP effect. There was no such reversal of the PoP effect for participants asked to verbalize rather than imagine an upcoming target color. In Experiment 3, we explored whether the PoP effect was indeed eliminated in the prior experiments, or instead obscured by the opposing visual imagery effect. Two conditions were compared, 1 in which a PoP effect could oppose the visual imagery effect, and another in which no such effect was possible, allowing inferences about whether a PoP effect was present. The results indicated that the PoP effect was present, but obscured by the larger visual imagery strategy effect that pushed performance in the opposite direction. Overall, the results suggest that the PoP effect is sensitive to top-down strategies that involve visual representations. (PsycINFO Database Record