Visual mental imagery influences attentional guidance in a visual-search task

Influence of flavor information on visual search: Attentional capture by and suppression of flavor-associated colors

Numerous studies have demonstrated the impact of flavor cues on visual search, yet the underlying mechanisms remain elusive. In this experiment, we used event-related potentials (ERPs) to examine whether, and if so, how flavor information could lead to attentional capture by, and suppression of, flavor-associated colors. The participants were asked to taste certain flavored beverages and subsequently complete a shape-based visual search task, while their neural activities were simultaneously recorded. The behavioral results revealed that the participants made slower responses when a distractor in the flavor-associated color (DFAC) was present, suggesting an attentional bias toward the flavor-associated color. The ERP results revealed that the N2pc was detected if the target and the DFAC were shown in the same visual field (e.g. both target and DFCA on the right side of the screen), when the pairings between flavor cues and target colors were incongruent. However, the N2pc was not observed if the target and the DFAC were shown in the opposite visual fields (e.g. target on the right and DFCA on the left side of the screen) for the incongruent color-flavor pairings. Moreover, the distractor positivity (Pd) was observed if the target and the DFAC were shown in the opposite visual field for the congruent color-flavor pairings. These results suggest that both attentional capture and suppression are involved in the influence of flavor information on visual search. Collectively, these findings provide initial electrophysiological evidence on the mechanisms of the crossmodal influence of flavor cues on visual search.

Visual mental imagery: Evidence for a heterarchical neural architecture

Theories of Visual Mental Imagery (VMI) emphasize the processes of retrieval, modification, and recombination of sensory information from long-term memory. Yet, only few studies have focused on the behavioral mechanisms and neural correlates supporting VMI of stimuli from different semantic domains. Therefore, we currently have a limited understanding of how the brain generates and maintains mental representations of colors, faces, shapes - to name a few. Such an undetermined scenario renders unclear the organizational structure of neural circuits supporting VMI, including the role of the early visual cortex. We aimed to fill this gap by reviewing the scientific literature of five semantic domains: visuospatial, face, colors, shapes, and letters imagery. Linking theory to evidence from over 60 different experimental designs, this review highlights three main points. First, there is no consistent activity in the early visual cortex across all VMI domains, contrary to the prediction of the dominant model. Second, there is consistent activity of the frontoparietal networks and the left hemisphere's fusiform gyrus during voluntary VMI irrespective of the semantic domain investigated. We propose that these structures are part of a domain-general VMI sub-network. Third, domain-specific information engages specific regions of the ventral and dorsal cortical visual pathways. These regions partly overlap with those found in visual perception studies (e.g., fusiform face area for faces imagery; lingual gyrus for color imagery). Altogether, the reviewed evidence suggests the existence of domain-general and domain-specific mechanisms of VMI selectively engaged by stimulus-specific properties (e.g., colors or faces). These mechanisms would be supported by an organizational structure mixing vertical and horizontal connections (heterarchy) between sub-networks for specific stimulus domains. Such a heterarchical organization of VMI makes different predictions from current models of VMI as reversed perception. Our conclusions set the stage for future research, which should aim to characterize the spatiotemporal dynamics and interactions among key regions of this architecture giving rise to visual mental images.

Visual mental imagery of atypical color objects attracts attention to an imagery-matching object

Mental imagery attracts attention to imagery-matching stimuli. However, it remains unknown whether voluntarily imagined atypical color also attracts attention to a stimulus that matches the imagery when the imagined stimuli are color-diagnostic objects, which are strongly associated with typical color. This study investigated whether people can voluntarily imagine atypical colors of such objects and attend to imagery-matching stimuli. Participants in the imagery group were instructed to imagine an atypical color of the black-white objects according to the instructed color or voluntarily selected color, whereas participants in the control group were instructed to attend to the objects without any instruction of imagery. Thereafter, they detected a color target in a visual search task. Results revealed that participants in the imagery group directed attention to the imagery-matching atypical color, not to the original color of the object in the search. Meanwhile, participants in the control group did not demonstrate any attentional guidance. These results suggest that voluntarily imagining atypical color can attenuate mental representations of the original color imagery and change attention to a stimulus that matches imagery.

Mental imagery and visual attentional templates: A dissociation

There is a growing interest in the relationship between mental images and attentional templates as both are considered pictorial representations that involve similar neural mechanisms. Here, we investigated the role of mental imagery in the automatic implementation of attentional templates and their effect on involuntary attention. We developed a novel version of the contingent capture paradigm designed to encourage the generation of a new template on each trial and measure contingent spatial capture by a template-matching visual feature (color). Participants were required to search at four different locations for a specific object indicated at the start of each trial. Immediately prior to the search display, color cues were presented surrounding the potential target locations, one of which matched the target color (e.g., red for strawberry). Across three experiments, our task induced a robust contingent capture effect, reflected by faster responses when the target appeared in the location previously occupied by the target-matching cue. Contrary to our predictions, this effect remained consistent regardless of self-reported individual differences in visual mental imagery (Experiment 1, N = 216) or trial-by-trial variation of voluntary imagery vividness (Experiment 2, N = 121). Moreover, contingent capture was observed even among aphantasic participants, who report no imagery (Experiment 3, N = 91). The magnitude of the effect was not reduced in aphantasics compared to a control sample of non-aphantasics, although the two groups reported substantial differences in their search strategy and exhibited differences in overall speed and accuracy. Our results hence establish a dissociation between the generation and implementation of attentional templates for a visual feature (color) and subjectively experienced imagery.

Difficulty limits of visual mental imagery

While past work has focused on the representational format of mental imagery, and the similarities of its operation and neural substrate to online perception, surprisingly little has tested the boundaries of the level of detail that mental imagery can generate. To answer this question, we take inspiration from the visual short-term memory literature, a related field which has found that memory capacity is affected by the number of items, whether they are unique, and whether and how they move. We test these factors of set size, color heterogeneity, and transformation in mental imagery through both subjective (Exp 1; Exp 2) and objective (Exp 2) measures - difficulty ratings and a change detection task, respectively - to determine the capacity limits of our mental imagery, and find that limits on mental imagery are similar to those for visual short-term memory. In Experiment 1, participants rated the difficulty of imagining 1-4 colored items as subjectively more difficult when there were more items, when the items had unique colors instead of an identical color, and when they scaled or rotated instead of merely linearly translating. Experiment 2 isolated these subjective difficulty ratings of rotation for uniquely colored items, and added a rotation distance manipulation (10° to 110°), again finding higher subjective difficulty for more items, and for when those items rotated farther; the objective measure showed a decrease in performance for more items, but not for rotational degree. Congruities between the subjective and objective results suggest similar costs, but some incongruities suggest that subjective reports can be overly optimistic, likely because they are biased by an illusion of detail.

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.

Attention, flexibility, and imagery in misophonia: Does attention exacerbate everyday disliking of sound?

INTRODUCTION

Misophonia is an unusually strong aversion to everyday sounds, such as chewing, crunching, or breathing. Here, we ask whether misophonia might be tied to an unusual profile of attention (and related traits), which serves to substantially heighten an otherwise everyday disliking of sounds.

METHODS

In Study 1, we tested 136 misophonics and 203 non-misophonics on self-report measures of attention to detail, cognitive inflexibility, and auditory imagery, as well as collecting details about their misophonia. In Study 2, we administered the Embedded Figures task to 20 misophonics and 36 non-misophonics.

RESULTS

We first showed that the degree to which sounds trigger misophonia reflects the pattern by which they are (more mildly) disliked by everyone. This suggests that misophonia is scaffolded onto existing mechanisms rather than qualitatively different ones. Compared to non-misophonics, we also found that misophonics self-reported greater attention to detail, cognitive inflexibility, and auditory imagery. As their symptoms worsen, they also become more accurate in an attentional task (Embedded Figures).

CONCLUSIONS

Our findings provide a better understanding of misophonia and support the hypothesis that dispositional traits of attention to detail may be key to elevating everyday disliking of sound into the more troubling aversions of misophonia.

Imagine, and you will find - Lack of attentional guidance through visual imagery in aphantasics

Aphantasia is the condition of reduced or absent voluntary imagery. So far, behavioural differences between aphantasics and non-aphantasics have hardly been studied as the base rate of those affected is quite low. The aim of the study was to examine if attentional guidance in aphantasics is impaired by their lack of visual imagery. In two visual search tasks, an already established one by Moriya (Attention, Perception, & Psychophysics, 80(5), 1127-1142, 2018) and a newly developed one, we examined whether aphantasics are primed less by their visual imagery than non-aphantasics. The sample in Study 1 consisted of 531 and the sample in Study 2 consisted of 325 age-matched pairs of aphantasics and non-aphantasics. Moriya's Task was not capable of showing the expected effect, whereas the new developed task was. These results could mainly be attributed to different task characteristics. Therefore, a lack of attentional guidance through visual imagery in aphantasics can be assumed and interpreted as new evidence in the imagery debate, showing that mental images actually influence information processing and are not merely epiphenomena of propositional processing.

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.

Attention driven phantom vision: measuring the sensory strength of attentional templates and their relation to visual mental imagery and aphantasia

When we search for an object in an array or anticipate attending to a future object, we create an 'attentional template' of the object. The definitions of attentional templates and visual imagery share many similarities as well as many of the same neural characteristics. However, the phenomenology of these attentional templates and their neural similarities to visual imagery and perception are rarely, if ever discussed. Here, we investigate the relationship between these two forms of non-retinal phantom vision through the use of the binocular rivalry technique, which allows us to measure the sensory strength of attentional templates in the absence of concurrent perceptual stimuli. We find that attentional templates correlate with both feature-based attention and visual imagery. Attentional templates, like imagery, were significantly disrupted by the presence of irrelevant visual stimuli, while feature-based attention was not. We also found that a special population who lack the ability to visualize (aphantasia), showed evidence of feature-based attention when measured using the binocular rivalry paradigm, but not attentional templates. Taken together, these data suggest functional similarities between attentional templates and visual imagery, advancing the theory of visual imagery as a general simulation tool used across cognition. This article is part of the theme issue 'Offline perception: voluntary and spontaneous perceptual experiences without matching external stimulation'.

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.

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.