Learned spatial suppression is not always proactive.

Learning to ignore distractors is critical for navigating the visual world. Research has suggested that a location frequently containing a salient distractor can be suppressed. How does such suppression work? Previous studies provided evidence for proactive suppression, but methodological limitations preclude firm conclusions. We sought to overcome these limitations with a new search-probe paradigm. On search trials, participants searched for a shape oddball target while a salient color singleton distractor frequently appeared in a high-probability location. On randomly interleaved probe trials, participants discriminated the orientation of a tilted bar presented briefly at one of the search locations, allowing us to index the spatial distribution of attention at the moment the search would have begun. Results on search trials replicated previous findings: reduced attentional capture when a salient distractor appeared in the high-probability location. However, critically, probe discrimination was no different at the high-probability and low-probability locations. We increased the incentive to ignore the high-probability location in Experiment 2 and found, strikingly, that probe discrimination accuracy was greater at the high-probability location. These results suggest that the high-probability location was initially selected before being suppressed, consistent with a reactive mechanism. Overall, the accuracy probe procedure demonstrates that learned spatial suppression is not always proactive, even when response time metrics seem consistent with such an inference. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Eye movements reveal the contributions of early and late processes of enhancement and suppression to the guidance of visual search.

In visual search attention can be directed towards items matching top-down goals, but this must compete with factors such as salience that can capture attention. However, under some circumstances it appears that attention can avoid known distractor features. Chang and Egeth (Psychological Science, 30 (12), 1724-1732, 2019) found that such inhibitory effects reflect a combination of distractor-feature suppression and target-feature enhancement. In the present study (N = 48), we extend these findings by revealing that suppression and enhancement effects guide overt attention. On search trials (75% of trials) participants searched for a diamond shape among several other shapes. On half of the search trials all objects were the same colour (e.g., green) and on the other half of the search trials one of the non-target shapes appeared in a different colour (e.g., red). On interleaved probe trials (25% of trials), subjects were presented with four ovals. One of the ovals was in either the colour of the target or the colour of the distractor from the search trials. The other three ovals were on neutral colours. Critically, we found that attention was overtly captured by target colours and avoided distractor colours when they were viewed in a background of neutral colours. In addition, we provided a time course of attentional control. Within visual search tasks we observed inhibition aiding early attentional effects, indexed by the time it took gaze to first reach the target, as well as later decision-making processes indexed by the time for a decision to be made once the target as found.

Standing out in a small crowd: The role of display size in attracting attention.

Strong evidence supporting the top-down modulation of attention has come from studies in which participants learned to suppress a singleton in a heterogeneous four-item display. These studies have been criticized on the grounds that the displays are so sparse that the singleton is not actually salient. We argue that similar evidence of suppression has been found with substantially larger displays where salience is not in question. Additionally, we examine the results of applying salience models to four-item displays, and find prominent markers of salience at the location of the singleton. We conclude that small heterogeneous displays do not preclude strong salience signals. Beyond that, we reflect on how further basic research on salience may speed resolution of the attentional capture debate.

Can salient stimuli really be suppressed?

Although it is often assumed that a physically salient stimulus automatically captures attention even when it is irrelevant to a current task, the signal-suppression hypothesis proposes that observers can actively suppress a salient-but-irrelevant distractor. However, it is still unknown whether suppression alone (i.e., without target enhancement) is potent enough to override attentional capture by a salient singleton in an otherwise-homogeneous background. The current study addressed this issue. On search trials (70% of trials), participants searched for a shape target on trials that either did or did not contain an irrelevant color singleton. The effects of learning to suppress the color of the singleton were examined on interleaved probe trials (30% of trials). On these trials, participants searched for a probe target letter; those letters were presented on four ovals (one colored oval and three gray ovals). Each colored oval was a singleton that was one of three types: the color of the distractor on search trials, the color of the target on search trials, or a neutral color that had not appeared on search trials. Responses were faster for the probe target on a neutral-colored or target-colored item than on a gray-colored item; however, responses were slower for the probe target on a distractor-colored item than on a gray-colored item. The results demonstrate a powerful suppression mechanism overriding attentional capture by a singleton item.

Enhancement and Suppression Flexibly Guide Attention.

Previous research suggests that observers can suppress salient-but-irrelevant stimuli in a top-down manner. However, one question left unresolved is whether such suppression is, in fact, solely due to distractor-feature suppression or whether it instead also reflects some degree of target-feature enhancement. The present study (N = 60) addressed this issue. On search trials (70% of trials), participants searched for a shape target when an irrelevant color singleton was either present or absent; performance was better when a color singleton was present. On interleaved probe trials (30% of trials), participants searched for a letter target. Responses were faster for the letter on a target-colored item than on a neutral-colored item, whereas responses were slower for the letter on a distractor-colored item than on a neutral-colored item. The results demonstrate that target-feature enhancement and distractor-feature suppression contribute to attentional guidance independently; enhancement and suppression flexibly guide attention as the occasion demands.

Sequential effects in preference decision: Prior preference assimilates current preference.

An important factor affecting preference formation is the context in which that preference decision takes place. The current research examined whether one's preference formed for a previously presented stimulus influences the processing of a subsequent preference decision, henceforth referred to as the preference sequence effect. Using a novel sequential rating/judgment paradigm, the present study demonstrated the presence of a preference sequence effect using artistic photographs and face stimuli: A neutral stimulus was preferred more following a preferable stimulus than a less preferable stimulus. Furthermore, a similar trend was found even when the potential influence of response bias was controlled. These results suggest that an assimilative sequential effect exists even when sequential judgments are made solely based on one's subjective feeling; preference formed for a preceding stimulus modulates preference for a subsequent stimulus. This implies the need for a consideration of trial sequence as a factor creating a psychological context affecting the subsequent preference decisions.

Adjustment to Subtle Time Constraints and Power Law Learning in Rapid Serial Visual Presentation.

We investigated whether attention could be modulated through the implicit learning of temporal information in a rapid serial visual presentation (RSVP) task. Participants identified two target letters among numeral distractors. The stimulus-onset asynchrony immediately following the first target (SOA1) varied at three levels (70, 98, and 126 ms) randomly between trials or fixed within blocks of trials. Practice over 3 consecutive days resulted in a continuous improvement in the identification rate for both targets and attenuation of the attentional blink (AB), a decrement in target (T2) identification when presented 200-400 ms after another target (T1). Blocked SOA1s led to a faster rate of improvement in RSVP performance and more target order reversals relative to random SOA1s, suggesting that the implicit learning of SOA1 positively affected performance. The results also reveal "power law" learning curves for individual target identification as well as the reduction in the AB decrement. These learning curves reflect the spontaneous emergence of skill through subtle attentional modulations rather than general attentional distribution. Together, the results indicate that implicit temporal learning could improve high level and rapid cognitive processing and highlights the sensitivity and adaptability of the attentional system to subtle constraints in stimulus timing.

Polarity correspondence effect between loudness and lateralized response set.

Performance is better when a high pitch tone is associated with an up or right response and a low pitch tone with a down or left response compared to the opposite pairs, which is called the spatial-musical association of response codes effect. The current study examined whether polarity codes are formed in terms of the variation in loudness. In Experiments 1 and 2, in which participants performed a loudness-judgment task and a timbre-judgment task respectively, the correspondence effect was obtained between loudness and response side regardless of whether loudness was relevant to the task or not. In Experiments 3 and 4, in which the identical loudness- and timbre-judgment tasks were conducted while the auditory stimulus was presented only to the left or right ear, the correspondence effect was modulated by the ear to which the stimulus was presented, even though the effect was marginally significant in Experiment 4. The results suggest that loudness produced polarity codes that influenced response selection (Experiments 1 and 2), and additional spatial codes provided by stimulus position modulated the effect, generating the stimulus eccentricity effect (Experiments 3 and 4), which is consistent with the polarity correspondence principle.