What is the Role of Spatial Attention in Statistical Learning During Visual Search?

Our ability to learn the regularities embedded in our environment is a fundamental aspect of our cognitive system. Does such statistical learning depend on attention? Research on this topic is scarce and has yielded mixed findings. In this preregistered study, we examined the role of spatial attention in statistical learning, and specifically in learned distractor-location suppression. This phenomenon refers to the finding that during visual search, participants are better at ignoring a salient distractor at a high-probability location than at low-probability locations - a bias persisting long after the probability imbalance has ceased. Participants searched for a shape-singleton target and a color-singleton distractor was sometimes present. During the learning phase, the color-singleton distractor was more likely to appear in the high-probability location than in the low-probability locations. Crucially, we manipulated spatial attention by having the experimental group focus their attention on the target's location in advance of the search display, using a 100%-informative spatial precue, while the control group was presented with a neutral, uninformative cue. During the subsequent test phase, the color-singleton distractor was equally likely to appear at any location and there were no cues. As expected, the results for the neutral-cue group replicated previous findings. Crucially, for the informative-cue group, interference from the distractor was minimal when attention was diverted from it (during learning) and no statistical learning was observed during test. Intertrial priming accounted for the small statistical-learning effect found during learning. These findings show that statistical learning in visual search requires attention.

Attentional guidance by target-location probability cueing is largely inflexible, long-lasting, and distinct from inter-trial priming.

There is growing consensus that selection history strongly guides spatial attention and is distinct from current goals and physical salience. Here, we focused on target-location probability cueing: when the target is more likely to appear in one region, search performance gradually improves for targets appearing in that region. Probability cueing is thought to reflect a long-lasting, inflexible and implicit attentional bias. However, strong evidence for these claims is lacking. We re-examined them in four experiments. The target was more likely to appear in one than in the other regions during the learning phase, whereas all regions were equiprobable during the extinction phase. We manipulated set size in all experiments. Probability cueing reduced search slopes during learning and extinction, suggesting that the bias is attentional and long-lasting. Although intertrial priming from several previous trials had an influence, it did not account for all the effects. We also found the bias to be largely inflexible: informing participants that the probability imbalance during learning would be discontinued during extinction did not reduce the bias. Moreover, the acquired bias remained the default determinant of attentional priority when goal-directed guidance failed (i.e., when a cue instructing participants to start their search in a given region during the extinction phase was omitted or invalid). Finally, many more participants than predicted by chance showed awareness of the probability manipulation, although we could not establish whether awareness was associated with the bias. We conclude that probability cueing is a long-lasting and inflexible attentional bias, distinct from intertrial priming. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Is Statistical Learning of a Salient Distractor's Color Implicit, Inflexible and Distinct From Inter-Trial Priming?

Being able to overcome distraction by salient distractors is critical in order to allocate our attention efficiently. Previous research showed that observers can learn to ignore salient distractors endowed with some regularity, such as a high-probability location or feature - a phenomenon known as distractor statistical learning. Unlike goal-directed attentional guidance, the bias induced by statistical learning is thought to be implicit, long-lasting and inflexible. We tested these claims with regard to statistical learning of distractor color in a high-power (N = 160) pre-registered experiment. Participants searched for a known-shape singleton target and a color singleton distractor, when present, appeared most often in one color during the learning phase, but equally often in all possible colors during the extinction phase. We used a sensitive measure of participants' awareness of the probability manipulation. The awareness test was administered after the extinction phase for one group, and after the leaning phase for another group - which was informed that the probability imbalance would be discontinued in the upcoming extinction phase. Participants learned to suppress the high-probability distractor color very fast, an effect partly due to intertrial priming. Crucially, there was only little evidence that the bias survived during extinction. Awareness of the manipulation was associated with reduced color suppression, suggesting that the bias was implicit. Finally, results showed that the awareness test was more sensitive when administered early vs. late. We conclude that learnt color suppression is an implicit bias that emerges and decays rapidly, and discuss the methodological implications of our findings.