Contextual cueing of visual search reflects the acquisition of an optimal, one-for-all oculomotor scanning strategy

Effect of cue validity on the contextual cueing effect

Purpose

In daily life, people are adept at extracting task-relevant information from complex visual environment to guide attention more effectively toward the target. This process underpins the contextual cueing effect, where repeated exposure allows individuals to learn associations between contextual cues and targets, thereby enhancing visual search efficiency. However, the cue validity of context -how consistently cues predict target locations-is not always guaranteed in real life. This study focused on cue validity as a critical factor in understanding the contextual cueing effect. Within the study of contextual cueing, cue validity specifically refers to the probability that contextual cues accurately indicate the location of a target.

Methods

In Experiment 1, we manipulated three levels of cue validity (100, 75, and 50%) using a classic contextual cueing paradigm. Experiment 2 examined the potential impact of an imbalanced predictable vs unpredictable trial ratio. In Experiment 3, we explored whether the absence of the contextual cueing effect was due to unsuccessful learning or unsuccessful later expression.

Results

Results from Experiment 1 revealed that higher cue validity (100 and 75%) significantly elicited the contextual cueing effect, resulting in faster responses for repeated displays, whereas lower cue validity (50%) did not result in this effect because the repeated displays could not be effectively learned. Experiment 2 showed that the contextual cueing effect remained robust despite an imbalanced ratio of predictable to unpredictable displays. Experiment 3 further showed that low cue validity affects the early learning phase of context-target associations rather than the later expression in visual search.

Conclusion

Our study highlights the significant role of cue validity in implicit learning from visual cues. High cue validity enhances learning by providing highly stable context-target associations, while low cue validity does not actively facilitate attention allocation, thereby not promoting the learning process. These findings underscore the importance of cue validity in processing visual information.

Contextual facilitation: Separable roles of contextual guidance and context suppression in visual search

Visual search is facilitated when targets are repeatedly encountered at a fixed position relative to an invariant distractor layout, compared to random distractor arrangements. However, standard investigations of this contextual-facilitation effect employ fixed distractor layouts that predict a constant target location, which does not always reflect real-world situations where the target location may vary relative to an invariant distractor arrangement. To explore the mechanisms involved in contextual learning, we employed a training-test procedure, introducing not only the standard full-repeated displays with fixed target-distractor locations but also distractor-repeated displays in which the distractor arrangement remained unchanged but the target locations varied. During the training phase, participants encountered three types of display: full-repeated, distractor-repeated, and random arrangements. The results revealed full-repeated displays to engender larger performance gains than distractor-repeated displays, relative to the random-display baseline. In the test phase, the gains were substantially reduced when full-repeated displays changed into distractor-repeated displays, while the transition from distractor-repeated to full-repeated displays failed to yield additional gains. We take this pattern to indicate that contextual learning can improve performance with both predictive and non-predictive (repeated) contexts, employing distinct mechanisms: contextual guidance and context suppression, respectively. We consider how these mechanisms might be implemented (neuro-)computationally.

Visual statistical learning requires attention

Statistical learning is a person's ability to automatically learn environmental regularities through passive exposure. Since the earliest studies of statistical learning in infants, it has been debated exactly how "passive" this learning can be (i.e., whether attention is needed for learning to occur). In Experiment 1 of the current study, participants performed a serial feature search task where they searched for a target shape among heterogenous nontarget shapes. Unbeknownst to the participants, one of these nontarget shapes was presented much more often in location. Even though the regularity concerned a nonsalient, nontarget item that did not receive any attentional priority during search, participants still learned its regularity (responding faster when it was presented at this high-probability location). While this may suggest that not much, if any, attention is needed for learning to occur, follow-up experiments showed that if an attentional strategy (i.e., color subset search or exogenous cueing) effectively prevents attention from being directed to this critical regularity, incidental learning is no longer observed. We conclude that some degree of attention to a regularity is needed for visual statistical learning to occur.

Contextual cuing survives an interruption from an endogenous cue for attention

Three experiments explored how the repetition of a visual search display guides search during contextual cuing under conditions in which the search process is interrupted by an instructional (endogenous) cue for attention. In Experiment 1, participants readily learned about repeated configurations of visual search, before being presented with an endogenous cue for attention towards the target on every trial. Participants used this cue to improve search times, but the repeated contexts continued to guide attention. Experiment 2 demonstrated that the presence of the endogenous cue did not impede the acquisition of contextual cuing. Experiment 3 confirmed the hypothesis that the contextual cuing effect relies largely on localized distractor contexts, following the guidance of attention. Together, the experiments point towards an interplay between two drivers of attention: after the initial guidance of attention, memory representations of the context continue to guide attention towards the target. This suggests that the early part of visual search is inconsequential for the development and maintenance of the contextual cuing effect, and that memory representations are flexibly deployed when the search procedure is dramatically interrupted.

Learning regular cross-trial shifts of the target location in serial search involves awareness - An eye-tracking study

People can learn and use both static and dynamic (cross-trial) regularities in the positioning of target items during parallel, 'pop-out' visual search. Static target-location learning also works in serial search, however, acquiring dynamic regularities is hindered by the demands of item-by-item scanning. Also, questions have been raised regarding whether explicit awareness is necessary for using dynamic regularities to optimize performance. The present study re-examined if dynamic regularities can be learned in serial search when regular shifts of the target location occur frequently, and if such learning correlates with awareness of the dynamic rule. We adopted the same regularity used by Yu et al. (2023) to demonstrate dynamic learning in parallel search: a cross-trial shift of the target location in a (counter-)clockwise direction within a circular array in 80 % of the trials, compared to irregular shifts in the opposite direction (10 %) or some other random direction (10 %). The results showed that about 70 % of participants learned the dynamic regularity, with performance gains correlating with awareness: the more accurately they estimated the likelihood of the target shifting in the frequent direction, the greater their gains. Importantly, part of the gains accrued already early during the search: a large proportion of the very first and short-latency eye movements were directed to the predicted location, regardless of the target appeared there. We discuss whether this rule-driven behavior is causally mediated by conscious control.