Reward history modulates visual attention in an avian model

Attention can be biased towards previously reward-associated stimuli even when they are task-irrelevant and physically non-salient, although studies of reward-modulated attention have been largely limited to primate (including human and nonhuman) models. Birds have been shown to have the capacity to discriminate reward and spatial cues in a manner similar to primates, but whether reward history involuntarily affects their attention in the same way remains unclear. We adapted a spatial cueing paradigm with differential rewards to investigate how reward modulates the allocation of attention in peafowl (Pavo cristatus). The birds were required to locate and peck a target on a computer screen that was preceded by a high-value or low-value color cue that was uninformative with respect to the location of the upcoming target. All birds exhibited a validity effect (performance enhanced on valid compared to invalid cue), and an interaction effect between value and validity was evident at the group level, being particularly pronounced in the birds with the greatest amount of reward training. The time course of reward learning was conspicuously incremental, phenomenologically slower compared to primates. Our findings suggest a similar influence of reward history on attention across phylogeny despite a significant difference in neuroanatomy.

Neural correlates of value-driven spatial orienting

Reward learning has been shown to habitually guide overt spatial attention to specific regions of a scene. However, the neural mechanisms that support this bias are unknown. In the present study, participants learned to orient themselves to a particular quadrant of a scene (a high-value quadrant) to maximize monetary gains. This learning was scene-specific, with the high-value quadrant varying across different scenes. During a subsequent test phase, participants were faster at identifying a target if it appeared in the high-value quadrant (valid), and initial saccades were more likely to be made to the high-value quadrant. fMRI analyses during the test phase revealed learning-dependent priority signals in the caudate tail, superior colliculus, frontal eye field, anterior cingulate cortex, and insula, paralleling findings concerning feature-based, value-driven attention. In addition, ventral regions typically associated with scene selection and spatial information processing, including the hippocampus, parahippocampal gyrus, and temporo-occipital cortex, were also implicated. Taken together, our findings offer new insights into the neural architecture subserving value-driven attention, both extending our understanding of nodes in the attention network previously implicated in feature-based, value-driven attention and identifying a ventral network of brain regions implicated in reward's influence on scene-dependent spatial orienting.

A comparison of mental imagery and perceptual cueing across domains of attention

Mental imagery and perceptual cues can influence subsequent visual search performance, but examination of this influence has been limited to low-level features like colors and shapes. The present study investigated how the two types of cues influence low-level visual search, visual search with realistic objects, and executive attention. On each trial, participants were either presented with a colored square or tasked with using mental imagery to generate a colored square that could match the target (valid trial) or distractor (invalid trial) in the search array that followed (Experiments 1 and 3). In a separate experiment, the colored square displayed or generated was replaced with a realistic object in a specific category that could appear as a target or distractor in the search array (Experiment 2). Although the displayed object was in the same category as an item in the search display, they were never a perfect match (e.g., jam drop cookie instead of chocolate chip). Our findings revealed that the facilitation of performance on valid trials compared with invalid trials was greater for perceptual cues than imagery cues for low-level features (Experiment 1), whereas the influence of these two types of cues was comparable in the context of realistic objects (Experiment 2) The influence of mental imagery appears not to extend to the resolution of conflict generated by color-word Stroop stimuli (Experiment 3). The present findings extend our understanding of how mental imagery influences the allocation of attention.

Pavlovian learning in the selection history-dependent control of overt spatial attention

Learning from rewarding and aversive outcomes shapes how sensory signals are processed by the attention system, reflecting a consequence of selection history. Substantial evidence points to Pavlovian associative learning as the mechanism by which previously reward-associated and aversively conditioned stimulus features gain attentional priority. On the basis of differences between reward-dependent feature-based and space-based attentional biases, it has been suggested that reinforcement learning underlies the influence of selection history on spatial attention. By pairing the orienting of overt spatial attention with aversive electric shock, we provide direct evidence that Pavlovian learning between locations and outcomes can shape spatial attention. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The past, present, and future of selection history

The last ten years of attention research have witnessed a revolution, replacing a theoretical dichotomy (top-down vs. bottom-up control) with a trichotomy (biased by current goals, physical salience, and selection history). This third new mechanism of attentional control, selection history, is multifaceted. Some aspects of selection history must be learned over time whereas others reflect much more transient influences. A variety of different learning experiences can shape the attention system, including reward, aversive outcomes, past experience searching for a target, target‒non-target relations, and more. In this review, we provide an overview of the historical forces that led to the proposal of selection history as a distinct mechanism of attentional control. We then propose a formal definition of selection history, with concrete criteria, and identify different components of experience-driven attention that fit within this definition. The bulk of the review is devoted to exploring how these different components relate to one another. We conclude by proposing an integrative account of selection history centered on underlying themes that emerge from our review.

Inertia in value-driven attention

Previously reward-associated stimuli persistently capture attention. We attempted to extinguish this attentional bias through a reversal learning procedure where the high-value color changed unexpectedly. Attentional priority shifted during training in favor of the currently high-value color, although a residual bias toward the original high-value color was still evident. Importantly, during a subsequent test phase, attention was initially more strongly biased toward the original high-value color, counter to the attentional priorities evident at the end of training. Our results show that value-based attentional biases do not quickly update with new learning and lag behind the reshaping of strategic attentional priorities by reward.

Selection history is relative

Visual attention can be tuned to specific features to aid in visual search. The way in which these search strategies are established and maintained is flexible, reflecting goal-directed attentional control, but can exert a persistent effect on selection that remains even when these strategies are no longer advantageous, reflecting an attentional bias driven by selection history. Apart from feature-specific search, recent studies have shown that attention can be tuned to target-nontarget relationships. Here we tested whether a relational search strategy continues to bias attention in a subsequent task, where the relationally better color and former target color both serve as distractors (Experiment 1) or as potential targets (Experiment 2). We demonstrate that a relational bias can persist in a subsequent task in which color serves as a task-irrelevant feature, both impairing and facilitating visual search performance. Our findings extend our understanding of the relational account of attentional control and the nature of selection history effects on attention.

Reward learning biases the direction of saccades

The role of associative reward learning in guiding feature-based attention and spatial attention is well established. However, no studies have looked at the extent to which reward learning can modulate the direction of saccades during visual search. Here, we introduced a novel reward learning paradigm to examine whether reward-associated directions of eye movements can modulate performance in different visual search tasks. Participants had to fixate a peripheral target before fixating one of four disks that subsequently appeared in each cardinal position. This was followed by reward feedback contingent upon the direction chosen, where one direction consistently yielded a high reward. Thus, reward was tied to the direction of saccades rather than the absolute location of the stimulus fixated. Participants selected the target in the high-value direction on the majority of trials, demonstrating robust learning of the task contingencies. In an untimed visual foraging task that followed, which was performed in extinction, initial saccades were reliably biased in the previously rewarded-associated direction. In a second experiment, following the same training procedure, eye movements in the previously high-value direction were facilitated in a saccade-to-target task. Our findings suggest that rewarding directional eye movements biases oculomotor search patterns in a manner that is robust to extinction and generalizes across stimuli and task.