Mary MacLean

Neural evidence reveals the rapid effects of reward history on selective attention.

Selective attention is often framed as being primarily driven by two factors: task-relevance and physical salience. However, factors like selection and reward history, which are neither currently task-relevant nor physically salient, can reliably and persistently influence visual selective attention. The current study investigated the nature of the persistent effects of irrelevant, physically non-salient, reward-associated features. These features affected one of the earliest reliable neural indicators of visual selective attention in humans, the P1 event-related potential, measured one week after the reward associations were learned. However, the effects of reward history were moderated by current task demands. The modulation of visually evoked activity supports the hypothesis that reward history influences the innate salience of reward associated features, such that even when no longer relevant, nor physically salient, these features have a rapid, persistent, and robust effect on early visual selective attention.

Irrelevant learned reward associations disrupt voluntary spatial attention.

Attention can be guided involuntarily by physical salience and by non-salient, previously learned reward associations that are currently task-irrelevant. Attention can be guided voluntarily by current goals and expectations. The current study examined, in two experiments, whether irrelevant reward associations could disrupt current, goal-driven, voluntary attention. In a letter-search task, attention was directed voluntarily (i.e., cued) on half the trials by a cue stimulus indicating the hemifield in which the target letter would appear with 100 % accuracy. On the other half of the trials, a cue stimulus was presented, but it did not provide information about the target hemifield (i.e., uncued). On both cued and uncued trials, attention could be involuntarily captured by the presence of a task-irrelevant, and physically non-salient, color, either within the cued or the uncued hemifield. Importantly, one week prior to the letter search task, the irrelevant color had served as a target feature that was predictive of reward in a separate training task. Target identification accuracy was better on cued compared to uncued trials. However, this effect was reduced when the irrelevant, and physically non-salient, reward-associated feature was present in the uncued hemifield. This effect was not observed in a second, control experiment in which the irrelevant color was not predictive of reward during training. Our results indicate that involuntary, value-driven capture can disrupt the voluntary control of spatial attention.

Irrelevant reward and selection histories have different influences on task-relevant attentional selection

Task-relevant and physically salient features influence visual selective attention. In the present study, we investigated the influence of task-irrelevant and physically nonsalient reward-associated features on visual selective attention. Two hypotheses were tested: One predicts that the effects of target-defining task-relevant and task-irrelevant features interact to modulate visual selection; the other predicts that visual selection is determined by the independent combination of relevant and irrelevant feature effects. These alternatives were tested using a visual search task that contained multiple targets, placing a high demand on the need for selectivity, and that was data-limited and required unspeeded responses, emphasizing early perceptual selection processes. One week prior to the visual search task, participants completed a training task in which they learned to associate particular colors with a specific reward value. In the search task, the reward-associated colors were presented surrounding targets and distractors, but were neither physically salient nor task-relevant. In two experiments, the irrelevant reward-associated features influenced performance, but only when they were presented in a task-relevant location. The costs induced by the irrelevant reward-associated features were greater when they oriented attention to a target than to a distractor. In a third experiment, we examined the effects of selection history in the absence of reward history and found that the interaction between task relevance and selection history differed, relative to when the features had previously been associated with reward. The results indicate that under conditions that demand highly efficient perceptual selection, physically nonsalient task-irrelevant and task-relevant factors interact to influence visual selective attention.

Reward-based involuntary capture interacts with voluntary attentional control during search

Non-salient task-irrelevant features previously associated with reward can involuntarily capture attention (Anderson et al., 2011). Here we investigated the interaction between this reward-associated involuntary capture effect and voluntary attentional control. In a training task, participants (n=17) learned to associate two target colors (red and blue) with monetary reward (high/low). In a visual search task conducted one week later, target letters and distracter numbers, contained within differently colored circles, were briefly (232 ms) presented and then masked. Participants were then probed to indicate which of two letters had been presented in the search array. To manipulate voluntary attention, the search arrays were preceded by valid spatial cues (x or v) that indicated which hemifield would contain the target letter (left or right) or by neutral cues (=) that did not provide information about the target location. On half of the trials, one circle containing a distracter number was rendered in a previously rewarded color. Neutral trials did not contain a reward-associated color. Overall, there was a reward-associated capture effect, such that accuracy was significantly lower when a high, but not a low, reward-associated distracter was presented in the hemifield opposite the target. There was also a voluntary cueing effect, such that accuracy was greater in the cued condition than in the uncued condition. However, the cueing effect was diminished when the location of the reward-associated distracter was incongruent with the cued location, particularly on cued trials. The role of reward magnitude was examined by subtracting performance on neutral trials from performance on cued trials containing a reward-associated feature. Cue-distracter congruency only influenced performance on cued trials with high, but not low, reward-associated features. Our findings suggest that the involuntary capture by task-irrelevant and physically non-salient reward-associated features interacts with the voluntary control of attention to mediate visual search performance. Meeting abstract presented at VSS 2015.

Dual process coding of recalled location in human oscillatory brain activity

A mental representation of the location of an object can be constructed using sensory information selected from the environment and information stored internally. Human electrophysiological evidence indicates that behaviorally relevant locations, regardless of the source of sensory information, are represented in alpha-band oscillations suggesting a shared process. Here we present evidence from human subjects of either sex for two distinct alpha-band based processes that separately support the representation of location, exploiting sensory evidence sampled either externally or internally. Significance Statement Our sensory environment and our internal trains of thought are coded in patterns of brain activity and are used to guide coherent behavior. Oscillations in the alpha frequency band are a predominant feature of human brain activity. This oscillation plays a central role in both selective attention and working memory, suggesting that these important cognitive functions are mediated by a unitary mechanism. We show that the alpha oscillation reflects two distinct processes, one that is supported by continuous sampling of the external sensory environment, and one that is based on sampling from internal representations coded in visual short-term memory. This represents a significant change in our understanding of the nature of alpha oscillations and their relationship to attention and memory.

Reward history enhances working memory precision in a continuous partial report task

Features previously associated with reward capture attention, even when task-irrelevant and physically non-salient. We investigated the effect of such reward-associated features on the precision of working memory representations. We hypothesized that reward-associated features would enhance the precision of WM representations for items presented with that feature. Participants first learned to associate two colors with different magnitudes of reward (

Can value-driven attentional capture be extinguished?

0.01 or

Irrelevant social status cues drive visual attention

0.05). One week later participants completed a partial report task where they remembered the orientations of three or six masked gratings presented for either 232 ms (Exp.1, n=18) or 1,800 ms (Exp.2, n=11) and then estimated the target orientation on a continuous scale. WM precision for the probed item was measured as the standard deviation of error (degree offset) in the estimation of orientation (SDerror). Importantly, on some trials a task-irrelevant and physically non-salient reward associated feature surrounded either the probed item or a non-probed item. On neutral trials no reward-associated feature was present. The presence of a reward-associated feature affected SDerror only for short exposures (Exp.1), such that SDerror was greater when the high, but not the low, magnitude reward-associated feature surrounded the probed target as compared to neutral trials (Mdiff = 2.74 SD, p = .019) and trials with a low magnitude reward-associated feature (Mdiff = 2.72 SD, p = .002). This effect was only reliable for set size six. There was no significant effect of the reward-associated feature when it surrounded a non-probed item. These results support our hypothesis that irrelevant, and physically non-salient reward-associated features improve WM precision for the stimuli towards which they direct attention, especially when WM load was high, but only when data was limited by short exposure. However, we did not find evidence that the WM precision for a given item was diminished when attention was directed elsewhere by a reward-associated feature. Meeting abstract presented at VSS 2015.