A simple trip to the grocery store can be an exercise in trying to keep your attention focused on a task. You may have a list of items you need to buy but have a constant barrage of sale signs and displays enticing you to reward yourself. How do these incentives affect our attention? A new study finds that we actively suppress high-incentive cues in our environment to enhance our efficiency in paying attention to a task.
Using electroencephalography (EEG), the researchers, led by Risa Sawaki of the University of Birmingham in the UK, investigated exactly what occurs in the brain during different phases of a task. They measured electrical brain signals (called event related potentials, ERPs and neural oscillations) of participants who first viewed an incentive cue promising small or large reward, then experienced a short preparation interval, and then performed a simple visual search task to gain the predicted reward.
“Importantly, the incentive cues did not predict the specific motor response required but did offer an opportunity to engage in cognitive preparation,” Sawaki says. “By using EEG-based measures, we could distinguish incentive-related neural activity patterns at each phase of the task.”
As published this month online in the Journal of Cognitive Neuroscience, they found three specific EEG patterns that suggest the brain processes high- versus low-incentive cues differently to maximize cognitive efficiency. Sawaki spoke with CNS about these results and their implications, including for clinical populations.
CNS: How did you become interested in this research?
Sawaki: I became interested in how incentives affect attention since I adopted a puppy from a shelter. When I trained him to fetch a ball, he completely ignored my order at the beginning but quickly learned it when I introduced an incentive, i.e., a treat. He was a totally different dog depending on whether there was an incentive or not. And then, I realized that there are incentive cues everywhere in our environment, from a “buy 2 get 1 free” sign at supermarket to a ringtone announcing a new text message on a cell phone, and our behavior is influenced by such motivational signals. I was at Steve Luck’s lab (University of California, Davis) when Jane Raymond (University of Birmingham, UK) was visiting UC Davis for her sabbatical, and we teamed up to study how attention changes in response to incentives.
CNS: What have we known until now about how incentives affect attention?
Sawaki: As we all know, incentives can have a large impact on performance, from sports to social interactions. Previous studies have shown that, when items are associated with rewarding outcomes, they are more likely to capture attention. Also, it has been known that incentives can increase the speed of our responses by enhancing motor preparation. However, how incentives modify internal cognitive and attentional processes was poorly understood. One of the most puzzling issues was that incentive cues – signals that predict an opportunity to acquire a reward – have strong reward associations by their very nature but a strong focus of attention toward them could interfere with performance needed to obtain the reward (e.g., looking at the incentive cues instead of the target).
CNS: What were your most excited to find?
Sawaki: The present study provided three exciting neural findings: first, attention to high- but not low-incentive cues was actively suppressed. This was indexed by the “PD“ ERP component in response to the incentive cues. We think that active suppression toward high-incentive cues was observed because a strong focus of attention toward them could interfere with the target search needed to obtain the actual reward.
Second, visual readiness was heightened following the high-incentive cues. This was demonstrated by reduced alpha electrical activity during the preparation phase.
Third, attentional orienting to the search target was deployed with relatively little effort on high-incentive trials, as indexed by a reduced “N2pc” ERP component.
These results reveal the sequence of neural operations that allow cognitive processing to be sharpened “on the fly” in response to incentive cues.
CNS: How does this work fit in with past work on attention?
Sawaki: Our finding of active suppression toward high-incentive cues is consistent with recent attention studies (e.g. this study) showing that active suppression is critical for the successful completion of goal-oriented behavior. Using the PD component, it has been demonstrated that the active suppression is used to prevent attention from being directed to a distractor and to terminate attention after it has been focused on an item. The present study makes a contribution to this growing literature by providing new evidence that active suppression has an important role in optimizing cognitive performance in order to obtain a reward.
CNS: What is the significance of your findings for the general population?
Sawaki: Our findings suggest that, in some situations, incentive cues are salient but, rather than focusing attention to them, the cues are actively suppressed so that we can have better cognitive preparation and efficiently use our attentional resources in order to gain the actual reward. It is possible that this sequence of neural operations is functioning poorly in some clinical populations – such as for people suffering from addiction, some types of obesity, mood disorders, and ADHD – suggesting avenues for further research.
CNS: What’s next for this work?
Sawaki: The present study focused on neural activity that was observed at posterior electrode sites. Therefore, the role of frontal executive control in the incentive-modulated attention is still unknown. I think future work needs to reveal intercommunications between the frontal and posterior systems and ultimately elucidate how deficits in the brain intercommunication are associated with attentional and motivational disorders.
-Lisa M.P. Munoz