In a nutshell: New research disproves a commonly held belief that attention and decision-making are two independent processes.

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We constantly adapt our behaviour in response to our surroundings. In each situation, we decide on the appropriate response by processing sensory information – such as what we see or hear around us. Processing irrelevant or distracting stimuli may lead to errors, so it is essential that the brain pays attention to relevant stimuli only and disregards other sensory input.

For example, when deciding whether to cross a busy road, we pay attention to traffic signals and cars to our left or right. But we disregard the movement of pedestrians or objects around us. We continue to process this sensory input until we have enough relevant information to make a decision.

Most neuroscience research on attention and decision-making has examined these two processes independently. Little was known about whether, or how, they interact.

To find out, Brain Function CoE investigators Dragan Rangelov and Jason Mattingley from the University of Queensland designed an experiment that required people to pay attention and make decisions at the same time.

Participants performed a simple visual task as their brain activity was monitored using electroencephalography. They viewed a computer screen showing two fields of moving dots – the target and the distractor. The two fields overlapped, were coloured differently, and moved in different directions. The participants were asked to focus their attention on the target field and to report what direction it moved in.

In principle, participants could first identify the target by its colour, and then decide what direction it moves in. In this case, the movement of the distractor should not influence the participants’ decision.

Contrary to this expectation, the results showed that the movement of the distractor influenced the participants’ decisions about the target motion. It also affected their associated brain activity.

This means that even when the participants paid attention only to the target, their brains still processed some information about the distractor. It also suggests that paying attention to relevant stimuli and deciding on the appropriate response happen at the same time.

In contrast to previous research, which assumed that attention and decision-making are relatively independent, the results of this study show that they are closely related.

Photo credit: Jon Tyson on Unsplash.

Next steps:
The researchers plan to study what happens at the cellular level when attention and decision-making interact. They will also use computational modelling of behaviour and corresponding brain activity to learn more about the processes in the brain that support both selective attention and accurate decision-making.

Rangelov, D., & Mattingley, J. B. (2020). Evidence accumulation during perceptual decision-making is sensitive to the dynamics of attentional selection. NeuroImage, 117093. doi: 10.1016/j.neuroimage.2020.117093

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Photo by Jon Tyson on Unsplash.