IISc study throws light on bias, attention in humans

New findings

Anyone who has ever walked down a busy street and has subconsciously focused on an attractive member of the opposite sex while filtering out all others might be forgiven for thinking that their eyes are to be blamed.

A new study at the Indian Institute of Science has found that the tendency of the eye to focus on certain objects or people originate from the central part of the brain that classifies inferences based on priority and forms a critical component of the mind’s decision-making powers.

Using a diffusion MRI to create snapshots of the brain and modeling techniques, Professor Sridharana Devarajan, assistant professor, Centre for Neuroscience, IISc, and his PhD student Varsha Sreenivasan have determined that a mid-area region of the brain — called the Superior Colliculus (SC) — gives humans the ability to selectively channel elements in their line of sight and allow them to focus their ‘attention’ on things.

“The human brain is constantly bombarded with information. It is through attention that it makes decisions efficiently: it processes relevant information and tunes out distractions,” said Professor Devarajan, explaining that this process is called ‘bias’.

The findings could potentially help scientists understand disorders such as Attention-Deficit Hyperactivity Disorder.

“The study highlights the idea that ‘attention’ is not really a single thing. There can be many different types of attention deficits. The implications of the study could offer scientists a better means to detect early-stage dementia and educators a means to address learning difficulties in students,” Professor Devarajan said.

Scientists have long suspected that the Superior Colliculus played a role in attention because lab monkeys were found to be more attentive when the SC was stimulated and distracted when this part of the brain was silenced. The study suggests that if subjects are taught to pay attention in a particular way, then additional changes in the connection profile of the brain can be seen.

The study involved a test group of 22 core participants, all from Bengaluru, and data from 60 others from a public database.

According to Sreenivasan, the first author, the SC is an evolutionary conserved midbrain structure that can be found in all vertebrates, including fish, lizards, birds and mammals. It is usually studied for its role in controlling eye movements. The findings were published in the proceedings of the National Academy of Sciences.