After being blind for life, new sighted people can instantly detect human movements

Sau khi bị mù suốt đời, những người mới được nhìn thấy có thể xác định được ngay chuyển động của con người

Abstract graphic. Credit: Neuropsychologia (In 2022). DOI: 10.1016 / j.neuropsychologia.2022.108307

Humans are very sensitive to other people’s body movements. Our ability to understand body language is vital to our social development, providing information about emotional and behavioral projections through subtle cues.

When and how do we develop awareness? human movement and distinguish it from other forms of movement? Newborns as young as 2 days old can distinguish between random and coordinated movements like animals. But the ability to distinguish between the body movements of humans and other animals is reported to appear only about five months after birth. Therefore, many researchers believe that infants learn to recognize human movements during these first months through repeated visual contact.

A new study by MIT researchers suggests that a rethink may be required. This research is part of the Prakash Project, a program dedicated to the treatment of early blindness in children and adolescents. youth was founded by Pawan Sinha, a professor in MIT’s Department of Brain and Cognitive Sciences (BCS). The surgeries were conducted at Dr Shroff’s Charity Eye Hospital in New Delhi, India, allowing patients to start seeing late. In addition to the humanitarian goal of the project, patients with cataracts that have been significantly hindered since birth also participate in studies on the development of vision. Such research on patients with late-life amblyopia opens up new methods for studying the development of visual processing.

In an article published in Neuropsychologia, researchers from MIT, Project Prakash, and the University of York sought to determine whether a person’s ability to identify movement depends on extensive visual exposure. The study included two participants, aged 7 and 20, both almost completely blind from birth, who were only able to perceive light strong enough to pass through a dense cataract. their. As part of the study, participants watched videos showing light patterns representing the coordinated movements of pedestrians, pigeons, and cats, as well as similar motion patterns. lack of shape of the body structure of these animals. They were then asked to describe what they saw.

Patients watched videos in several cases before and after cataract removal. Before the removal, blind people could only see the lights up close, a few centimeters away from the screen. However, they were unable to describe any meaning to these patterns, which to them appeared to be just random movements of light with no consistent overall pattern or structure.

Immediately after surgery, as the patient’s visual clarity improves, they are able to produce finer image details. Within the first minutes of unobstructed visual exposure, two patients identified light patterns that were representative of human movement. Both did so six out of eight times. They also successfully identified human movement patterns even when they were overturned. However, at this early stage, they only recognize human movement with the structure of the human body structure. Moreover, they completely failed to recognize the movement patterns of animals.

“Patients with very limited exposure to human body movement prior to cataract removal may first notice it immediately after resection, once their vision is good enough to see the cataracts. details Shlomit Ben-Ami, a Prakash Project researcher and former MIT postdoc now at Tel Aviv University, who led the research, says the ability to identify human movement. participants being able to recognize upside down human movement reinforces the idea that visual experience may not be central to achieving this visual faculty.”

Researchers are exploring possible reasons why the participants were able to identify human movements but not the movements of other animals. One theory they are looking at is that learning to interpret other people’s body movements may be based in part on familiarity with their own body movements and structures. This hypothesis could explain why, after surgery, the participants did not recognize animal movement but only human movement – and only as long as it had the configuration of a human body.

“We should be careful with drawing conclusions about the underlying mechanism here,” says Ben-Ami. “Although the results are suggestive, they need to be verified with a larger group of participants. This study was not designed to answer the mechanism that explains the process we are looking to confirm. define human. move. It should also be remembered that patients who have been blind for most of their lives have not had normal development of vision. So they can use their knowledge of body movements as a resource more efficiently than others. “

“This study addresses a very interesting question in sight: what are the beginning stages of our development and how are they created?” Sinha, the study’s lead author. “It’s a pleasure that the Prakash Project has given us the opportunity to address this and many other questions about how the brain learns to execute vision. I look forward to further work that can help examine the findings. attractive so far.”

Motion can help with visual information processing

More information:
Shlomit Ben-Ami et al., Able to recognize human (but not animal) movement at first sight — After treating congenital blindness, Neuropsychologia (In 2022). DOI: 10.1016 / j.neuropsychologia.2022.108307

This story is republished with permission from MIT News (, a popular website that includes news about MIT research, innovation, and teaching.

Quote: After being blind for life, new visionary people can instantly identify human movement (2022, October 18) retrieved October 18, 2022 from news/2022-10-lifetime-newly-sighted-im Right-human.html

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