Babies as young as 5 months have conscious vision, says a new study.
This is the first time that researchers have been able to demonstrate that babies can see things. Although previous research has shown that babies can respond to visual stimulation, it was never found whether they really have visual consciousness.
"Our study suggests that babies are much more conscious than we believed before, and they're probably much more conscious of pain when they experience [it]," said Dr. Sid Kouider of the École Normale Supérieure in Paris, lead author of the study, according to Livescience.
The study involved 80 children who were 5, 12 and 15 months old. Each child's head was fitted with a cap that had electrodes in it. The children were shown pictures of human faces and their response was measured. The pictures were shown at varying durations of time; with initially pictures moving so fast that even adults wouldn't be able to consciously see them, to later pictures being shown for a greater duration, reports Medical Xpress.
When an adult human eye detects an object that's moving, the vision center of the brain gets activated. This happens despite the fact that the object might be moving too fast for the eye to really see. If the object remains in the visual field, the signal travels from the back of the brain to the prefrontal cortex, where it stays till you are ready to "see" it, explains Sciencemag.org. This signal is known as the late slow wave or nonlinear cortical response, and is associated with being conscious.
This adult-level of visual consciousness was seen in almost all babies, except for some younger ones who had to be shown the image for about 900 ms to a second (the adult brain becomes aware of the image if it is displayed for about 300 ms).
These spikes in brain activity, called as event-related potentials (ERPs), were strongest in babies who were about a year old. A weaker ERP was also detected in babies as young as 5 months old.
However, some experts say that the rise in brain activity may not co-relate with consciousness.
"ERP components change dramatically over the first few years of life. I would be reluctant to attribute the same mental operation (i.e., consciousness) in infants as in adults simply because of similar patterns of brain activity," Charles Nelson, a neuropsychologist at Harvard Medical School in Boston, told Sciencemag via email.
The study is published in the journal Science.