Scientists have discovered emerging patterns of 'consciousness' in babies of different ages before they speak.
The New Scientist reports that medics at the Ecole Normale Supérieure in Paris, France used electroencephalography (EEG) to record electrical activity in the brains of 80 infants while they were briefly shown pictures of faces.
Adult awareness of a stimulus is already known to be associated with a two-stage pattern of brain activity, with parts of the brain lighting up after a visual stimulus is presented, and conscious awareness only occurring after the second stage of neural activity gets to a specific threshold. Adults are then able to verbally describe the effects of the stimulation, which babies obviously cannot.
Dr Kouider from the Ecole Normale Supérieure worked with colleagues to see if they could get babies to present a similar measure of conscious awareness via brain activity, before they learned to speak.
Groups of infants aged five, 12 and 15 months had their brain activity recorded whilst being shown rapidly changing pictures, mostly of randomly patterned ovals. Among the ovals was a face, showed fleetingly for between 17 and 300 milliseconds.
All of the babies responded to the picture of the face with the expected two-stage pattern, but the activity linked to conscious awareness was much slower in the five-month-old babies than in the children in the older groups.
The babies of a year old responded 800 to 900 milliseconds after the image was displayed, while the 15-month-old group had similar brain activity. With the youngest babies, there was a delay of more than one second before the second pattern appeared.
In grown ups, it take 300 milliseconds, on average for the second stage activity to occur.
"Babies have the same mechanisms as adults but they are very slow," concluded Dr Kouider. "There are things happening in the brain but they are unable to deal with the information."
Ron Chrisley at the Sackler Centre for Consciousness Science at the University of Sussex, UK, told the New Scientist that the research could be extended to animals to see if consciousness could also be attributed to non-humans.
"There might be more than one way in this universe to be conscious," he said.