Early signs of visual awareness emerge in human babies five months after being born, a study has shown.
A weak spark of conscious perception can be measured in the infants which strengthens with age, scientists revealed.
The finding may provide a new method of assessing patients in vegetative or minimally conscious states who cannot communicate.
Demonstrating visual consciousness in infants is difficult because, like some patients with severe brain injuries, they cannot report what they have seen.
The new research focused on an electrical signal produced in the brain when someone notices and is aware of a visual scene observed for a brief snatch of time.
The same signal was seen in babies shown a series of natural and altered faces. Each face was shown for a fraction of a second.
The signal appeared in all infants aged five to 15 months, but was "weak and delayed" in the youngest.