TEL AVIV, Israel, Dec. 2 (UPI) -- Israeli scientists say the interval between the brain's registration of a visual stimulus and the conscious recognition of it is 1/3 to 1/2 second.
Tel Aviv University Professor Yair Bar-Haim and researchers Moti Salti and Dominique Lamy said they used electroencephalography to measure the brain activity of research participants as they were exposed to computer images of cubes that quickly flashed on and off. They asked the study participants whether they had seen the stimulus and to report its location on the computer screen.
The scientists said the EEG data showed conscious awareness of the visual stimulus occurred 300 to 400 milliseconds after exposure to the stimulus.
"The time it takes for the conscious mind to kick in depends on the complexity of the stimulus," said Salti. "The more complex the stimuli -- like eye color or words written on a passerby's T-shirt -- the longer the conscious mind will delay. Our new discovery isn't only about timing this effect, but also about using unconscious perception as a tool for studying consciousness."
The study is reported in the Journal of Cognitive Neuroscience.
