Now you see it, now you know you see it

November 30, 2009,

There is a tiny period of time between the registration of a visual stimulus by the unconscious mind and our conscious recognition of it ― between the time we see an apple and the time we recognize it as an apple. Our minds lag behind our eyes, but by how long? And how does this affect our reactions to the world around us?

Some estimates say the time delay lasts only 100 milliseconds, others say 500 milliseconds. A new study by Tel Aviv University psychologists says that the answer is somewhere close to the latter, but can vary depending on the complexity of the stimulus.

Researcher Moti Salti and his supervisors Dominique Lamy and Prof. Yair Bar-Haim of TAU's Department of Psychology reported their findings in the Journal of Cognitive Neuroscience.

"We are hunting for the brain activity associated with conscious perception," says Salti. "When you wander through this world, you see and hear things that may reveal themselves to your conscious mind ― and others that don't. We are interested in what cues the brain gives us to open that unconscious perception to the conscious mind -- what makes our conscious mind tick."

A conscious connection

This basic science, Salti says, won't immediately provide marketers with the basis for a new and advanced kind of subliminal advertising. But it may answer long-debated questions about the mysterious nexus between our conscious and unconscious minds.

In their study, the researchers measured neural activity related to conscious perception. They connected test subjects to an electroencephalograph (EEG) that measured their brain activity, then exposed them to rapid visual stimuli ― square cubes on a computer screen that flashed on and off very quickly. Participants were instructed to indicate whether they had seen the stimulus and to report its location on the screen.

Some participants were able to identify where the stimulus appeared, but could not identify it as a square cube, allowing the researchers to explore how correlated with conscious perception.

Finding what the eyes can't see

The study sought to map what the eyes do not "see," but the brain or unconscious mind registers. The EEG data showed that the conscious mind kicked in about a half second -- 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," says 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."

Until about 20 years ago, science neglected the field of consciousness, saying it was too subjective for precise scientific examination. Now the very complexity of the problem encourages young psychologists to study the mystery of consciousness; they argue that the conscious mind is a "splendor of creation" and helps us understand humanity itself.

Salti is about to begin a post-doctorate study position at INSERM in France, the European equivalent of America's National Institutes of Health, under Prof. Stanislas Dehaene.

Source: Tel Aviv University (news : web)

Related Stories

Recommended for you

Midbrain 'start neurons' control whether we walk or run

January 17, 2018
Locomotion comprises the most fundamental movements we perform. It is a complex sequence from initiating the first step, to stopping when we reach our goal. At the same time, locomotion is executed at different speeds to ...

Recording a thought's fleeting trip through the brain

January 17, 2018
University of California, Berkeley neuroscientists have tracked the progress of a thought through the brain, showing clearly how the prefrontal cortex at the front of the brain coordinates activity to help us act in response ...

Brain zaps may help curb tics of Tourette syndrome

January 16, 2018
Electric zaps can help rewire the brains of Tourette syndrome patients, effectively reducing their uncontrollable vocal and motor tics, a new study shows.

Miles Davis is not Mozart: The brains of jazz and classical pianists work differently

January 16, 2018
Keith Jarret, world-famous jazz pianist, once answered in an interview when asked if he would ever be interested in doing a concert where he would play both jazz and classical music: "No, that's hilarious. [...] It's like ...

New study reveals why some people are more creative than others

January 16, 2018
Creativity is often defined as the ability to come up with new and useful ideas. Like intelligence, it can be considered a trait that everyone – not just creative "geniuses" like Picasso and Steve Jobs – possesses in ...

A 'touching sight': How babies' brains process touch builds foundations for learning

January 16, 2018
Touch is the first of the five senses to develop, yet scientists know far less about the baby's brain response to touch than to, say, the sight of mom's face, or the sound of her voice.

4 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

VOICEOFTRUTH
Nov 30, 2009
This comment has been removed by a moderator.
jgelt
not rated yet Nov 30, 2009
but I thought this was already established and known as the N400 pulse...
Yellowdart
Dec 01, 2009
This comment has been removed by a moderator.
melajara
not rated yet Dec 02, 2009
400ms from presentation to REACTION time or 400ms from presentation to "Aha" time? This is not stated and, indeed, how to devise a good experiment to measure the delay from awareness to effectors (gesture or word uttered etc)?

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.