Research has shown that meditation practice can increase our state of awareness so that we actually perceive more of what is going on around us.
The amount of information the brain can process at one time is typically limited. For example, processing of visual information (i.e., detection of light in the environment by the eye, propagation of this signal through visual processing areas of the brain, and then the conscious identification of the object) can take up to half a second. While the brain is busy doing this the attention available for detection of a second stimulus is reduced. So, if a second visual stimulus is presented within that half a second it can often go undetected. This is called an “attentional blink”, and is examined in the lab using the attentional blink paradigm.
The amount of information the brain can process at one time is typically limited. For example, processing of visual information (i.e., detection of light in the environment by the eye, propagation of this signal through visual processing areas of the brain, and then the conscious identification of the object) can take up to half a second. While the brain is busy doing this the attention available for detection of a second stimulus is reduced. So, if a second visual stimulus is presented within that half a second it can often go undetected. This is called an “attentional blink”, and is examined in the lab using the attentional blink paradigm.
Example of a trial used in the attentional blink paradigm (ms: milliseconds)
During
the paradigm participants are presented with a rapid stream of letters and
within the stream are two targets numbers that they are asked to identify. Participants
largely ignore the letters but when they see the first number (T1) they react,
meaning that their attention increases so they can process the stimulus. This
means that they often miss the second number (T2).
But,
it's been shown that for most people the “attention blink” doesn’t occur all the
time, sometimes people are able to detect both visual stimuli. This led a team
of researchers in Wisconsin to think that through training a person could
become better at the task. For a person to do this they would need to learn to
reduce the brain resources associated with detecting the first stimulus so that
there is enough left to process the second.
The
researchers examined whether Vipassana meditation could change the brain
processing capacity of meditators. During Vipassana meditation a person starts
by concentrating on one object, like the breath. They then broaden their focus
and aim to non-reactively witness incoming sensory information or thoughts. To
be non-reactive an individual aims to be aware but not get caught up in the
sensory information or thoughts that may arise.
The
researchers examined how 17 people performed on the attentional blink paradigm at
the beginning and end of a 3-month intensive meditation retreat. During testing
the researchers also measured brain activity within visual areas using an EEG (electroencephalogram), which is
essentially a hat-like device that sits on your head with electrodes that measure
electrical brain activity. The researchers found that after the retreat the
meditators were more likely to detect both the first and second target. They
also found that this was associated with reduced brain activity during
detection of the first target.
This research suggest that learning to be non-reactive during meditation translates over to observing objects in our environment. We may simply see objects without being overly involved. As a result it reduces the amount of brain resources required to see an object in the environment. Because the brain doesn't need so much processing power to detect something it has left over resources to detect additional information. So through the practice of meditation a person develops an increased state of awareness.
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Reference:
Slagter, H. A., Lutz, A., Greischar, L. L., Francis,
A. D., Nieuwenhuis, S., Davis, J. M., & Davidson, R. J. (2007). Mental
training affects distribution of limited brain resources. PLoS Biology, 5(6), e138.