The Amygdala Bypass System

Explanations > How the Brain Works > The Amygdala Bypass System

Six steps to unthinking response | So what?

When we say 'I didn't think, I just reacted' we may be exactly right. A little thing called the Amygdala that controls our fear responses can stop us from thinking.

Six steps to unthinking response

1. Sensory data fed to thalamus

All sensory data (except, curiously, for the sense of smell) is sent by the body first to the Thalamus, which acts like a switchboard, sending it to the relevant part of the brain.

2. Data sent to amygdala

The thalamus sends the data both to the relevant part of the cortex and also to a small part of the mid-brain called the amygdala.

3. Data also sent to cortex

When the information is sent to the cortex, we, of course, think about it. The problem is, that sometimes there is no time to think -- in fact too much thinking can sometimes leave you dead.

4. Amygdala does quick threat assessment

The senses are compared in the amydala with our stored fear responses. If any of these are triggered, then the amygdala has to act quickly.

5. Amygdala blocks 'slow' thinking

If the fear response is triggered, then the amygdala floods the cortex with chemicals to stop it taking over.

6. Unthinking response

The result is that we act without conscious thought. We jump out of the way of a falling branch or dive into the river to save a child.

So what?

You can get people to act by giving them a sudden and deep shock. Sometimes this shock treatment that leads to unthinking responses can be useful in the way that it causes the person to reflect afterwards.

See also

Carter, Rita (2000), Mapping the Mind, University of California Press