Brief Answer:
Rather a lot of ways.

Detailed Answer:
But the biggest and most general is this.....
All input goes into deep brain centers at the bottom of the brain.
To quote from the chapter "the anatomy of addiction" XXXXXXX JR Beveridge and XXXXXXX CS Roberts:
"THis phylogentically older brain is responsible for the organism avoiding things that are "disagreeable" and approaching those that are "agreeable".

These parts of the brain are involved with learning, and learned reactions. They integrate emotions (both positive and negative) and reactions and meanings. But, the deep brain structures of the amygdala and limbic system have particular distinguishing features from other learning. The learning is immediate, usually with an emotional component, not with much words/intellectual components AND it tends to block/forstall/impede rational thought or verbal thought. Simply put, pain and discomfort produce stereotypical reactions that impede the ability to have thought, free will, and communication.

Probably not what your teacher wanted, but it is the more important answer. The more usual answer is derivative from the one above and would be something like: pain and discomfort color perceptions and make people less inclined to talk, have a poor sense of well being, and to hamper communication. It tends to lead to depression.

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