How does television viewing affect behavior?

There are two major dangers to watching excessive TV. The first is that people who are sitting in front of a TV are not exercising, and lack of exercise and its complications are the leading health problem in the US. This is a behavioral issue, not a biological one.

The second is that people who are watching TV are having information and entertainment streamed into their heads without having to do any original or critical thinking on their own. This results in millions of people who simply accept what they hear without either considering the source or discussing it with anyone -- except to agree with what they just heard. This creates major problems as well. While psychological, it affects behavior such as relationships with other people, other nations, voting, ability to make decisions in ones best interest, and so forth.