social psychology

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The branch of psychology that deals with the behavior of groups and the influence of social factors on the individual.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The interplay between the individual and society.
• noun The study of how people and groups interact.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the branch of psychology that studies persons and their relationships with others and with groups and with society as a whole