People do not live in isolation (at least most don't), but come in contact or interact with others on a regular basis. As a result, people are influenced by other people. As the PsychGuy's advisor states, "We humans are social species" (Forsyth, 1995, p.2), and as a social species, we are influenced by other people at a variety of levels. Social Psychology seeks to understand these interactions, and can thus be defined as the scientific investigation of how the thoughts, feelings, and behaviors of people are influenced by the presence of others. It is important to note that the presence of others does not have to be real; people only have to perceive that others are there. The underlying premise of Social Psychology is that people are not merely their personalities, not merely a product of their environments, but are who they are as a result of the interaction of the environment and personality. The following formula was presented by Kurt Lewin and expresses the interaction between personality and the environment: B=f(P, E): in this formula, B=behavior, P=person, E=environment, and f=the function of.