The term zeitgeist is translated to the ‘spirit of the time’ which denotes the underlying dominant cultural, social and intellectual tendencies of a specific time period and in psychology how the prevailing social attitudes and contexts impact the behavior, theories, and discoveries of that time.
To illustrate, Freud’s theories on sexuality were postulated in a conservative Vienna when the time was so repressive with the prevailing morality. Freud positioned a lot of sexuality theory on repression because of these eras. Also, behaviorism was more popular in the America of the early 20th century when the fascination was on the objective and the quantifiable science dominantly and certainly. This is what the time was like.
These examples illustrate that psychological theories, like any other theories, do not and cannot come into existence in a vacuum, devoid of the historical and cultural context of the time. At times, an idea is accepted and acknowledged in one time period and during a different time period the idea is debunked and also revised entirely. This is also explained with the idea of ‘zeitgeist.’ Psychological theories which appear to be context free can be explained and understood by the influence of ‘zeitgeist.’