Subsequent generations of psychoanalysts questioned Freud's work on the libido. Several stressed the point that Freud had overemphasized biological development and underemphasized the impact of cultural and social factors on sexual attitudes and practices. Carl Jung, a Swiss psychiatrist and psychoanalyst, broke with Freud's view of the libido by rejecting the idea that sexual experiences during infancy are the principal determinants of adult emotional problems. Jung developed an alternative theory of the libido that viewed the will to live rather than sexual desire as the strongest drive. Jung emphasized the distinction between introverted and extroverted personality types.
Extroverts tend to feel comfortable in social situations and tend to be gregarious.
Introversion labels the opposite characteristics, including directing attention inward toward internal processes and thoughts. Introverts tend to be self-reliant, introspective, thoughtful and comparatively uncomfortable in large social groups. He did not believe individuals were strictly introverted or extroverted, but tended to mix these qualities in varying amounts. How sexual motivations are structured, and through which acts sexual drives are fulfilled, as well as whether certain behaviors are labeled and avoided as inappropriate, are determined primarily by these social influences.