Curt Richter
Curt Paul Richter was a biologist, psychobiologist and geneticist who made important contributions in the field of circadian rhythms. Notably, Richter identified the hypothalamus as a "biological pacemaker" involved in sleeping and wakefulness. In particular, this region suspected by Richter was later identified as the suprachiasmatic nucleus.
Richter's parents emigrated to the Unites States from Germany and settled in Denver, Colorado where he was born. He studied at the Harvard University and later under John Watson at Johns Hopkins University.
Richter induced need states in experimental animals by depriving them of substances essential to survival, or manipulating the hormone levels, and showed that these need states generate appetites, and behaviours precisely fitting the animal's need even if the animal had never before experienced the need; demonstrating genetic programming of behaviour. He also triggered other pre-programmed behaviours, such as nest building, by manipulating hormone levels.
