1. A basic compelling urge. 2. In psychology, classified as either innate (e.g., hunger) or learned (e.g., hoarding) and appetitive (e.g., hunger, thirst, sex) or aversive (e.g., fear, pain, grief). See also motive, motivation.
acquired d.'s secondary d.'s
exploratory d. the d. typical of toddlers and some animals to investigate the unfamiliar or unknown.
learned d. motive (1)
meiotic d. differential fitness in males and females.
physiological d.'s those d.'s such as hunger and thirst which stem from the biological needs of an organism.primary d.'s;
primary d.'s physiological d.'s
secondary d.'s those d.'s not directly related to biological needs; a secondary d. can be learned as an offshoot of a primary d., in which case it is often referred to as a motive.acquired d.'s;
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