embryonic stage

in human prenatal development, the roughly 6-week period in which the three-layered embryo (gastrula) develops. The embryonic stage follows the 2-week germinal stage and precedes the fetal stage, which begins in the 3rd month of pregnancy. The term is, however, sometimes used to refer to the full first 8 weeks of pregnancy.

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

November 15th 2024

tandem reinforcement

a schedule of reinforcement for a single response in which two or more schedule requirements must be completed in sequence before reinforcement occurs and no stimulus change accompanies completion of each requirement. For example, in a tandem, fixed-interval 1-minute, fixed-ratio 10 schedule, the first response after 1 minute would initiate the fixed-ratio schedule, and the 10th response would result in reinforcement. Also called tandem schedule of reinforcement. Compare chained schedule.