all-or-none law

the principle that the amplitude of the action potential in a neuron is independent of the magnitude of the stimulus. Thus, all stimuli above the neuron’s threshold trigger action potentials of identical magnitude (although they may vary in frequency); stimuli below this threshold may produce local graded potentials but no propagated impulses. Also called all-or-none principle.

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Psychology term of the day

February 2nd 2025

premoral stage

1. in Jean Piaget’s theory of moral development, the stage at which young children (under the age of 5) are unaware of rules as cooperative agreements; that is, they are unable to distinguish right from wrong. Compare autonomous stage; heteronomous stage.

2. the stage that precedes the preconventional level in Kohlberg’s theory of moral development and corresponds to infancy (birth to roughly 18 months).