When1: 1902
When2: 1927
Who: Ivan Petrovich Pavlov [Pavlov, Ivan Petrovich]
What: physiologist
Where: St. Petersburg, Russia
works\ Work of the Digestive Glands [1902]; Conditional Reflexes [1927]
Detail: He lived 1849 to 1936 and studied neurosis, peripheral nerves, digestion physiology, classical conditioning, and reflexes.
Contradictory stimuli can disturb balance between nervous-system excitatory and inhibitory processes, and personality affects whether neurosis develops.
Vagus nerve controls blood pressure, and four nerves control and vary heartbeat rhythm and intensity. Depending on saliva and food, tasting food {sham feeding} can release gastric juice, which has enzymes {enterokinase}.
Dogs associate neutral stimulus with reflex. Conditional reflex forms more easily if unconditional stimulus, such as food, follows conditional stimulus, such as bell, than if they are simultaneous or if conditional stimulus follows unconditional stimulus. Conditional reflex forms more easily if conditional stimulus is nearer in time to unconditional stimulus. Conditional stimulus that starts just before unconditional stimulus is as effective as conditional stimulus that started long before unconditional stimulus and lasted until just before. More intense conditional and unconditional stimuli cause greater conditioned responses. Training conditional stimulus allows testing similar conditional stimuli to investigate animal sense discriminations. External inhibition, internal inhibition, new environments, and new stimuli affect conditioning. If conditional and unconditional stimuli no longer pair, conditioned reflex gradually decreases. Maintaining conditioned reflex requires regular reinforcement. Conditioned reflex is similar to other reflexes. Conditional reflex formation is adaptation whereby animal can survive better in changing environment.
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Date Modified: 2022.0224