hydraulic model

any physiological or psychological model based on the analogy of fluid flowing through a system under pressure, such that pressure may build up in the system and seek release. Sigmund Freud’s model of the libido as an energy that can build pressure and seek release (catharsis) is a notable example. A more literal use of the hydraulic model was the erroneous concept of the nervous system introduced in the early 17th century by René Descartes, who believed that nerves were tubes through which animal spirits flowed from the brain to the muscles. According to this model, habits were formed when repeated use of the nerve tubes caused them to become distended and blocked.

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Psychology term of the day

January 26th 2025

congenital oculomotor apraxia

a condition, present at birth, in which a child is unable to fixate objects normally (see oculomotor apraxia). It is characterized by the absence of saccades and smooth-pursuit eye movements in the horizontal plane, but vertical eye movements are preserved: Children with this condition are often mistakenly thought to be blind. Between the ages of 4 and 6 months, they develop thrusting, horizontal head movements, sometimes blinking prominently or rubbing their eyelids when they attempt to change fixation. The cause of congenital oculomotor apraxia is unknown, but there is usually an improvement with age.