What is "echopraxia"

"meaningless imitation of the movements of others," 1902, from Greek ekho (see echo (n.)) + praxis "action" (see praxis).

n. The involuntary repetition or imitation of the observed movements of another.

Echopraxia (also known as echokinesis) is the involuntary repetition or imitation of another person's actions. Similar to echolalia, the involuntary repetition of sounds and language, it is one of the echophenomena ("automatic imitative actions without explicit awareness"). It has long been recognized as a core feature of Tourette syndrome, and is considered a complex tic, but it also occurs in autism spectrum disorders, schizophrenia and catatonia, aphasia, and disorders involving the startle reflex such as Latah. Echopraxia has also been observed in individuals with frontal lobe damage, epilepsy, dementia and autoimmune disorders; the causes of and the link between echopraxia and these disorders is undetermined.

The etymology of the term is from Ancient Greek: "ἠχώ (ēkhō) from ἠχή (ēkhē "sound") and "πρᾶξις (praksis, "action, activity, practice)".

Echopraxia is a hard science fiction novel by Peter Watts. It is a " sidequel" to his 2006 novel Blindsight. It follows the story of a biologist who gets caught up in a voyage into the heart of the solar system among members of a transcendentalist monastic order and allies (including a vampire escaped from a research facility and her cadre of zombified soldiers) to investigate a mysterious signal seemingly coming from the mission sent to initiate first contact in Watts' previous novel.