exaptation
Compiled with AI assistance and selectively reviewed. Please consult the cited passages; the books remain the authoritative source. About this companion
Editorial synthesis · provisional
Definition
Exaptation is the co-option of an existing trait for a function different from the one for which it evolved. The books extend this pattern to technologies acquiring unplanned uses and to cognitive capacities or neural circuits recruited for new tasks. The later function is not treated as the cause of the earlier origin; cognitive applications retain their source-local evidential qualifications.
Explanation
AB and RB1 illustrate biological exaptation with feathers, probably first useful for warmth or display and later recruited for flight. RB1 attributes the concept to Gould and Vrba and connects evolutionary tinkering with Jacob. Its warning against selection for a merely future utility preserves the distinction between origin and subsequent function; the quoted formulation is Jacob in the author's translation, not a quotation attributed to Gould.
AB extends the term to later uses of the laser. RB1 develops technological and everyday repurposing through medicines and objects used otherwise than intended. Its Viagra discussion explicitly leaves possible Alzheimer's applications unproven. Adjacent examples of accidental discovery illustrate serendipity, which should not make every accident an exaptation without an existing feature acquiring another role.
RB2 calls the recruitment of physical-action circuits for abstract cognition neural reuse or exaptation, presenting grammatical aspect through Lakoff and Narayanan's account over evolutionary and developmental time. RB3 suggests that a general capacity for recursion may have been exapted for language. These cognitive applications are distinct from technological reuse and preserve the tentative language of their local arguments rather than establishing a single demonstrated neural history.
Scope and attribution
AB and RB1 support biological and technological uses; RB2 supports neural reuse; RB3 supports biological mention and a tentative cognitive-linguistic application. PB receives no positive treatment. Neural reuse is a local variant, not a universal alias for exaptation.
AB — The Actual Book
Feathers illustrate old structures acquiring new functions, making future uses difficult to foresee. The laser's later communications and surgical uses extend the term to technology.
Occurrence locators: 48, 51, 54, 97; Notes: 239.
RB1 — The Real Book, Volume I: The Possible Is Real
Gould/Vrba's biological co-option is developed through feathers and Jacob's tinkering. Human repurposing extends the pattern to drugs and objects, while the Alzheimer's possibility remains clinically unproven and accidental discovery is discussed separately.
Occurrence locators: 157, 173, 174, 178, 179, 182, 183, 185, 188, 199, 228, 245; Notes: 183.
RB2 — The Real Book, Volume II: Becoming Is Being
Neural reuse names the suggested recruitment of physical-action circuitry for abstract cognition. Grammatical aspect is the focal example from Lakoff and Narayanan, with evolutionary and developmental timescales both mentioned.
Occurrence locators: 101, 102, 103, 272.
RB3 — The Real Book, Volume III: Murmurations
Exaptation appears among biological novelties. A separate cognitive application suggests that recursion may have arisen in other tasks before being recruited for language; the modal qualification is retained.
Occurrence locators: 73, 74, 82.
Background used in the editorial explanation
Domain-specific mechanisms and wider analogies remain distinguished. Original definitions retain their scope; local cross-references do not rewrite them. Named theories and mechanisms are distinguished from neighboring background, homonyms and the author’s own synthesis. Reproduced AI passages retain their separate voice.