On Exploratory vs. Performatory Manipulation and the Experiments being Performed to Distinguish Them
J. J. Gibson, Cornell University
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The difference between exploratory and performatory manipulation might be said to be one of attention, but I rather say it is a difference of intention. The purpose is information in one case and achievement in the other.
Held’s experiments fail to distinguish between exploratory and performatory action (Cf. “Useful Dimensions”). He only distinguishes “active movements” from “passive movement”. What he ought to say is that only intended movements cause adaptation to the prism situations, not unintended movements of the hands. And I would add that either the intention to explore or to perform would be sufficient to yield adaptation. (Exploratory eye-movements with head movements are never performatory responses, but they are probably sufficient for phenomenal adaptation to spectacles, as Kohler and I conclude. Note thatunintended eye movements cause illusory motions of the world).
The stimulus information obtained from exploratory activity of the hands may be quite different from the stimulus feedback from performatory activity of the hands. The first is a selection from an inexhaustible supply; the second is in selective. How can we further elaborate and test these hypotheses?