For years cognitive psychologists have used visual illusions as crucial experiments in testing theories of perception, but the fundamental concepts employed in the descriptions of what we see, like "depth ambiguity" in the famous Necker cube drawing, have rarely received critical attention. The concept of ambiguity has been investigated since Aristotle's Topics. In recent linguistics and logic, ambiguity has been contrasted with semantical non-specificity--for example, the multiple meanings of 'bank' contrasted with the sex-non-specific sense of 'neighbor' (male, female, hermaphroditic and angelic neighbors are all neighbors in the same sense of 'neighbor').
J.R. Ross and Noam Chomsky suggested a test for ambiguity. The compound sentence I don't like John's cooking any more than Bill's is ambiguous because it can mean: (a) I don't like the fact that John cooks any more than I like the fact that Bill cooks, (b) I don't like the quality of John's cooking any more than I like the quality of Bill's cooking, or (c) (the cannibalistic sense) I don't like John's being cooked any more than I like Bill's being cooked. Importantly, the sentence cannot mean any of the crossed interpretations, such as: I don't like the quality of John's cooking any more than I like the fact that Bill cooks. Ambiguity does not permit crossed interpretations in compound sentences with a common but deleted element like 'Bill's cooking.'
In considering the perception of drawings and figures, Pomona's Professor Jay Atlas has created a visual analogue of the Ross-Chomsky test for ambiguous sentences. "If you can see the compound Necker Cube drawing in the crossed visual interpretation, 'one inward, one outward,' you know that the Necker Cube drawing cannot be depth ambiguous, contrary to what you have been taught in your psychology classes," Atlas says. "It is non-specific between the visual interpretations. The distinction between ambiguity and non-specificity makes a difference in the construction of linguistic and perceptual theories."
For another exercise in cognitive science, see Alumni Puzzler
