ABSTRACT
In teaching Sarah “if-then” we did not use preverbal tests to study the conceptual structure underlying “if—then” and the other logical connectives but used the preverbal period to build in a kind of experience which, if it were described with words, would require the use of “if—then” or some equivalent phrase. In a preliminary step, we gave her a series of choices between pieces of apple and banana; she chose apple 28 times in 66 trials, confirming, as we suspected, that she did not have a marked preference for either fruit. In the more important next step we arranged a contingency between the choice of apple and the receipt of chocolate. She preferred chocolate to both fruit and, with the contingency in effect, chose apple 26 times in 30 trials.
