He claimed that, in a task involving certain "nonstandard" conditionals that are implied rather than directly stated in the instructions, subjects often adopt a strategy of devising a plausible alternative hypothesis and using the testing strategy that if a combination of events is at least possible under both hypotheses it tells you nothing, but if it is possible under one and not the other it supports the hypothesis that makes it possible and disproves the other.
Patterns of reply at Items 5 and 6, which involved evaluation of standard conditionals, were coded into the common patterns outlined by Langford (1992, in press-b), which are the following replies to examples of X and Y, Y without X, X without Y, neither X nor Y: "Supports, any reply except disproves, disproves,-"; "Supports, disproves, disproves, -"; and "Supports, -, -, -," where - is any response.
The dominant pattern of reaction to the simulated conjunctive interpretation presented in item 4 was "supports, disproves, disproves, disproves," whereas the predominant conjunctive-like reactions to the conditional evaluation task at Items 5 and 6 were, as in other studies, "supports, -, -, -," where - is any response.
When presented for evaluation at Items 1 and 3 these gave rise to the response patterns: "supports, tells you nothing, disproves, tells you nothing"; "supports, supports, disproves, supports"; "supports, tells you nothing, disproves, disproves"; "supports, supports, disproves, disproves.
Does this: (a) support my claim, (b) tell you nothing, (c) disprove my claim.