2×2 contingency tables showing the four possible combinations of action – effect information.

<p>Note: The upper table shows generic information from which <i>P</i> is calculated, where A, B, C and D refer to the frequencies of action – effect conjunctions. <i>ΔP</i> = A/(A+B) – C/(C+D). The lower tables show examples of three contingency conditions with a <i>ΔP</i> of −.5, 0 and +.5 respectively (left to right). P(O|A) refers to the conditional probability of the outcome given the presence of the action and P(O|noA) refers to the conditional probability of the outcome given the absence of the action.