A causal schema refers to the way a person thinks about plausible causes in relation to a given effect. It provides him or her with the means of making causal attributions when the information provided is limited. The three causal schemata recognized by Kelley are
Multiple Sufficient Causes,
Multiple Necessary Causes, and
Causal Schema for Compensatory Causes (Kelley, 1973). Multiple Sufficient Causes: He or she may believe that either cause A or cause B suffices to produce a given effect (Kelley et al., 1980). For example, if an athlete fails a
drug test (effect), we reason that he or she may be attempting to cheat (cause A) or may have been tricked into taking a banned substance (cause B). Either cause sufficiently attributes to the effect (McLeod, 2010). Multiple Necessary Causes: Both A and B are necessary to produce a given effect (Kelley et al., 1980). For example, if an athlete wins a marathon (effect), we reason that he or she must be very fit (cause A), and highly motivated (cause B) (McLeod, 2010). Causal Schema for Compensatory Causes: The effect occurs if either A or B is maximally present, or if both A and B are moderately present. For example, success (effect) depends on high ability (cause A) or low task difficulty (cause B). Success will occur if either cause is highly present or if both are moderately present (Kelley 1973). ==Limitations==