Evidence for an equality heuristic in social decision making

Subjects read a story in which five business partners needed to allocate the profits and expenses of the partnership in a fair and reasonable manner. Each of the partners worked independently and produced different gross incomes between $140 and $285. The gross incomes were to be divided into expenses and profits. Subjects were asked to fill in fair allocations in an accounting ledger. Three factors were manipulated: the target of the allocation task (either the expenses or the profits), the causal attributions for the differences in gross incomes (internal, external, or both), and whether the subjects were asked to fill in both columns (expenses and profits) or just one.

The results supported the hypothesis that the subjects heuristically used equality to make their allocations. Over 70% of the subjects allocated at least one column equally (although the frequency of equality use varied as a function of both the target of the allocation and the attribution given). Subjects allocated the target columns equally more often than non-target columns, even though equality for one column implied inequality for the other. The use of equality was also sensitive to the attribution given for the performance differences. Differences due to external factors, i.e., the number of people showing up at the market, produced the most equal allocations of profits (with unequal expenses) while the internal attribution produced the highest proportion of equal expense allocations (with unequal profits).