Hertwig,R.
Davis,J.N.
Sulloway,F.J.

The equity heuristic is a decision rule specifying that parents should attempt to subdivide resources more or less equally among their children. This investment rule coincides with the prescription from optimality models in economics and biology in cases in which expected future return for each offspring is equal. In this article, the authors present a counterintuitive implication of the equity heuristic: Whereas an equity motive produces a fair distribution at any given point in time, it yields a cumulative distribution of investments that is unequal. The authors test this analytical observation against evidence reported in studies exploring parental investment and show how the equity heuristic can provide an explanation of why the literature reports a diversity of birth order effects with respect to parental resource allocation.

Hertwig, R., Davis, J. N., & Sulloway, F. J. (2002). Parental investment: How an equity motive can produce inequality. Psychological Bulletin, 128, 728-745.(Reprinted in Verhaltenswissenschaftliche Grundlagen in ökonomischen Systemen, pp. 96-137, by D. K. Tscheulin, & H. Schüpbach, Eds., 2009, Berlin: Berliner Wissenschafts-Verlag)(Reprinted in Heuristics: The foundations of adaptive behavior, pp. 670-694, by G. Gigerenzer, R. Hertwig, & T. Pachur, Eds., 2011, New York: Oxford University Press) (Full text)

Publication year	2002
Document type:	Article
Publication status:	Published
External URL:	http://library.mpib-berlin.mpg.de/ft/rh/RH_Parental_2002.pdf View
Categories:	Investment
Keywords:	allociationequity heuristicheuristicsparental investment