A laboratory simulation of parental investment decisions: The role of future reproductive opportunities and quality of offspring in determining levels of parental investment

From the book : Evolutionary Psychology 4: 197-207.
Hagen’s Defection Hypothesis (2002) predicts that a mother’s age and the quality of her offspring are critical factors in determining her investment in her newborn.
We tested this hypothesis using hamster races in which 113 college student participants received a hamster (“offspring”) and 10 poker chips (“resources”) to “invest” into the hamster based on information about the quality of the hamster and about the possibility of future races.
Subjects invested the most in low quality offspring when they expected to run only one race and the least in low quality offspring when they expected more racing opportunities in the future.
Offspring quality affected investment differently depending on the presence or absence of future investment opportunities and the sex of the subject.
Overall, the results supported Hagen’s model of parental investment and also suggest that parental investment may be explained by conscious as well as unconscious decision-making.