Parental supply and offspring demand amongst Karo Batak mothers and children.

The resolution of parent-offspring conflict (POC) might sway in favour of the offspring if the parent relies on offspring-supplied information about need. Here, three hypotheses from a resolution model of POC were tested using data on sickness histories and mother-infant interactions from 24 Karo Batak women and their young children from two rural villages in North Sumatra, Indonesia. First, as predicted, offspring with greater need (measured as age and propensity to illness) tended to fuss more often. Second, as expected, observed fussiness predicted the number of suckling occurrences observed during sampling periods. Third, contrary to the prediction, the duration of fussing observed after breast-feeding occurrences was longer than the duration of the breast-feeding occurrences themselves. Parental decisions were made based on offspring-supplied information about need, but offspring failed to garner resources in excess of the parental optimum. This suggests that a POC interpretation is unnecessary to account for these results.