10.18710/DQJS4AFolstad, IvarIvarFolstadUiT The Arctic University of NorwayReplication Data for: Do mothers also "manipulate" grandparental care?DataverseNO2018Medicine, Health and Life SciencesEvolutionary PsychologyEvolutionary BiologyPaternity UncertaintyGrandparental InvestmentsResemblance DescriptionManipulationMotherFatherManipulative Mother HypothesisFolstad, IvarIvarFolstadUiT The Arctic University of NorwayUiT The Arctic University of NorwayUiT The Arctic University of NorwayUiT The Arctic University of Norway2018-03-142023-11-0110.7717/peerj.59241591134331111091162018282162010051text/plainapplication/pdfapplication/pdftext/tab-separated-valuestext/plaintext/tab-separated-valuestext/plain2.4CC0 1.0Data on resemblance descriptions within families from two questionnaires. One is related to grandparents experience of resemblance descriptions among their children and one about parents resemblance descriptions of their children and their parents. Data are collected in Northern Norway in 2015 and 2016.</p>Abstract The ultimate hypotheses based on paternity uncertainty have proven robust in predicting the higher investment in grandchildren observed among maternal grandparents compared to that of paternal grandparents. Yet, the proximate mechanisms for generating such preferred biases in grandparental investment remains unclear. Here we follow two different approaches for better understanding the mechanisms leading to the observed bias in grandparental investments: (i) is there a larger emphasis on resemblance descriptions (between grandparent and grandchildren) among daughters than among sons, and (ii) do mothers really believe that their offspring more resemble their parents than fathers do? From questioning grandparents, we find that daughters more often and more intensely than sons express opinions about resemblance between their parents and their grandchildren. Additionally, daughters also believe that their children more resemble their grandmother than sons do. The latter is however not the case for believes about children’s resemblance to grandfathers. In sum, our results suggest that even in a population of Norwegians, strongly influenced by ideas concerning gender equality, there exist a sexual bias among parents in opinions and descriptions about grandparent-grandchild resemblance. This resemblance bias, which echo that of mothers biasing resemblance descriptions of newborns to putative fathers, does not seem to represent a conscious manipulation. Yet, it could be instrumental for influencing grandparental investments. We believe that a “manipulative mother hypothesis” might also parsimoniously account for many of the results relating to biased alloparenting hitherto not entirely explained by “the paternity uncertainty hypothesis”.