K03 – Birth Order and Human Behavior: Understanding an Elusive Relationship
For more than half a century, studies of birth order and human behavior have been mired in disagreement over the existence, magnitude, and specific nature of this relationship. In this talk I argue that much of the previous research in this field has been substantially impeded because birth order is an imperfect proxy for multiple within-family influences that shape personality development within families, but that are overlooked in most studies. Much of the previous disagreements in this field can also be can be attributed to other methodological problems, including a failure to consider individual differences and their sometimes complex interactions with birth order, as well as the role of the behavioral context. This talk presents the results of a novel research design aimed at overcoming these problems and involving 438,251 responses collected using Internet surveys. These results reveal extensive suppression of birth order effects, which in turn indicates that birth order appears to explains upwards of ten the variance in personality compared with what has previously been documented.