Over the years, there has been a great deal of conjecture about how our siblings influence our personalities. For instance, studies have suggested that second born children are often more creative and rebellious as they have to fight for attention against their older siblings who have gained approval for doing the regular things kids do.
Alas, many of these studies have based their findings on self reported data, which of course raises the specter of subjectivity and various forms of bias. A recent study attempted to overcome some of these issues as it explored one particular part of the equation - whether our siblings affect our competitive nature, and in particular whether having an older sister makes men less competitive.
To try and overcome the subjectiveness of past studies, this research asked participants to complete a simple mental test. Successful completion would earn a reward, with more points equalling more rewards. A second group performed their own tasks in a tournament format, so they were directly competing against other participants. At a later point in the study, each participant was given the chance to choose the format they liked most.
When given the choice, it emerged that male participants overwhelmingly opted for the tournament approach, with roughly three times as many men as women choosing this method. When the men had an elder sister, however, this changed significantly, with roughly half as many men choosing the tournament method. This difference was then replicated in a second experiment, with again, the men with an older sister proving to be less competitive than the other men in the study.
The authors found that these findings were consistent even after they had taken account of other possible factors such as over-confidence or risk aversion. When participants were given the opportunity to change from a piece rate method to a tournament based approach, it was designed to reveal whether the participant was risk averse or excessively confident.
So why are men with older sisters so much less competitive? The authors propose a number of possible explanations. The first suggests that it is all to do with so called role assimilation, which is where people absorb some of the stereotypical traits in their siblings. Another possible explanation is that children born later are less competitive than their older siblings, because older siblings face more pressure to meet the expectations of their parents, and then must defend themselves from their new, younger rivals.
Interestingly, whilst having an older sister seemed to reduce the competitive urges of the male participants, this melted away when the man also had either an older brother or a younger sister. The authors suggest this is because the additional siblings counteract the influences and effects of birth order.
Also of note is that women with an older sister were found to be more competitive than normal, resulting in them tending to act more like the average man than an average woman in their love of competition. The authors suggest this is because an older sister is likely to have similar interests and requirements, therefore increasing female competition within the family.
I’d love to hear your own experiences on this issue. Do you have an older sister, and does this influence how competitive you are?