Humans are a social species, we interact with other people – aided by language- and exchange information on daily basis. The effects of social isolation have been demonstrated and predicted to be very severe and “de-humanising” in many cases with a long list of adverse effects on cognitive abilities and emotional stability. The question often posed when considering this feature of mankind is whether it is an adaptation to the presence of others in our environment, a simple product of proximity; or it is a function developmentally wired into our genes and is ,thus, needed for proper growth and development. The latter also would imply the evolutionary advantage of cooperation and living in a group.
In a recent study, researchers tackled the question of whether we are genetically wired to be social, and they did so by finding one of the most controlled environments in human developmental studies, and chose the ideal subjects for most genetic questions. Twins in utero!
using ultrasound, Castiello et. al. , developed a kinematic profile of movement in twin fetuses. They’ve recorded 4-dimensional ultrasound videos of fetuses in weeks 14 and 18 of gestation, movements of the fetuses were observed and categorized. With this approach they can study the frequency of movements which are directed , intentionally, towards the other sibling; if said movements were observed to be statistically significant then it would suggest that there is a genetic component wired into our DNA which gears us to interact socially with others in our environment.
The reliance of human observation to categorize the types of motion is a limiting factor to the accuracy of this study, this effect was reduced by having more than one observer creating the kinematic profile of fetus motion, and subsequently test their data for consistency.
Results, interestingly the researchers have found not only that a significant portion of fetus motion in their twin-pairs were directed towards their sibling, a significant increase in said motion was observed from the first observation at 14-weeks and the second one at the 18-weeks, 29% increase! This observed increase is significant because normally spontaneous limb movement is observed to decrease with time due to neurological maturation and decrease of uterine space as a result of fetal growth; which suggest that motion directed towards the other twin was intentional and positively reinforced.
The intentional nature of movements directed towards the other twin is an important observation from this study; it suggests that we are , in fact, genetically wired to be social. To me this opens up many questions; genetically-speaking what is the difference between living in a herd as opposed to small family units? This question might seem silly at first, at least it does to me on second-reading, but anthropological studies suggest that man has spread through earth as a nomad, migrations occurred frequently, but it is often suggested that a small portion of the population carried out said migrations. i.e. not an entire ‘herd’ of our early ancestors migrated, rather a smaller group. I can’t help but wonder if this is an advantageous adaptation or a mere coincidence; sadly I’m not well read in anthropology, perhaps I must hit the books again. sigh.
If you found this interesting, or you have any input feel free to contribute, I’d love to hear more on this.
Umberto Castiello, Cristina Becchio, Stefania Zoia, Cristian Nelini, Luisa Sartori, Laura Blason, Giuseppina D’Ottavio, Maria Bulgheroni, & Vittorio Gallese (2010). Wired to be Social: the ontogeny of human interaction. PLoS ONE