Is bigger always better? Well, when it comes to something like the human brain, one would certainly think so, especially in an age where human-intelligence has been thoroughly showcased through consistent technological advances. So it may come as a bit of a surprise that despite the fact that we are known to be the ‘most advanced civilisation’, our ancestors’ brains were actually bigger than ours are now. However, what does that actually mean in the greater scheme of things and why are our brains smaller 3000 years later?

Despite the fact that humans have advanced significantly over the last 300,000 years, since the first homo sapiens emerged in Africa, cranial studies show that our brain size has decreased notably in the last 100 generations. Jeremy DeSilva, who is an anthropologist at Dartmouth College in the US, is working on a study with colleagues that look to analyse the cranial size deterioration and determine what could have contributed to this. According to the study, the average human brain has shrunk by approximately the size of four ping pong balls. Both the loss of brain volume as well as when in the human timeline it occurred comes as a surprise to DeSilva and his team as “this is much more recent than we anticipated. We were expecting something closer to 30,000 years ago.”

The reason why this time line is so surprising can be attributed to the fact that humans made some of their key civilisation advancements in the period that largely shaped the way we do things today. It is estimated that agriculture became a part of the way we cultivate food between five and ten thousand years ago. With the establishment of more set agricultural methods of subsistence, it was only natural that settlements would follow and be set up in proximity to the agricultural sites. In addition to agriculture, there is also evidence to show that writing as a means of recording and communicating appeared at a similar time. Both of these showcase some of the biggest advancements to date that were made as a civilisation and evidenced complex thought processes. The study plays around with the notion that quantity may not equal quality, as there are a number of species with physically bigger brains than ours, but do not have the same cognitive capacity as humans do

There are a few factors that could have an impact on the physical size of a brain, including of course – body size. However, as noted by DeSilva and his team in their study, the decrease in human body size is not enough to provide sufficient rationale behind the subsequent brain shrinkage too. The study, which was quite a lengthy one – looked into other avenues to understand why brain sizes in species change and what contributes to this. The team turned to ants and birds and a number of mammals in between. As it transpires, humans are born with more neurons then actually required, and overtime as we age, this number decreases. The study also looked into what species’ utilise their brains for i.e. thinking versus survival, or both. Ultimately, as another researcher, Simon Cox notes, “the brain remains ‘phenomenally complex’ and it is difficult to know exactly what difference the structural make-up of a particular brain will have on a person’s intelligence.” Size isn’t always everything.