Education and travel both increase the scope for more complex, novel stimulus to the brain. In turn the complexity of the brain EEG signal increases in complexity with both higher levels of travel and education.
In a previous blog post I showed the systematic relationship between stimulus consumption and complexity of the EEG signal . What are the key stimulus drivers of EEG complexity?
Education and EEG Complexity
Education is probably the first stimulus type that most of us would think of – it increases the scope and complexity of knowledge we would otherwise typically encounter. Studies have shown that education is associated with increases in grey matter volume and improved cognitive performance ([2, 3] also see related post College in the Brain) . However, how does this reflect in the EEG?
Our study  across 450 adults spanning education levels from no education (illiterate) to people with college level education in India shows that average EEG complexity increases quite systematically with years of education with a good linear fit. Of course, years of education is only a gross measure of stimulus complexity since quality of education can vary and people can have very different levels of rigor in their education depending on the school. Those who do not complete high school are typically low-income populations who also do not have access to the better private schools. Those who go to college therefore tend to come from higher income families who can afford better private schools. This may explain why those who do complete college – shown on the graph as 16 years of education tend to have complexity values higher than the overall linear fit.
Travel on your brain
Another key stimulus enhancing factor is travel. This has a very different kind of stimulus profile relative to education. Unlike education which is the formal study of the symbolic systems of literacy and numeracy and their didactic applications, travel is a fully interactive sensory experience that involves navigating new physical environments and potentially new languages and cultures and requires planning. There is much research on increased neurogenesis and changes in gene expression induced by placing rodents into more complex novel environments [4.5]. Travel is perhaps the closest natural stimulus equivalent in humans.
In this study individuals travel footprint was classified based on the distance traveled away from home in the past year. The coding used was as follows
- – Never left home town
- – Traveled within a 100 km radius of hometown
- – Traveled beyond a 100 km radius but within state (in India each State has a different official language)
- – Traveled beyond a 100 km radius including out of State but within the Country
- – Traveled outside of the country (almost always >100 km)
This is of course only an ordinal coding where 5 does not explicitly mean 1 more than 4 but rather represents the next most complex category of travel.
Not surprisingly then, complexity was higher in each successive category. Thus more travel is associated with greater complexity.
Parsing out the effects of Travel and Education
Those with more education are also likely to travel more. In turn both are linked to income. It is thus important to understand if each has a distinct effect or is one driving the effect while the other is just a correlate along for the ride. It is of course, immensely difficult to have all the controls in living breathing human systems the way you can orchestrate in lab animals. However, the data provides some strong clues. Both high and low education groups showed the same increases in complexity with travel. Similarly both high and low income groups showed increases in complexity with travel strongly suggesting that travel has its own effect.
What does an increase in complexity mean?
This metric of complexity is relatively new and represents the diversity of complex waveform shapes in the EEG on the order of 100-300 ms which is the time scale of human perception. We don’t yet know a lot about its implications for cognition or other aspects of mental functioning. However, some initial studies have shown that it does a much better job predicting outcomes on a pattern recognition task than other related measures such as Sample Entropy and Lempel-Ziv Complexity. This means that this effects of travel and education reflects something cognitively meaningful – which is not surprising since both travel and education are associated with cognitive gains.
 Parameshwaran D et al., The Impact of Socioeconomic and Stimulus Inequality on Human Brain Physiology, Nature Scientific Reports, April 2021
 Boller B et al., Relationships between years of education, regional grey matter volumes, and working memory-related brain activity in healthy older adults. Brain Imaging Behav. 2016.
 Cox SR et al. Associations between education and brain structure at age 73 years, adjusted for age 11 IQ. Neurology. 2016;87(17):1820-6
 Rampon C et al. Effects of environmental enrichment on gene expression in the brain. Proc Natl Acad Sci U S A. 2000;97(23):12880-4.
 Bayat M et al., Enriched environment improves synaptic plasticity and cognitive deficiency in chronic cerebral hypoperfused rats. Brain Res Bull. 2015;119(Pt A):34-40.