The “nature versus nurture” debate is one which comes into play in discussions about a range of topics, from IQ and intellectual capabilities to personality and behavior. It’s a debate which has been largely prevalent in conversations around synesthesia, as well. Synesthesia is a neurological condition by which individuals can experience overlaps in their senses. This could include sensations like “hearing” colors, “smelling” sounds, or “tasting” words.


While there are those that believe synesthesia is a matter of genetics, there are others who believe it comes down to environmental and other external factors during the formative years of childhood. A new study is contributing to the debate after finding that synesthesia can be taught to some extent through training.


Led by a team of psychologists at the University of Sussex, the aim of the study was to determine whether or not it would be possible for adults without synesthesia to essentially “learn” to experience the sensations felt by those who do.


The psychologists developed a nine-week training program to assess the theory, observing 14 test subjects against a control group which didn’t participate in the training program. The study interestingly found that the test subjects developed synesthesia-level overlap in the senses in the form of letter-color associations. Many also began associating different letters with certain personality traits, describing some as boring, calm, etc. Participants even saw a jump in their IQ after the training, suggesting a fascinating link between synesthesia and heightened brain function.


Those who associate synesthesia with nurture reference influences like colored alphabet blocks and toys in childhood (

Those who associate synesthesia with nurture reference influences like colored alphabet blocks and toys in childhood (

The findings of the study can have various effects moving forward. For starters, the unanticipated link between synesthesia and a rise in cognitive function could play a major role in developing cognitive training tools based on synesthetic training that could benefit individuals with conditions like ADHD or dementia. While the extent to which any synesthesia-related increase in brain function could be considered long-term or permanent is not clear, the findings of the study nevertheless suggest a link worth exploring, even if its effects may presently seem transient.


Furthermore, while not entirely conclusive regarding the “nature versus nurture” debate as it pertains to synesthesia, the findings of this study absolutely contribute a considerable level of evidence to the conversation in support of synesthesia’s roots in nurture. This is true, even in light of the fact that participants of the study were observed to eventually lose the synesthetic abilities they acquired through training. In this regard, the study’s co-author, Dr. Nicolas Rothen, stated:


“It should be emphasized that we are not claiming to have trained non-synesthetes to become genuine synesthetes. When we retested our participants three months after training, they had largely lost the experience of seeing colors when thinking about the letters. But it does show that synesthesia is likely to have a major developmental component, starting for many people in childhood.”


Rothen’s final statement is particularly valid considering that those who argue that synesthesia is linked to environmental factors discuss these factors in infancy, a time at which the human brain is at its developmental prime and is particularly shaped by the influences surrounding it.


While the subjects of the study may have lost their synesthetic abilities over time, just their acquisition of these skills is indicative of the role nurture plays in synesthesia. In a way, it can be paralleled to language. While an infant’s brain easily absorbs language, learning a language in adulthood is a considerably different experience. Moreover, an adult is far more likely to forget a language learned in adulthood than one learned in infancy. In terms of synesthesia, if the condition is in fact based in nurture, whether the brain holds on to those abilities or loses them can certainly come down to factors like age and the cognitive stage at which synesthesia-promoting influences are introduced.


Where do you stand on the “nature versus nurture” debate when it comes to synesthesia? Share you thoughts below or tweet me @tamarahoumi