The Synesthesia Twin Project
In this project we investigate synesthesia and its links to changed sensory processing, better memory, and creativity. We also explore its connections to mental health conditions such as autism spectrum condition.
What is synesthesia?
Do you automatically link letters, numbers, or weekdays with specific colors? Or do the months of the year together form a particular shape, for instance when you are planning your next holiday? Then you might belong to the roughly four percent of the population that experiences synesthesia. From an early age, people with synesthesia form connections between different concepts, such as between numbers and colors. Although these connections can vary early on, they tend to become more stable with age. For instance, the color experience of a number can change in childhood – but by adulthood, the same number will consistently and automatically lead to the same specific color experience.
Synesthesia and autism
Synesthesia is not a disorder – in contrast it seems to be correlated with advantages such as better memory and increased creativity. On the other hand, synesthesia seems to be more common in people with certain mental health conditions, such as autism. Like many people with autism, synesthetes have on average an increased attention to details and increased sensory sensitivity.
What we investigate
We are interested in the shared characteristics of synesthesia and autism, and the potentially partly shared way they develop. In this project, we use brain imaging, eye tracking, cognitive testing, and other techniques, in order to investigate the similarities and differences between the two conditions in the way sensory information is processed and integrated, and to what extent the underlying brain mechanisms are the same. In addition, we study memory, creativity and other strengths in association with both conditions.
We investigate these questions in twin pairs, where one twin has synesthesia, or a diagnosis of autism, and the other twin does not. This helps us to determine the influence of environmental and genetic factors linked to each condition, and how they are associated. The twins are primarily recruited from other twin studies, namely Roots of Autism and ADHD Twin Study in Sweden, and Child and Adolescent Twin Study in Sweden.
Besides autism, some other conditions are also indicated to be linked to synesthesia, including obsessive-compulsive disorder and anxiety disorders. Therefore, we also investigate whether synesthesia is linked to a wider set of psychological traits, linked to these and other conditions.
The project consists of two parts. The first part is an online study assessing synesthesia and neuropsychiatric traits, which takes one to two hours. The second part is a one-day assessment at Karolinska Institute Center for Neurodevelopmental Disorders (KIND). The day includes a series of cognitive tests, an interview, and a one-hour MRI session at Stockholm University Brain Imaging Center (SUBIC). It is possible to participate in the first part only.