Is synaesthesia a dominantly female trait?

Area of Science:

• Neuroscience
• Psychology
• Genetics

Background:

• Synaesthesia is a neurological condition characterized by secondary perceptions.
• Previous studies suggested a significant prevalence of synaesthesia in females, potentially up to six times higher than in males.
• This observed female bias has been questioned as a potential recruitment artifact due to higher self-referral rates among women.

Purpose of the Study:

• To investigate the prevalence of synaesthesia and determine if there is a significant gender bias.
• To re-evaluate previous findings of a female bias in synaesthesia prevalence.
• To present the largest published prevalence study on grapheme-color synaesthesia.

Main Methods:

• Re-analysis of previous reports on synaesthesia prevalence to identify methodological issues, particularly self-referral bias.
• Conducting the largest published prevalence study to date on grapheme-color synaesthesia.
• Statistical analysis to detect gender bias with sufficient statistical power.

Main Results:

• Re-analysis of prior studies indicated that apparent female biases in synaesthesia prevalence likely resulted from self-referral or other methodological limitations.
• The largest published prevalence study on grapheme-color synaesthesia reported a prevalence of 1.39% in the general population.
• The study found no statistically significant gender bias in the prevalence of grapheme-color synaesthesia, even with adequate power to detect such a difference.

Conclusions:

• The extreme female bias previously reported in synaesthesia prevalence is likely an artifact of study recruitment methods.
• Synaesthesia, specifically grapheme-color synaesthesia, appears to have a more equitable prevalence between males and females than previously suggested.
• This research provides robust evidence against a substantial gender disparity in synaesthesia, emphasizing the need for methodologically sound prevalence studies.