The prevalence and cognitive profile of sequence-space synaesthesia.
Level 4 - case-series / case-control
Cross-sectional survey and case-control behavioral validation study
PubMed 29673773 · doi:10.1016/j.concog.2018.03.012
What was done
The authors estimated the prevalence of sequence-space synaesthesia using a recently developed spatial consistency test and a novel questionnaire administered to naive participant samples across two studies. They evaluated the diagnostic validity by testing identified individuals on laboratory tasks, including a spatial Stroop-like interference task, detection of low-visibility Gabor stimuli, self-reported visual imagery, and memory for public events.
What was found
The estimated prevalence of sequence-space synaesthesia was 8.1% in Study 1 and 12.8% in Study 2. Classified synaesthetes demonstrated a spatial Stroop-like interference response, superior detection of low-visibility Gabor stimuli, higher self-reported use of visual imagery, and better memory for specific types of public events compared to non-synaesthetes. The abstract reports no sample sizes, effect sizes, or p-values.
Why it matters
This study provides standardized behavioral and questionnaire-based validation for diagnosing sequence-space synaesthesia. It demonstrates that the condition is relatively common and linked to broader traits of enhanced visual imagery and low-level visual perception.
Limits
The abstract does not report participant counts, demographic characteristics, effect sizes, or confidence intervals. Relying partly on self-report questionnaires introduces potential subjective bias, and the observational design cannot establish whether enhanced perceptual abilities cause or result from sequence-space synaesthesia.