People with exceptional short-term memory are strong systemisers: A large online study

Background: The cognitive basis of exceptional memory needs to be better understood. Strong ‘systemising’, defined as the drive to analyse and construct rule-based systems, has been implicated in exceptional skills in autistic people, but the role of systemising in exceptional memory remains unknown. Here, in the largest study to date, we test whether exceptional short-term memory (STM) is associated with an enhanced drive to systemise, and whether exceptional STM is associated with a cognitive or ‘brain type’ of greater systemising relative to empathising. Method: Volunteers (n =2,256, ages 16–60) completed 3 STM tasks: digit span (numerical short-term memory), spatial span (visuospatial memory), and paired associates (visual-associative memory). Exceptional memory was defined as scoring 3 standard deviations above the mean on a STM task, while average memory was defined as scoring within 1 SD. Systemising, autistic traits, and empathy were measured using 10-item versions of the Systemising Quotient (SQ-10), the Autism-Spectrum Quotient (AQ-10), and the Empathy Quotient (EQ-10). Results: Fewer that 5% of participants had exceptional STM. As predicted, there were significant positive associations between systemising and exceptional STM for digit span and paired associates, although this was not seen with spatial span. Also as predicted, having a ‘brain type’ of higher systemising, captured via high D scores (difference between systemising and empathising), predicted exceptional STM for the digit span and paired associates. We were under-powered to test these differences in autistic people. Conclusion: These results provide evidence that exceptional STM is linked to stronger systemising and systemising-dominant cognitive profiles.