Indicators of Dyscalculia Series
by Jan Thomson-Long
What is Subitising?
“The innate ability to sense numbers”. – Kaufman, E.L (1949)
Subitus means “sudden” in Latin. Subitising is that moment when you just know how many items you can see. It only applies to small quantities known as the subitising range which is up to four (maybe five). Quantities above that can only be subitised if they are in a familiar pattern such as dice and even then, you’re really using ‘numberness’ which is a future blog.
Babies and animals can subitise and researchers are using fMRI scans to identify the part of the human brain that is involved.
There’s been a bit of definition creep with the word subitising. This matters in terms of ensuring mutual understanding as part of the definition of dyscalculia (BDA & SASC, 2019) refers to the inability to subitise. The definition creep is where the innate ability which perhaps we should refer to as perceptual subitising is being used to develop number sense by grouping together patterns that then enable conceptual subitising. Conceptual subitising is used to teach number facts.
So, from the perspective of indicating Dyscalculia, we are looking for an inability to instantly perceive a small quantity. Individuals can still be taught recognition of dot patterns and in fact that’s what we do to support dyscalculic individuals to manage in the numeric world.
References
BDA, & SASC. (2019). Dyscalculia and maths difficulties (Vol. 2019, Issue Aug 4,). https://www.bdadyslexia.org.uk/dyslexia/neurodiversity-and-co-occurring-differences/dyscalculia-and-maths-difficulties
Kaufman, E.L.; Lord, M.W.; Reese, T.W. & Volkmann, J. (1949). “The discrimination of visual number”. American Journal of Psychology. The American Journal of Psychology. 62 (4): 498 – 525.
