Enumeration of small and large numerosities in adolescents with mathematical learning disorders.
Teens with math learning disorders keep the same subitizing range as peers; their unique speed-accuracy pattern means timed tests can under-count their skill.
01Research in Context
What this study did
The team asked teens with math learning disorders to name how many dots flashed on a screen. They timed the answers and checked accuracy for tiny sets (one to four) and larger sets (five to nine).
A control group of typical math teens did the same task. The study compared speed, accuracy, and how each group traded speed for accuracy.
What they found
The teens with math disorders named the numbers just as fast and as correctly as their peers. Their subitizing range was not smaller.
The difference was in the speed-accuracy trade-off. Kids with math disorders used a different timing plan across set sizes, so a quick timed test can hide their true skill.
How this fits with other research
Schwenk et al. (2017) pooled many studies and found that symbolic comparison speed, not subitizing range, best flags math trouble. The new teen data match that view.
Peters et al. (2020) saw no magnitude deficit at all in kids labeled dyscalculic; they point to spatial skill gaps instead. The teen study agrees: accuracy on number tasks can look normal, so missing math may stem from other roots.
Brugnaro et al. (2024) later built enumeration probes into a school screener because speed-accuracy patterns still help spot severe MLD. The teen findings gave early proof that the pattern, not a cut-off score, matters.
Why it matters
Stop assuming a child who counts slowly has a tiny subitizing span. Watch how they balance speed and accuracy across set sizes. If you need a quick probe, add mixed-format items and give teens a little extra time so their true number sense can show.
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Add two untimed enumeration trials after your timed ones and compare the accuracy curve before writing a math goal.
02At a glance
03Original abstract
The accuracy and speed in an enumeration task were investigated in adolescents with typical and atypically poor development of arithmetic skills. The number naming performances on small and large non-symbolic numerosities of 18 adolescents with mathematical learning disorders (MLD) and 28 typically achieving age-matched (TA) adolescents were compared. A mixed logistic regression model showed that adolescents with MLD were not significantly less accurate on numbers within the subitizing range than control peers. Moreover, no significant differences in reaction times were found between both groups. Nevertheless, we found that within the control group adolescents with higher ability tended to respond faster when taking into account the whole range (1-9) of numerosities. This correlation was much weaker in the MLD group. When looking more closely at the data, however, it became clear that the correlation between accuracy and speed within the control group differed in direction dependent on the range (subitizing or counting) of the numerosities. As such, our findings did not support a limited capacity of subitizing in MLD. However, the data stressed a different correlation between speed and accuracy for both groups of adolescents and a different behavioral pattern depending on the numerosity range as well. Implications for the understanding and approach of MLD are considered.
Research in developmental disabilities, 2014 · doi:10.1016/j.ridd.2013.10.018