Effects of age, intelligence and executive control function on saccadic reaction time in persons with intellectual disabilities.
Among teens and adults with ID, poor executive control makes eye reaction times swing wide, while lower IQ makes them slow, so measure both.
01Research in Context
What this study did
Haishi et al. (2011) looked at how IQ and executive control affect eye movement speed in teens and adults with intellectual disability. They measured how fast each person moved their eyes toward a sudden light. They also gave short tests of intelligence and a motor test that shows how well someone can hold back an action.
The team wanted to know if smarter scores or better self-control make eye reactions faster or less jumpy.
What they found
People with higher IQ scores had quicker average eye jumps. People who scored worse on the motor control test had eye reaction times that bounced around more. The two effects did not overlap; IQ and control scores each told a separate story.
The study shows that speed and steadiness are two different skills in this group.
How this fits with other research
Sutton et al. (2022) later saw the same split in school kids with ID. Working memory and age improved a little, but teacher ratings stayed flat, lining up with Koichi's finding that IQ and control are separate tracks.
Danielsson et al. (2012) showed kids with ID can match mental-age peers on quick word lists yet still fail stop-tasks. That fits Koichi's picture: some EF parts stay weak while others look okay.
Bouck et al. (2016) found that once inhibition problems hit a clinical level, the usual IQ-math link disappears. Their pattern mirrors Koichi: when control is very poor, IQ alone cannot keep performance steady.
Why it matters
When you test a client with ID, check both IQ and executive control. Quick eye jumps may hide shaky self-control, and steady IQ scores may hide slow speed. Use simple motor-stop tasks alongside standard smarts tests. Target speed drills for high-IQ clients and variability drills for low-control clients. This two-lens view can sharpen your skill-building plans.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Add a 30-second 'hold the buzzer' task to your intake; mark high variability as a separate goal from speed.
02At a glance
03Original abstract
The current research aimed to clarify the influence of age, intelligence and executive control function on the central tendency and intraindividual variability of saccadic reaction time in persons with intellectual disabilities. Participants were 44 persons with intellectual disabilities aged between 13 and 57 years whose IQs were between 14 and 70. Executive control function was evaluated by a test of sustained simple motor action. To elicit saccades, a predictive visually guided saccade paradigm was used. Intelligence and executive control function were significantly associated with saccadic reaction time. The central tendency of saccadic reaction time was negatively correlated with intelligence. The more serious the degree of executive control dysfunction was, the larger the intraindividual variability of saccadic reaction time. It is thought that intelligence and executive control function have relatively independent influences on saccadic reaction time. However, there is a possibility that the increase of intraindividual variability in saccadic reaction time due to the problem of executive control function extends the central tendency of saccadic reaction time.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.06.009