Poor reaction times associated with greater risk of death, study finds

Reaction times are associated with major causes of mortality, according to a study published in the journal Intelligence.

A growing body of evidence indicates that there is a relationship between intelligence and mortality. But the cause of this relationship is unclear.

Researchers have proposed that this relationship could be a result of intelligence tests assessing “some aspect of bodily integrity that affects the efficiency of information processing,” the authors of the new study explained.

“Reaction times can be considered as simpler and more fundamental measures of information processing than intelligence tests are. They make little, if any, reliance on prior knowledge and so are less likely to be influenced by educational or social background.”

The researchers analyzed data collected from 1,350 individuals during the West of Scotland Twenty-07 Study, a longitudinal study that started in 1986 when the participants were aged 56. The study included a test of general intelligence, along with a test of reaction times.

There were 833 deaths over the course of 29 years. The researchers found that both intelligence and reaction times were associated with major causes of mortality, including coronary heart disease, smoking-related cancers and respiratory disease.

Participants who died during follow up were more likely to have lower intelligence scores as well as longer and more variable reaction times. They were also more likely to be male and smokers.

“One major implication of our results is that the association between intelligence and the major causes of mortality is unlikely to be due to any social, cultural or educational biases that could be ascribed to measures of intelligence,” the researchers concluded.

“Just as intelligence is associated both with all-cause mortality and most of the major causes, so too are reaction times. Effect sizes are of similar magnitude, possibly suggestive of a common cause. The major exception is cancers, particularly those unrelated to smoking, and, in this dataset, stroke.”

The study, “Reaction times match IQ for major causes of mortality: Evidence from a population based prospective cohort study“, was authored by Geoff Der and Ian J. Deary.