Reaction times do increase with age, but different types of reactions are affected differently by the aging process. Your ability to react depends on whether you are dealing with a fairly simple situation or a more complex situation requiring you to pay attention to several different things at once.
Simple Reaction Tests
A simple reaction test involves only one stimulus and one response. An experimental psychologist might test simple reaction times by sounding a buzzer, which would be the stimulus, and instructing a person to press a button whenever he hears it, which would be the response. Simple reaction time improves from childhood until the late 20s. After the late 20s, reaction times increase, but very slowly, until people reach their early fifties. As people reach their late sixties and seventies, reaction times increase markedly.
Men and women differ in their reaction times. As might be expected, men are faster, but women make fewer errors during the learning phase. After the task has been learned, males make the same number of errors as women, but their reaction times remain faster. As women age, their reaction times increase more rapidly than do those of men.
Choice Reaction Times
A more complex test of reaction times would have more than one stimulus and response. For example, an experimenter might flash even or odd numbers on a screen and ask someone to press one button when presented with an even number and another button when presented with an odd number. The time it takes to decide what button to press and then do it is called a choice reaction time.
Choice reaction tests show a different pattern. Unlike reaction times for simple tests, which barely increase until people are fifty years old, reaction times for choice tests increase rapidly once people are no longer young adults. Women's scores on these tests increase more markedly than do those of men. Performance on complex reaction tests is highly correlated with I.Q.: the higher the subject's intelligence, the better his performance.
Reaction Time and Driving
Driving is a type of choice reaction test. Drivers must evaluate various stimuli and make different decisions depending on individual circumstances. Older drivers showed a markedly increased reaction time on simulated driving tests, a difference that appears to be due to cognitive factors rather than reduced mobility.
Older drivers can take steps to compensate for their longer reaction times. The National Highway Traffic Safety Administration advises elderly drivers to leave larger following distances between cars, to avoid driving at night, to make left turns at stoplights with turn arrows and to have a companion along to serve as an extra pair of eyes.
As an added precaution, seniors should be especially careful to avoid drinking and driving. Even low levels of alcohol in the bloodstream that might not impair younger drivers can decrease driving performance in older people.
Factors Affecting Reaction Times
A number of factors have been shown to affect reaction times. Your reaction time will be fastest when you are interested in an activity without feeling stressed. Being too relaxed or too tense will increase those times.
If you are reacting to something that could affect your survival or health, you will react faster. People respond more rapidly to unpleasant food odors, which could indicate spoilage, than they do to pleasant odors.
Studies of exercise and reaction time have shown mixed results. Exercise seems to cause faster reactions during the exercise period but regular exercise doesn't seem to affect reaction times in other situations.
- "Accident Analysis and Prevention"; Differences of Drivers’ Reaction Times According to Age and Mental Workload; Hiroshi Makashita, et al.; March 2008
- "Developmental Neuropsychology"; The Driving-Reaction Time Test: Assessing Age Declines in Dual-Task Performance; Thomas H. Crook, et al.; 1993
- National Highway Traffic Safety Administration: Driving Safely While Aging Gracefully: How Is Your Attention and Reaction Time?
- "BMC Research Notes"; Even Low Alcohol Concentrations Affect Obstacle Avoidance Reactions in Healthy Senior Individuals
- Clemson: A Literature Review on Reaction Time; Robert J. Kosinski; September 2010