A small study comparing 38 younger adults (average age 22) and 39 older adults (average age 68) found that the older adults were less able to recognize when they made errors.
The simple test involved looking away from a circle that appeared in a box on one side of a computer screen. It’s hard not to look at something that’s just appeared, and each time the participant glanced at the circle before shifting their gaze, they were asked whether they had made an error. They were then asked to rate how sure they were of their answer.
The younger participants were correct in acknowledging when they had erred 75% of the time, while the older test-takers were correct only 63% of the time. Moreover, when they judged themselves correct in error, the younger participants were far less certain of their judgment than the older ones.
This was confirmed by their eye dilation. Our pupils dilate when something unexpected occurs, and when we think we’ve made a mistake. Younger adults' pupils dilated when they thought they erred, and dilated to a smaller extent when they didn’t recognize their error. Older adults, on the other hand, showed no dilation at all when they committed an error they didn’t recognize.
Research has recently discovered the existence of "error neurons" — specific neurons in the human medial frontal cortex that signal the detection of errors. Perhaps future research will find that these neurons are, in some way, vulnerable to loss during the aging process. But this is pure speculation, and there are other possible causes for older adults' decreasing ability to recognize errors.
The important thing, on a practical level, is to be aware of this danger. I suspect, for most people, this will go a long way to improving the situation.
(2018). A blunted phasic autonomic response to errors indexes age-related deficits in error awareness.
Neurobiology of Aging. 71, 13 - 20.
(2019). Single-Neuron Correlates of Error Monitoring and Post-Error Adjustments in Human Medial Frontal Cortex.
Neuron. 101(1), 165 - 177.e5.