Optimum Time of Day for Optimum Performance

Optimum Time of Day for Optimum Performance

by Dr. Bob Bailey

December, 1999

How can we ensure that older users perform as well as younger users in systems? Do younger and older users perform better at different times of the day?

Optimum Time of Day for Optimum Performance 1

Intons-Peterson, et.al. (1998) evaluated the effect of time-of-day preferences on user performance. Past research in this area found that younger adults prefer to perform later in the day, and older adults prefer performing in the morning. This study found the following preferences:

	Young	Old

Definite morning	0%	34%
Moderate morning	8%	49%
No preference	57%	10%
Moderate evening	29%	6%
Definite evening	6%	1%

More younger people preferred the afternoon, and more older people preferred the morning. Also, more of the younger subjects had no strong preferences. Using this preference data, they conducted an experiment.

Participants were tested at optimal and non-optimal times. Both older and younger groups showed improved performance on a memory task when tested at their preferred time of day. Perhaps more importantly, when tested at preferred times, older adults showed memory effects similar to those of younger subjects.

Optimum Time of Day for Optimum Performance 2

Can In a follow-on study, Intons-Peterson and Rocchi (1999) attempted again to determine if people perform better when tested at their preferred times of day. They measured time-of-day preferences using the “Morningness-Eveningness Questionnaire.”

The questionnaire correlates significantly with:

Self-reported measures of sleep habits (going to bed and arising times),
Times of best mental and physical performance and alertness,
School performance, and
Peak time of oral temperature.

To gain new information, they attempted to determine if age differentials in optimality were more pronounced in recall than in recognition memory. Participants were 77 young college students (average age of 20) and 42 older adults (average age of 72). Two groups were tested:

Optimal	Those who preferred morning were tested in the morning Those who preferred afternoon in the afternoon
Non-optimal	Those who preferred morning were tested in the afternoon Those who preferred afternoon in the morning

Only non-optimally tested older adults showed reliably greater evidence of poorer performance. With recall performance, the younger group remembered reliably more. There was no reliable difference between the age groups on the recognition memory task.

This may be a good way to help ensure that older users perform at the same level as younger users. Younger users seem to be able to perform well at all times, but older users perform certain, memory-related, tasks best when participating at their optimal times.

References

Intons-Peterson, M.J., Rocchi, P., West, T., McLellan, K. and Hackney, A., Age, testing at preferred or nonpreferred times (testing optimality), and false memory, Journal of Experimental Psychology: Learning, Memory, and Cognition, 25(1), 23-40 (1999).

Intons-Peterson, M.J., Rocchi, P., West, T., McLellan, K. and Hackney, A., Aging, optimal testing times, and negative priming, Journal of Experimental Psychology: Learning, Memory, and Cognition, 24(2), 362-376 (1998).