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:

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:

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.