Pearson correlations revealed no significant correlation between the two independent variables, time of day and age (Brown, Goddard, Lahar, & Mosley, 1999).
These results caused the researchers to conclude that time of day does not exert a significant influence on adult cognitive performance.
Significant three-way interactions were found for Verbal IQ, Verbal Comprehension, and Processing Speed factors among time of day, time-of-day preference, and first versus second test administration; a two-way interaction was found for Processing Speed between time of day and time-of-day preference.
If that is the case, then the case for a biological preference for time of day is challenged.
This may be because peak temperature moves to an earlier time of day as people age (Anderson et al.
Monk and Leng (1982) were able to specify the type of task performed in accordance with time-of-day preference when they found no interaction between morningness-eveningness and time of day on perceptual-motor tasks, but a significant effect for cognitive tasks.
The individual may be tested by changing the time of day while maintaining tasks expected to arouse approximately the same level of motivation; an alternative is to maintain the time of day while varying the motivation.
The question to be answered, then, is whether individuals matched to their preferred time of day can be expected to exhibit higher levels of academic achievement than those who are not.
In an upcoming empirical study, Catholic high school students will be tested to ascertain if matching them to their preferred time of day, as measured by two valid instruments, will result in any significant difference in academic achievement.
Intelligence, Time of Day, and Time-of-Day Preference (Doctoral dissertation, Hofstra University, 1994).
Individual differences in the effect of time of day on long-term memory access.
The effects of time of day on cognitive and visuo-motor performance efficiency.