| Abstract: | The effect of time of day on recall of words and drawings was studied in 29 French shiftworkers. Tests were carried out at 18:00, 22:00, 02:00 and 06:00. The task involved memorizing a list of 18 drawings for one half of the group, and 18 words (designating the corresponding figures) for the other half. At each time of day, the lists were presented both with and without an interpolated task. In the interpolated task condition, the first 9 items were followed by an interpolated imagery task and the last 9 by a spelling task, or vice versa. The results indicated an overall effect of time of day on the recall test, especially when memorizing drawings. At 18:00 in both the control and the interference condition, subjects recalled more words and drawings from the beginning of the list. Conversely, at 02:00, subjects recalled more words and drawings from the end of the list. The time spent in the interpolated comparison task varied with the time of day and was longer when memorizing drawings. The same time of day pattern of performance was found for spelling times. The implications upon issues concerning shiftwork and job demands are also discussed. |
