Concealed inefficiency of late-night study

Abstract

PRESSURES of work often force people to stay up late, attempting to commit material to memory during the early hours of the morning. ‘Burning the midnight oil’ in this way often seems reasonably efficient at the time, despite the fact that a wide range of physiological and psychological circadian (24 h) rhythms are then at their lowest point. However, recent research would predict that although people's immediate memory for the material studied might be reasonably good, much more will be forgotten with time than if the learning had taken place at a more ‘normal’ time of day. This prediction was tested and verified on a group of part-time night workers. An ‘in service’ training film was shown at either 2030 h or 0400 h. When tested immediately after seeing it, memory for the film was, if anything, slightly better at 0400 h than at 2030 h. However, the group that was shown the film at 0400 h forgot more than twice as much over a 28-d period as the group shown it at 2030 h. Thus, although studying late at night might seem to be efficient at the time, long-term retention of the material will be rather poor.