In this paper, we aim to discover what factors influence memory retention, and how to improve our ability to retain relevant information to recall at a later time. Previous research has predicted levels of memory retention by variables such as the amount of sleep a person has each night, the level of anxiety-depression a person experiences, the level of physical activity someone does each day, and study duration, frequency, and spacing. In our first (correlational) study, we tested the strength of these relationships by examining naturalistic daily changes in their variables longitudinally over one week. We measured sleep by tracking the number of minutes of sleep during each night, and the level of anxiety-depression by tracking heart rate, urine and subjective mood of anxiety-depression. We recorded physical activity by tracking how much exercise we did throughout the day and the intensity of the exercise on a 1-9 scale. For studying we tracked the overall amount of time spent studying, the number of times studying took place, how long each study session was, and how long the space was in between study sessions. Memory retention was tested by our ability to remember at the end of the day a set of 20 randomized words given in the morning. Based on the strength of correlation found between study time and memory retention, we then conducted a second (experimental) study to test for a causal relationship between these two variables. Over eight days we assigned participants on alternating days to have either 3 separate 5-minute study sessions or just 1 single study session and measured the effect this had upon memory and anxiety-depression. Data pooled across participants in our correlational study showed significant correlations of memory retention with anxiety-depression subjective measurements, overall study time, study session frequency, duration, and spacing, but not with sleep amount, heart rate, time spent urinating, nor with physical activity amount and intensity. Data from our experimental study showed that increasing study time caused an enhancement of memory retention, which could not be accounted for by changes in anxiety-depression. Based on our experimental results, we recommend that in order to improve the ability to retain and recall information, more time should be spent studying.
