The Relationships Between Frontal Alpha Asymmetry, Mood, and Emotional Memory

Frontal alpha asymmetry is often used as a metric to compare activation between homologous frontal brain sites. A positive asymmetry refers to greater activation in the left hemisphere than in the right hemisphere, while the opposite is true of negative asymmetries. Two expansive but largely separate bodies of research have examined the relationships between (1) frontal asymmetry scores and mood, and (2) mood and emotional memory performance. Specifically, one body of research has found that positive moods are associated with positive asymmetries while negative moods are associated with negative asymmetries. A second body of literature has examined the effects of mood on affective memory performance found that individuals tend to preferentially recall stimuli whose valence (positivity or negativity) is consistent with their current moods, often at the expense of stimuli whose valence is inconsistent with their current moods. Researchers in this area report that individuals in positive moods tend to recall more positive than negative words while those in negative moods recall more negative than positive words in memory tasks. This effect has been termed mood-congruent memory. As frontal asymmetry appears to underlie mood, and mood differentially affects performance on emotional memory tasks, it is surprising that no research has focused on a possible direct relationship between frontal asymmetry and emotional memory performance. The present study attempted to replicate previously described relationships between (1) frontal asymmetry and mood, and (2) mood and emotional memory performance. The main goal of the study, however, was to bridge the gap between frontal asymmetry and selective recall of emotional words by attempting to correlate frontal asymmetry indices with emotional memory performance. Results supported the expected mood-congruent memory effects and a significant relationship between asymmetry and mood in the expected direction. While a correlation between asymmetry and affective memory performance was not found, groups based on asymmetry scores found that the positive asymmetry group showed increased memory performance for positive words and total words, while the negative asymmetry group showed impaired memory for positive words and total words. Further examination of links between alpha asymmetry and affective memory could corroborate the present asymmetry group differences in memory. Future findings would provide the first neuropsychological underpinning of mood-congruent memory effects. Additionally, support for a relationship between asymmetry and affective memory could lead to the formation of a unifying theory of asymmetry and memory that draws on current models of brain activation, executive function, emotion, and memory