Medial Prefrontal Theta Oscillations Track the Time Course of Interference during Selective Memory Retrieval

Memory retrieval is often challenged by other irrelevant competing memories that cause interference. This phenomenon is typically studied with the retrieval practice paradigm in which a category cue (e.g., Fruits) is presented together with an item-specific cue (e.g., Or::). Presentation of the category cue usually induces interference by reactivating competing memories (e.g., Banana, Apple, etc.), which is thought to be solved by means of inhibition, leading to retrieval-induced forgetting of these competing memories. Previous studies associated interference with an increase in medial prefrontal theta band (4–8 Hz) oscillations, but these studies could not disentangle the interference from the inhibition processes. We here used a retrieval practice procedure in which the category cue was presented before the item-specific cue to disentangle the interference from the inhibition signal. Furthermore, a competitive retrieval condition was contrasted with a noncompetitive condition. At a behavioral level, retrieval-induced forgetting was found in the competitive but not in the noncompetitive condition. At a neural level, presentation of the category cue elicited higher levels of theta power in the competitive condition, when compared with the noncompetitive retrieval condition. Importantly, this difference was localized to the ACC, which has been associated with the detection and mediation of interference. Additionally, theta power decreased upon presentation of the item-specific cue, and this difference was related to later forgetting. Our results therefore disentangle, for the first time, interference and inhibition in episodic memory retrieval and suggest that theta oscillations track the fine-grained temporal dynamics of interference during competitive memory retrieval.

Performance on Two Attention Tasks as a Function of Sex and Competition

Effects of sex and competition on receptive attention and Stroop task performance of 59 college students were investigated. 33 participants in a competitive condition were informed that performance would be ranked by sex; 36 in a noncompetitive condition were given no information regarding competition. Consistent with previous research, no significant main effects or interactions were found for scores on the receptive attention task. Contrary to previous findings, though, the Stroop task also yielded no significant main effects; however, a significant interaction was found. Men experienced more interference in the competitive condition, whereas women showed no significant effects of competition. Women did experience more interference than men in the Noncompetitive condition. Conclusions suggest that men may be more sensitive to sex-based performance comparisons.

Militancy and Black Women's Competitive Behavior in Competitive versus Noncompetitive Conditions

Fifty high militant and 50 low militant black women were assigned to one of five experimental conditions: noncompetitive, competition with black male confederates, competition with black female confederates, competition with white male confederates or competition with white female confederates. Subjects in competitive conditions worked for longer periods of time, produced more words from an anagram, and felt more self-confident than subjects in the noncompetitive condition. Subjects worked for longer periods of time with male confederates than with female confederates. High militants, in comparison to low militants, produced significantly more words on the anagram task, indicated a great number of pride, anger, and/or revenge responses and endorsed more masculinity items relative to femininity items on the Bem Sex-Role Inventory as being self-descriptive. Contrary to prediction, high militant black women competing with black men showed little evidence of fear of success.