Retrieval Competition in Proactive Interference: Effects of Encoding Strength and Consolidation in the Modified Modified Free Recall Paradigm

This study examined how the relative encoding strength of pre-existing associations influences proactive interference (PI), and whether memory consolidation modulates this effect over time. Using a Modified Modified Free Recall (MMFR) paradigm, participants studied overlapping (A–B, A–C) and non-overlapping paired associates(E-F, G-H). The encoding strength of List 1 was manipulated (one vs. three study repetitions), while List 2 was held constant. Recall was tested immediately and after a 24-hour delay.Results showed that PI was strongest when both lists were studied once, consistent with maximal cue-based competition. When List 1 was studied three times, PI was attenuated, suggesting reduced retrieval ambiguity. After a 24-hour delay, PI was eliminated in the equal-strength condition but persisted slightly in the strong List 1 condition. Co-retrieval analyses revealed consistent associative dependency between B and C across all conditions, indicating robust integration between overlapping traces.These findings demonstrate that retrieval competition in PI is modulated by both encoding strength and consolidation. While stronger encoding can reduce immediate competition, it may also prolong interference. The results underscore a dual-process framework in which cue overlap leads to both interference and cooperative retrieval, depending on the balance between differentiation and integration mechanisms.