Emotional Amplifier: How Event Boundaries influence Time and Source Memory

Event boundaries, marked by contextual changes, segment continuous experiences into memory units. Day-to-day emotional arousal also affects memory structure. Yet their joint impact remains unclear. We examine whether emotional arousal modulates memory boundary effects. Participants viewed negative or neutral image sequences, with contexts shifted via auditory cues (Experiment 1, n = 61) or visual cues (Experiment 2, n = 60), followed by temporal and source memory tests. Across both experiments, boundaries impaired order memory, increased perceived temporal distance, and enhanced source memory. Importantly, negative arousal amplified boundary effects across modalities but in a modality-specific fashion: it amplified effects on temporal distance memory in Experiment 1 and on source memory in Experiment 2. Exploratory analyses revealed boundaries modulated the correlation between order and distance memory under neutral contexts, but this modulation disappeared under negative arousal. These findings offer insights into how emotional arousal modulates memory boundary effects and their joint effects on multiple components of episodic memory.