Not mine, it's yours: Liberal decision threshold underpins self-other memory prioritization

The Self-reference effect (SRE) is a well-established phenomenon of enhanced memory for self-associated stimuli. Previous research assumed the SRE is underpinned by an attentional boost enhancing early visual processing, as speculated in the Self-attention Network (SAN¹). If so, self-relevance should counteract impaired memory for visually degraded stimuli (e.g., those presented at low contrast). In two experiments we investigated if the attentional enhancement attributed to the SAN occurs at the encoding (Experiment 1) or retrieval (Experiment 2) stage of recognition memory. Using a computerised version of the shopping task, participants sorted miscellaneous shopping objects into self- and other-owned bags (encoding) and then completed a surprise recognition source memory test, indicating if the object was self-, other-owned or not recognised (retrieval). Notably, in Experiment 1, half the objects appeared under low-contrast conditions during the object sorting task (encoding). Conversely, in Experiment 2 the low-contrast manipulation occurred in the subsequent surprise recognition source memory test. Contrary to previous findings, neither manipulation produced the SRE at the behavioural level, with equally accurate source memory for self- and other-owned objects. A Hierarchical Linear Ballistic Accumulator model probed the decisional mechanisms underlying memory performance. This model revealed a caution decision threshold for self- compared with other-owned objects potentially accounts for self-relevance memory advantages. This suggests decision-level factors contribute to the SRE and potentially play a larger role than early attentional factors.