Mood-state dependent retrieval

Biological Parallel

Memory retrieval is context-indexed across species because environmental and physiological conditions predict situational demands. The classic Godden & Baddeley (1975) underwater study found divers showed approximately 50% better word recall when tested in the same environment (land-land or water-water) versus different environments—though recent replications have shown mixed results, suggesting context effects depend on how distinctive the environments are. Honeybees show context-dependent learning: foraging routes learned under specific conditions are better retrieved in matching conditions. Salmon navigating to natal streams use olfactory memories encoded during juvenile development—retrieval requires matching the chemical environment of smoltification. The brain treats environmental and bodily state as contextual tags: if conditions feel similar to when you learned something, that information is flagged as probably relevant now. Context-dependency isn't a bug but an adaptive indexing feature.