False Recognition in Aging is Due To an Emphasis on Semantic Information at Encoding

Poster Session C - Sunday, April 14, 2024, 5:00 – 7:00 pm EDT, Sheraton Hall ABC

Loris Naspi¹ (lorisnaspi@gmail.com), Paola Gega¹, Şafak Erener¹, Teuta Dzaferi¹, Roberto Cabeza²; ¹Humboldt University of Berlin, ²Duke Univeristy

According to the semantic categorization account, older adults' overreliance on pre-existing semantic knowledge at encoding causes false recognition by reducing the quality of visual representations. Alternatively, the impaired perceptual encoding hypothesis suggests that older adults demonstrate reduced encoding of visual details that would allow successful discrimination of similar lures, irrespective of the copresence of semantic information. The current fMRI study investigated whether older adults' emphasis on pre-existing semantic knowledge at encoding impaired visual encoding while increasing false recognition, as well as the brain regions engaged. Participants encoded unique fonts associated with words (meaningful condition) and pseudowords (meaningless condition), making a pleasantness decision task. At retrieval, participants were asked to judge the font as 'old' or 'new' with confidence levels. 1) In the meaningful condition, representational similarity analysis at encoding with a model of vision (AlexNet) revealed an age-related dedifferentiation for visual representations in the early visual cortex. This was associated with an age-related hyperdifferentiation for semantic representations (Word2Vec) in the ventral anterior temporal lobe. Data suggests that older adults with lower specificity of visual representations in combination with higher specificity of semantic representations falsely recognised more fonts. 2) Encoding-retrieval similarity revealed that the reduction of specificity of the encoded fonts in aging in the meaningful condition is reflected as an increased neural pattern similarity in the early visual cortex. The behavioral and fMRI results are consistent with the semantic categorization account and potentially suggest that perceptually-based false recognition can be reduced if older adults do not emphasize semantic information.

Topic Area: LONG-TERM MEMORY: Episodic