Novelty detection for categorical associations of real-world objects is reduced by cognitive ageing

Orienting attention towards novel stimuli (Novelty Preference, NP) is a well-established phenomenon during Visual Paired Comparison (VPC) tasks and is thought to reflect underlying memory processes. Objects are conceptually associated in memory based on their categorical (e.g., apricot/grape) or functional (e.g., nut/nutcracker) relationships. Yet, how these associations influence attentional orienting and whether cognitive ageing impacts this remains unclear. In an eye-tracking experiment, twenty-five younger and twenty-six older adults were familiarized with pairs of objects varying in their categorical and functional relationships. Subsequently, they were presented with familiar and novel (unseen) pairs side-by-side. NP was quantified as the empirical logit of fixation proportions over time for novel versus familiar pairs. Growth-curve analyses revealed that older adults exhibited an overall reduced NP compared to younger adults. This effect was more pronounced for categorically associated pairs than for functionally related pairs. Notably, NP was stronger in older adults when objects were functionally but not categorically related compared to those related on both dimensions (e.g., dart/dartboard), suggesting that categorical information may generate more significant memory interference, hindering pattern separation and consequently diminishing the magnitude of NP. Our findings demonstrate that the type of conceptual associations mediates the strength of their encoding in long-term memory, as reflected in how attention is oriented towards novel stimuli. Critically, cognitive ageing appears to selectively hinder the retention of categorical associations, highlighting an implicit hierarchy in the strength of the representational organization of conceptual knowledge.