Associative memory in aging: The effect of unitization on source memory.

Abstract

In normal aging, memory for associations declines more than memory for individual items. Unitization is an encoding process defined by creation of a new single entity to represent a new arbitrary association. The current study tested the hypothesis that age-related differences in associative memory can be reduced following encoding instructions that promote unitization. In two experiments, groups of 20 young and 20 older participants learned new associations between a word and a background color under two conditions. In the item detail condition, they had to imagine that the item is the same color as the background; an instruction promoting unitization of the associations. In the context detail condition, that did not promote unitization, they had to imagine that the item interacted with another colored object. At test, they had to retrieve the color that was associated to each word (source memory). In both experiments, the results showed an age-related decrement in source memory performance in the context detail but not in the item detail condition. Moreover, Experiment 2 examined receiver operating characteristics in older participants and indicated that familiarity contributed more to source memory performance in the item detail than in the context detail condition. These findings suggest that unitization of new associations can overcome the associative memory deficit observed in aging, at least for item-color associations.

Contributions of attention and elaboration to associative encoding in young and older adults

“…This pattern was observed despite the interactive imagery instructions, which in some prior studies ( (Treat and Reese, 1976); see also (e.g., Bastin et al, 2013)) abolished the age difference in associative memory. The number of eye gaze transitions between the objects of a pair at encoding correlated with recognition performance in both age groups, supporting the idea that attention shifts support the generation of associative links between items.…”

Differential age-related effects on conjunctive and relational visual short-term memory binding

“…But age-related differences can be attenuated, and even suppressed, when associations are unitized in such a way that the components become fused into a coherent whole. This was notably the case for object-colour associations that older adults were better able to remember when colour was integrated as a feature of the object compared to when colour was associated to the object as a distinct item (Bastin et al, 2013;Zheng, Li, Xiao, Ren, & He, 2016).…”

“…Actually, such conjunctive binding promotes familiarity-based memory, which is better preserved in aging than recollection that is required for relational binding (Bastin et al, 2013;Diana, Yonelinas, & Ranganath, 2008;Zheng et al, 2016). It may be that, in the current shortterm memory tasks, older adults could use efficiently familiarity-like judgements to recognize studied associations in conjunctive trials because coloured objects were processed as unitized wholes.…”

Associative recognition processes are modulated by the semantic unitizability of memoranda

“…Top-down approaches to unitization focus on encoding instructions to process pairs of memoranda as a single unit (in high-unitization conditions) or as separate elements of the same episode (for low-unitization conditions). Unitizing instructions can take the form of compound definition versus use-in-sentence encoding of words (Bader, Mecklinger, Hoppstädter, & Meyer, 2010;Haskins, Yonelinas, Quamme, & Ranganath, 2008), or of encoding source and item information in an internal versus an external manner, thus forming intra-versus inter-item associations, e.g., ''imagine each item in the color indicated by the background screen color'' versus ''imagine why the item would be associated with a stop sign or dollar bill'' (Bastin et al, 2013;Diana, Van den Boom, Yonelinas, & Ranganath, 2011), or the ''strategy type'' manipulation employed by Rhodes and Donaldson (2008).…”