Normal aging is usually accompanied by greater memory decline for associations than for single items. Though associative memory is generally supported by recollection, it has been suggested that familiarity can also contribute to associative memory when stimuli can be unitized and encoded as a single entity. Given that familiarity remains intact during healthy aging, this may be one route to reducing age-related associative deficits. The current study investigated age-related differences in associative memory under conditions that were expected to differentially promote unitization, in this case by manipulating the spatial arrangement of two semantically unrelated objects positioned relative to each other in either spatially implausible or plausible orientations. Event-related potential (ERP) correlates of item and associative memory were recorded whilst younger and older adults were required to discriminate between old, recombined and new pairs of objects. These ERP correlates of item and associative memory did not vary with plausibility, whereas behavioral measures revealed that both associative and item memory were greater for spatially plausible than implausible pair arrangements. Contrary to predictions, older adults were less able to take advantage of this memory benefit than younger participants. Potential reasons for this are considered, and these are informed by those lines of evidence which indicate older participants were less sensitive to the bottom-up spatial manipulation employed here. It is recommended that future strategies for redressing age-related associative deficits should take account of the aging brain's increasing reliance on pre-existing semantic associations.
Bibliographical noteFunding Information:
This work was supported by Grant 1083-5.4/2010 of the German-Israeli Foundation for Scientific Research and Development (G.I.F.). Roni Tibon is funded by a Newton International Fellowship from the Royal Society and the British Academy. Open access fees were paid by the UK Medical Research Council Program MC A060 5PR10 (Richard Henson). We would like to thank Siri M. Kamp for helpful comments on earlier versions of this manuscript, Hannah Schmidt for her support with neuropsychological testing and Carolin Hecker and Marcelle Gross for their help with data acquisition. We are grateful to all volunteers who participated in this study.
© 2017 The Authors
- Associative memory
- Episodic memory
- Event-related potentials