Lateralized processing of false memories and pseudoneglect in aging.

Aging is associated with higher propensity to false memories and decreased retrieval of previously studied items. When young adults (YA) perform on a lateralized version of the Deese-Roediger-McDermott (DRM) paradigm, the right cerebral hemisphere (RH) is more sensitive than the left (LH) to false memories, suggesting hemispheric imbalance in the cerebral mechanisms supporting semantic and episodic memory processes. Since cerebral asymmetries tend to be reduced with age, we surmised that behavioral asymmetries in the generation of false memories would be diminished with aging. To probe this hypothesis, a lateralized version of the DRM paradigm was administered to healthy older adults (OA) and YA. During the encoding phase, lists of semantically associated words were memorized. During the retrieval session, targets (previously seen words), lures (LU) (never seen strongly semantically related words) and distracters (never seen, unrelated words) were briefly displayed either in the left or right visual fields, thus primarily stimulating the RH or LH, respectively. Participants had to decide whether the word was previously studied (Old/New), but also whether they had a strong episodic recollection (Remember) or a mere feeling of familiarity (Know) about Old words. In line with our predictions, false memories were globally higher in OA than YA, and vivid false recollections (i.e., Remember responses) were higher when LU were presented in the RH in YA, but not in OA. Additionally, we found significant correlations between YA participants' Familiarity scores and leftward attentional bias as previously evidenced using a visuospatial landmark task (Schmitz and Peigneux, 2011), an effect not present in OA. This result is in line with the hypothesis of an interplay between attentional resources allocated to visuospatial and memory processes, suggesting a memory pseudoneglect phenomenon that would be altered with aging.