Collins , K . P . , &

General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: Explore Bristol Research is a digital archive and the intention is that deposited content should not be removed. However, if you believe that this version of the work breaches copyright law please contact [email protected] and include the following information in your message: • Your contact details • Bibliographic details for the item, including a URL • An outline of the nature of the complaint On receipt of your message the Open Access Team will immediately investigate your claim, make an initial judgement of the validity of the claim and, where appropriate, withdraw the item in question from public view. Performance of younger and older adults in lateralized right and left hemisphere asymmetry tasks supports the HAROLD model Abstract The population of industrialized societies has increased tremendously over the last century, raising the question on how an enhanced age affects cognition. The relevance of two models of healthy aging are contrasted in the present study that both target the functioning of the two cerebral hemispheres. The right hemi-aging model (RHAM) assumes that functions of the right hemisphere decline before those of the left hemisphere. The Hemispheric Asymmetry Reduction in Older Adults (HAROLD) Model suggests that the contralateral hemisphere supports the normally superior hemisphere in a given task resulting in a reduced hemispheric asymmetry overall. In a mixed design, 20 younger and 20 older adults performed both a task assessing a left (lateralized lexical decisions) and a right (sex decisions on chimeric faces) hemisphere advantage. Results indicated that lateralized performance in both tasks was attenuated in older as compared to younger adults, in particular in men. These observations support the HAROLD model. Future studies should investigate whether this reduced functional hemispheric asymmetry in older age results from compensatory processes or from a process of de-differentiation.