The Effect of Aging on Object Representation

This thesis project had the overall aim of investigating older adults (OA) representation of real-world objects through different cognitive paradigms probing visual working memory (vWM) and attention. OAs are known to demonstrate difficulties in these two cognitive domains, however, an under-researched in the aging field is the possible influence of the quality of representations in conjunction with the amount of representations in determining OA’s performances. Moreover, a majority of research in the aging field has utilized geometrical shapes, therefore I was interested to investigate whether the previous findings extend when real-world objects are used. Accordingly, the main questions accordingly probed in this study were 1) whether the content of object representations influence OAs’ performances when vWM and attention are probed, or whether effects are solely due to the amount, and 2) whether age-effects found in previous vWM and attention studies in aging, extend when real-world objects are used. To this aim, Chapter 3 describes two experiments where I manipulated the perceptual and conceptual similarity amongst objects presented to OAs and young adults (YAs) when performing a change detection task taxing vWM. Results indicated both age groups had significantly lower performances when there 3 objects to retain and recall, but no age-related differences in the maintenance and recall of these types of objects. Chapter 4 and Chapter 5 report three experiments addressing the impact of object numerosity and/or nature in OAs’ attention deployment during a visual search task. Results of two experiments in Chapter 4 with manual responses found that OAs’ performance was detrimentally impacted by the amount of object representations, irrespective of the relation amongst the items. Chapter 5 illustrates an eye movement study, aimed at exploring more in detail the visual exploratory behavior of older and young individuals. Overall, OAs were slower and showed a larger tendency to get distracted than YAs, regardless of the perceptual or conceptual target-distractor similarity. Overall, the studies presented in this thesis indicated that aging negatively affects the ability to ignore distracting information. However, little evidence was provided as to whether aging negatively influences the content representation of an object. This result confirms previous research indicating that some, but not all aspects, decline in late adulthood.