Visual perception and cognition in healthy aging

Chard, James Henry (2025) Visual perception and cognition in healthy aging. PhD thesis, Birkbeck, University of London.

Abstract

Healthy aging is accompanied by a complex set of physiological, neurophysiological and psychological changes. There has been particular interest in social cognition deficits in older adults, which are often attributed to changes in a postulated ‘social brain’ network. Lower level perceptual difficulties tend to be discounted due to an expectation that they could not account for a nuanced pattern of preservations as well as deficits. This thesis focuses on visual perception, presenting signal detection experiments assessing whether older adults exhibit difficulties processing global configurations, alongside relative preservation in processing local features. Chapter 3 presents evidence of age-related decline in sensitivity to postural cues in point light walkers, with preserved kinematic sensitivity. Chapter 4 demonstrates reduced sensitivity to the presence of an emotion thought to be conveyed primarily by postural body language cues (happiness) but preserved sensitivity to emotions conveyed primarily by kinematics (sadness and anger). Cross-experiment comparisons support the conclusion that impaired postural processing contributes to that pattern. Chapters 5 and 6 assess whether findings on posture and kinematics reflect broader deficits in sensitivity to global configurations relative to local features. Chapter 5 does not find evidence of age-related configural processing difficulties employing a composite face paradigm, but more direct manipulation of configurations and features in Chapter 6 provides evidence of such a deficit. A range of changes in healthy aging could account for patterns of change in visual perception. However, the underlying hypothesis arose from evidence of impaired neural connectivity related to reduced white matter tract integrity in older adults. Chapter 7 reports an experiment involving older adults’ sense of agency, implicating a wider neural network. Significantly reduced sensitivity was found in a task involving identifying whether self-generated hand movements corresponded with visual feedback, compared with a control task involving passive observation of an avatar. In conclusion, this thesis provides evidence of difficulties in older adults processing spatial configurations, alongside preliminary evidence of broader integration problems. Findings provide an alternative explanation for social cognition changes in later life and may prove key in scaffolding strategies to reduce real-world effects.

Metadata

Statistics

DownloadsShow export options

Export as XMLCSVJSON

Activity Overview

6 month trend

94Downloads

6 month trend

230Hits

Additional statistics are available via IRStats2.

Archive Staff Only (login required)

Edit/View Item