Individual differences in visual attention related to healthy aging - ELPHINSTONE

Visual attention is a process of selectively concentrating on aspects of the environment, while ignoring others. Previous research suggests that visual attention can be allocated to specific locations in the visual environment (space-based attention) but also to objects (object-based attention). A common way to measure space- or object-based attention is to use cues, that is, visual signals that indicate the likely location or identity of an upcoming target and attract or focus attention on relevant locations or features. Cueing effects (i.e. shorter reaction times to respond to cued relative to uncued targets) provide a quantifiable measure of attention effects. Cueing effects associated with space-based attention tend to be large and are found consistently across experiments. Object-based attention effects, however, are relatively smaller and less consistent [1-3]. In a recent paper, we showed that object-based effects are subject to large individual differences, i.e., some people are faster at detecting a target on previously cued objects, whereas others are even slower, which means that the cue is disadvantageous and even directs attention away from the target [4].

One critical factor for object-based paradigms is the time interval between the cue and the target (CTI). Cueing effects are typically biphasic; that is, cues facilitate target detection early, but after approximately 300ms, the effect reverses, and target detection is slower at the cued than uncued location. This reverse-cueing effect is known as inhibition of return (IOR) and is thought to reflect the withdrawal of attention from inspected locations. IOR, like cueing effects, can also be found for both locations and objects [5], but the relationship between object-based cueing effects and object-based IOR is not known.

The current project will use a variety of object-based paradigms to determine cue-to-target intervals for each individual observer for which he or she shows maximal object-based attention effects. Using bootstrapping techniques in addition to commonly used parametrical statistics, we will be able to determine biphasic cueing effects in individual observers. Age may contribute particularly important individual differences in object-based attention. Our results from younger adults suggest that there are large individual differences in object-based attention. Many previous studies on age-related perceptual changes have shown that the variance within groups of older adults is often much larger than the variance within groups of younger adults. Therefore, testing individual differences in object-based attention in older adults will not only resolve the discrepant findings mentioned above but also provide a great opportunity to study the mechanisms underlying object-based attentional selection in general, based on a more diverse sample.
This project combines different methodologies and approaches from visual attention and ageing research. The student will design psychophysical experiments and collect behavioural data from participants across the lifespan. In addition, the student will gain experience in a variety of different analysis methods. Further, the student will have the opportunity to learn and use electroencephalography to assess age-related changes in object-based attention.

To be considered for funding you will need to be UK or EU students, with the equivalent to a 1st class Honours undergraduate degree or a 2.1 Honours undergraduate degree alongside a Masters with Merit or Distinction. International applicants who meet this condition and can pay the difference between the Home and International Fees would also be considered.

Applications must include: 1) An on-line form completed through the applicant portal. 2) a letter of support from the project supervisor. 3) Two academic references – please attach the references to the application or include full referee contact details. 4) A CV outlining your academic qualifications and research experience to date. 5) academic transcripts from previous degree(s).