This project relates to a sort of ‘memory illusion’: On a recognition memory test, increasing the perceptual fluency of a test cue increases the likelihood that the word will be endorsed as ‘familiar’, even if it hasn’t been seen in the study phase (and therefore should have been called ‘new’). This effect is often interpreted as the misattribution of fluency to memory, as if participants infer ‘I processed that item quickly, therefore I must have seen it in the recent past’, as when a familiar face ‘pops out’ of a crowd. When words are used as stimuli, this memory illusion can be induced using masked, subliminal repetition primes during the test phase (e.g., ‘horse’ flashed briefly before the test word ‘HORSE’; Jacoby & Whitehouse, 1989; Woollams, Taylor, Karayanidis, & Henson, 2008).
Recently, however, we have found that masked conceptual primes (e.g., ‘cow’ flashed briefly before ‘HORSE’) do not affect familiarity, but instead increase correct ‘remember’ responses, meaning that participants are more likely to correctly recollect that the word has been studied (Taylor & Henson, 2012; Taylor, Buratto, & Henson, 2013; Li, Taylor, Wang, & Guo, 2017). This conceptual priming effect on recollection does not appear to be an illusion, since it only increases recollection for studied items (i.e., hits, not false alarms). Instead, conceptual primes may help reinstate the semantic context that was activated by the target word in the study phase, which in turn makes recollection more likely.
This PhD project will use functional magnetic resonance imaging (fMRI), electroencephalography (EEG), behavioural and eye tracking methods to investigate the cognitive and neural mechanisms underlying the effects of masked priming on recognition memory and the implications for our understanding of familiarity and recollection.
Training/techniques to be provided:
This project will involve the collection and analysis of functional magnetic resonance imaging (fMRI), electroencephalography (EEG) data, and eye-tracking measures (eye movements and pupil responses). Both supervisors are experts in recognition memory. Dr Taylor has extensive expertise in EEG and fMRI. He teaches the theoretical foundations and practical application of these methods on our MSc in Neuroimaging for Clinical and Cognitive Neuroscience and on a training course for statistical parametric mapping (SPM) run by the software developers at UCL. Dr Kafkas has extensively used eye tracking to study memory as well as fMRI and EEG methodologies. Advanced analysis methods may include representational similarity analysis (RSA) for assessing representational content, or effective dynamic causal modelling (DCM) for connectivity between brain regions, methods with which both supervisors have experience. Consumables funds will enable the student to attend training courses related to these methods: SPM/DCM EEG and fMRI course in London each May; one of various RSA workshops held in the UK (two have been held in Cambridge in the last 5 years, 1 in Manchester in September 2018).
Candidates are expected to hold (or be about to obtain) a minimum upper second class honours degree (or equivalent) in a related area (cognitive neuroscience, psychology, neuroscience), or bachelor’s degree in a computational field (e.g., engineering, computer science) with a master’s degree in a related field. Candidates with experience in neuroimaging (EEG, MEG, fMRI), eye tracking or with an interest in human memory are encouraged to apply.
For international students we also offer a unique 4 year PhD programme that gives you the opportunity to undertake an accredited Teaching Certificate whilst carrying out an independent research project across a range of biological, medical and health sciences. For more information please visit http://www.internationalphd.manchester.ac.uk
Jacoby, LL & Whitehouse, K. (1989). An illusion of memory: False recognition influenced by unconscious perception. Journal of Experimental Psychology: General, 118(2), 126-135.
Li, B, Taylor, JR, Wang, W, & Gao, C. (2017). Electrophysiological correlates of with fluency of different levels of processing reveal multiple contributions to recognition memory. Consciousness and Cognition, 53, 1-13.
Taylor, JR, Buratto, LG, & Henson, RN (2013). Behavioral and neural evidence for masked conceptual priming of recollection. Cortex, 49 (6), 1511-1525.
Taylor, JR, & Henson, RN (2012). Could masked conceptual primes increase recollection? The subtleties of measuring recollection and familiarity in recognition memory. Neuropsychologia, 50 (13), 3027-3040.
Woollams, AM, Taylor, JR, Karayanidis, F, & Henson, RN. (2008). Event-related potentials associated with masked priming of test cues reveal multiple potential contributions to recognition memory. Journal of Cognitive Neuroscience, 20(6): 1114-29.