A multimodal neuroimaging investigation of the effects of fluency on recognition memory

Patients with profound memory disorders often paradoxically demonstrate effects of prior learning despite a lack of recollection for the original experience. This has been explained as due to an implicit memory system which is cognitively and neurally distinct from the explicit memory system responsible for retrieval of our past experiences. However, some research has shown that explicit memory judgements may ‘tap in’ to implicit memory processes. For example, the feeling of familiarity that accompanies seeing something you have encountered recently may be partly attributable to how quickly you process that item, so-called fluency of processing, as when a familiar face pops out of a crowd. Indeed, experiments that artificially increase fluency can induce an illusory sense of familiarity, causing participants to declare the primed item to be ‘old’ whether or not it had been seen previously. Perceptual fluency, an implicit effect of previous exposure, can serve as an explicit memory signal.

We recently found that masked semantic priming of memory test cues (e.g., cow-HORSE) increased correct recollection, not familiarity. Rather than inducing a memory illusion, semantic priming actually improved memory performance, helping participants to correctly recollect the training episode. The mechanism responsible for this increase in recollection is presently unknown, but it is unlikely to be due to the misattribution fluency to memory, because only correct recollection is increased.

This project will attempt to uncover the neurocognitive mechanisms underpinning the effects of fluency on familiarity and recollection. We will use multimodal neuroimaging methods, EEG and fMRI, combined with cutting-edge analysis techniques, dynamic causal modelling (DCM) and representation similarity analysis (RSA), to build spatiotemporal models of the neural regions supporting fluency, memory, and attributions. The results will have implications for neurocognitive models of recollection and familiarity, and may predict the pattern of memory impairments found when these brain regions are damaged.

This 3.5-year full-time MRC DTP studentship provides full support for tuition fees, annual tax-free stipend at Research Council UK rates (currently £14, 057) and conference/travel allowance. The project is due to commence October 2016 and is open to UK/EU nationals only due to the nature of the funding.

This project will lead to the acquisition of a wide range of research skills in experimental cognitive psychology and cognitive neuroscience, such as the application of statistics, collecting and analysing EEG and fMRI data, and the application of advanced imaging analysis methods to model multimodal data.

Applicants should hold (or be expected to obtain) a minimum upper-second class undergraduate degree in a related area. A relevant Masters degree or equivalent research experience would be an advantage. Any queries regarding the suitability of qualifications should be directed to the primary supervisor.

Please direct applications in the following format to Dr Jason Taylor ([Email Address Removed]):
• Academic CV
• Official academic transcripts
• Contact details for two suitable referees
• A personal statement (750 words maximum) outlining your suitability for the study, what you hope to achieve from the PhD and your research experience to date.

Any enquiries relating to the project and/or suitability should be directed to Dr Taylor. Applications are invited up to and including 25 November 2015.

Further details on the MRC DTP scheme and additional PhD project opportunities can be found on our website: www.mhs.manchester.ac.uk/mrcdtp

http://www.psych-sci.manchester.ac.uk/staff/jasontaylor