Josh Davis was interviewed in the Daily Express at the start of January 2020, alongside Emma Mitchell from Super-Recognisers International.
The quote (substantially cut from the original interview) by Josh Davis in the article referring to the brain scanning research is based on Dr Elena Belanova's PhD research published in Cortex.
Belanova, E., Davis, J. P., & Thompson, T. (2018). Cognitive and neural markers of super-recognisers' face processing superiority and enhanced cross-age effect. Cortex, 98, 91-101. DOI:10.1016/j.cortex.2018.07.008
Using EEG, Elena found significant differences in brain activity between super-recognisers and controls 100 milliseconds (ms) (often called P100) after previously displayed face stimulus presentation. There were also more substantial differences in brain activity at P600 - 600ms after display. The reasons for these effects are speculated on in the paper. However, further research is required to substantiate outcomes..
ResearchGate link for free pre-print download:-