Null effect of anodal and cathodal transcranial direct current stimulation (tDCS) on own- and other-race face recognition

ABSTRACT

Successful face recognition is important for social interactions and public security. Although some preliminary evidence suggests that anodal and cathodal transcranial direct current stimulation (tDCS) might modulate own- and other-race face identification, respectively, the findings are largely inconsistent. Hence, we examined the effect of both anodal and cathodal tDCS on the recognition of own- and other-race faces. Ninety participants first completed own- and other-race Cambridge Face Memory Test (CFMT) as baseline measurements. Next, they received either anodal tDCS, cathodal tDCS or sham stimulation and finally they completed alternative versions of the own- and other-race CFMT. No difference in performance, in terms of accuracy and reaction time, for own- and other-race face recognition between anodal tDCS, cathodal tDCS and sham stimulation was found. Our findings cast doubt upon the efficacy of tDCS to modulate performance in face identification tasks.

KEYWORDS:

• Transcranial electrical stimulation
• brain stimulation
• face perception
• face memory
• tDCS

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authors’ contributions

The authors confirm contribution to the paper as follows: study conception and design: Siew Kei Kho and Alejandro J. Estudillo; data collection: Siew Kei Kho; analysis and interpretation of results: Siew Kei Kho and Alejandro J. Estudillo; draft manuscript preparation: Siew Kei Kho, David R. T. Keeble, Hoo Keat Wong and Alejandro J. Estudillo. All authors reviewed the results and approved the final version of the manuscript.

Ethics approval

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Science and Engineering Research Ethics Committee (SEREC) at the University of Nottingham Malaysia (approval code: KSK050320).

Availability of data and materials

The data that support the findings of this study are openly available in Open Science Framework (OSF) at https://osf.io/8t4zr/?view_only=654e85d7b3db43f38bf97385bea11a8e.

Open Practices Statements

The data for the experiment are available in Open Science Framework (OSF) at https://osf.io/8t4zr/?view_only=654e85d7b3db43f38bf97385bea11a8e and the experiment was preregistered via the OSF before data collection (https://osf.io/6cf7w).

Notes

1 Results of analysis by stage (2 (CFMT type: own-race vs. other-race) × 3 (CFMT stage: learn vs. novel vs. novel-with-noise) × 3 (simulation group: a-tDCS vs. c-tDCS vs. sham) ANOVA) conducted on accuracy and reaction time are included in Appendix B.

Additional information

Funding

This work was supported by the Fundamental Research Grant Scheme (FRGS) from the Ministry of Education (MOE) Malaysia (Grant number: FRGS/1/2018/SS05/UNIM/02/4) and the Society for Applied Research in Memory & Cognition (SARMAC) Student Caucus Research Grant.