The Danish Version of the 20-Item Prosopagnosia Index (PI20): Translation, Validation and a Link to Face Perception

Abstract

Developmental prosopagnosia (DP) is a neurodevelopmental condition characterized by face recognition problems. Psychometrically sound self-report measures of face recognition problems are important tools in classification of DP. A widely used measure of such problems is the 20-item prosopagnosia index (PI20). Here, we present a Danish translation of the PI20 (PI20_DK). We administered the PI20_DK alongside three objective measures of face and object processing performance to 119 participants to validate the PI20_DK. Further, we assess the underlying factor structure of the PI20_DK. Finally, as the first study in the field, we investigate the association between self-reported face recognition ability and face perception performance. The project was preregistered prior to data collection. The results suggest excellent convergent validity, discriminant validity and internal consistency for the PI20_DK. A confirmatory factor analysis, however, indicates a suboptimal fit of the PI20_DK to a one factor solution. An investigation of the association between the PI20_DK and face perception suggests that the poor fit may reflect that the PI20_DK measures problems with face recognition in general and not specifically face memory problems.

Keywords: developmental prosopagnosia; face perception; face recognition; object recognition; self-report measures.

Figure 1

Scatter plots of scores on the PI20_DK and performance on the three objective measures (N = 119). The blue lines are linear regression models with 95% confidence intervals in grey. PI20_DK = the Danish version of the 20-item prosopagnosia index; CFMT = Cambridge Face Memory Test; CCMT = Cambridge Car Memory Test; CFPT = Cambridge Face Perception Test. The two extreme outliers on CFPT have been kept in the analysis, as specified in the preregistration. If these two points are excluded from the analysis, the result is r = −0.167, p = 0.072.