Therapeutic potential and research progress of microecological agents in kidney diseases.

Face processing is a crucial ability for identifying others in human social interactions. Nevertheless, face processing ability varies considerably across individuals (White and Burton, ). One manifestation of such individual differences is prosopagnosia, which is a selective impairment in the processing of familiar faces despite normal visual acuity, intelligence, and perception other than facial identity (Barton, ; Susilo and Duchaine, ). Prosopagnosia comprises two subtypes: acquired and developmental prosopagnosia. Acquired prosopagnosia is recognized as a higher-order cognitive dysfunction arising from brain injury, whereas developmental prosopagnosia is a neurodevelopmental property characterized by lifelong difficulties in face processing in the absence of overt brain injury (Bate and Tree, ; Duchaine and Nakayama, ; Nørkær et al., ). Although developmental prosopagnosia is a famous topic in cognitive neuroscience, it lacks an official diagnostic category within major classifications such as the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, ; Corrow et al., ; Gainotti, ). The prevalence rates of developmental prosopagnosia are reported to be 2.5% in Germany (; Kennerknecht et al., ), 2.0% in China (; Zhao et al., ), 2.1%–2.9% in Australia (; Bowles et al., ), and 0.1%–5.4% in the United States (; DeGutis et al., ). Given these high prevalence rates, calls for its inclusion in diagnostic frameworks have become more pronounced. However, research on developmental prosopagnosia suffers from the challenges in establishing diagnostic criteria, such as insufficient clarity in understanding its symptoms and a lack of precision in measurement (Bate and Tree, ; Burns, ; DeGutis et al., ; DeGutis and Campbell, ; Gerlach et al., ; Susilo and Duchaine, ). Therefore, identifying symptoms and establishing metrics are essential research topics in developmental prosopagnosia. Measuring individual differences in face processing is crucial not only for developmental prosopagnosia but also for the theoretical understanding of face processing and the clinical assessment of individuals with strengths or difficulties in face processing. To achieve these ends, researchers have developed various experimental instruments that assess different stages of face processing. Several experimental instruments have been developed, and they can be broadly divided into perception-, recognition-, and identification-based tests (Robotham and Starrfelt, ). Perception-based tests focus on simultaneous discrimination and identity-matching processes for faces, such as the Cambridge Face Perception Test (Duchaine et al., ), Benton Facial Recognition Test (Benton and Van Allen, ; Murray et al., ; Rossion and Michel, ), Glasgow Face Matching Test (Burton et al., ; White et al., ), Kent Face Matching Test (Fysh and Bindemann, ), and Oxford Face Matching Test (Stantic et al., ). Recognition-based tests include the widely used the Cambridge Face Memory Test (Duchaine and Nakayama, ; Russell et al., ), Warrington Recognition Memory for Faces Test (Warrington, ), and Ege Face Memory Test (Amado et al., ), which measure the ability of delayed discrimination and old/new face recognition. In identification, the Famous Faces Doppelgangers Test (Pozo et al., ), Famous Faces Recognition Test (Rizzo et al., ), and Italian Famous Face Test (Ventura et al., ) have also been employed to evaluate name-to-face matching and face naming, which rely on long-term and autobiographical memories for socially familiar identities. Together, these experimental measurement methods provide standardized and reproducible evaluations and are widely applied in research on individual differences in face processing. Experimental measures of face processing ability tend to encounter several challenges, as they involve the use of face photographs as visual stimuli. One such challenge is the own-group bias in face processing. Faces differ in characteristics such as race and sex, and these attributes can influence face processing performance (Hugenberg et al., ; Meissner & Brigham, ; Wright & Sladden, ; cf., Herlitz & Lovén, ). Indeed, several face processing tests are designed to account for race and sex, and methods appropriate for each group are needed (Arrington et al., ; Kho et al., ; McKone et al., ). Nevertheless, considering all of these influences simultaneously remains a formidable challenge. Another challenge to overcome is reducing the time required for screening for developmental prosopagnosia and combining multiple tests. Experimental tasks typically last approximately 10 min, which is rather long for screening purposes. Furthermore, while combining multiple tests enhances accuracy, prolonging cognitively demanding tasks may decrease examinee performance. Therefore, simpler and fewer photograph-based screening tests are likely to result in greater social demand.