Representative tests are essential in all empirical sciences. For instance, good visual acuity, measured with eye doctors’ Snellen E test, is assumed to predict good acuity when other visual acuity tests are used. A test is useless if performance in a test does not correlate with the performance of similar tests.
Surprisingly weak correlations are found in vision research in both young adults (Cappe et al., 2014), in healthy aging (Shaqiri et al., 2019; Garobbio et al., 2024) , and schizophrenia research (Gordillo et al., 2023). For example, we found that older adults performed worse than young adults in a battery of visual tests and illusions. However, within each population, performance in the various tests was largely uncorrelated, despite good test-retest reliability. In other words, poor performance in one test does not indicate poor performance in a similar test. In even other words: test validity is not good.
Therefore, tests are less representative than often expected, or the intra-individual variability is significantly higher than previously assumed. We propose to rethink the traditional approach of using a single test. Batteries of tests are needed.
Publications
Individual differences- Cretenoud AF, Barakat A, Milliet A, Choung OH, Bertamini M, Constantin C, Herzog MH (2021). How do visual skills relate to action video game performance? Journal of Vision, 21(7):10, p1-21.
- Cretenoud AF, Francis G, Herzog MH (2020). When illusions merge. Journal of Vision, 20(8):12, p1-15.
- Cretenoud AF, Grzeczkowski L, Bertamini M, Herzog MH (2020). Individual differences in the Müller-Lyer and Ponzo illusions are stable across different contexts. Journal of Vision, 20(6):4, p1-14.
- Cretenoud AF, Karimpur H, Grzeczkowski L, Francis G, Hamburger K, Herzog MH (2019). Factors underlying visual illusions are illusion-specific but not feature-specific. Journal of Vision, 19(14):12, p1-21.
- Shaqiri A, Roinishvili M, Grzeczkowski L, Chkonia E, Pilz K, Mohr C, Brand A, Kunchulia M, Herzog MH (2018). Sex-related differences in vision are heterogeneous. Scientific Reports, 8(1):7521, p1-10.
- Grzeczkowski L, Clarke AM, Francis G, Mast FW, Herzog MH (2017). About the individuality of vision. Vision Research, 141, p282-292.
- Cappe C, Clarke A, Mohr C, Herzog MH (2014). Is there a common factor for vision? Journal of Vision, 14(8):4, p1-11.
Individual differences in aging populations
- Garobbio S, Kunchulia M, Herzog MH (2024). Weak correlations between visual abilities in healthy older adults, despite long-term performance stability. Vision Research, 215:108355, p1-8.
- Garobbio S, Pilz KS, Kunchulia M, Herzog MH (2023). No common factor underlying decline of visual abilities in mild cognitive impairment. Experimental Aging Research, 49(3), p183-200.
- Shaqiri A, Pilz KS, Cretenoud AF, Neumann K, Clarke A, Kunchulia M, Herzog MH (2019). No evidence for a common factor underlying visual abilities in healthy older people. Developmental Psychology, 55(8), p1775-1787.
- Ballhausen N, Lauffs MM, Herzog MH, Kliegel M (2019). Investigating prospective memory via eye tracking: No evidence for a monitoring deficit in older adults. International Journal of Psychophysiology, 146, p107-116.
- Pilz KS, Kunchulia M, Parkosadze K, Herzog MH (2015). Ageing and visual spatiotemporal processing. Experimental Brain Research, 233(8), p2441-2448.
- Roinishvili M, Chkonia E, Stroux A, Brand A, Herzog MH (2011). Combining vernier acuity and visual backward masking as a sensitive test in aging research. Vision Research, 51(4), p417-423.
Individual differences in EEG
- Garobbio S, Lin WH, Kunchulia M, Herzog MH (2025). To what extent do EEG measures reflect performance in perceptual tests? Behavioural Brain Research, 488, p115602.
- Gordillo D, Ramos da Cruz JN, Chkonia E, Lin WH, Favrod O, Brand A, Figueiredo P, Roinishvili M, Herzog MH (2023). The EEG multiverse of schizophrenia. Cerebral Cortex, 33(7), p3816-26.