Research

A famous issue in the Neurosciences is the question of how we can define functional sub-processes within the human cognitive system. Current theories often assume that the neuronal areas and processes that create visual awareness or that are relevant for object recognition are different from those that guide visual actions. We have shown that these processes are more similar than is currently thought—which was very unexpected and surprising for many scientists. This project is also part of the DFG research unit 'Modal and amodal cognition'. Sample publications:

• Bhatia, K., Osenberg, A., Janczyk, M., & Franz, V. H. (2025). Reviewing evidence for the perception-action model from Garner interference. Journal of Experimental Psychology: Human Perception and Performance, 51(2), 217-242. [ DOI | Website | PDF | Pre-registrations: 1 | 2 | 3 | Open materials & data | Abstract ]

• Bhatia, K., Löwenkamp, C., & Franz, V. H. (2022). Grasping Follows Weber's Law: How to Use Response Variability as a Proxy to JND. Journal of Vision, 22(12), 1-27. [ DOI | Website | PDF | Open materials & data | Abstract ]

• Kopiske, K. K., Bruno, N., Hesse, C., Schenk, T., & Franz, V. H. (2016). The functional subdivision of the visual brain: Is there a real illusion effect on action? A multi-lab replication study. Cortex, 79, 130-152. [ DOI | Website | PDF | Explanation of this preregistered report | Open materials & data | Abstract ]

• Franz, V. H., & Gegenfurtner, K. R. (2008). Grasping visual illusions: Consistent data and no dissociation. Cognitive Neuropsychology, 25(7), 920-950. [ DOI | PDF | Abstract ]

• Franz, V. H., Gegenfurtner, K. R., Bülthoff, H. H., & Fahle, M. (2000). Grasping visual illusions: No evidence for a dissociation between perception and action. Psychological Science, 11(1), 20-25. [ PDF | Abstract ]

Humans constantly track their environment for statistical regularities and use internal models to make predictions about the world. It is possible to detect when such predictions are violated by measuring the pupil in the eye -- which seems suprising in itself. This project is also part of the DFG collaborative research center 'Robust Vision'. Sample publications:

• Basgol, H., Dayan, P., & Franz, V. H. (2025). Violation of auditory regularities is reflected in pupil dynamics. Cortex, 183, 66-86. [ DOI | Website | PDF | Pre-registration | Open materials & data | Abstract ]

• Basgol, H., Dayan, P., & Franz, V. H. (2022). Is pupil-linked arousal a marker of model violation but not model update? (Poster at the 44th European Conference on Visual Perception (ECVP)) [ DOI ]

It is often assumed that even complex mental processes can be performed outside consiousness. If true, this would have far-reaching implications for the understanding of the functional role of consiousness. However, we found a serious methodological limitation that affects a large number of studies in this realm. In consequence, it is necessary to reassess the empirical evidence for many of the stronger claims about unconscious vs. consious processing. Sample publications:

• Meyen, S., Zerweck, I. A., Amado, C., von Luxburg, U., & Franz, V. H. (2022). Advancing research on unconscious priming: When can scientists claim an indirect task advantage? Journal of Experimental Psychology: General, 151(1), 65-81. [ DOI | Ask for copy | Preprint | Online ITA-calculator | Open materials & data | Abstract ]

• Meyen, S., Vadillo, M. A., von Luxburg, U., & Franz, V. H. (2024). No Evidence for Contextual Cueing Beyond Explicit Recognition. Psychonomic Bulletin & Review, 31, 907-930. [ DOI | Website | PDF | Pre-registration | Open materials & data | Abstract ]

• Schnepf (nee Zerweck), I. A., Friedrich, F., Hepting, C., Meyen, S., & Franz, V. H. (2022). Neural mechanisms of response priming do not support veridical unconscious processing. Consciousness & Cognition, 102, 103348. [ DOI | Website | Ask for copy | Abstract ]

Researchers sometimes report that humans have an intuitive feeling of when somebody is lying. If true this would have far-reaching practical consequences (for example for our legal system and for jurors at court). We described a similar methodological problem as we found for unconsciousness research above for studies on lie detection, which calls into question whether humans really have intuitive lie-detection capabilities that go beyond what they can report. Sample publications:

• Franz, V. H., Meyen, S., & von Luxburg, U. (2024). Technical comment on Gunderson, ten Brinke, and Sokol-Hessner (2023). When the body knows: Interoceptive accuracy enhances physiological but not explicit differentiation between liars and truth-tellers. Personality & Individual Differences, 204, 112039. Personality & Individual Differences, 217, 112439. [ DOI | Website | Ask for copy | Preprint | Open materials & data | Abstract ]

• Franz, V. H., & von Luxburg, U. (2015). No evidence for unconscious lie detection: A significant difference does not imply accurate classification. Psychological Science, 26(10), 1646-1648. [ DOI | Website | PDF | Preprint | Open materials | Abstract ]

• Franz, V. H., & von Luxburg, U. (2014). Unconscious lie detection as an example of a widespread fallacy in the Neurosciences. (preprint at arXiv:1407.4240; this preprint is more comprehensive than the corresponding Psychological Science article) [ DOI | Website | Abstract ]

A longstanding question in the cognitive sciences is the question of the representational format of human cognition. Is, for example, a dog represented in the brain by abstract concepts? Or is it represented by the sensory quality, when we experience and interact with the dog? In the DFG research unit 'Modal and amodal cognition' we work on these and related questions. Sample publications:

• Kaup, B., Ulrich, R., Bausenhart, K. M., Bryce, D., Butz, M. V., Dignath, D., Dudschig, C., Franz, V. H., Friedrich, C., Gawrilow, C., Heller, J., Huff, M., Hütter, M., Janczyk, M., Leuthold, H., Mallot, H., Nürk, H.-C., Ramscar, M., Said, N., Svaldi, J., & Wong, H. Y. (2023). Modal and Amodal Cognition: An Overarching Principle in Various Domains of Psychology. Psychological Research, 1-31. [ DOI | Website | PDF | Abstract ]

• Janczyk, M., Eichfelder, L., Liesefeld, H. R., & Franz, V. H. (2024). Learning and transfer of response-effect relations. Quarterly Journal of Experimental Psychology. [ DOI | Website | PDF | Pre-registration | Open data | Abstract ]

• Eichfelder, L. A., Franz, V. H., & Janczyk, M. (2023). Is there hierarchical generalization in response-effect learning? Experimental Brain Research, 241, 135-144. [ DOI | Website | PDF | Pre-registration | Open materials & data | Abstract ]

• Bhatia, K., Osenberg, A., Janczyk, M., & Franz, V. H. (2025). Reviewing evidence for the perception-action model from Garner interference. Journal of Experimental Psychology: Human Perception and Performance, 51(2), 217-242. [ DOI | Website | PDF | Pre-registrations: 1 | 2 | 3 | Open materials & data | Abstract ]

• Bhatia, K., Löwenkamp, C., & Franz, V. H. (2022). Grasping Follows Weber's Law: How to Use Response Variability as a Proxy to JND. Journal of Vision, 22(12), 1-27. [ DOI | Website | PDF | Open materials & data | Abstract ]

We investigated classic information theory for the combination of different cues. This has surprisingly general applications for biological as well as technical systems. In the DFG collaborative research center 'Robust Vision', we work on these and related questions. Sample publications:

• Meyen, S., Sigg, D. M. B., von Luxburg, U., & Franz, V. H. (2021). Group decisions based on confidence weighted majority voting. Cognitive Research: Principles and Implications, 6(18), 1-13. [ DOI | PDF | Open materials & data | Abstract ]

• Meyen, S., Göppert, F., Alber, H., Luxburg, U. von, & Franz, V. H. (2021). Specialists Outperform Generalists in Ensemble Classification. (preprint at arXiv:2107.04381) [ Website ]

It can be frustratingly difficult to replicate certain scientific claims ('replication crisis'). We contributed to the ensueing discussion by showing that we should expect even better replication rates than is sometimes assumed. Sample publications:

• Göppert, F., Bhatia, K., Meyen, S., & Franz, V. H. (in press). Realistic expectations for replications: Expecting too little is just as bad as expecting too much. Advances in Methods and Practices in Psychological Science. [ Ask for copy | Abstract ]

In a number of projects, we worked on confidence intervals for empirical data. Sample publications:

• Göppert, F., Bhatia, K., Meyen, S., & Franz, V. H. (in press). Realistic expectations for replications: Expecting too little is just as bad as expecting too much. Advances in Methods and Practices in Psychological Science. [ Ask for copy | Abstract ]

• Franz, V. H., & Loftus, G. R. (2012). Standard errors and confidence intervals in within-subjects designs: Generalizing Loftus & Masson (1994) and avoiding biases of alternative accounts. Psychonomic Bulletin & Review, 19(3), 395-404. [ DOI | Website | PDF | Abstract ]

• von Luxburg, U., & Franz, V. H. (2009). A geometric approach to confidence sets for ratios: Fieller's theorem, generalizations, and bootstrap. Statistica Sinica, 19(3), 1095-1117. [ Website | PDF | Abstract ]

• Franz, V. H. (2007). Ratios: A short guide to confidence limits and proper use. (preprint at arXiv:0710.2024) [ Website | Abstract ]

We investigate how benefitial advanced statistical methods and machine learning are to improve environmentally friendly heating systems (like solar thermal systems, heat-pumps, etc). Although those systems are becoming increasingly complex (and therefore lend themselves to such an analysis), they are still much less complex than the human brain. They therefore provide a good baseline and comparison for the other work we are doing. Sample publications:

• Ebmeier, F., Ludwig, N., Martius, G., & Franz, V. H. (2024). PaSTS: An operational dataset for domestic solar thermal systems. In Proceedings of the 15th ACM International Conference on Future and Sustainable Energy Systems (pp. 529-534). New York, NY, USA: Association for Computing Machinery. [ DOI | Website | PDF | Open materials & data | Abstract ]

• Ebmeier, F., Ludwig, N., Martius, G., & Franz, V. H. (2022). Fault Detection in Solar Thermal Systems Using Machine Learning. (Poster presented at the ISES & IEA SHC International Conference on Solar Energy for Buildings and Industry; EuroSun2022; 25-29 September 2022; Kassel, Germany). [ Abstract ]