Psychophysical Effects on an Interference Pattern in a Double-Slit Optical System: An Exploratory Analysis of Variance
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Plain English Summary
Can human minds affect how light behaves? This study revisits an online double-slit experiment (where light makes a stripy pattern passing through two tiny openings) with nearly 3,000 people and over 5,000 robot controls. Earlier analysis found no evidence attention shifted the pattern. So the researchers changed tactics: they measured whether human sessions showed more variability than robot ones, reasoning wandering minds flip the effect back and forth. Results were striking — significant in both year one and a held-out replication, with combined odds around one in ten million against chance. Laser wobbles and time-of-day artifacts were ruled out. The catch? Critics call this moving the goalposts — changing your hypothesis after the original fails is a red flag.
Actual Paper Abstract
Objective: A two-year online experiment tested the hypothesis that focused human attention alternatively directed toward or away from a double-slit optical system would affect the interference pattern in a predictable, unidirectional fashion. A control condition was employed by having a web server periodically simulate a human observer. Method: Based on the results of an independent reanalysis of these data and the outcome of an independent conceptual replication, we revisited the original directional hypothesis to explore the possibility that mind-wandering and other distractions might have caused attention or intention to unpredictably fluctuate. That in turn might have caused the hypothesized psychophysical influence to be more readily detected as a bidirectional effect (i. e., a shift in variance) rather than as unidirectional effect (a shift in mean). To test this idea, we developed a variance-based analysis using data collected during the first year of the experiment and applied it to data from the second year. Results: The first year's data showed that experimental sessions conducted by humans resulted in significant variance differences as compared to control sessions conducted by a computer, z = 4.16, p = .00002. The same analysis applied to the second year's data resulted in z = 3.14, p = .0008. Examination of environmental and apparatus variables indicated that those factors were not responsible for the observed changes in variance. Conclusion: The results suggest that a variance analysis may be more sensitive to psychophysical effects in this type of experiment.
Research Notes
Part of the Radin/IONS double-slit series (2012–2022), responding directly to Tremblay (2019, 2021) and Walleczek & von Stillfried (2019) critiques that found no directional effect. The shift from directional to variance hypothesis is methodologically controversial: skeptics view it as post-hoc revision; proponents argue bidirectionality is theoretically expected given mind-wandering.
Exploratory reanalysis of a two-year online double-slit optical experiment (2013–2014) in which 2,825 human participants and 5,469 robot control sessions were recorded. The original directional hypothesis (focused attention collapses the interference pattern) was not confirmed by prior reanalysis (Tremblay 2019). A new variance-based bidirectional metric (|Δv|) — motivated by the hypothesis that mind-wandering causes psychophysical effects to fluctuate — found significant differences between human and robot sessions: z = 4.16 (p = .00002) in 2013 data and z = 3.14 (p = .0008) in 2014 held-out replication. Combined Stouffer Z = 5.57 (p = 1.3 × 10⁻⁸). Environmental controls ruled out laser power and time-of-day artifacts.
Links
Related Papers
Same Research Program
- Consciousness and the Double-Slit Interference Pattern: Six Experiments — Radin, Dean (2012)
- Observer Influence on Quantum Interference: Testing the von Neumann-Wigner Consciousness-Collapse Theory — Radin, Dean (2025)
- Psychophysical Interactions with a Double-Slit Interference Pattern: Exploratory Evidence of a Causal Influence — Radin, D.I (2021)
- Commentary: False-Positive Effect in the Radin Double-Slit Experiment on Observer Consciousness as Determined With the Advanced Meta-Experimental Protocol — Radin, Dean (2020)
Cites
- Examining Psychokinesis: The Interaction of Human Intention With Random Number Generators—A Meta-Analysis — Bösch, Holger (2006)
- Distant intentionality and the feeling of being stared at: Two meta-analyses — Schmidt, Stefan (2004)
- The Capricious, Actively Evasive, Unsustainable Nature of Psi: A Summary and Hypotheses — Kennedy, J.E (2003)
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📋 Cite this paper
Radin, Dean, Delorme, Arnaud (2022). Psychophysical Effects on an Interference Pattern in a Double-Slit Optical System: An Exploratory Analysis of Variance. Journal of Anomalous Experience and Cognition. https://doi.org/10.31156/jaex.24054
@article{radin_2022_psychophysical_effects_double_slit,
title = {Psychophysical Effects on an Interference Pattern in a Double-Slit Optical System: An Exploratory Analysis of Variance},
author = {Radin, Dean and Delorme, Arnaud},
year = {2022},
journal = {Journal of Anomalous Experience and Cognition},
doi = {10.31156/jaex.24054},
}