Date Published: February 7, 2019
Publisher: Public Library of Science
Author(s): Nicolas Tremblay, L. Krister Shalm.
A two year long experimental dataset in which authors of Radin, et al., 2016 claim to find evidence of mind-matter interaction is independently re-analyzed. In this experiment, participants are asked to periodically shift their attention towards or away from a double-slit optical apparatus. Shifts in fringe visibility of the interference pattern are monitored and tested against the common sense null hypothesis that such shifts should not correlate with the participant’s attention state. We propose a deeper analysis of the dataset, identifying all the necessary arbitrary pre-analysis choices one needs to make, and carefully assessing the results’ robustness regarding these choices. Results are twofold. Firstly, even with a conservative correction for the multiple statistical tests the analysis calls for, we confirm the existence of significant although small anomalies in the direction predicted by the mind-matter interaction hypothesis. On the other hand, and unlike Radin, et al., 2016, we also report significant although even smaller anomalies in the control dataset. This leads us to conclude that this particular dataset does not provide strong evidence of mind-matter interaction, yet certainly contains inexplicable anomalies that should motivate replication attempts in highly controlled environments.
The hypothesis of a mind-matter interaction, that is, the possibility that human intention may have an impact on matter at a distance, is usually regarded by most physicists as a highly controversial concept. It is nonetheless related to von Neumann’s interpretation  of the quantum measurement problem, namely that consciousness causes the collapse of the wave function when a quantum system in a superposition of states is observed. Even if this interpretation has been and still is considered by many minds of quantum mechanics [2–4], it is today blatantly disregarded by a majority of physicists  partly because it flirts with the overwhelmingly complex mind/body problem. This mysterious link between consciousness and matter appears indeed to have an infinite number of uncontrollable parameters, and therefore does not seem to lend itself to rigorous scientific inquiry. Moreover, von Neumann’s interpretation being by all means only one out of many possible interpretations of quantum mechanics  –most of which keep consciousness aside–, physicists generally prefer mathematically controlled objective concepts such as quantum decoherence  or Everett’s many-worlds interpretation . It is nevertheless well worth reminding that, however strong and heated are personal convictions around this debate, consensus over the quantum measurement problem has not yet been reached  and that any attempt to provide empirical information on this matter should be widely welcome.
The preliminary analysis proposed in Section 2.4 is subject to four seemingly arbitrary choices: the fringe number, the minimal length of a session, the outlier percentage and the choice of the fringe visibility estimation method. In Section 2.5, we observe that different fringe choices change the output of the statistical tests, and thus the conclusions that may be drawn from the data. We therefore propose two more robust methods that avoid choosing fringes: the first one is to encompass all fringes in the null hypothesis, leading to H0′, and the second is to average the fringe visibility over central intervals of fringes, leading to H0″. We summarize the observed results of the tests at the end of Section 2.5. We not only show that these results are robust i/ regarding the minimal session length in Section 2.7, ii/ regarding the fringe visibility estimation method in Section 2.8, iii/ to random subsampling of the data in Section 2.9; but we also show in Section 2.6 that the significance of the anomalies increase as the percentage of outliers increases, which is a strong indication that the core of the data is truly anomalous.
The thorough analysis pursued in this paper gives a much broader and full picture of the data than the ones previously published in  and . On the one hand, we find undeniable anomalies in the human data with shifts of the fringe visibility in the direction expected by human intention. The fact that fringe visibility decreases when human intention tries to make it decrease, and increases when human intention tries to make it increase is remarkable. On the other hand, significant anomalies are found in the 2013 controls with shifts in the opposite direction than the anomalies in the human data. Effect sizes show a small (none exceeding 0.11) but non-negligeable size of the effect, with human effect sizes slightly higher than control ones. Our efforts to find systematic biases explaining these anomalous shifts are not conclusive. Finally, all our analysis and figure-plotting Matlab codes, along with all the raw data, are publicly available on the Open Science Framework database platform at the address https://osf.io/ywktp/, to aid further investigations on this particular dataset.