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LIT-1271: Trait phenomenological control predicts experience of mirror synaesthesia and the rubber hand illusion

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StatusActive — read in full 2026-10-20 (NOTE-990), with its supplementary information and the peer review file; worth reading as the first large-sample test of whether the rubber hand illusion, as it is usually measured, tracks the trait that hypnosis scales measure. In 353 undergraduates, hypnotisability predicted agreement with the ownership items after synchronous brushing (about half a scale point per SWASH point, rs 0.26), and just as well after asynchronous brushing and for a visual "control" item; it predicted synchronous proprioceptive drift weakly (rs 0.11). In separate samples of 404 and 154 it predicted vicarious pain and mirror touch. The planned manipulation of expectations failed, so nothing here is causal, and the pre-registered test, hypnotisability against the synchronous-minus-asynchronous difference, was inconclusive. Read it as strong evidence that the standard asynchrony and control-item checks do not control for suggestion, and as no evidence on whether the synchrony effect survives such a control. Seth, author of LIT-1263, is a co-author.
Tagsself, psychometrics, embodied-cognition, consciousness
Cited as “paper” byNOTE-990 — Lush, Botan, Scott, Seth, Ward & Dienes — Trait phenomenological control and the rubber hand illusion
Cited as “source” byTHEORY-766 — Brushing a seen rubber hand in synchrony with the hidden real hand, against asynchronous brushing, raises reports that touch is felt at the rubber hand and, more weakly and less reliably, that the rubber hand is one's own; the proprioceptive drift toward the rubber hand that accompanies these reports is not a measure of them; the standard comparison conditions do not equalise participants' expectations, so whether the stimulation or the expectation produces the report difference is open

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Lush, P., Botan, V., Scott, R. B., Seth, A. K., Ward, J. & Dienes, Z. (2020). Trait phenomenological control predicts experience of mirror synaesthesia and the rubber hand illusion. Nature Communications 11, 4853. DOI 10.1038/s41467-020-18591-6.

Key takeaways

From the reading, NOTE-990.

  • The ownership reports track a suggestion trait. In 353 participants, each point of SWASH hypnotisability (0–5) went with about 0.57 points more agreement (−3 to +3) with the touch, cause and ownership items after synchronous brushing (rs 0.26), and 0.70 points after asynchronous brushing. The visual “control” item, that the rubber hand came to resemble one’s own, was predicted at least as well (rs 0.31).
  • The drift tracks it only weakly. Synchronous drift rose about 0.6 cm per SWASH point (rs 0.11, R² 0.02); asynchronous drift showed no sensitive evidence either way. Combined with an earlier study’s difference-score correlation, drift was related to hypnotisability (r 0.22).
  • The standard controls do not control for suggestion. Asynchronous scores and control items are predicted by the same trait, and participants expect the illusion under synchrony and not under asynchrony. A synchronous-minus-asynchronous difference is therefore no check against expectation unless expectations and difficulty are matched across conditions, which the authors say future studies must do.
  • The causal test failed. Telling participants that asynchrony would work best did not change their expectations, so the pre-registered analyses could not be run. The pre-registered test that was run, hypnotisability against the synchrony difference in the uninstructed group, gave anecdotal evidence for drift and insensitive evidence for the questionnaire. The headline analyses were not pre-registered.
  • Mirror-sensory synaesthesia too. Hypnotisability predicted the number and intensity of vicarious pain responses (R² 0.07–0.08) and mirror-touch responses to humans and to objects (R² 0.04–0.06).

Standing in the record

Filed on 2026-10-20 at the owner’s request for experimental work that builds on the rubber hand illusion and bears on the record’s accounts of it. It is the study that tests the alternative the record’s synchrony THEORY, THEORY-765, most needs excluded. It measures trait suggestibility and expectations in a large sample with named tests and effect sizes, which is the form that THEORY’s promote_when asks for. It does not show that the synchrony effect survives suggestion, because the expectation manipulation failed and the difference-score test was inconclusive, so it neither promotes nor refutes that THEORY. It does show that the questionnaire evidence Botvinick & Cohen 1998 (LIT-1277) and Lenggenhager et al. 2007 (LIT-1279) rest on is confounded with a suggestion trait. The same applies to the cardio-visual contrasts Seth 2013 (LIT-1263) reports, and Seth is a co-author here. The NOTE says what it does to each THEORY.

It is half of a dispute the record is filing together. Lush 2020 in Collabra, on demand characteristics in the illusion, is its companion. The Nature Communications exchange between Ehrsson et al. 2022 and Lush & Seth 2022 contests this paper’s inference, and Roseboom & Lush 2022, also in Collabra, is filed alongside them. It carries no instruction for machine-learning practice.

One of the sources of THEORY-766 (filed 2026-10-20), which restates the rubber hand synchrony effect as a difference in reports, separates drift from those reports, and leaves open whether expectation produces the difference.

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