Source
Apps & Tsakiris (2014), LIT-1262, Neuroscience & Biobehavioral Reviews 41, read in full from the PMC author manuscript in NOTE-991: §4 (the self as a prior), §5 (the illusions), §6 (anatomical predictions) and §7 (caveats). Botvinick & Cohen (1998), LIT-1277, read in NOTE-1006, is the primary result the account is built to explain.
What was actually shown
Apps and Tsakiris report no data and no model. They argue, within the free-energy and predictive-coding framework, which they take as given (§3), that one’s own body is “the one which has the highest probability of being ‘me’”, because no other object reliably evokes the same correlated input across the senses. “The notion that there is a ‘self’ is the most parsimonious and accurate explanation for sensory inputs” (§4).
On this account the rubber hand, enfacement and rubber-voice illusions are one process. Synchronous stimulation leaves “considerable bottom up sensory surprise” in one sense, multimodal areas explain it away, and the representation of one’s body part shifts (§§5.1–5.2, Fig. 1). “The driving effect for each illusion is an increase in the probability that the other object … will be represented as part of the body and a decrease in the probability that one’s actual body will be represented as ‘self’” (§5.2). Context acts as a prior: the illusion is weaker or absent for a non-bodily object, a hand of another skin tone, or a hand in an incongruent place (§5.3).
What the account adds to the bare finding of THEORY-765 is two commitments that could fail:
- Ownership is graded. It is a probability, not a switch.
- It is shared. What the other object gains, the real part loses. The authors cite cooling of the real hand and raised histamine reactivity as signs of this (§5.2).
What this does not say
- It is not tested. “There is, as yet, little direct evidence that predictions and prediction errors related to self-stimuli are processed anywhere in the brain” (§7). “Empirical data neither largely supports nor refutes our account” (§8). Every finding the paper uses was gathered under other accounts.
- The physiology is interpretation. Cooling and histamine are read as falling probability of ownership. No mechanism links them, so they cannot carry the second commitment on their own. That is why the promotion test asks for another measure.
- The prior can explain either result. The account explains why the illusion fails for a box by a prior against boxes being hands. A different prior would explain the opposite result. Until priors are measured apart from the outcome they explain, this part of the account is not falsifiable, as NOTE-991 notes.
- It says nothing about being a self. The account explains how a body is modelled as one’s own. It does not say why the model is experienced as a self rather than as a model, which is THEORY-064’s claim.
- It does not model interoception. Interoception is named among the inputs but none of the worked cases uses it. That is THEORY-767.
- It is about ownership, not agency. It makes motor signals one kind of prediction among others, so that self-recognition needs no action. That is argued, not shown.
Added on 2026-10-20
- The finding it explains is narrower than first filed. THEORY-765, which this account was built to explain, is Rejected and corrected by THEORY-766. Drift is not a measure of ownership reports, and the ownership report is the weakest of the illusion items and tracks trait suggestibility. An account that predicts drift and ownership from one belief now has two outputs to fit, not one.
- The source’s authors are on one side of an open dispute. Tsakiris signs Ehrsson et al. (2022, LIT-1264), which reads the rubber hand data as multisensory perception. Whether they are is THEORY-766’s open question.
- The cooling evidence is thinner than its citation. Hohwy & Paton (2010, LIT-1272), which the source cites for cooling of the real hand, report 0.13 °C in one comparison of four. It is significant only one-tailed and uncorrected, under a real foreign arm, not a rubber one, and with no ownership measure. Their box result, touch referred to a box only after the illusion has begun, is explained there by a prior that drops once the illusion is running. That is the after-the-fact move this account is warned against above. The promote_when already asks for a measure other than temperature, so the THEORY’s standing does not change.
Connections
No relation is declared: no open question asks how body ownership arises.
- THEORY-765 is the finding this explains. Botvinick & Cohen’s own constraint-satisfaction account is an earlier, non-probabilistic account of the same kind; the mapping is the record’s.
- THEORY-767 extends the same inference to interoceptive signals, and Seth (LIT-1263) takes this paper as his frame.
- LIT-1181, NOTE-960. The account adopts Friston et al.’s treatment of motor signals as proprioceptive predictions, and draws the consequence that motor efference has no special standing for the self.
- THEORY-064. Close in wording (“the notion that there is a ‘self’”), but it does not test transparency or deny a self.