How minds differ
Strong expectations, quieter senses
In shortExpectations held very firmly can shape what a person perceives more than what is there.
The idea
When what someone expects is held with great confidence, it can shape what they perceive more than what is there. A stomach that is expected to hurt before school can hurt; a noise that is expected to be someone calling can sound like a voice. The person feels it fully, because perception is built from both. Changing it takes evidence that is strong enough, and repeated enough, to compete with the expectation.
What to try
- Take the experience seriously as an experience, and stay curious about what shapes it.
- Look for situations where the expectation is weaker (holidays, another place, another person) and compare.
- Build new evidence slowly and often: small, repeated experiences count for more than one big argument.
The common mistake
Trying to argue the expectation away, or treating the experience as made up.
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Short, plain pieces by the researchers and good writers.
Books
Experience as a ‘controlled hallucination’: the body and world perceived from predictions.
See on Amazon ›How the predictive brain shapes what we see, feel and do, with many everyday examples.
See on Amazon ›Amazon links are affiliate links: if you buy, Bounded Uncertainty receives a small commission at no cost to you.
The science behind itHow strong the evidence is, the model, videos and references.
How strong the evidence is
Promising Good studies, but little tested with children at home or school, or the step to daily life is our interpretation.
When the precision of high-level priors is high relative to sensory prediction errors, perception is pulled towards the prior. Powers, Mathys and Corlett (2017) induced conditioned hallucinations by pairing tones with lights, and people who hear voices were more susceptible; Corlett et al. (2019) review strong-prior accounts of hallucinations. Similar accounts have been proposed for functional symptoms (Edwards et al., 2012) and for symptom perception and placebo (Ongaro and Kaptchuk, 2019). For formulation with children: separate the signal, the expectation and the context; look for a dose-response relationship with expectation (anticipation, place, people) more than with physical load; and design graded exposures that give precise, repeated evidence the other way. These are accounts of mechanism; they do not mean a symptom is ‘psychological’ in the dismissive sense.
References
- Edwards, M. J., Adams, R. A., Brown, H., Pareés, I., & Friston, K. J. (2012). A Bayesian account of ‘hysteria’. Brain, 135(11), 3495–3512.
- Powers, A. R., Mathys, C., & Corlett, P. R. (2017). Pavlovian conditioning–induced hallucinations result from overweighting of perceptual priors. Science, 357(6351), 596–600.
- Corlett, P. R., Horga, G., Fletcher, P. C., Alderson-Day, B., Schmack, K., & Powers, A. R. (2019). Hallucinations and strong priors. Trends in Cognitive Sciences, 23(2), 114–127.
- Ongaro, G., & Kaptchuk, T. J. (2019). Symptom perception, placebo effects, and the Bayesian brain. Pain, 160(1), 1–4.
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