Vestibular stimulation attenuates unrealistic optimism

Ryan McKay, Corinne Tamagni, Antonella Palla, Peter Krummenacher, Stefan Hegemann, Dominik Straumann, Peter Brugger

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Introduction: Unrealistic optimism refers to the pervasive tendency of healthy
individuals to underestimate their likelihood of future misfortune, including illness. The phenomenon shares a qualitative resemblance with anosognosia, a neurological disorder characterized by a deficient appreciation of manifest current illness or impairment. Unrealistic optimism and anosognosia have been independently associated with a region of right inferior frontal gyrus, the pars opercularis. Moreover, anosognosia is temporarily abolished by vestibular stimulation, particularly by irrigation of the left (but not right) ear with cold water, a procedure known to activate the right inferior frontal region. We
therefore hypothesized that left caloric stimulation would attenuate unrealistic optimism in healthy participants.
Methods: Thirty-one healthy right-handed adults underwent cold water caloric
vestibular stimulation of both ears in succession. During each stimulation episode, and at baseline, participants estimated their own relative risk of contracting a series of illnesses in the future.
Results: Compared to baseline, average risk estimates were significantly higher during left-ear stimulation, whereas they remained unchanged during right-ear stimulation. Unrealistic optimism was thus reduced selectively during cold caloric stimulation of the left ear.
Conclusions: Our results point to a unitary mechanism underlying both anosognosia and unrealistic optimism, and suggest that unrealistic optimism is a form of subclinical anosognosia for prospective symptoms.
Original languageEnglish
Pages (from-to)2272-2275
Issue number8
Early online date30 Apr 2013
Publication statusPublished - 21 Aug 2013

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