School of Humanities and Informatics, University of Skövde, Skövde, Sweden.
PLoS One. 2011;6(10):e26374. doi: 10.1371/journal.pone.0026374. Epub 2011 Oct 24.
Hypnosis has had a long and controversial history in psychology, psychiatry and neurology, but the basic nature of hypnotic phenomena still remains unclear. Different theoretical approaches disagree as to whether or not hypnosis may involve an altered mental state. So far, a hypnotic state has never been convincingly demonstrated, if the criteria for the state are that it involves some objectively measurable and replicable behavioural or physiological phenomena that cannot be faked or simulated by non-hypnotized control subjects. We present a detailed case study of a highly hypnotizable subject who reliably shows a range of changes in both automatic and volitional eye movements when given a hypnotic induction. These changes correspond well with the phenomenon referred to as the "trance stare" in the hypnosis literature. Our results show that this 'trance stare' is associated with large and objective changes in the optokinetic reflex, the pupillary reflex and programming a saccade to a single target. Control subjects could not imitate these changes voluntarily. For the majority of people, hypnotic induction brings about states resembling normal focused attention or mental imagery. Our data nevertheless highlight that in some cases hypnosis may involve a special state, which qualitatively differs from the normal state of consciousness.
催眠在心理学、精神病学和神经科学中有着悠久而颇具争议的历史，但催眠现象的基本性质仍不清楚。不同的理论方法对于催眠是否可能涉及改变的心理状态存在分歧。到目前为止，如果催眠状态的标准是它涉及一些可以客观测量和复制的行为或生理现象，而这些现象不能被非催眠对照受试者伪造或模拟，那么催眠状态从未得到令人信服的证明。我们提出了一个高度催眠的个体的详细案例研究，当给予催眠诱导时，该个体的自动和随意眼球运动可靠地显示出一系列变化。这些变化与催眠文献中提到的“恍惚凝视”现象非常吻合。我们的结果表明，这种“恍惚凝视”与视动反射、瞳孔反射和编程单次注视目标的眼球运动的大而客观的变化有关。对照受试者无法自愿模仿这些变化。对于大多数人来说，催眠诱导会产生类似于正常专注或心理意象的状态。然而，我们的数据强调，在某些情况下，催眠可能涉及一种特殊的状态，这种状态在质量上与正常意识状态不同。
