The Power of mind: Blocking visual perception by hypnosis

Abstract

The present study investigated the effects of suggestion on the processing of visual stimuli. Participants counted rare visual stimuli presented on a screen, once during a hypnosis condition where they were suggested that their vision of the screen is blocked by a virtual wooden board in front of their eyes and once during a control condition without suggestion. In the hypnosis condition, counting performance was about 20% worse than in the control condition. At the same time, the P3b amplitude of the event-related brain potential was about 37% reduced. Smaller P3b amplitudes were significantly associated with deficient counting performance, and this effect was largest in participants who reported the blockade as real. In contrast, earlier brain responses (N1, P2) that reflect basic processing of the visual stimuli were not affected by the suggested blockade. We conclude that the suggestion of the blockade affects later stages of visual perception, leaving early processes intact. This illustrates the impact of suggestions and the power of mind.

Hypnotic Suggestions Given Before Nighttime Sleep Extend Slow-Wave Sleep as Compared to a Control Text in Highly Hypnotizable Subjects

“…What could be a possible mechanism for how hypnotic suggestions given before sleep induce later SWS? Generally, hypnotic suggestions given during a state of hypnotic trance are capable of inducing changes in behavior with measurable psychophysiological effects (e.g., reducing pain perception, motor paralysis, vision, etc., Cojan et al, 2009;Derbyshire, Whalley, & Oakley, 2009;Kosslyn, 2000;Schmidt, Hecht, Naumann, & Miltner, 2017), probably due to processes of autoimagination. In addition, posthypnotic suggestions are known to effectively influence behavior, and their neuronal correlates also after hypnosis, i.e., effects of posthypnotic suggestions on decision making (Ludwig et al, 2014), posthypnotic amnesia (Mendelsohn, Chalamish, Solomonovich, & Dudai, 2008), automatic processing (Lifshitz, Aubert Bonn, Fischer, Kashem, & Raz, 2013;Raz, Kirsch, Pollard, & Nitkin-Kaner, 2006), etc.…”

Mental Training for Better Achievement: Effects of Verbal Suggestions and Evaluation (of Effectiveness) on Cognitive Performance

“…In one study, the performance in the Flanker task, for example, was only influenced by posthypnotic suggestions in highly suggestible participants compared to (the same) non-hypnotic suggestions in an alert state ( 7 ). Thus, the advantage of using verbal suggestions after a hypnotic induction or with highly suggestible participants instead of only verbal instructions is that hypnotic suggestions were able to even demonstrate control over some cognitive processes, as described before ( 5 , 6 ). However, there is only some literature regarding the enhancement of cognitive performance only via verbal suggestions.…”

“…Automatic visual perception and cognitive processes, as they are for example assumed for the Stroop effect, can be influenced and even controlled just by receiving verbal suggestions during a hypnotic experience. This effect was most pronounced in highly suggestible individuals ( 5 , 6 ). For example, the interference in the Stroop effect, when the ink color and the word color are incongruent, could be eliminated when suggesting subjects to view word stimuli as neutral and meaningless ( 5 ).…”

“…For example, the interference in the Stroop effect, when the ink color and the word color are incongruent, could be eliminated when suggesting subjects to view word stimuli as neutral and meaningless ( 5 ). Furthermore, the performance of counting visual stimuli was reduced when suggesting participants after a hypnotic induction that a wooden board would cover the screen ( 6 ). In one study, the performance in the Flanker task, for example, was only influenced by posthypnotic suggestions in highly suggestible participants compared to (the same) non-hypnotic suggestions in an alert state ( 7 ).…”

Can hypnosis displace the threshold for visual consciousness?

“…On a more recent note, Schmidt et al. (2017) implemented a slight variation of hypnotic blindness paradigms by hypnotically suggesting to their participants that their visual field was obstructed by a wooden board.…”