Hockenbury Discovering Psychology 5th txtbk

160 CHAPTER 4 Consciousness and Its VariationsHypnotic Suppression of Pain In this classicphoto taken at the Stanford Laboratoryof Hypnosis Research, psychologist ErnestHilgard (1904–2001) instructs this hypnotizedyoung woman that she will feel nopain in her arm. Her arm is then immersedin circulating ice water for several minutes,and she reports that she does not experienceany pain. In contrast, a nonhypnotizedsubject perceives the same experienceas extremely painful and can keep hisarm in the ice water for no more than afew seconds.posthypnotic suggestionA suggestion made during hypnosis that theperson should carry out a specific instructionfollowing the hypnotic session.posthypnotic amnesiaThe inability to recall specific informationbecause of a hypnotic suggestion.hypermnesia(high-perm-NEE-zha) The supposedenhancement of a person’s memory for pastevents through a hypnotic suggestion.Sensory and PerceptualChangesSome of the most dramatic effectsthat can be produced with hypnosisare alterations in sensation and perception.Sensory changes that canbe induced through hypnosis includetemporary blindness, deafness,or a complete loss of sensation insome part of the body (Kihlstrom,2007). For example, when the suggestionis made to a highly responsivesubject that her arm is numband cannot feel pain, she will notconsciously experience the pain of apinprick or of having her arm immersedin ice water. This property ofhypnosis has led to its use as a techniquein pain control (Martinez-Salazer & others, 2008). Painfuldental and medical procedures, including surgery, have been successfully performedwith hypnosis as the only anesthesia (Hilgard & others, 1994).People can experience hallucinations under hypnosis. If a highly responsive hypnoticsubject is told that a close friend is sitting in a chair on the other side of theroom, she will not only report seeing the friend in vivid detail but can walk over and“touch” the other person. Under hypnosis, people can also not perceive somethingthat is there. For example, if the suggestion is made that a jar of rotten eggs has nosmell, a highly suggestible person will not consciously perceive any odor.Hypnosis can also influence behavior outside the hypnotic state. When aposthypnotic suggestion is given, the person will carry out that specific suggestionafter the hypnotic session is over. For example, under hypnosis, a student was giventhe posthypnotic suggestion that the number 5 no longer existed. He was broughtout of hypnosis and then asked to count his fingers. He counted 11 fingers! Countingagain, the baffled young man was at a loss to explain his results.Some posthypnotic suggestions have been reported to last for months, but mostlast only a few hours or days (Barnier & McConkey, 1999). So, even if the hypnotistdoes not include some posthypnotic signal to cancel the posthypnotic suggestion,the suggestion will eventually wear off.Hypnosis and MemoryMemory can be significantly affected by hypnosis (see Kihlstrom, 2007). Inposthypnotic amnesia, a subject is unable to recall specific information or eventsthat occurred before or during hypnosis. Posthypnotic amnesia is produced by ahypnotic suggestion that suppresses the memory of specific information, such asthe subject’s street address. The effects of posthypnotic amnesia are usually temporary,disappearing either spontaneously or when a posthypnotic signal is suggestedby the hypnotist. When the signal is given, the information floods back intothe subject’s mind.The opposite effect is called hypermnesia, which is enhancement of memory forpast events through hypnotic suggestion. Police investigators sometimes use hypnosisin an attempt to enhance the memories of crime victims and witnesses. Despitethe common belief that you can “zoom in” on briefly seen crime details under hypnosis,such claims are extremely exaggerated. Compared with regular police interviewmethods, hypnosis does not significantly enhance memory or improve theaccuracy of memories (Mazzoni & Lynn, 2006).