Frederick J. Evans

Monitoring attention deployment by random number generation: An index to measure subjective randomness

The generation of random number sequences as a measure of attention deployment has been limited due to the lack of a satisfactory index of pseudorandomness for relatively short response sequences (Wagenaar, 1972). A new index of subjective randomization (RNG) is presented that provides a sensitive measure of departures from randomness (reflecting the disproportion with which any number follows any other number) in a series as short as 100 responses, typically verbalized at a rate of 1/sec. The RNG index of sequential response bias is a minor modification of Tulving’s (1962) subjective organization index that measures clustering in the repeated free recall of randomly presented word lists. Calculation of the practice-free RNG index and comparisons with another common measure are illustrated with individual data and with data obtained from random number tables. The use of RNG as a probe or simultaneous task to measure the deployment of attention or attentive effort is discussed.

Two types of posthypnotic amnesia: Recall amnesia and source amnesia

Abstract Posthypnotic recall amnesia traditionally refers to Ss inability to recall, when challenged posthypnotically, the events which occurred during hypnosis. Posthypnotic source amnesia, only indirectly alluded to in the literature, occurs when S subsequently remembers the experiences of hypnosis, but has no recollection of acquiring the experiences: S knows the information presented during hypnosis, but does not know how or why he knows. Data from 3 samples are presented to support the distinction between the 2 types of posthypnotic amnesia. Of 243 Ss, 18 experienced recall amnesia, 26 displayed source amnesia, but only 4 developed both kinds of amnesia. There were no differences in rated depth of hypnosis of these 3 subgroups. Correlations between both types of amnesia with both rated depth of hypnosis and objective measures of susceptibility to hypnosis were significant but low. Recall amnesia and source amnesia correlated .37, .38, and .39, respectively (p < .001) in the 3 samples. The evidence in...

Recovery of Memory After Posthypnotic Amnesia.

Documentation of the reversibility of posthypnotic amnesia has been hampered by the correlation of hypnotizability with the initial level of response to amnesia suggestions. In a sample of 691 subjects, groups differing in hypnotic susceptibility could be matched for initial amnesia recall, thereby eliminating the ceiling effect. At virtually every point along the distribution of initial amnesia response, hypnotizable subjects were significantly better able than insusceptible subjects to recapture the previously blocked memories after the amnesia suggestion was lifted. Conversely, those subjects who showed reversibility of amnesia were more responsive overall to hypnosis than those who did not. Reversibility is of value in distinguishing between amnesia and pseudoamnesia and between partial amnesia and nonamnesia. Furthermore, reversibility helps define posthypnotic amnesia as a process involving the disruption of retrieval processes in memory.

The relation between the Hypnotic Induction Profile and the Stanford Hypnotic Susceptibility Scales, forms A and C.

Abstract Measures from the clinically derived Hypnotic Induction Profile (HIP) of Spiegel (1974a) were correlated with those from the laboratory derived Stanford Hypnotic Susceptibility Scales, Forms A and C (SHSS:A, SHSS:C) of Weitzenhoffer and Hilgard (1959, 1962), and with some scores from the related Harvard Group Scale of Hypnotic Susceptibility, Form A (Shor & E. Orne, 1962). Ss were paid volunteers from student populations at the University of Pennsylvania (N = 87) and from Stanford University (N = 58). Some differences in sampling procedures and orders of testing are discussed, but only minimal differences between the 2 samples resulted. Positive but nonsignificant correlations were found between the Eye-Roll sign alone and SHSS in the 2 samples. Both the Induction (IND) and Profile scoring methods of HIP were compared with SHSS. The IND, an actuarial scale, was positively correlated with SHSS. A representative value is the significant correlation of .34 between IND and SHSS:(A + C)/2 scores when ...

Relationship between the harvard group scale of hypnotic susceptibility and the stanford hypnotic susceptibility scale: Form c

Abstract 3 subgroups of 20 Ss with high, medium, or low scores on a slightly modified, tape-recorded version of the Harvard Group Scale of Hypnotic Susceptibility, Form A (HGSHS:A) of Shor and E. Orne (1962) were later administered the Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and Hilgard (1962). HGSHSrA and SHSSrC correlated .59 which is lower than would be predicted by scale reliabilities. This, together with other data based on item characteristics, indicates that the 2 scales are not equivalent, but in part measure different aspects of hypnotic performance. Scores on HGSHSrA for low Ss are predictive of SHSS:C scores, but the stability of performance between HGSHS:A and SHSS:C is not as marked for medium and high Ss on HGSHS:A. This is partly a result of the failure of passive motor (primary) suggestibility to discriminate between levels of susceptibility, although challenge items do. The 2 clusters of items correlate .23 and .43 in HGSHS:A and SHSS:C respectively. The p...

Inadvertent termination of hypnosis with hypnotized and simulating subjects

Abstract 12 Ss-6 highly hypnotizable, and 6 unhypnotizable but with instructions to simulate hypnosis-were given hypnotic instructions by means of a tape-recordmg. All Ss had participated in at least 2 previous tape-recorded sessions which took place in the same room, equipped with a one-way screen. The E did not know which Ss were hypnotizable and which had instructions to simulate hypnosis. Continuous measures of subjective hypnotic depth and GSP were recorded to allow E to take the role of technician. After Ss had been hypnotized by the tape-recorder, a light went out, the tape-recorder stopped, and E rushed from the room-apparently in search of a fuse box. The Ss were observed for 30 minutes through the one-way screen after which the current was turned on, and 2% minutes later E returned. During this time the hypnotic suggestions appeared to lose their effectiveness, and the hypnotized Ss gradually awoke. However, 5 of 6 simulating Ss behaved as though they were in hypnosis throughout. On inquiry, it ...

Response during Sleep with Intervening Waking Amnesia

During stage 1 sleep, subjects responded to suggestions on two or more nights, up to 5 months apart. While they were awake they did not recall the material to which they successfully responded while asleep on a subsequent night.

Verbally induced behavioral responses during sleep.

This study explored the possibility of eliciting motor responses from sleeping Ss. Nineteen Ss slept in the laboratory for 2 nights. Some Ss responded behaviorally, while remaining asleep, to verbal suggestions which had been administered previously during stage 1 sleep. Many responses were obtained without elieiting alpha activity during the suggestion, after the cue word was administered, or before and after the response. When a successful response occurred, alpha frequency was not significantly different from the slowed frequency occurring spontaneously during stage 1 sleep. The average response latency was 32 seconds, and this increased as the temporal dissociation between the administration of the suggestion and the eue word increased. After the S awakened, he did not remember the verbally presented material, nor could he remember responding, and he did not respond to the eue word while awake. When S returned to sleep the next night, or even 5 months later, the mere repetition of the relevant eue word (without repetition of the suggestion itself) was sufficient to elicit the appropriate response. It is concluded that a subject is capable of some interaction with his environment while he is aslcep.

Restricted Use of Success Cues in Retrieval During Posthypnotic Amnesia

Memory for successful and unsuccessful responses to hypnotic suggestions was evaluated in partially amnesic subjects and in those subjects with normal forgetting. Two analyses (N = 278) demonstrated that highly hypnotizable subjects experiencing partial posthypnotic amnesia tended to show no selective recall for their successes or failures during amnesia, whereas the remainder of the subjects showed definite selective recall of hypnotic success posthypnotically. These findings lend support to the hypothesis put forth by Evans and Kihlstrom that posthypnotic amnesia involves a disruption of memory organization and suggests that the phenomenon may be mediated by a restriction in the use of normally employed retrieval cues.

HYPNOSIS AND SLEEP: THE CONTROL OF ALTERED STATES OF AWARENESS*

In spite of some obvious phenomenological similarities between hypnosis and sleep, they appear to be unrelated physiologically. I t will, however, be hypothesized in this report that hypnosis and sleep may share some control mechanism that may partly account for individual differences in the ability to experience hypnosis and in the ease of falling asleep and maintaining voluntary control of sleep processes.