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Hypnosis research – attention and memory

Hypnosis research – attention and memory

Hypnosis research topic: ‘Does hypnosis, induced in a conference environment, influence attention or memory?’

Researcher: Dr Kate Beaven-Marks –


A good way of understanding research is to get involved in it as a participant first. Exploring how someone else conducts research can give you a clear idea of what approaches may work well for you.

My presentation workshop at the UK Hypnosis Convention on 5th November 2017 gave participants the opportunity to find out more about hypnosis research by participating in some ‘live’ formal hypnosis research.

The research activity was supplemented by a handout covering key aspects of how hypnotherapists and hypnotists can engage with evidence-based practice, and practice-based evidence, together with an easy to use ‘five-stage model’ for conducting research and the different types of research possible for the hypnotherapy practitioner.

A Participant Information Sheet and Consent Form were provided in advance, via the UK Hypnosis Convention Facebook forum, as well as on the day, thus giving potential participants sufficient time and information in order to make an informed decision whether to participate; optimising the available time for research during the presentation. Furthermore, the study was designed to generally demonstrate and observe good research ethics practice.


The purpose of the study (aims)

This research study aimed to explore whether hypnosis, induced in a conference environment, had any influence on attention or memory. Adaptations were made to the Stroop Test (attention) and the Benton Test (memory). There is research literature regarding the influence of hypnosis on the Stroop Test. However, there appears little use of hypnosis with the Benton Test in research literature. Furthermore, there also appears to be little research conducted in a conference environment. This hypnosis-related study intended to evaluate two effects, that of attention and memory, specifically in a conference environment.


Organisation of the research (methodology)

At the start of the workshop, participants were divided into pairs, and those pairs were assigned either ‘Zebra group’ or ‘Giraffe group’ research packs. The two differently named groups allowed for each test to be explored two ways; with a hypnosis test and then an alert test, and with an alert test and then a hypnosis test (see Figure 1). By changing the order of when hypnosis would be used in each test, this would indicate whether rehearsal was an influencing factor, or whether hypnosis would have an influence irrespective of whether it was tested first or second (see Figure 1). In the briefing notes at the start of the research pack, participants were invited to assign roles between them in their pairs, of ‘participant A’ and ‘participant B’.

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 1: Distribution of group activities


Within the research packs, in addition to the briefing sheets (with instructions for completion of the data forms and how to conduct each test) were two Participant Information Sheets and two Consent Forms (1 per participant), together with the test materials and data collection forms including a sheet collecting demographic information such as age and gender.

As this is a hypnosis and hypnotherapy convention, it was anticipated that those who were participating would be aware of whether or not they were contra-indicated from hypnosis and by participating they were indicating that they were of sufficient mental and physical health to engage in the research and, by reading the Participant Information Sheet were able to give informed consent.

The participant information sheet (for participants to retain) indicated that they were under no obligation to take part in this research. Participation was not linked to their attendance nor participation in the UK Hypnosis Convention. Participants were informed that all outcome responses would be anonymised, and thus the researcher will retain the right to use this anonymised data even if they choose to withdraw from the study after the data has been submitted.

The briefing sheet guided participants to complete one test as a hypnotist and one test as a subject, according to their assigned roles (see Figure 1). The outcomes of their test as a subject were recorded. The entire test process took approximately 30 minutes.

The first test (Test 1) was the Stroop Test. This test used a one A4 page with 5 columns and 15 rows of colour name words, where the word e.g. blue, was in a different font colour to the colour name text (see Figure 2). The aim was for the research subject to say out loud the actual colour of each word and the researcher would time them and record the total time in seconds. As this test would be done twice, to reduce the ‘rehearsal’ effect, two similar sheets, called ‘Sky’ and ‘Land’ were provided. For the alert state phase, subjects were given the simple instruction to say the colour of each word out loud, reading from left to right, row by row. For the hypnosis phase of the test, a simple rapid progressive relaxation (2 minutes) and 10 to 1 countdown deepener was employed by all researchers, followed by instructions (direct suggestions) that the text of the words would change into meaningless symbols. The research subject participant was then asked to open their eyes (whilst remaining in hypnosis) say the colours for each meaningless symbol, reading from left to right and row by row. This test was also timed in seconds. During the hypnosis suggestions, the subject was informed that their normal reading abilities would be fully restored upon re-alerting. At the end of the reading phase, the subject was formally awakened (with counting, direct suggestions and reinforcing that normal reading ability is restored).

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 2: Extract of ‘Sky’ test sheet for Test 1


The second test (Test 2) was the Benton Test. Ten graphic shape pictures (see Figure 3) were presented on numbered flash cards. Five of the pictures would be used for the alert phase of the test and five of the pictures for the hypnosis phase of the test. In the alert phase of the test, the first of the five assigned flashcards (see Figure 3) were presented to the research subject participant, who was then instructed to look at it for 10 seconds and to remember it. The card was then removed and 5 seconds allowed to elapse. The subject was then asked to replicate the picture in the correspondingly numbered box (1-10) on the answer sheet. This process was repeated for each of the five flashcards. For the hypnosis phase of the test, a rapid progressive relaxation induction (2 minutes) and countdown 10 to 1 deepener were specified. The subject was then give the instruction to open their eyes and look at the picture (for 10 seconds), whilst being given the instruction to “pay attention to the picture and remember it” and then told to close their eyes. After a further 5 seconds the subject was asked to open their eyes and draw the picture as they remembered it on the answer sheet. They were then asked to close their eyes. Each of the remaining four flashcards were then presented in the same way. Finally, the subject was formally re-alerted with counting and alerting suggestions.

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 3: Example of a Benton Test flash card


Data management

Participants names or other identifying information was not sought. Only the participants’ initials and house numbers were requested as identifiers on the outcomes record sheets to match with their demographic sheets. The data from the outcomes record sheets is kept securely and treated with confidentiality. The information is used solely for the purpose of this research and any subsequent papers and disseminations and the raw data will not be shared with any agencies or other external organisations. Anonymity will be maintained in all publications and uses of the data.


Results and outcomes

A total of 26 participants engaged in the research activity (see Figure 4). These were randomly assigned to either the Zebra group (7 research pairs) or the Giraffe group (6 research pairs).

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 4: Participant demographics


For Test 1, the Stroop Test, it was noticed that, for this research event, the rehearsal effect made a difference, the hypnosis did not. However, for the Zebra group (alert test followed by the hypnosis test) the hypnosis (i.e. 2nd test) generated a 9.6% decrease in test performance time, whereas for the Giraffe group (hypnosis test followed by the alert test) the alert test (i.e. 2nd test) generated a 16.8% decrease in time (See Figure 5).

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 5: Test one results


For Test 2, the Benton Test, it was observed that hypnosis, irrespective of whether it was employed first or second in order within the test, generated slightly higher scores. For the alert test followed by the hypnosis test, the hypnosis test had a 6.7% increase in score, whereas for the hypnosis test followed by the alert test, hypnosis scores were higher by 12.5% (see Figure 6).

Hypnosis research attention memory stroop test benton test uk hypnosis convention 2017

Figure 6: Test 2 results


Discussion – Stroop

The use of hypnosis in attention and concentration fields is well established. The Stroop Test, as a series of colour names (e.g. Red, blue, green) in non-related colour fonts (e.g. the word ‘red’ is presented in a blue font) requires the subject to go against natural lexical processing and instead name the font colour. Where words are not legible/comprehendible, this makes it easier for the reader to say the font colour without interference from the text words (the Stroop Interference Effect, or SIE). Generally, regardless of how skilled the reader, they will still access the word’s meaning, even if consciously instructed not to.

This particular use of the Stroop Test was designed to assess whether hypnotic suggestion would impair the lexical processing (reading of single words) by the subject accepting the suggestions for the words to become meaningless, and thus not cause interference with incongruent word text and colour combinations.

Earlier research, such as by Blum and Graef (1971), found the SIE greater in hypnosis, even without suggestion. In other words, it was easier for subjects to ignore the text colour name and say out loud the font colour. However, Sheehan et al (1988) found that the Stroop interference is higher in hypnosis for those who are highly suggestible. However, when given attention-focused suggestions in hypnosis, the highly hypnotisable subjects were better able to reduce the Stroop effect than the low hypnotisable subjects. Thus, performance can be  significantly enhanced by means of an attentional manipulation(hypnosis) accompanied by a specific posthypnotic suggestion to thwart reading. Specifically, the reported data show that hypnosis plus a carefully crafted suggestion (containing no reference to a specific attentional strategy) can obviate the effect of automatic word reading and suffice to eliminate the SIE in operationally defined highly suggestible proficient English readers. Also, Raz et al (2002) considers that hypnotic suggestions containing explicit attentional strategies seem to obviate the prepotent inclination to read in the highly suggestible.

A study by Raz et al (2002) using 16 highly suggestible and 16 low/medium suggestible subjects found that the SIE can be removed for some subjects and that Stroop Test performance can be significantly enhanced with hypnosis and carefully crafted suggestions. Furthermore, they found that the order for the experiment (hypnosis first or second) did not significantly affect the outcome.

To reflect upon the results of the UK Hypnosis Convention research for Test 1, the Stroop Test, it was noticed that the application of hypnosis did not consistently result in lower scores for that part of the test. Instead, it was demonstrated that whether alert or hypnosis, the second use of the Stroop Test resulted in quicker performance. Therefore, the findings from this research do not fully reflect earlier research. However, it is noted that those who self-reported being high hypnotisable who were the subject in the Stroop Test (n=3) all had a 5% improvement in their reading speed in hypnosis as compared to being in the alert state and this supports the earlier findings of Sheehan et al (1988).

A number of variables could be responsible for the differences in this research Stroop test results, compared to earlier studies.  Firstly, there was a range of level of experience from not being a qualified hypnotherapist, to one individual who has 30 years’ experience. Thus, some of the hypnosis work may be stronger than others. There was a range of hypnotisability (self-scaled), from low to high, with some participants (n=5) declining to indicate this. Furthermore, the research was conducted at 9am on the morning after a gala dinner evening and some participants may still be tired or hungover.  Whilst there is some evidence that a little alcohol can enhance suggestibility (Semmens-Wheeler et al 2013), there appears to be little research to indicate whether an alcohol related hangover may have any influence on hypnotisability. Furthermore, participants were not asked whether they were experiencing any form of hangover. Finally, there are the potential effects of the conference environment, as compared to a more conventional research environment.


Discussion – Benton

The Benton Test examines visual retention, perception, memory and visuo-constructive abilities. Commonly, 10 images are individually presented to a subject, and after studying the image for 10 seconds, a further period of time, often 5 seconds elapses before the participant is allowed unlimited time to draw a reproduction of the image.  Then the next image is presented to the subject and the process repeated.

Test interpretation is based on an evaluation of the number and type of errors in replicating the images presented to the subject. Errors are scored by comparing the original drawings against presented form, shape, pattern and arrangement on the paper, together with omissions, distortions, rotations, misplacements and size differences). One application of the Benton Test uses the number of errors (‘error rate’) as an indicator of potential neurological impairment. Some errors can be associated with different areas of brain function. For example, omission of peripheral aspects of the drawings may relate to less activity in the right parietal lobe. For this study, it was enquired whether hypnosis would enhance, impair or have no influence on visual retention, perception, memory and visuo-constructive abilities as demonstrated by the subject’s ability to replicate the images on the test flashcards.

Although hypnosis does not seem to have been widely used with the Benton Test, it has been widely used in areas related to memory and recall. Nogrady et al (1985) found that neither hypnosis nor imagination enhanced recall beyond that of normal repeated testing. Dwyan and Bowers (1983) found highly hypnotisable subjects were actually less accurate whilst in hypnosis.  This also seems supported by Whitehouse et al (1988) whose studies of hypnotic enhanced recall offered inconsistent evidence of any memory enhancement.

To reflect upon the results of the UK Hypnosis Convention research for Test 2, the Benton Test, similar to the Test 1 (Stroop Test) outcomes, the results from this study also differ somewhat to that found by other researchers. In this study, the hypnosis phase test generated slightly higher scores than the alert phase test, irrespective of whether it was first or second in order. Furthermore, where the hypnosis phase was after the alert phase it was notably more effective in raising scores (12.5% compared to 6.7%). However, this could be due to rehearsal effects.



It is recognised that there are several limitations to this study.  Firstly, in terms of numbers of participants (n=26).

There are potential limitations of using a repeated measures test (doing a test twice). This could result in the second use of the test either being better (positive learning) or worse (possible confusion or lack of confidence).

Also, as two tests were performed consecutively, it could be considered that the participants may have been ‘warmed up’ by the first test or conversely feel tired by the time of the second test.



This research study aimed to explore whether hypnosis, induced in a conference environment, had any influence on attention or memory. The outcomes indicate that whilst hypnosis did not have the anticipated beneficial effect on Stroop Test performance (attention) for all research subjects, it did have an influence of Benton Test performance (memory). The outcomes of this study do differ somewhat from results of earlier studies and the possible reasons for these have been explored.

It is accepted that there are relatedly low numbers (n=26) of this study, which limits the extent of statistical analysis, although the Raz et al study itself only had 32 participants, so low numbers are not uncommon in these types of studies.

Despite the relatively low participant numbers, some interesting observations can be made of the data. Much hypnosis research published appears to focus on the effects on high hypnotisable subjects. Yet, so many of the population are either low or medium hypnotisable, whether by informed or uniformed self-scale, or by formal testing, such as with the Stanford Hypnotic Susceptibility Scale (SHSS). It is commonly accepted that low and medium hypnotisable subjects are more common in the population that high hypnotisable subjects.  Thus, some of this report explored the data of just the low and medium hypnotisable subjects and made some interesting observations. For the Test 1 (Stroop Test) all medium hypnotisable subjects had lower time scores for the second phase of their test.  Where hypnosis was the second phase their scores reduced (from the alert scores) by 12%. However, where hypnosis was the first phase, their scores reduced (compared to the following alert scores), by 26.4%. It could be suggested that in this situation, the hypnosis relaxed the subjects and that they were thus better able to focus more on the task for the alert phase. This is partly supported by the performance of the low hypnotisable subjects, where 67% of them has score reductions of 34.7% with hypnosis as the first phase, and for those with hypnosis as the second phase, there was no difference in scores between either phase.



There are three separate strands to the recommendations arising from this study.

It is recognised that the field of hypnotherapy is growing in terms of practitioners, depth and understanding of knowledge and skills and technical and scientific knowledge. Each year there appears to be a new hypnotherapy conference. Furthermore, the topics of hypnosis and hypnotherapy are starting to be mentioned at other allied and unrelated conferences. Many of these conferences have practical workshops. It would be useful to conduct further research into whether the conference environment has any different influence on low, medium and high hypnotisable subjects. This could enable conference organisers to accommodate any aspects of practice which would enhance the conference participants experience.

This study found that hypnosis when engaged with before a subsequent test in the alert state had a positive influence on reducing test performance time, even in the absence of suggestions to that effect. This has potential implications for helping individuals in a wide range of test situations where actually being in hypnosis at the time would not be helpful or possible, and so broader research is suggested. Furthermore, it would be interesting to explore whether this applies to all three groups of suggestibility.

Finally, as much of hypnosis research is focused around the effects and influences of and for high hypnotisability, despite those individuals representing a smaller overall percentage of the population, it is recommended that more research is conducted, published and made available to therapists and the public, regarding the benefits for low and medium hypnotisable subjects. The conducting of such research may result in adaptations and developments of practice more focused towards individual suggestibility and, as a result, increase and enhance the effectiveness of hypnosis and hypnotherapy for each person as an individual, regardless of the level of hypnotisability.


References & Further Reading

Benton S.A. (1992). Benton Visual Retention Test. San Antonio, TX: Psychological Corporation.

Blum, G.S., & Graef, J.R. (1971). The detection over time of subjects simulating hypnosis.  International Journal of Clinical and Experimental Hypnosis. 19211- 224 

Carret, N., Rainville, C., Lechevallier, N., Lafont, S., Letenneur, L., & Fabrigoule, C. (2003). Influence of education on the Benton Visual Retention Test performance as mediated by a strategic search component. Brain and Cognition, 53, 408-411.

Dywan, J., & Bowers, K. (1983). The use of hypnosis to enhance recall. Science, 222, 184–185.

Nogrady, H., McConkey, K. M., & Perry, C. (1985). Enhancing visual memory: Trying hypnosis, trying imagination, and trying again. Journal of Abnormal Psychology, 94(2), 195-204.

Raz, A., Shapiro, T., Fan, J., & Posner, M. I. (2002). Hypnotic suggestion and the modulation of Stroop interference. Archives of General Psychiatry, 59(12), 1155-1161.

Semmers-Wheeler, R., Dienes, Z., & Duka, T. (2013) Alcohol increases hypnotic susceptibility. Consciousness and Cognition. 22(3), 1082-91

Sheenan, P.W., Donovan, P., MacLeod, C.M. (1988).  Strategy manipulation and the Stroop effect in hypnosis.  Journal of Abnormal Psychology. 94, 249- 255

Whitehouse, W. G., Dinges, D. F., Orne, E. C., & Orne, M. T. (1988). Hypnotic hypermnesia: Enhanced memory accessibility or report bias? Journal of Abnormal Psychology, 97(3), 289-295.


We hope this blog on hypnosis research has been helpful, and if you have any questions relating to this blog, do please get in touch, because we’re always happy to help!

– written by Dr Kate Beaven-Marks
(HypnoTC Director)

Dr Kate Beaven-Marks HypnoTC the Hypnotherapy Training Company

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