Introduction
In the process of examining the supposedly overwhelming evidence against NLP referred to by some critics, I've made a quite remarkable discovery - most of that "evidence" doesn't exist.
Let me put it another way: Most of the academic criticism of "NLP" is based, directly and/or indirectly, on just two articles written by Dr. Christopher Sharpley. They appeared in the peer-reviewed Journal of Counseling Psychology, in 1984 and 1987 (see section on Critical Material for details).
This obviously creates an interesting situation.
If Sharpley's articles were valid - in their content and their conclusions - then none of the later critics have anything to worry about.
BUT, if there is even one fundamental error in Sharpley's two reviews then those who have based their own claims on Sharpley's work are in trouble.
And as we'll see in just a moment, there isn't one important error in Sharpley's two articles - there are three. And each of them is indeed sufficient, all on its own, to invalidate both of Sharpley's articles.
In this examination of Sharpley's 1984 review I will show that Sharpley's article and all subsequent criticisms of the FoNLP* which are wholly, or for the most part, based on the 1984 article are pretty much useless as indicators of the usefulness/validity of the NLP-related techniques they allegedly investigate.
(* FoNLP - The FoNLP (field of NLP) consists of NLP itself (a specific, non-analytical, baturally occurring form of modelling), the various authentic (i.e. devised ny or consistent with, the concepts, models and techniques devised by Bandler, Grinder and Pucelik); and training in any element(s) in the authentic FoNLP.)
*** The Short Version ***
Critic(s):
(at the time of publication)
Dr. Christopher F. Sharpley: Lecturer in Psychology at Monash University and practicing as a Clinical Psychologist in Melbourne.
Critical Material:
Predicate Matching in NLP: A Review of Research on the Preferred Representational System (1984). Journal of Counseling Psychology. Vol. 31, No. 2. Pages 238-248.
Nature of criticism:
Sharpley's first article was essentially a review of 15 experiments which allegedly investigated claims made about certain genuine NLP-related methods and concepts, specifically in regard to "eye accessing cues" and a person's "preferred representational system", along with "predicate matching". Sharpley treated the reports as though they addressed authoritative claims relating to the FoNLP (field of NLP). On this basis he alleged that a majority of the results failed to support the claims and implied that this somehow invalidated "NLP" in general.
Original/derivative:
According to his own account, Sharpley took an NLP-related training course which left him rather unimpressed with what he perceived "NLP" to be. This motivated him, by his own account, to look for examples of academic research which supported what he imagined were current, authoritative claims made for "NLP" - and allegedly found very few. In fact Sharpley claimed that (a) only 9 experimental findings out of 29 (some researchers combined several different lines of investigation) provided support for "NLP" claims and (b) that the results of another 3 were uncertain (Sharpley, 1984, page 246). So being dependent on other people's research the article can hardly be thought of as original. Nor was it the first generally recognized attempt to review the state of research into NLP and present the results in public since this "honour" fell to another poorly researched paper by Dorn, Brunson, Bradford and Atwater published in 1983.
It was, morever, derivative insofar as it was based entirely on Sharpley's opinions about research carried out by other people.
Flaw(s):
There are three basic assumptions underlying Sharpley's first review, none of which stand up to serious examination.
They are:
- Sharpley assumed that he understood "NLP" in enough accurate detail to conduct a review of the research;
- In particular Sharpley, and possibly many of the researchers, seem to have assumed that NLP was a "one trick pony" - a single concept linked to a single technique;
- Sharpley appears to have assumed that the researchers whose work he was reviewing understood "NLP" in enough accurate detail to design meaningful experiments to support their research;
In practice, all three assumptions were demonstrably untrue.
Conclusions:
Sharpley was not acting as an unbiased observer. On the contrary, by his own account he was on a sort of crusade against what he perceived as being some kind of threat to the existing psychology community. Another Australia-based professor - Grant Devilly - sounded a similar alarm in his 2005 article (also evaluated on this site): Power Therapies and possible threats to the science of psychology and psychiatry
Most of Sharpley's difficulties arose from the fact that "he didn't know what he didn't know" - combined with the fact that what he didn't know was a far, far bigger piece of the pie than he realized.
Because of his lack of relevant knowledge Sharpley severely overestimated his competence to carry out the task he had set himself, reporting his own opinions as facts instead of reporting the research results, and allowing his readers to draw their own conclusions in what I am given to understand is the appropriate manner for such an article.
The nub of Sharpley's argument was that there was very little valid research that supported the claims made for what he seemed to regard as "NLP". And in strictly literal terms that was completely correct. But only because very few of the researchers were investigating genuine, authoritative claims made about the elements of the FoNLP that they were supposedly addressing. So even if Sharpley had been totally neutral his findings would have told us very little about the valiability of authentic NLP-related concepts, models and techniques.
In practise, however, Sharpley did more to add to the general confusion with comments like:
Hammer (1983, p.178) made the point that "consistently and effectively matching any behavior, regardless of the specific cue" may be the causal variable here. Empathy has been referred to by many authors as one of the primary ingredients of effective counseling (e.g., Ivey & Simek-Downing, 1980; Rogers, 1957)
(Sharpley, 1984, page 246)
Was this meant as praise or criticism? It is true that Bandler and Grinder were emphasizing the importance of creating rapport - and they were providing specific techniques that could be used to help to create/build/maintain rapport. So Sharpley's comment is appears to be citing the existence of evidence for the validity of some NLP-related techniques. A few lines later, however, Sharpley apparently tries to undo this positive comment, but only digs himself a deeper hole:
Although [creating rapport] is a worthwhile procedure for counselors, it does not justify NLP [sic] as a separate theoretical position
(Sharpley, 1984, page 246).
This is another shot in the foot for Sharpley because it implies that he did indeed believe that this one technique was pretty much all there was to "NLP".
Likewise, in that same paragraph, Sharpley writes:
... if NLP is suggesting that counselors who demonstrate high levels of reflection and empathy will be more effective than those who do not, then little new is being said.
(Sharpley, 1984, page 246).
But remember, on the first page of his article Sharpley records the fact that the creation of the FoNLP was to a large extent based on modeling the communication patterns of certain existing therapists - "Satir, Erickson, and Perls". In which case Bandler and Grinder were obviously identifying and codifying existing practices and techniques. And far from exposing a limitation, Sharpley was merely stating the obvious.
By seemingly developing tunnel vision at an early stage of his investigation, Sharpley excluded a substantial number of the elements that make up the overall FoNLP, and thereby sabotaged the possibility of his being able to recognise the ways in which Bandler and Grinder had extrapolated information from, and built upon, the results of their early modelling work.
What's even sadder is that so many academics have subsequently allowed themselves to be guided down that same cul-de-sac, apparently without making the least effort to check out the reliability of Sharpley's reports.
*** End of Short Version ***
*** 'Director's Cut' ***
Starting at the Beginning
Sharpley's first (1984) review concentrated on just 15 studies which all addressed a single topic within the FoNLP. Since that time it has been referred time and again, often by other academics who clearly have little or no idea what the authentic FoNLP is about and are thus, like Sharpley himself, completely unable to make an accurate evaluation of the experiments Sharpley reviewed.
In addition to the initial "abstract", the general outline of Sharpley's paper went as follows:
- Introduction - in which Sharpley sets up a number of pieces of misinformation concerning some featues of the FoNLP
- The Review - Part 1 - including a chart which summarises Sharpley's views on the 15 studies he is reviewing. Covers 6 studies
- The Review - Part 2 - entitled Matching PRS for Noncounseling Interventions. Covers 2 studies
- The Review - Part 3 - entitled Matching PRS for Counseling. Covers 8 studies
- Discussion
- Conclusion
The original version of this article got up to a little over 10,000 words. In order to keep it down to a more practical size I have stuck to the main points in the review, and accompanying comments.
Introduction
The article starts by acknowledging that although "NLP"* started out concentrating on counselling, it is, by 1984, being considered for use in personnel training and marketing. Almost immediately, however, the focus switches to Sharpley's concern about the lack of supporting evidence for the claim that "NLP" can be used as "an effective intervention procedure for use by counselors and other seeking to facilitate human communication" (Sharpey, 1984. Page 238).
(* The author never does seem to understand that NLP itself is a specific modelling process and nothing else.)
The next section of the article is somewhat confusing, when read in context. Sharpley writes:
"The present article examines 15 [research] reports, performed to evaluate one of the basic tenets of NLP"
(Sharpley, page 238).
Although it wasn't actually spelled out for the reader until Sharpley's second article (Sharpley, 1987. Page 103), it seems that it was "predicate matching" which Sharpley thought of as a "basic tenet" (i,e, basic belief) of "NLP". Just how a process can be a belief escapes me, but no matter. Another important factor was that predicate matching was intertwined with the concept of preferred representational systems (PRSs). It must be admitted that this was not (in my opinion) as carefully explained as it might have been in The Structure of Magic II, in if Sharpley and the researchers had been relying on that one book then one could understand how the misinterpretation had occurred, though it would still not be justified. The details of both referred representational systems, eye accessing cues and predicate matching were, however, spelled out by 1978 (see Frogs into Princes, based on the transcript of a course conducted by Bandler and Grinder in that March of that year - some 5 years before Sharpley wrote his article (1983), and before most of the experiments were conducted.
The next mistake goes as follows:
"Bandler and Grinder proposed that persons process reality through five sensory and representational systems: visual, auditory, kinaesthetic, gustatory, and olfactory ... although this theory is applicable to right-handed persons only."
(Sharpley, page 238).
I am constantly intrigued by the academics who use the description in the first part of this sentence. Our sensory faculties clearly consist of eyes, ears, skin, a mouth (especially the tongue), and a nose, and we have clearly discernable areas within the cortex which service these systems. What on earth is the point of describing the representational systems as a "theory", as though Bandler and Grinder had made it up?
The second part of the sentence is, I believe, either plain daft or an indication of the bias behind the article. Although he includes Frogs into Princes in his list of references, and quotes from that book, Sharpley adheres to this nonsensical claim through both of his reviews, based on a highly unlikely and unsubstantiated claim by three of the researchers that Bandler said this in a seminar they attended. Why Sharpley thinks we should believe these three students over what Bandler and Grinder have written in a number of books (including Frogs into Princes), and have said in countless seminars, is anyone's guess. Though having said that, commonsense alone might move one to ask: If only right-handed people get to use the five conventional senses, what alternative representational/sensory systems were Bandler and Grinder supposed to have in reserve for left-handers?
The allegation becomes all the more unbelievable when we realise that Bandler himself is - drum roll - left-handed! (See, for example, Bandler's book Make Your Life great, page 27.)
Not surprisingly, perhaps, Sharpley never attempted to address the glaringly obvious flaw in this allegation.
We then come to one of Sharpley's most basic mistakes, which occurs when he writes:
"This 'surface structure' can be classified into (most commonly) visual, auditory representational systems | by careful observation of client eye movements or verbalizations."
(Sharpley, 1984. page 238. Vertical bar used to break sentence for analysis)
Bad start. The first part of the sentence makes no sense at all, and without a detailed reference there is no way of knowing what Sharpley had in mind. The second part of the sentence demonstrates Sharpley's failure to distinguish between the information that can be gleaned from watching someone's eye movements, and what we can tell from listening to their use of verbalized sensory predicates.
"The system that an individual uses most of the time is termed the Preferred Representational System (PRS), and Bandler and Grinder suggested that matching this PRS is the key to effective counseling."
(Sharpley, 1984. Pages 238-239.)
If this had been written in the very early days of the Bandler/Pucelik/Grinder partnership Sharpley would have had a coherent reason for this assumption. But that development was not static - it was work in progress. the research went on, and the co-creators soon recognized the importance of context in almost everything that people think, do and say. Thus they noticed that people did not have a fixed PRS. And in Frogs into Princes we have documentary evidence that they were telling seminar delegates:
Our claim is that you are using all [representational] systems all the time. In a particular context you will be aware of one system more than another. I assume that when you play athletics or make love, you have a lot of kinesthetic sensitivity.*nbsp; When you are reading or watching a movie, you have a lot of visual consciousness."
(Bandler and Grinder, 1978/1979. Page 36)
In simple terms, far from claiming that that people had one overarching representational system or PRS, Bandler and Grinder were saying that we use whichever representational seems most appropriate to us in a given situation. A current PRS, so to speak. A "currently preferred representational system", a CPRS. Moreover, since a person's "context" is not determined by their their situation but by their perceptions regarding their situation, the context might change several times within any given interaction. It might remain stable for quite a time, or under certain circumstances it could change as rapidly as every 20-30 seconds, according to John Grinder.
That both Sharpley and most of the experimenters failed to recognize this crucial fact was something of a disaster since, as Sharpley went on to say:
"The presence of PRS, procedures for identifying it, and the effectiveness of matching or otherwise utilizing the PRS of a selected individual is the focus of the studies reviewed here, with results either supporting or failing to support this basic tenet of NLP."
(Sharpley, 1984. Page 239.)
Which totally missed the point that, as we've just seen, most researchers were trying (and I use the word advisedly) to investigate claims that simply hadn't been made about any element of the authentic field of NLP.
In the next section of his article, The Studies Reviewed(* (page 239), Sharpley describes, with the aid of a chart on pages 240-242, how far he and the experimenters have strayed from an accurate, up-to-date understanding of this particular element of the FoNLP.
(* Text like this, (in italic font), is used to indicate Sharpley's own sub-headings within the reviews section of his article.)
In Presence of the PRS we are introduced to the first experimenter whose work Sharpley has reviewed, though we are not told that she had rather ambitiously carried out eight different studies at once (Birholtz, 1981). Unfortunately the experimenter not only tried to "verify the presence of the PRS in individuals over time" (which wasn't a genuine NLP_related claim, she also made the error of assuming that a if someone exhibits a certain PRS at a particular moment in time one Monday, and again at a certain moment on the following Monday, then they must have been using that same PRS all the way through the intervening period. This is a very weak experimental design, yet Sharpley seems not to have noticed it.
The next section of Sharpley's review fared as badly as the first three. In Identifying the PRS the first experimenter's work was carried out in the grey area (Owens, 1977/1978). But the other experimenters (Gumm, Day and Walker, 1982; Beale (1980/1981); Thomason, Arbuckle and Cady, 1980; and Hernandez, 1981) all used the erroneous PRS description. Three of the six experiments assumed, as did Sharpley, that someone's PRS should be indicated by eye-movements, self-report and verbalized predicates, even though Bandler and Grinder clearly stated, in 1976 and again in 1978/1979, that a person's use of verbal predicates is the one way to detect their PRS/CPRS.
In what was arguably the most misguided experiment of all, one student tried to "test the level of agreement between sensory-specific statements ... and the postulated corresponding eye movement patterns" not by watching eye-movements when the subjects themselves used sensory predicates but by reading 24 "experimental statements (visual, auditory, kinesthetic and non-specific in nature) which were developed by the investigator" - and videotaping the reactions.
Once again Sharpley gives no indication, in his review, that he realizes how inappropriate the experimental design is as a means of achieving the declared objective.
It should be noted, however, that at the end of this section Sharpley does manage to come up with an assessment which accurately reflects genuine NLP claims, though (inevitably?) he seems to interpret the findings as being unfavourable to "NLP":
"The usefulness of eye movements to identify the PRS (assuming it exists) is seriously in doubt. Lack of agreement between the three measures used in these studies (i.e. eye movements, verbalizations, self-report) does not in itself refute the existence of the PRS, but suggests that only one (if any) measure can be accurate."
(Sharpley, 1978/1979. Page 242)
For some reason Sharpley then claims that "No evidence to date strongly supports any of these three measures" (page 242), though what exactlly he means by "strongly" is unclear since he later repeats his comment about the three measures but with the qualification that: "They are not interchangeable, with verbalizations emerging as the only procedure that shows any reliability" (page 246).
The section headed Matching PRS for Noncounseling Interventions, covers the work of just two experimenters. One experimenter got apparently supportive results even though he used an erroneous method pre-establishing the subjects' PRS. The second experimenter got confused results, though being the only experimenter to submit his dissertation pre-1978 it must be remembered that he was therefore limited to basing his research on the 1976 description of PRSs (page 243)
Unfortunately both sets of results were invalid because, like the student described above, both of these experimenters tried to evoke responses to sensory predicates instead of tracking the subjects' own use of sensory predicates.
And lastly, in the reviews section, we come to Matching PRS in Counseling, which covers results obtained seven experimenters.
Paxton (1980/1981) and Falzett (1981) both used a single, pre-determined PRS, with Falzett making the additional error of basing them on the subject's eye movements (page 243).
The descrtiption of Ellickson's experiment (1980/1981) looked more hopeful, since the counsellors were using a "tracking and matching approach. Until we discover that the tracking was based on the subjects eye movements rather than their verbal predicates! (pages 243-244)
Freiden's experiment (1981) was remarkable in that it included only two subjects. Nevertheless, Freiden did manage to discover a major problem with trying to apply a "scientific" approach to a psychological experiment - there were "marked individual differences in subject responses that were not revealed in averaged data". Sharpley also notes that Freiden's method of evaluating his results was by measuring change in the subjects' behaviour. Though he decided to perform this measurement "by use of paper-and-pencil test rather than actual observation"! (page 244).
Dowd and Pety (1982) tried to measure the effectiveness of predicate matching by having their subjects listen to an audiotape of a counselling interview (pages 244-245).
And Dowd and Hingst (1983) had "postgraduate counseling students who were trained in predicate matching" (italics added for emphasis), who either matched, mismatched or nonmatched (used predicates in a random fashion) the subjects' use of verbal sensory predicates during an interview. Not only did the researchers point out a possible reason for the unpredicted results, but the "trained counselors" were in fact so inexperienced that they were monitored and instructed (via "bug-in-the-ear devices") "to ensure that they maintained their correct treatments" (page 245).
Despite these limitations Sharpley insists that "The nonsupportive outcomes of this study [sic] cast doubt on the efficacy of predicate matching, either first or second-hand" (page 243).
And last, in this section, we have experimenter Allen Hammer (1983) who seems to have produced some very sound results. His only error, that I'm aware of, was his apparent belief that his results disproved genuine NLP-related claims.
Like several other experimenters, Hammer went for a "tracking and matching" approach. In this case, however, the three "postgraduate student counseling [sic] therapists" correctly tracked the subjects' use of vebal predicates rather than their eye movements.
So where did it go wrong (right?).
Sharpley reports that Hammer's results showed that:
"the difference in frequency between the PRS and the next most frequently used type was less than or equal to five predicates" (p.177) in 50% of subjects, ...
And here comes the allegedly nonsupportive evidence:
suggesting that the prediction of there being one PRS may not be accurate, and further supporting the use of ongoing predicate matching over prior determination of clients' PRS."
(Sharpley, 1984. page 245)
Which is pretty much exactly what Bandler and Grinder had already been saying for several years:
a person may have more than one most highly valued [preferred] representational system, alternating them. This is common in people who are incongruent in their communication"
(The Structure of Magic II, 1976. page 26)
Given that Hammer's subjects were "sixty-three female graduates", i.e. a group of people in the final stages of brain development and quite likely to go through phases of incongruency we might say that it wasn't in the least surprising, from an FoNLP-based perspective, to find so many subjects flipping back and forth in this way.
It is at the end of this section that Sharpley makes the pronouncement which could be said to undermine the credibility of both reviews:
... although there are several specific findings that provide support for NLP [sic], the majority are either nonsupportive (17/29) or uncertain (3/29), with only nine of these findings (i.e. less than oner third) in support of NLP on this issue of the PRS and its use
(Sharpley, 1984. Page 246)
On what basis does Sharpley arrive at these figures? Does he simply assume that the students all knew exactly what they were doing and accept their views of their findings without a second thought? Or does he assume that his own knowledge is adequate to make an accurate assessment?
We aren't even told which studies belong in each group, in Sharpley's opinion, and to be blunt, even on the limited basis of this review of the evidence, neither approach seems justified. In short, we are offered no means of telling whether the statistics are useful (highly unlikely, IMO), more or less valueless (highly likely, IMO), or somewhere inbetween.
Discussion
This section (pages 246-247), which seems to be reviewing the review, goes off in so many directions that one can't help feeling that it might have beem much more useful to have presented the information in some kind of tabular form. Nevertheless, Sharpley (living in Australia) did raise 4 very valid points at the end of this section, such as the final observation that: "One may hesitate to generalize from a sample of right-handed female college students to the general or clinical population".
Indeed, one wonders how long people would go on taking notice of claims made by psychologists if the realised just how much of the evidence is based entirely on groups of American college and university students.
Conclusion
The material in this section (pages 247-248) might have been genuinely useful, if only Sharpley had had the knowledge to make sense of it all. But he didn't, so all we get are rather vague comments which confirm, to anyone who really does know the subject, that Bandler and Grinders 'observations' lead them in the right direction. Even if there were a few hiccups along the way.
Although Sharpley remains unaware of the PRS definition error, he does at least confirm Bandler and Grinders observations which indicated that eye-movements and self-report were no use in determining someone's (current) PRS. Unfortunately, however, it remains clear to the last paragraph that Sharpley is unsure what "NLP" actually is. Thus he writes:
No psychotherapeutic procedure can claim credibility until it has shown its effectiveness with persons who present themselves for counseling"
(Sharpley, 1984, page 248)
Now I guess it depends, here, what we mean by "psychotherapy". For what it's worth I was under the impression that counselling and psychotherapy were sufficiently different to make them distinct entities. Yet here the author seems to be rolling them into one.
In fact NLP itself is a modelling procedure, and nothing else. The "field" of NLP (FoNLP) consists of NLP + genuine NLP-related techniques + training in NLP and/or the related techniques. Given the following definition of psychotherapy, supplied by a much respected Professor of Psychology, there seems to be no reasonable basis for describing the FoNLP as a form of psychotherapy:
'Any specialized set of techniques directed toward either treating mental illness or enhancing adjustment [to mental illness].'
And quite obviously a clearly defined modelling process would not qualify either.
It would be entirely reasonable that the "fast phobia cure", for example, is one of a small number of therapeutic techniques which exist within the overall collection of NLP-related techniques. But this group does not include predicate matching, or the concept of a CPRS (currently preferred representational system). The same technique and concept can be used in virtually any situation where verbal communication is going on - business, education, etc., - without the need for any adjustment of the way the process is conducted.
On that basis, Sharpley's final assumption, that "NLP" is a form of psychotherapy and needs to be validated as such, is shown to be itself invalid.
We will look at some further elements of Sharpley's views on the FoNLP in our evaluation of his second article: Research Findings on Neurolinguistic Programming: Nonsupportive Data or Untestable Theory? (1987).
References
Bandler, R., & Grinder, J. (1978/1979). Frogs into Princes. Moab, UT: Real People Press.
Beale, R. (1981). The testing of a model for the representation of consciousness (Doctoral dissertation, Fielding Institute, 1980). Dissertation Abstracts International, 41, 3565B. (University Microfilms No. 8106799)
Birholtz, L. (1981). Neurolinguistic Programming: Testing some basic assumptions (Doctoral dissertation, Fielding Institute, 1981). Dissertation Abstracts International, 42, 3565B. (University Microfilms No. 8118324)
Dilts, R., Grinder, J., Bandler, R., Bandler, L., & Delozier, J. (1980). Neuro-Linguistic Programming, Volume 1. The Study of the Structure of Subjectivity. Cupertino, CA: Meta Publications.
Dowd,T.,&Hingst,A. (1983). Matching therapists' predicates: An in vivo test of effectiveness. Perceptual and Motor Skills, 57, 207-210.
Dowd, T., & Pety, J. (1982). Effect of counselor predicate matching on perceived social influence and client satisfaction. Journal of Counseling Psychology, 29, 206-209.
Ellickson, J. (1981). The effect of interviewers responding differentially to subjects' representational systems as indicated by eye movement (Doctoral dissertation, Michigan State University, 1980). Dissertation Abstracts International, 41, 2754B. (University Microfilms No. 81-01102)
Falzett, W. C. (1981). Matched versus unmatched primary representational systems and their relationship to perceived trustworthiness in a counseling analogue. Journal of Counseling Psychology, 28, 305-308.
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Gumm, W., Walker, M., & Day, H. (1982). Neurolinguistics Programming: Method or myth?. Journal of Counseling Psychology, 29, 327-330.
Hammer, A. (1983). Matching perceptual predicates: Effect on perceived empathy in a counseling analogue. Journal of Counseling Psychology, 30, 172-179.
Hernandez, V. (1981). A study of eye movement patterns-in the Neuro-Linguistic Programming model (Doctoral dissertation, Ball State University, 1981). Dissertation Abstracts International, 42, 1587B. (University Microfilms No. 8120505)
Owens, L. (1977). An investigation of eye movements and representational systems (Doctoral dissertation, Ball State University, 1977). Dissertation Abstracts International, 38, 4992B. (University Microfilms No. 7803828)
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Shaw, D. (1978). Recall as effected by the interaction of presentation representational system and primary representational system (Doctoral dissertation, Ball State University, 1977). Dissertation Abstracts International, 38, 5931A. (University Microfilms .Order No. 7803830)
Singer, M.T. and Lalich, J. Crazy Therapies. Jossey-Bass Publishers, San Fransisco, 1996.
Thomason, T. C., Arbuckle, T., & Cady, D. (1980). Test of the eye movement hypothesis of neurolinguistic programming. Perceptual and Motor Skills, 51, 230.
Wilson, N, Commercializing Mental Health Issues: Entertaining, Advertizing and Psychological Advice, in Lilienfeld, S.O., Lynn, S.J. and Lohr J.M., Science and Pseudoscience in Counseling Psychology. pp. 446 and 455.
Yapko, M. (1981). Neurolinguistic Programming, hypnosis, and interpersonal influence (Doctoral dissertation, United States International University, 1981). Dissertation Abstracts International, 41, 3204B. (University Microfilms No. 8103393)
Andy Bradbury can be contacted at: bradburyac@hotmail.com