NLP is one of those topics that has been abandoned by academia and psychology but still soldiers on in the training world. To be fair, the NLPers have retreated to a position of 'science and evidence is irrelevant'. However, as Christopher Hitchins often says, "What can be asserted without evidence can be dismissed without evidence."

I was pleased, therefore, to receive a pre-publication paper from Tomasz Witkowski that takes all of the current academic work on NLP, including that which purports to support its theory, and puts it to the test. The paper's title is, 'Thirty-Five Years of Research on Neuro-Linguistic Programming: NLP Research Data Base - State of the Art or Pseudoscientific Decoration?'  

Despite its aggressive marketing and application in training, Witkowski asks; "Why is NLP completely absent from psychology textbooks?" Rather conveniently, Richard Bandler didn't think that empirical testing was necessary and is openly contemptuous of such an approach. However, it is important to look at the theory from a perspective that is free from the biases of its practitioners (as they believe the theory and make money from the practice) and the patients (who may be subject to manipulation and false belief).

Witkowski starts on NLP's home territory with the Neuro-Linguistic Programming Research Data Base found on the web pages of NLP Community. It is the largest of such databases and includes hundreds of empirical studies from 1974-2009, and is often used by NLP proponents to defend the empirical nature of their theory and practice. First, he applied a credibility filter to the database (the respected 'Master Journal List of the Institute for Scientific Information in Philadelphia') to identify the reliable journals. This took the 315 down to 63.

 

A qualitative analysis of these 63 articles showed; 33 relevant empirical studies, 14 that were of little or scientific significance and 16 that appear to have been included in the database by accident, as they weren't relevant. Of the 33 relevant papers; 18 were non-supportive of the NLP tenets and the tenets-derived hypotheses (54.5%), nine supported NLP tenets and the tenets-derived hypotheses (27.3%), and six had uncertain outcomes (18.2%).

He then applied a national test, based on relevance and impact, to find that the papers not supporting NLP had more status in the academic and professional world. He concludes that, "The numbers indicate unequivocally that the NLP concept has not been developed on solid empirical foundations". His point is that the numbers alone don't tell the whole story, what matters is the weight of the evidence. A problem uncovered in the supporting papers was the common absence of a control group, and trials that could not be seen as scientifically valid.

The non-supportive papers, that showed no evidence for the eye movement hypothesis (Thomason, Arbuckle & Cady, 1980; Farmer, Rooney & Cunningham, 1985; Poffel & Cross, 1985; Burke et al., 2003) and preferred modalities (Gumm, Walker and Day (1982), and also Coe and Scharcoff (1985)), were much more rigorous. Elich, Thompson and Miller (1985) tested claims that eye movement direction and spoken predicates are indicative of sensory modality of imagery and showed no evidence for the NLP-derived hypotheses. Graunke and Roberts (1985) tested the impact of imagery tasks on sensory predicate usage, again showing no evidence for NLP theory. By this point the case was clear, the case for the defence was baseless.

Witkowski builds on the metastudies of Sharpley, Einspruch & Forman and Heap published in the 80s, to show that NLP claims are still unproven. Interestingly, 11 of the original Sharpley studies (1984) are not in the NLP database. Not surprising, as Sharpley in his first review dismissed claims of PRS, eye movements, self-reporting, predicate matching and the ability of NLP to change clients. In his second review, building on the results of Einspruch & Forman (1985), Sharpley (1987) he went even further, dismissing the claims made for its therapeutic benefits, namely anxiety, pacing and metaphor. Finally, NLP is dismissed as a method for improving performance by the US Army (Swets & Bjork, 1990). "The conclusion was that little if any evidence exists either to support NLP's assumptions or to indicate that it is effective as a strategy for social influence." Heap (1988) drew similar conclusions, after examining 63 empirical studies. PRs, eye movements, predicate matching and their role in counselling, were dismissed as baseless. This is exactly what Witowski confirms, when considering subsequent research.

Witkowski's discussion is particularly relevant. He makes the point that much of the research in the 80s was designed to test NLP on the back of its popularity. The file drawer effect would suggest that many non-supporting studies were quietly dropped. What is clear is that there was a stark bifurcation between theory and practice. The NLP community went on to aggressively market its wares, while serious academia ignored the whole field as irrelevant and unworthy of research. This is similar to the difference between astrology and astronomy. No one is interested in testing astrology, as it is so patently weak in its hypotheses and predictive ability.

What is so powerful about this paper is the fact that he uses NLP's own database to expose their 'supporting evidence', and found it wanting. A damning statement is made about the status of the evidence invoked by NLP theorists and practitioners, "The base (NLP database) is commonly invoked by NLP followers and indicated as evidence for the existence of solid empirical grounds of their preferred concept. It is most likely that most of them have never looked through the base. Otherwise they might have come to the conclusion that it provides evidence to the contrary – for the lack of any empirical underpinnings".

This is pretty damning. The paper asks a key question: "Is using and selling something non-existent and ineffective ethical?" Witkowski’s answer is clear: that it is "pseudoscience" and should be "mothballed".

citations:

Sharpley, C. F. (1984). Predicate matching in NLP: a review of research on the preferred representational system. Journal of Counseling Psychology, 31, 238-248.

Einspruch, E. L., & Forman, B. D. (1985). Observations concerning research literature on Neurolinguistic Programming. Journal of Counseling Psychology, 32, 589-596.

Sharpley, C. F. (1987). Research findings on Neurolinguistic Programming: nonsupportive data or untestable theory? Journal of Counseling Psychology, 34, 103-107.

Heap, M. (1988). Neurolinguistic programming: An interim verdict. In M. Heap (Ed.) Hypnosis: Current Clinical, Experimental and Forensic Practices (pp.268-280). London: Croom Helm.