Enhancing Human Performance Background Papers, Issues of Theory and Methodology (1988) / Chapter Skim
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3 Human Performance Technologies and Expectancy Effects
3 Human Performance Technologies and Expectancy Effects
Pages 8-57
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From page 8... ...
With respect to the behavior-outcome link, again all four factors were statistically significant, but in terms of effect size, feedback did not seem to be very important: climate, r=.36; feedback, r-.07; input, r=.33; and output ~ r=.20 . Human Performance Technologies and Expectancy Effects We now turn to a more focused discussion of the possible influence of expectancy effects on research on techniques for the enhancement of human performance.
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From page 9... ...
The last part of the preliminary phase is of particular relevance to expectancy effects, for it involves the explicit induction of positive expectancies-for learning. The teacher repeatedly stresses to the class that the SALT technique makes learning easy and fun, and that as long as the students go along with the interesting things the teacher has them do, they will find themselves learning better than they had ever imagined possible.
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From page 10... ...
191. Another aspect of this phase is "early pleasant learning restimulation," or inducing a positive attitude toward learning by asking students to remember some prior experience where learning was exciting and fun ~ for example learning to ride a bicycle.
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From page 11... ...
wanted to test SALT on a large class of adults learning English as a second language. Rather than randomly assigning students to the experimental and control conditions , though, she instead described the procedures for the two conditions to the 80 subjects and asked them to choose which class they preferred: the traditional teaching control class, or the experimental SALT class!
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From page 12... ...
The experimental manipulation consisted of using SALT techniques (exercises, relaxation, early pleasant
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From page 13... ...
Furthermore, experimental treatment was completely confounded with teacher, so any significant results could be due simply to the characteristics of the different teachers rather than to the SALT technique itself. The remaining empirical articles we have examined tend to fall somewhere in between the two examples described above.
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From page 14... ...
The second column of the table shows the effect sizes, expressed as the correlation coefficient r, illustrating the degree of effectiveness of SALT obtained in the various studies. We estimated these correlations from the data provided by the authors; we corrected statistical errors when they could be identified before computing the effect size.
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From page 15... ...
In many cases, one teacher taught the experimental SALT class, and another teacher taught the control class. As noted earlier, such a design completely confounds treatment with teacher; any obtained differences could be due to SALT or they could be due to other, irrelevant differences between the two teachers.
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From page 16... ...
As noted earlier, the teachers were always aware of the hypotheses and experimental condition of the students; because they believed in the SALT technique, they undoubtedly expected better performance from the subjects in the SALT condition. These expectations could have been communicated clearly to the students, either overtly or subtly.
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From page 17... ...
Teachers using SALT deliberately adopt a warm, friendly interpersonal style; they praise and encourage frequently. Also present are nonverbal behaviors that go into the climate factor, for example, smiles, dynamic voice tone, speech rate, body gestures, and eye contact.
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From page 18... ...
This condition could also use tape-recorded relaxation exercises and class material to minimize expectancies communicated during the presentation phase. We could then compare the results found in this condition against those found for the regular SALT technique.
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From page 19... ...
Lastly, if the eyes move to the lower right, the PRS is kinesthetic. The theoretical basis for this assessment method is neurological in nature ~ involving brain lateralization ~ and an often overlooked aspect of the entire NLP model is that it holds only for left-hemisphere dominant (e.g.,
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From page 20... ...
studies validating the PRS concept by examining the agreement among the three assessment methods of eye movements, verbalizations, and self-report; and (b) studies examining the effect of PRS matching or mismatching on communication effectiveness.
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From page 21... ...
studies in which there is no prior assessment of PRS ant counselors are instructed to either match or mismatch the subject's use of perceptual predicates as it occurs during the ongoing interaction. This distinction has important implications for the potential expression of interpersonal expectancy effects, so we will discuss prototypical research examples from each subcategory.
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From page 22... ...
Following the interview, subjects were administered the Coun~elor.Rating Form Trustworthiness scale, which constituted the dependent variable of subject sa t is fac t ion wi th the interview. Analyses showed a large, positive effect of PRS matching; subjects in the matching condition felt the counselor was significantly more trustworthy than did subjects in the mismatching condition.
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From page 23... ...
In addition to the responses to the eye movement questionnaire, the author tabulated sub jects' responses during the interview and made an assessment of their PRS using the verbalization method. However, all but three of the subjects were shown to have a kinesthetic PRS under this classification method, in sharp disagreement with the results from the eye movement method, and the author thus decided to ignore the verbalization results.
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From page 24... ...
He enter up omitting over 28% of the interactions, however, a sizable amount that restricts the generalizability of his results. Analyses Shower that subjects in the matching condition obtained significantly higher empathy scores than did subjects in the mismatching condition, F(1,56)
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From page 25... ...
The possibility that interviewers may unintentionally behave differently in the matching vs mismatching conditions, and thus the possibility of interviewer expectancy effects, is therefore eliminated. However, it must be noted that the kind of standardization suggested here involves an inevitable trade-off with experimental realism; watching a prepared videotape is not as natural and realistic as taking part in a one-on-one interview.
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From page 26... ...
. This lack of support leaves open the very real possibility that interpersonal expectancy effects are responsible in part for the positive results found in the predicate tracking studies.
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From page 27... ...
The results of the Feltz and Landers (1983) meta-analysis show that the mean effect Size for mental practice across the 60 studies was equivalent to a correlation coefficient of .23, a small to medium effect.
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From page 28... ...
A third possibility, more relevant to the goals of this paper, is that if interpersonal expectancy effects are operating in this area of research, performance on cognitive tasks would most likely be more susceptible to influence from expectations than would strength tasks. Now that we have outlined some of the major issues and findings of this research area, we turn to a more detailed description of some examples of typical research.
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From page 29... ...
In Mendoza & Wichman (1978) , 32 undergraduates were pretested on dart-throwing ability and randomly assigned to one of four groups: control, mental practice only, mental practice plus simulated dart-throwing movements, and physical practice.
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From page 30... ...
The difference for the mental practice condition was not statistically significant, but the effect size was moderate and similar to that for the preparatory arousal condition, r=.34. In sum, then, this study found support for both mental practice and preparatory arousal in improving leg strength.
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From page 31... ...
The distinction drawn earlier in our discussion of the SALT technique between interpersonal expectancies and self-expectancies becomes relevant here. Certainly, the subjects are not themselves blind to their condition; subjects who are using mental practice know they are using it and undoubtedly
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From page 32... ...
In terms of the exogenous tendogenous distinction made earlier. there is some possibility of exogenous expectancy effects in that the experimenters are almost always aware of the experimental condition of their subjects.
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From page 33... ...
meta-analysis showed a small, positive effect of mental practice, actual physical practice has been shown in many studies to be much more effective in improving performance (Corbin, 1972)
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From page 34... ...
For example, Jessup, Neufield, & Mersky ( 1979 ~ reviewed 28 studies and found no support for the specific benefit of biofeedback in reducing migraine headaches. Furthermore, this review found that the most promising results were obtained in uncontrolled studies, where the potential for expectancy effects or other experimental artifacts is greater.
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From page 35... ...
Banner ~ Meadows (1983) randomly assigned 63 subjects to one of six experimental conditions: (a)
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From page 36... ...
Analyses showed, disappointingly, no significant differences among groups on any of the dependent measures: EMG levels, finger temperatures, self-reported tension, or self-reported frequency of problems. Unfortunately, the article did not report means for the six conditions on any of these measures so we are unable to estimate effect sizes or see whether the results were even in the right direction.
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From page 37... ...
Results showed, however, that both treatment groups showed significantly greater improvement than the wait list control on the dependent variables of frequency of headaches (r=.48, number of headache days (r=.49) , intensity of headaches (r=.53)
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From page 38... ...
In terms of exogenous expectancy effects, we find that researchers in the biofeedback area, like those in the other areas we have discussed, are most often not blind to the experimental condition of their subjects. This leaves open the possibility of differential experimenter behavior toward experimental and control subjects.
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From page 39... ...
617~. Clearly, then, the potential for exogenous expectancy effects is real .
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From page 40... ...
There are masses of clinical and lab studies showing that biofeedback is effective, but many of these studies suffer from methodological and design flaws, and there are also many failures to replicate. We have also seen that experimenter- and subject self-expectancy effects are pervasive in this area.
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From page 41... ...
41 Parapsychology There are two transition points in the recent history of parapsychology. At each point parapsychology advanced to a new level of more rigorous research and scientific respectability, though neither point earned for it full acceptance as a respectable field of scientific inquiry (Boring, 1962; Murphy, 1962, 1963; Truzzi, 1981)
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From page 42... ...
42 3 of parapsychological investigations, we have confined our discussion to a focused domain of parapsychological inquiry: the ganzfeld experiments. Ganzfeld Experiments In these experiments subjects typically are asked to guess which of four stimuli had been "transmitted" by an agent or sender with these guesses made under conditions of sensory restriction (usually white noise and an unpatterned visual field)
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From page 43... ...
84~. The effect size estimates shown in Table 3 are in units of Cohen's h which is the difference between (a)
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From page 44... ...
Relative to what we would expect from a normal distribution, we have studies that show larger positive and larger negative effect sizes than would be reasonable. Indeed, the two largest positive effect sizes are significant outliers at p<.05, and the largest negative effect size approaches significance with a Dixon index of .37 compared to one of .40 for the largest positive effect size (Snedecor ~ Cochran, 1980, pp.
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From page 45... ...
The 95% confidence interval suggests the likely range of effect sizes to be from .11 to .45, equivalent to accuracy of guessing rates of .30 to .46 when .25 was expected under the null hypothesis. Significance testing.
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From page 46... ...
. In that analysis, eight areas of expectancy effects were summarized; effect sizes (Cohenls d, roughly equivalent to Cohen's h)
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From page 47... ...
. While it is difficult to rule recording error out of ganzfeld studies
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From page 48... ...
That was a possible tendency to report the results of pilot studies along with subsequent significant results when the pilot data were significant. At the same time it is possible that pilot s tud ie s we re conduc ted wi shout promi s ing re su 1 t s, pi lo t s tud ie s the t then
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From page 49... ...
Although a simple Bonferroni procedure can be used to adjust for this problem (e.g., by multiplying the lowest obtained ~ by the number of dependent variables tested) this adjustment is quite conservative (Rosenthal & Rubin, 1983~.
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From page 50... ...
. However, the lack of independence of the studies court have implications for the estimation of effect sizes if a small proportion of the investigators were responsible for all the nonzero effects.
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From page 51... ...
There was little evidence to suggest, however, that those investigators tending to conduct more studies obtained higher mean effect sizes; the F(1, 18) testing that contrast was 0.38, ps.54, r= .14 .: Cone lus ion On the basis of our summary and the very valuable meta-analytic evaluations of Honorton (1985)
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From page 52... ...
We now turn to questions regarding these areas of research taken together: How do the areas compare with respect to their overall effect sizes and methodological adequacy in general? What are the important characteristics of these domains in terms of their susceptibility to expectancy effects?
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From page 53... ...
Looking at Table 5, we see that the SALT studies do not compare favorably with the other areas with respect to these factors, and that only the ganzfeld ESP studies regularly meet the basic requirements of sound experimental design. The third section of Table 5 lists relevant endogenous factors, or characteristics that are actually part of the human performance technology.
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From page 54... ...
Interestingly, there is a strong inverse relationship between the rated quality of an area and its mean effect size; the correlation coefficient is r(3~=-.85, ~=.03, one-tailed. The last line of Table 5 gives our estimate of the sizes for each of the five areas, that is, our judgment effect size for an area would be after adjusting it for "residual" effect of what the ''true" any possible bias due to expectancy effects or methodological weaknesses.
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From page 55... ...
Lastly, the partial correlation between the residual effect size and the quality rating, controlling for the original effect size, was r=~413. The magnitudes of the effect sizes, both original and adjusted, for the five areas are not large.
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From page 56... ...
The effect sizes we have reported are means computed across multiple studies. We do not know what the underlying distributions of these effects are in the population.
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From page 57... ...
" rather than "Do the studies all obtain statistically significant results? " Defining replication in terms of similarity of effect sizes would obviate arguments over whether a study that obtained a ~=.06 was or was not a successful replication (Nelson, Rosenthal, & Rosnow, in press; Rosenthal, in press)
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