The last unit presented the Bad Science principle of No Control Group. The principle in this unit of No Blind Testing is related. However, this principle is goes beyond comparison groups, it's about knowing which group you are in. The problem creates possible bias. Expectancy effects may be a result. Some Expectancy effects are: thePlacebo Effect, Experimenter bias, Subject reactivity, Self-fulfilling Prophecy, Pygmalion Effect, and others. (subjects acting along with their expectations or acting oppositionally to expectations). As social creatures, we look for the roles and expectations of the setting and may feel compelled to fulfill the expectations.

To explore No Blind Testingplease reading the following article:

Interpersonal Expectancy Effects: A 30-Year Perspective (I've attached the article as pictures below)

In the Discussion thread for No Blind Testing:

1. Find an journal article that explores one of the Expectancy effects, e.g., Placebo Effect, Experimenter bias, Subject reactivity, Self-fulfilling Prophecy, Pygmalion Effect, etc, Post a summary of the article and include a reference for the journal article.
2. Next, present a example of an Expectancy effect. The strongest examples are ones of a lived experience.

Transcribed Image Text:

176 VOLUME 3, NUMBER 6, DECEMBER 1994 Interpersonal Expectancy Effects: A 30-Year Perspective Robert Rosenthal In the mid 1950s, the results of my doctoral dissertation were nearly ruined; it appeared that I might have treated my experimental subjects in such a way as to lead them to re- spond in accordance with my exper- imental hypothesis, or expectancy." All of this was quite unwitting, of course, but it did raise a sobering question about the possibility of in- terpersonal expectancy effects in the psychological laboratory. If it was my unintentional interpersonal ex- pectancy effect or my "unconscious experimenter bias" that had led to the puzzling and disconcerting re- sults of my dissertation, then pre- sumably my students and I could produce the phenomenon in our own laboratory, and with several ex- perimenters rather than just one. EARLY LABORATORY EXPERIMENTS The earliest studies were con- ducted with human subjects. Exper- imenters instructed the subjects to rate photographs of people, with half the experimenters led to expect high ratings and half led to expect low ratings. In the first several such studies, experimenters expecting high ratings obtained substantially Robert Rosenthal is Professor of Social Psychology at Harvard University, where he studies inter- personal expectancy effects, non- verbal communication, and data- analytic procedures. Address correspondence to Robert Rosenthal, Department of Psychol- ogy, Harvard University, 33 Kirk- land St., Cambridge, MA 02138. higher ratings than did experiment- ers expecting low ratings.2 To investigate the generality of these interpersonal expectancy ef- fects in the laboratory, my col- leagues and I conducted two studies employing animal subjects. Half the experimenters were told their rats had been specially bred for good maze (or Skinner box) performance, and half were told their rats had been specially bred for poor maze (or Skinner box) performance. In both experiments, when experi- menters had been led to expect bet- ter learning from their rat subjects, they obtained better learning from their rat subjects. PYGMALION EFFECTS IN THE CLASSROOM If rats became brighter when ex- pected to by their experimenters, then it seemed not farfetched to think that children could become brighter when expected to by their teachers. Jacobson and I conducted a study to test this hypothesis. All of the children in the study were ad- ministered a nonverbal test of intel- ligence, which was disguised as a test that would predict intellectual "blooming." The test was labeled "The Harvard Test of Inflected Ac- quisition." There were 18 class- rooms in the school, three at each of the six grade levels. Within each grade level, the three classrooms were composed of children with above-average ability, average abil- ity, and below-average ability, re- spectively. Within each of the 18. classrooms, approximately 20% of the children were chosen at random to form the experimental group. The teachers of these children were told that their scores on the "Test of In- flected Acquisition" indicated they would show surprising gains in intel- lectual competence during the next 8 months of school. The only differ- ence between the experimental group and the control group chil- dren, then, was in the minds of the teachers. At the end of the school year, 8 months later, all the children were retested with the same test of intelli- gence. Overall, the children from whom the teachers had been led to expect greater intellectual gain showed a significantly greater gain than did the children of the control group, thereby supporting the "Pyg- malion" hypothesis.4 GENERALITY AND MAGNITUDE OF THE EFFECT A dozen years after the Pygma- lion-in-the-classroom study was completed, the research literature on interpersonal expectancy effects had broadened to include 345 ex- periments in eight domains of re- search. For each of these domains, Table 1 gives an example of the types of studies conducted and the average magnitude of the effect ob- tained. After another dozen years had gone by, there were 464 stud- ies, with an overall d of 0.63, r of .30, and of .09.6,7 Unfortunately, evaluating the so- cial importance of these results is problematic because all three of these effect-size estimates suffer from the same problem: the under- estimation of the practical impor- tance of the effect of a behavioral or biomedical intervention. Something more is needed to address the ques- tion: What is the effect on the suc- cess rate (e.g., survival rate, cure rate, improvement rate) of any inter- vention? One approach is to use the binomial-effect-size display (BESD), which shows the change in outcome Published by Cambridge University Press 176 VOLUME 3, NUMBER 6, DECEMBER 1994 Interpersonal Expectancy Effects: A 30-Year Perspective Robert Rosenthal In the mid 1950s, the results of my doctoral dissertation were nearly ruined; it appeared that I might have treated my experimental subjects in such a way as to lead them to re- spond in accordance with my exper- imental hypothesis, or expectancy." All of this was quite unwitting, of course, but it did raise a sobering question about the possibility of in- terpersonal expectancy effects in the psychological laboratory. If it was my unintentional interpersonal ex- pectancy effect or my "unconscious experimenter bias" that had led to the puzzling and disconcerting re- sults of my dissertation, then pre- sumably my students and I could produce the phenomenon in our own laboratory, and with several ex- perimenters rather than just one. EARLY LABORATORY EXPERIMENTS The earliest studies were con- ducted with human subjects. Exper- imenters instructed the subjects to rate photographs of people, with half the experimenters led to expect high ratings and half led to expect low ratings. In the first several such studies, experimenters expecting high ratings obtained substantially Robert Rosenthal is Professor of Social Psychology at Harvard University, where he studies inter- personal expectancy effects, non- verbal communication, and data- analytic procedures. Address correspondence to Robert Rosenthal, Department of Psychol- ogy, Harvard University, 33 Kirk- land St., Cambridge, MA 02138. higher ratings than did experiment- ers expecting low ratings.2 To investigate the generality of these interpersonal expectancy ef- fects in the laboratory, my col- leagues and I conducted two studies employing animal subjects. Half the experimenters were told their rats had been specially bred for good maze (or Skinner box) performance, and half were told their rats had been specially bred for poor maze (or Skinner box) performance. In both experiments, when experi- menters had been led to expect bet- ter learning from their rat subjects, they obtained better learning from their rat subjects. PYGMALION EFFECTS IN THE CLASSROOM If rats became brighter when ex- pected to by their experimenters, then it seemed not farfetched to think that children could become brighter when expected to by their teachers. Jacobson and I conducted a study to test this hypothesis. All of the children in the study were ad- ministered a nonverbal test of intel- ligence, which was disguised as a test that would predict intellectual "blooming." The test was labeled "The Harvard Test of Inflected Ac- quisition." There were 18 class- rooms in the school, three at each of the six grade levels. Within each grade level, the three classrooms were composed of children with above-average ability, average abil- ity, and below-average ability, re- spectively. Within each of the 18. classrooms, approximately 20% of the children were chosen at random to form the experimental group. The teachers of these children were told that their scores on the "Test of In- flected Acquisition" indicated they would show surprising gains in intel- lectual competence during the next 8 months of school. The only differ- ence between the experimental group and the control group chil- dren, then, was in the minds of the teachers. At the end of the school year, 8 months later, all the children were retested with the same test of intelli- gence. Overall, the children from whom the teachers had been led to expect greater intellectual gain showed a significantly greater gain than did the children of the control group, thereby supporting the "Pyg- malion" hypothesis.4 GENERALITY AND MAGNITUDE OF THE EFFECT A dozen years after the Pygma- lion-in-the-classroom study was completed, the research literature on interpersonal expectancy effects had broadened to include 345 ex- periments in eight domains of re- search. For each of these domains, Table 1 gives an example of the types of studies conducted and the average magnitude of the effect ob- tained. After another dozen years had gone by, there were 464 stud- ies, with an overall d of 0.63, r of .30, and of .09.6,7 Unfortunately, evaluating the so- cial importance of these results is problematic because all three of these effect-size estimates suffer from the same problem: the under- estimation of the practical impor- tance of the effect of a behavioral or biomedical intervention. Something more is needed to address the ques- tion: What is the effect on the suc- cess rate (e.g., survival rate, cure rate, improvement rate) of any inter- vention? One approach is to use the binomial-effect-size display (BESD), which shows the change in outcome Published by Cambridge University Press