Experimenter Expectancy Effect On Children in a Classroom Setting

Rosenthal and Jacobson (1966) sought to test the experimenter expectancy effect by
examining how much of an outcome teachersí expectancies could have on a group of children.
Earlier investigations in this area were also conducted by Rosenthal (1963). He worked with
children in a research lab, giving each one a rat and telling them it was either bred for
intelligence or for dullness. The children were put in charge of teaching the rats how to learn
mazes. Rosenthalís results showed that the rats that were believed by the students to be smart,
were able to learn the mazes much quicker. What the children did not know, i.e., what
Rosenthal had kept hidden, was that the rats were chosen at random. There were no rats that
were especially bright or dull. Another case of the experimenter expectancy effect was that of
the horse known as ďClever HansĒ. It seemed to be able to read, spell, and solve math problems
by kicking his leg a number of times. The horse was tested and passed, but what the experts did
not realize was that their own hopes for the horse to answer the questions, were giving the horse
signs on which he based his answers. That is, if someone on the committee raised his/her
eyebrows in anticipation of the oncoming correct answer, the horse would stop stomping. Once
again, the experimenterís cues decided the outcome of the tests. Acting on these results,
Rosenthal and Jacobson hypothesized that teacherís expectancies would cause them
unintentionally to treat the students they thought to be bright in a different manner than those
they thought to be average or even less bright.
Rosenthal and Jacobson used some materials that were important in the completing their
investigation. The experimenters used students and their teachers as the subjects of their study.
As part of their experiment, they even chose which grades the students would be in. They also
used Flanaganís Tests of General Ability as a disguise to predict academic expectancies. The
experimenters did not use anything else in their experiment but instead let their subjects do the
rest. Rosenthal and Jacobsonís goal was to see how teachers would treat students whom they
thought were of above average intelligence in comparison to how they treated students whom
they believed were of below average intelligence.
As with all experiments, there needed to be variables. In trying to test teacherís
expectancies, Rosenthal and Jacobson used labels for children as their independent variable.
The labels used were ďbloomersĒ for children who were expected to be above average, while the
other group of children were labeled as average. Rosenthal and Jacobson wanted to see how
children being labeled as dull or bright would contribute to how teachers would react to them.
The teacherís reaction tended to be in the form of giving the bright children more attention and
expecting them to score higher grades and perform better in class. Because the teacherís
reaction depends on how the children were labeled, it was dependent on the first variable. The
teacherís reactions to the childrenís labels, was the experimenterís dependent variable.
Rosenthal and Jacobson controlled every aspect of the experiment. They chose which
children would be seen as dull or bright by having scores from Flanaganís Test of General
Ability sent to the teachers. They also chose which grades of children would be used and which
teachers would be in the experiment. The experimenters maintained a high degree of control,
and they told no one else of what they were really studying.
The children in the experimental group averaged 12.2 points of improvement in their
intellectual growth. The students in the control group averaged 8.2 points of intellectual growth.
Reporting the average is not an accurate way of showing the difference in IQ point increases
though. The third through sixth grade reported almost no difference in the gains, but the first
and second grades differed as much as 15 points. The difference in scores shows the effect that
teachers can have on their students. Particularly in the first and second grades, the amount that
teachers expect from their students is the amount they will receive.
This study could be improved in a few ways. First, the students were tested at the end of
the school year