The Halo Effect

The Halo Effect1
Background
The ‘halo effect’ is a classic finding in social psychology. It is the idea that global evaluations about a person
(e.g. she is likeable) bleed over into judgments about their specific traits (e.g. she is intelligent). Hollywood
stars demonstrate the halo effect perfectly. Because they are often attractive and likeable we naturally
assume they are also intelligent, friendly, display good judgment and so on. That is, until we come across
(sometimes plentiful) evidence to the contrary.
In the same way politicians use the ‘halo effect’ to their advantage by trying to appear warm and friendly,
while saying little of any substance. People tend to believe their policies are good, because the person
appears good. It’s that simple.
But you would think we could pick up these sorts of mistaken judgments by simply introspecting
and, in a manner of speaking, retrace our thought processes back to the original mistake. In the
1970s, well‐‐‐known social psychologist Richard Nisbett set out to demonstrate how little access we
actually have to our thought processes in general and to the halo effect in particular.
The Experiment
Nisbett and Wilson wanted to examine the way student participants made judgments about a lecturer
(Nisbett & Wilson, 1977). Students were told the research was investigating teacher evaluations. Specifically,
they were told, the experimenters were interested in whether judgments varied depending on the type of
exposure students had to a particular lecturer. This was a total lie.
In fact the students had been divided into two groups who were going to watch two different videos of the
same lecturer, who happened to have a strong Belgian accent (this is relevant!). One group watched the
lecturer answer a series of questions in an extremely warm and friendly manner. The second group saw
exactly the same person answer exactly the questions in a cold and distant manner. Experimenters made
sure it was obvious which of the lecturer’s alter‐egos was more likeable. In one he appeared to like teaching
and students, and in the other he came across as a much more authoritarian figure who didn’t like teaching
at all. After each group of students watched the videos they were asked to rate the lecturer on physical
appearance, mannerisms and even his accent (mannerisms were kept the same across both videos).

1 The text for this description comes from “The Halo Effect: When Your Own Mind is a Mystery” downloaded
from PsyBlog (http http://www.spring.org.uk/2007/10/halo‐effect‐when‐your‐own‐mind‐is.php)

Your Task
Below are some fictitious data consistent with the findings of Nisbett and Wilson. For the sake of
simplicity, we’ll only analyze the data for “Physical Appearance.” Physical appearance was measured
using five traits with each trait rated on a 5‐point scale (larger numbersindicate higher ratings of
physical attractiveness). Participants’ answers were added together to arrive at a final “physical
attractiveness” score that could range from 5 to 25. These data are presented in table 1.
Your task is to statistically analyze these data and decide whether or not there is evidence here for the
“halo effect.” A series of questions have been provided to help guide your exploration of the data.
Table 1. Ratings of Physical Attractiveness
Type of Exposure
‘Warm and Friendly Instructor’ ‘Cold and Distant Instructor’
23 17
17 12
20 9
18 13
23 10
20 15
19 14
24 11
17 15
20 13
Short Answers (total 400 – 500 words)
Type your answers. You should include the question number for each answer, but you do not need to
include the question itself.
1. In your own words, describe the halo effect and provide a specific example.
2. In this study, what was the independent and dependent variable?
3. What would be the null hypothesisfor this analysis? Why do we assume the null hypothesisis
true when doing inferentialstatistics?
4. What is the alternative (or research) hypothesis?
5. Describe the center of each distribution: What is the mean for each group?
6. Describe the variability in each distribution: What is the standard deviation for each group?
What does this measure tell us about the dispersion of scores in each group?
7. These data should be analyzed using a t‐test, but which one should be used (i.e., one sample t
test, t test for independentsamples, or t test for related samples) and why?
8. Should you conduct a one‐ or two‐tailed test? Explain your answer.
9. Describe the results of the t test. Were the results statistically significant at p < .05? Explain how you arrived at this decision (i.e., what was the t value you calculated) 10. From all this information, can you conclude that the “halo effect” was present in this study? Was the researchers’ hypothesis supported? Explain your reasoning. Reference Nisbett, R. E., & Wilson, T. D. (1977). The halo effect: Evidence for unconscious alteration of judgments. Journal of Personality and Social Psychology, 35(4), 250 ‐ 256.