(C8511) Research Skills in Psychology 1 – Convenor : Graham Hole
Laboratory Report LAB (40%) 2000 words
The effects of in-group/out-group categorisation on face recognition:
Introduction:
Your task is to write a complete lab-report based on the study described below. To write the
introduction and discussion, you will need to conduct some independent research on the topic,
starting with the references supplied here. The material supplied in this handout provides you with
sufficient detail for you to be able to write the methods and procedure sections of the report. You
will need the raw data and the statistical analyses that were performed on them: these are available
in two SPSS files on the RS1 Study Direct site, RS1-resit-lab.sav and RS1-resit-lab.spo.
Background to the study:
Repeated exposure to a stimulus can increase its attractiveness, even if these exposures are not
paired with any rewards. This is termed the "Mere Exposure Effect" (Zajonc, 1968). In one
experiment, Zajonc showed participants a set of faces. Each face was shown a different number of
times. Each participant then rated how much they liked each face, using a seven-point scale. There
was a positive correlation between how many times a face was presented, and its liking rating.
Numerous factors are known to affect the size of the Mere Exposure Effect (review in Bornstein,
1989): it is strengthened by presenting the stimuli briefly and by introducing a delay between
stimulus presentation and testing. For a maximum effect, the stimuli should not be shown more
than about 10-20 times. The fact that it can be produced by subliminally-presented stimuli, of which
the participant is unaware, suggests that the Mere Exposure Effect does not require conscious
attention to the stimuli. As Zajonc put it, "preferences need no inferences".
Mita, Derner and Knight (1977) produced a clever demonstration of the Mere Exposure Effect.
People normally see their own face in a mirror, and hence left-right reversed. They only see their
face in the correct orientation (i.e. the way that everyone else sees it) when they look at a
photograph. Mita et al. reasoned that, when shown two images of their own face, one normal and
one mirror-reversed, participants should prefer the mirror-reversed version - the one that they are
more used to seeing. This was found to be the case. Each participant also rated the corresponding
two images of their friend's face. In this instance, participants preferred the normal version to the
mirror-reversed one (again, showing a preference for the more commonly-experienced version).
Our experiment:
Nowadays, because of digital media and social networking, people are much more used to seeing
their face in photographs than they would have been in 1977. Would a replication of Mita et al.'s
study produce the same results today?
In our study, we had two groups of participants, one consisting of people who used social
networking sites frequently and the other consisting of people who never used them. We measured
each participant's preference for their own face in normal and mirror-reversed versions. On the
basis of the Mere Exposure Effect, we predicted that participants in the "no social networking"
group would show a stronger preference for the mirror-reversed version of their own face than
would the participants in the "social networking" group. This is because the social networking group
were more used to seeing their faces in photographs, and hence in "normal" (non-reversed) versions,
compared to participants in the no social networking group.
The following details will be required in order for you to write a lab-report on this study. You will
need to re-order them into the appropriate sections of the report, and you will need to re-write
them in your own words.
Stimulus photographs:
Each participant was digitally photographed on entering the laboratory, using a Canon EOS 7D
camera with an 50mm lens at a distance of two metres, under diffuse natural lighting. The
photograph was taken against a plain grey background, with the participant adopting a neutral
expression. Adobe Photoshop was used to digitally remove any obvious facial asymmetries, such as
moles and piercings. Two copies of the face were then produced: one was in normal orientation, and
the other was "flipped" horizontally so that it was mirror-reversed.
Each picture measured 10 cm high by 5 cm wide. The faces were displayed to participants using a
computer program called "Eprime 2".
Participants :
30 Caucasian female Sussex Psychology undergraduates, aged 19-30, recruited on the basis of an
initial questionnaire that asked a group of 100 students whether they used social networking sites,
and whether they had a digital camera/smartphone . On the basis of the questionnaire, 15 students
were assigned to the "no social networking" group, and 15 to the "social networking" group.
Procedure:
Each participant was tested individually. A photograph of their face was taken (and
manipulated as described above). Two images were then produced for presentation to the
participant. In one image, the normal and mirror-reversed faces were placed side by side, with the
normal face on the left and the mirror-reversed face on the right. In the other image, the mirrorreversed face was on the left and the normal face was on the right.
The testing session consisted of each participant repeatedly viewing these two images on a
computer screen. There were ten trials for each participant. Both images were presented five times,
in a different random order for each participant. Thus each participant saw the normal image on the
left and right sides of the screen for an equal number of trials.
Each image was shown for four seconds, and was then followed by a blank screen containing the
words "which face do you like better, the one on the left or the one on the right?" The participant
pressed "S" on the computer keyboard if they preferred the face on the left, and "L" if they
preferred the one on the right.
For each participant, on each trial the computer recorded which side the normal face appeared on,
and whether the participant pressed "L" or "R". From this, for each participant, we obtained a single
score: how many times they expressed a preference for the "normal" version of their face, out of a
maximum of ten.
One possible sequence of trials for a participant (N = normal, M = mirror-reversed)
N M
M N
N M
N M
M N
N M
N M
M N
M N
N M
Results:
Each participant provided one score: the number of times they preferred their own face in its
normal version, compared to the mirror-reversed version. The maximum score in each case is 10.
Further reading:
Bornstein, R.F. (1989). Exposure and affect: overview and meta-analysis of research, 1968-1987.
Psychological Bulletin, 106 (2), 265-289.
Mita, T.H., Derner, M. and Knight, J. (1977). Reversed facial images and the mere-exposure
hypothesis. Journal of Personality and Social Psychology, 35 (8), 597-601.
Zajonc, R.B. (1968). Attitudinal effects of mere exposure. Journal of Personality and Social
Psychology, 9(2), 1-27.