Psychology
2013. Vol.4, No.6A2, 8-13
Published Online June 2013 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2013.46A2002
8
Similar Physical Appearance Affects Friendship Selection in
Preschoolers
Wakako Sanefuji
Institute for Advanced Study, Kyushu University, Fukuoka, Japan
Received April 5th, 2013; revised May 8th, 2013; accepted June 10th, 2013
Copyright © 2013 Wakako Sanefuji. This is an open access article distributed under the Creative Commons At-
tribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the
original work is properly cited.
Previous studies suggest that one characteristic of friendship should be similarity in terms of attributions,
attitudes, and behavioral tendencies. Using an experimental approach, the present study investigated
whether preschool children judge that similarity in physical appearance or behavioral tendencies affects
friendship selection. Experiment 1, which used human-like figures as stimuli, revealed that both 4- and
5-year-olds (n = 32 and n = 30, respectively) judged that similar physical appearance affects friendship
selection. We conducted a second experiment to test whether children were making judgments according
to friendship selection, and not merely physical similarity; thus, in Experiment 2, we used nonhuman fig-
ures as stimuli, and found that 5-year-old children (n = 31) judged that similar physical appearance would
affect friendship selection, whereas 4-year-old children (n = 31) showed no significant responses to any
stimuli; this might be related to the development of the ability to make mental attributions to inanimate
figures. The present findings suggest that young children regard similar physical appearance as an impor-
tant factor for friendship selection. At least at the age of five, similarity might be an antecedent to friend-
ship.
Keywords: Similarity; Peer Relationship; Preschool; Physical Appearance
Introduction
The social world, which surrounds us from the time we are
born, gradually expands as we develop. Relationships with peers
play an essential role in social development; for instance, chil-
dren learn how to behave by becoming members of and identi-
fying with a peer group (Harris, 1995). Analysis of early peer
relationships and the process through which they are formed is
important in determining the subsequent social consequences
for children and their prospects.
The characteristics of children’s peer groups appear to be
universal. If the number of children in a given locality is large
enough, children generally divide into groups segregated by age,
sex, and other locally relevant factors (Edwards, 1992; Mac-
coby, 1990). Dyadic peer relationships are characterized by
members of the same sex (Masters & Furman, 1981). Many
previous studies, particularly those on antisocial behaviors,
have shown that children in the same peer group seem to have
similar behavioral tendencies—even antisocial children tend to
associate with other antisocial children (e.g., Cairns, R. B.,
Cairns, B. D., Neckerman, Gest, & Gariepy, 1988; Dishion, An-
drews, & Crosby, 1995; Kupersmidt, DeRosier, & Patterson,
1995). Adolescents also tend to bond with those who are simi-
lar in substance use (Dishion, Capaldi, Spracklen, & Li, 1995;
Eiser, Morgan, Grammage, Brooks, & Kirby, 1991; Fisher &
Bauman, 1988) and delinquent behavior (Fisher & Bauman,
1988; Kandel, 1978; Rodgers, Billy, & Udry, 1984).
These findings suggest that similarities in terms of social
categories, such as age, sex, behavioral tendencies, and values,
result in friendship (Byrne, 1971; Newcomb, 1961). This view
would then suggest that a lack of similarity results in the ter-
mination—or never forming in the first place—of social ties
(Fisher & Bauman, 1988). However, there is room for discus-
sion about whether children recognize similarity as an impor-
tant factor in peer relationships when selecting friendship. Most
of these previous studies investigated the characteristics of al-
ready formed peer relationships; thus, little attention has been
given to children’s considerations of similarity when initially
forming social connections. Investigating whether children make
use of the similarity of characteristics between themselves and
other persons during friendship selection should elucidate the
cognitive basis of the formation of social ties with peers. Using
forced-choice tasks in two experiments, this study attempted to
reveal whether children judge similarity to be a requirement for
friendship with other persons. If children regard similarity as an
important factor for friendship selection, then they will judge
that a person would befriend a peer who has the most similar
characteristics to that person.
Experiment 1
Experiment 1 examined whether children judge that similar
characteristics play a role in friendship selection.
Materials and Methods
Participants
The participants were 62 Japanese preschool children: 32

W. SANEFUJI
4-year-olds (14 boys and 18 girls, M = 50.93 months, SD = 9.87
months) and 30 5-year-olds (17 boys and 13 girls, M = 61.32
months, SD = 10.03 months). All participants were recruited
from nursery schools in Fukuoka, Japan. The participants and
their guardians were informed about the procedure and gave
their consent for their participation. Three additional children
were excluded from the analysis because they did not respond
during the experiment.
Stimuli
The stimuli were line drawings of human-like figures, which
were created using Macromedia Flash MX 2004, Adobe Sys-
tems. Figure 1 shows a sample of the stimuli. The figures were
displayed on a computer screen, which was divided into four
parts. The upper left part of the screen was colored pale yellow,
while the other parts were white. A human-like figure was
drawn in each part; thus, each stimulus included four human-
like figures. The figure in the pale yellow part of the screen
served as the “target person,” which was explained to partici-
pants in the experimental instructions. Five kinds of tasks were
prepared: appearance, activity level, motion track, combined ap-
pearance and activity level, and combined appearance and mo-
tion track.
In the appearance task, the four human-like figures differed
in height or fatness. Three figures were formed by expanding a
figure two, three, or four times in height or fatness through a
computer (Figure 1). The target person was the tallest, shortest,
fattest, or thinnest figure, while the other figures were similar,
moderately similar, or dissimilar to the target figure. All the
figures were still images and did not move at all during the
presentation.
In the activity level task, four human-like figures, which
were identical in physical appearance, moved at different speeds.
Each of three figures moved horizontally two, three, or four
times as fast as the target person. All four figures moved at the
same time, for 3 s, from left to right; this was repeated using the
computer. These differing speeds resulted in differing distances
that the figures moved, because the figures started moving and
Figure 1.
Sample of the stimuli used in Experiment 1 (appearance task).
returned to the ride side of their respective “rooms” at the same
time; for instance, the figure that moved twice as fast as the
target figure moved twice the distance as the target figure. The
target person was the fastest (that is, moved the longest distance)
or slowest (moved the shortest distance) figure; the others moved
at a speed that was similar, moderately similar, or dissimilar to
the target figure.
In the motion track task, four human-like figures, which were
identical in physical appearance, moved in a U-shaped track,
inverse U-shaped track, or a combination of the two (for exam-
ple, descending in a U-shaped track for the first half of the dis-
tance and in an inverse U-shaped track for the other half). The
target person moved in a U-shaped or inverse U-shaped track,
of which the inclination was greater or lesser than that of the
other figures; the other figures were again similar, moderately
similar, or dissimilar (thus moving in the opposite track) to the
target figure. All the figures moved from left to right, in 3 s at
the same speed; this was repeated using the computer.
In the combined appearance and activity level task, four dif-
ferent human-like figures moved at different speeds; the target
person was the tallest, shortest, fattest, or thinnest figure, and
also either the fastest or slowest figure. The other three figures
were prepared in relation to the target figure, as before: a figure
that was most similar in appearance but most dissimilar in ac-
tivity level (the “appearance” figure), a figure that was moder-
ately similar both in appearance and activity level (the “moder-
ate” figure), and a figure that was most similar in activity level
but most dissimilar in appearance (the “activity level” figure).
In the combined appearance and motion track task, the four
different human-like figures moved in different motion tracks.
As with the previous task, the target figure had the highest de-
gree for each appearance characteristic (tallest, shortest, fattest,
thinnest), but also moved in a U-shaped or inverse U-shaped
track, the inclination of which was greater or lesser than that of
the other figures. All the figures moved from left to right, in 3 s,
at the same speed. The following three kinds of figures were
prepared in relation to the target figure: a figure that was most
similar in appearance but most dissimilar in motion track (the
“appearance” figure), a figure that had a moderate level of
similarity both in appearance and motion track (the “moderate”
figure), and a figure that was most similar in motion track but
most dissimilar in appearance (the “motion track” figure).
Procedure
The experiment was conducted individually with each child
in a quiet room of the nursery school. The experiment began
when the participant appeared sufficiently relaxed to actively
participate in the test session. The participants were randomly
presented with each of the five kinds of tasks, one at a time, on
the computer screen (Fujitsu, FMVMG55EU, 768 × 1024 pix-
els). The order of presentation of the five kinds of tasks was
counterbalanced across the participants. After a 10-s exposure
to the stimuli, the experimenter asked the participants to point
to the human-like figure that would become a friend with the
target person. The experimenter’s instructions were conducted
in Japanese, as follows: “The four people on the screen are
meeting up for the first time today. Who would likely want to
be friends with the person in the yellow room? Please tell me
by pointing to the person.” If the participants made no response
for a while, then the experimenter would repeat the instructions.

W. SANEFUJI
Results
For each task, a binomial test (two-sided) was conducted on
the number of children who chose each figure as being the most
likely to befriend the target person. This would allow us to see
whether the number of children who chose each figure (similar,
moderate, dissimilar) was significantly higher or lower than
chance level. Table 1 shows the number of children who chose
each kind of figure during each task and the binomial test z-
scores.
In the 4-year-old group, for the appearance, combined ap-
pearance and activity level, and combined appearance and mo-
tion track tasks, a significantly greater number of participants (z
= 4.82, z = 3.70, and z = 3.32, respectively) judged the figure
that was similar in appearance as being the one who would
befriend the target figure. On the other hand, for the appearance,
combined appearance and activity level, and combined appear-
ance and motion track tasks, a significantly smaller number of
4-year-old participants (z = 3.07, z = 2.69, and z = 2.69, respec-
tively) judged the moderately similar figure as being the one
who would befriend the target figure. Regarding the 5-year-old
group, a significantly greater number of participants in the ap-
pearance, combined appearance and activity level, and com-
bined appearance and motion track tasks (z = 5.63, z = 4.85,
and z = 6.02, respectively) judged the figure similar in appear-
ance as the one who would befriend the target figure. On the
other hand, for the appearance, combined appearance and activ-
ity level, and the combined appearance and motion track tasks,
a significantly smaller number of 5-year-old participants judged
the moderately similar (z = 2.52, z = 2.52, and z = 2.91, respec-
tively) and dissimilar figures (z = 2.91, z = 2.14, and z = 2.91,
respectively) as those who would befriend the target figure.
Regarding the activity level and motion track tasks, the num-
bers of 4- and 5-year-olds who judged each figure as being
likely to befriend the target figure was within the chance level.
Table 1.
Total numbers and z-scores of children who chose each kind of figure
as the one who would befriend the target person in each task in Ex-
periment 1.
4-year-olds 5-year-olds
Task Figure n z-score n z-score
Similar 24 4.82 25 5.63
Moderate 2 3.07 3 2.52
Ap
Dissimilar 6 1.57 2 2.91
Similar 10 .06 15 1.75
Moderate 10 .06 9 .19 Ac
Dissimilar 12 .31 6 1.36
Similar 13 .69 7 .97
Moderate 13 .69 14 1.36 Mo
Invert 6 1.57 9 .19
Ap 21 3.70 23 4.85
Moderate 3 2.69 3 2.52 Ap × Ac
Ac 8 .81 4 2.14
Ap 20 3.32 26 6.02
Moderate 3 2.69 2 2.91 Ap × Mo
Mo 9 .44 2 2.91
Note: ap = appearance; ac = activity level; mo = motion track: In the combined
task (ap × ac; ap × mo), ap = a figure that was most similar in appearance but most
dissimilar in activity level or motion track; moderate = a figure that was moder-
ately similar both in appearance and activity level or motion track; ac = a figure
that was most similar in activity level but most dissimilar in appearance; mo = a
figure that was most similar in motion track but most dissimilar in appearance.
Discussion
These results indicated that 4- and 5-year-olds judged that
the human-like figure that was the most similar in appearance
to the target would be most likely to befriend the target figure,
when the figures shown to the participants all differed in ap-
pearance. The results for the stimuli combination tasks (ap-
pearance and activity level, and appearance and motion track)
suggest that children made use of the information pertaining to
appearance for judging whether people would become friends
when they first met, rather than similarity in movements—this
is evident from their performance on the activity level and mo-
tion track task, as both 4- and 5-year-olds chose none of the
figures significantly more often. It should be noted that our use
of motion might not have expressed a substantial difference in
movement patterns; further investigation with improvements
such as a larger screen and clearer differences in the move-
ments among figures is required.
These findings suggest that young children judged similarity
in appearance as influential in establishing friendships. How-
ever, the results might have been based on only the categoriza-
tion of similar physical characteristics; that is, children did not
consider which of the figures would be likely to befriend the
target. In fact, some studies have found that children as old as
five categorize objects according to objects’ physical, as op-
posed to functional, similarity (Graham, Williams, & Huber,
1999; Smith, Jones, & Landau, 1996; Tomikawa & Dodd, 1980).
Thus, regardless of the instructions in the experiment, children
might have simply assessed the degree of physical similarity in
the figures and chose the figure that was most similar in ap-
pearance to the target, without considering whether they would
be friends.
To further explore this, using nonhuman figures as stimuli
might be useful in preventing the possibility that children might
only categorize according to similar appearances. The ability to
meta-represent—which develops toward the end of the pre-
school years—allows children to think about beings through
representations of the world. Previous studies show that chil-
dren over five years of age can use trait information to predict
psychological causes (Baird & Astington, 2005; Yuill & Pear-
son, 1998). Thus, investigation using nonhuman figures would
require children to form mental representations about the fig-
ures; if the children had thought about which figure would be-
friend the target, as instructed, then task performances using
nonhuman figures would differ between 4- and 5-year-olds. On
the other hand, if the children only categorized via similar ap-
pearances, without thinking about the possible relationships
among figures, then there should be no difference between the
groups.
Experiment 2
Using nonhuman figures as stimuli, Experiment 2 examined
whether children judge that similarity is a factor for friendship
selection.
Materials and Methods
Participants
The participants of Experiment 2 were 62 children: 31 4-
year-olds (16 boys and 15 girls, M = 49.28 months, SD = 9.21
months) and 31 5-year-olds (14 boys and 17 girls, M = 62.01
10

W. SANEFUJI
months, SD = 9.32 months). All children were recruited from
nursery schools in Fukuoka, Japan. None of them participated
in Experiment 1. The participants and their guardians were
informed about the procedure, before giving their written con-
sent for participation. Five children were excluded from the
analysis because of lack of response during the experiment.
Stimuli
The stimuli were five types of nonhuman figures, which were
created using Macromedia Flash MX 2004, Adobe Systems
(Figure 2). Each stimulus and the five types of tasks were pre-
pared similar to those in Experiment 1 (see the example, Figure
3). The figures in one task were all of the same type, and dif-
ferent figures were shown to the participants for each task;
therefore, the children saw all five kinds of figures by the end
of the five tasks. The combinations of figures and stimuli con-
ditions were counterbalanced across the participants.
Procedure
The procedure used in Experiment 2 was the same as that
used in Experiment 1.
Figure 2.
The five kinds of meaningless figures used in Experiment 2.
Figure 3.
Sample of the stimuli used in Experiment 2 (appearance task).
Results
For each task, a binomial test (two-sided) was conducted to
determine the number of children who chose each figure as the
one that would befriend the target figure, in order to examine
whether the number of children who chose each figure was
significantly higher or lower than chance level. Table 2 shows
the number of children who chose each figure in each task and
the z-scores.
For all tasks, the number of 4-year-olds who judged each
figure as the one that would befriend the target figure was
within chance level. However, for the 5-year-olds, for the ap-
pearance, combined appearance and activity level, and com-
bined appearance and motion track tasks a significantly greater
number of participants (z = 6.56, z = 5.03, and z = 6.56, respec-
tively) judged the figure that was similar in appearance as the
one that would befriend the target figure. Furthermore, in the
appearance and combined appearance and motion track tasks, a
significantly smaller number of 5-year-old participants judged
the figures that were moderately similar (z = 2.61 and z = 2.23,
respectively) and dissimilar in appearance (z = 3.76 and z =
2.23, respectively) as those that would befriend the target figure;
in the combined appearance and activity level task, a signifi-
cantly smaller number of participants (z = 3.37) judged the
figure that was dissimilar in appearance as the one that would
befriend the target figure. As in Experiment 1, for the activity
level and motion track tasks, the number of 5-year-olds who
judged each figure as the one that would befriend the target
figure was at chance level.
Table 2.
Total numbers and z-scores of children who chose each kind of figure
as the one that would befriend the target person in each task in Experi-
ment 2.
4-year-olds 5-year-olds
Task Figure
n z-score n z-score
Similar 15 1.59 28 6.56
Moderate 9 .32 3 2.61 Ap
Dissimilar 7 1.08 0 3.76
Similar 11 .06 10 −.06
Moderate 13 .83 8 .70
Ac
Dissimilar 7 1.08 13 .83
Similar 11 .06 8 .70
Moderate 8 .70 14 1.21
Mo
Invert 12 .45 9 .32
Ap 14 1.21 24 5.03
Moderate 5 1.85 6 1.46
Ap × Ac
Ac 12 .45 1 3.37
Ap 13 .83 23 4.65
Moderate 8 .70 4 2.23
Ap × Mo
Mo 10 −.06 4 2.23
Note: ap = appearance; ac = activity level; mo = motion track. In the combined task
(ap × ac; ap × mo), ap = a figure that was most similar in appearance but most dis-
similar in activity level or motion track; moderate = a figure that was moderately
similar both in appearance and activity level or motion track; ac = a figure that was
most similar in activity level but most dissimilar in appearance; mo = a figure that
was most similar in motion track but most dissimilar in appearance.

W. SANEFUJI
Discussion
The results indicated that 4-year-olds, regardless of task, did
not choose any of the figures significantly more or less often. In
contrast, 5-year-olds judged the figure that was most similar in
appearance as the one that would befriend the target person.
The differing results of the combined tasks (appearance and
activity level, and appearance and motion track) and pure activity
level and motion track tasks suggested that the 5-year-olds
made use of the information pertaining to similarity in appear-
ance for making judgments about friendship selection during
two people’s initial encounter, rather than similarity of move-
ments. The different results between 4- and 5-year-olds when
using meaningless figures as stimuli suggested that the partici-
pants had thought of which figure would have the strongest
possible relationship with the target figure, beyond merely
categorizing similar appearances. Five-year-old children judged
that similarity would be an important cue for the friendship
selection even when meaningless figures were presented as
stimuli. In Experiment 2, 4-year-olds did not show similar
judgments as those in Experiment 1; thus, the 4-year-olds might
have had difficulty in conceptualizing the meaningless figures
as being able to befriend other figures. This supports previous
findings on the development of the ability to meta-represent
(Baird & Astington, 2005; Yuill & Pearson, 1998).
Conclusion
The results suggested that young children regard similarity as
an important cue for friendship. Previous studies on alrea-
dy-formed peer relationships showed that one characteristic of
friendship should be similarity in terms of attributions, attitudes,
and behavioral tendencies (e.g., Byrne, 1971; Newcomb, 1961).
The present study adds the findings that preschool children, at
least at the age of five years, recognize that similarity in physi-
cal appearance affects friendship selection.
The developmental origin of detecting similarities in other
individuals may be found in infancy; when infants encounter
other individuals, they tend to look at their peers (age-mates)
more eagerly: Infants looked longer at photos and movies of
same-aged infants than at those of different-aged infants and
older children (Lewis & Brooks, 1975; McCall & Kennedy,
1980; Sanefuji, Ohgami & Hashiya, 2006). Furthermore, in-
fants prefer others who are similar to themselves in sex; infants
have shown looking preferences for photographs and films of
infants of their own sex (Lewis & Brooks, 1974). Previous
studies interpreted their findings as evidence of the ability to
identify infants who share similar age or sex categories (in the
sense that those infants are like themselves). These perceptual
preferences for similar others in infancy might be the basis of
preschoolers’ knowledge about befriending those similar to
themselves. The developmental process from infants’ looking
preferences for peers to children’s cognitive judgment about
friendship selection should be analyzed in the future in a single
longitudinal study.
Regarding the issue of the temporal consequences between
similarity and friendship, there are other aspects: for instance,
people tend to adopt the behaviors, attitudes, or values of those
with whom they frequently interact. In other words, relation-
ships are characterized by a strong tendency for people to syn-
chronize their activities, leading to an increase in similarity
between people over time (Cairns, 1979, 1986). Furthermore,
children’s synchronization of their peer’s behaviors is effective
for becoming closer to the peer; peer imitation is a popular
form of ingratiation, that is, a way of making oneself liked by a
peer (Jones, 1964; Thelen, Dollinger, & Roberts, 1975). In the
later periods of development, association with antisocial peers
is said to be a strong correlate of future problem behavior (Coie,
Terry, Zakriski, & Lochman, 1995; Olweus, 1977). This proc-
ess and the degree of influence of children’s synchronization on
peers’ behaviors should also be investigated in relation to chil-
dren’s detection of similarity in their initial encounters.
Acknowledgements
I am grateful to the preschool children who participated in
this study. I also thank Yusuke Moriguchi for his assistance in
data collection.
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