[...] V. Social perception
elicits corresponding behavior
In the following paragraphs, evidence of
imitation of observable behavior will be
reviewed. The research on imitation of
observables can be divided into three domains.
First, there is a large literature on imitation
of facial expressions. In addition, others have
investigated imitation of gestures and
movements. Finally, there is evidence of
imitation of various speech related variables.
The major findings of all three domains will be
discussed, starting with facial expressions.
Facial expressions. The evidence for
imitation of facial expressions is abundant
(e.g., Dimberg, 1982; Vaughan & Lanzetta,
1980; Zajonc et al., 1982). An example of a
very contagious facial expression that is
familiar to all of us is yawning. If, after
a long car or trainride, a person starts to
yawn, usually his or her travel companions start
to yawn within a few minutes. This tendency to
imitate yawning has also been demonstrated
empirically. Provine (1986) asked participants
to watch a five minute videotape. In one
condition, participants watched a video with
yawning people, whereas in a control condition
participants watched a video with smiling
people. As expected, 55% of the participants in
the experimental (i.e., yawn) condition started
to yawn while watching the video, as opposed to
only 21% in the control (i.e., smile) condition.
Interestingly, Provine also obtained evidence
supporting our claim that activation of the
mental representation of an action (which can be
the result of perception but also of, for
instance, thought) is crucial in eliciting
corresponding behavior. That is, one does not
have to literally perceive a yawn to engage in
yawning. Provine found that reading about
yawning or thinking about yawning also caused
participants to yawn. Finally, the fact that one
of the authors of this paper is yawning right
now, can be taken as anecdotal evidence that
writing about yawning does the trick as
well.
Although no consensus emerged among
researchers as to the exact cause of the
phenomenon, various investigators have studied
imitation of facial expressions among newborns
(Anisfield, 1979; Field, Woodson, Greenberg
& Cohen, 1982; Jacobsen & Kagan, 1979;
Meltzoff & Moore, 1977, 1979, 1983).
Meltzoff and Moore (1977; 1979) showed that even
one-month-old babies imitate facial expressions.
If you look at a baby and open your mouth, the
baby will open her mouth. If you stick out your
tongue, the baby will often do the same.
An interesting early demonstration of
imitation of facial expression among adults can
be found in an experiment by O'Toole and Dubin
(1968). Their experiment was aimed at
investigating mother-child interactions during
feeding. They had observed that a mother would
usually open her mouth just prior to feeding
their infants a spoonful of food. Their
intuitive explanation for this finding was that
a mother would open her mouth in the hope that
her child would do the same and Ðmost
importantly- that the food would end up where it
is supposed to end up. They put their ideas to a
test by watching various mother-infant
interactions and observed indeed that both
mothers and infants open their mouth.
Surprisingly however, in almost 80% of the
cases, a mother opens her mouth only after the
child does so. In other words, it is the mother
who is imitating the child, not vice versa. The
child is merely opening his or her mouth upon
perceiving the food on its way.
Another example of adult imitation of facial
expressions comes from experiments carried out
by Bavelas and colleagues (Bavelas, Black,
Lemery & Mullett, 1986; 1987). In their
experiments, a confederate was the victim of a
painful injury that occurred in the presence of
the participants. As expected, the participants
imitated the expressions of the confederate,
that can best be described as a big wince.
Interestingly, they also manipulated the
visibility of the expression of the confederate.
In one condition, the expression of the
confederate was easier to see than in a second
condition. As a result, the degree to which
participants imitated the expression varied as
well. More visible expression led to more
imitation; that is, the easier it was to
perceive the expression the greater the effect
on one's own behavior.
Zajonc and colleagues (Zajonc, Adelmann,
Murphy & Niedenthal, 1987) reasoned that
couples who have lived together for a period of
time should have often experienced the same
emotions at the same times, and because frequent
facial expressions eventually lead to changes in
facial lines, they hypothesized that partners
should start to look more like each other the
longer they are together. In their experiment,
they gave participants 24 photographs. These
photographs were those of the partners of 12
married couples. Some photographs were made at
the wedding, whereas others were made 25 years
later. The task of the participants was to
assess the degree of resemblance of various
pairs of photographs. As predicted, partners who
were together for 25 years resembled each other
more than random pairs of the same age and than
newly-wed couples. Although Zajonc et al. (1987)
interpreted these findings in terms of shared
emotional experience, these findings are also
consistent with the present hypothesis of a
direct effect of perception on behavior; that
is, it may be that frequent perception of the
partner's expression leads one to adopt that
same expression repeatedly oneself, producing
over time the similarity in facial lines between
the two partners (see Bargh, 2000).
Imitation of facial expressions has also been
studied in the context of emotional contagion
(see e.g., Hatfield, Cacioppo & Berntson,
1994). Our facial expressions affect our
emotions through a process of feedback elicited
by facial muscles (Strack, Martin, &
Stepper, 1988). Imitation of facial expressions
therefore leads to shared emotions. In concrete
terms, the perception of a sad face evokes a sad
expression in the perceiver and the perceiver
will actually begin to feel sad as well. In the
Zajonc et al. (1987) research, the relation
between shared facial expressions and shared
emotions was obtained in a follow-up study. They
had observed variations as to the degree of
resemblance of life partners. This led to the
intriguing hypothesis that partners who have
grown to look like each other more may actually
be happier together than those who have not,
because their resemblance is due to a greater
history of shared emotions. And, in general at
least, shared emotions lead to a stronger bond
between partners. A questionnaire study indeed
confirmed this hypothesis with effects being
impressive in size (with a correlation of .49
between resemblance and self-reported
happiness).
Behavior matching. The evidence concerning
the imitation of movements and gestures is less
abundant than the evidence on imitation of
facial expressions. Although theorists have
always treated the automatic imitation of
postures, gestures and movements as a given
(e.g., Allport, 1968; Köhler, 1927), early
"evidence" was almost entirely anecdotal (see
Bavelas et al., 1986; for reviews, see Capella,
1981; Chartrand & Bargh, 1999; Dijksterhuis,
2000; LaFrance, 1979). Later reports, in which
posture imitation (or posture mirroring, as it
is called more often) was investigated
experimentally, suffered from methodological
weaknesses (Charney, 1966; Kendon, 1970).
Finally, research in the seventies and early
eighties was not so much concerned with the
occurrence of posture imitation per se, but
instead with the relation between imitation and
rapport. These studies (e.g., Bernieri, 1988;
LaFrance, 1979; LaFrance & Ickes, 1981)
speak to the possible function of posture and
gesture mirroring in that some experiments
clearly show a strong correlation between
posture imitation and rapport. However, they do
not shed light on how often people spontaneously
engage in posture imitation.
The only early investigation we could
identify that exceeds the level of mere
anecdotal evidence was reported by Eidelberg
(1929). In his experiment, participants were
instructed to point at their nose upon hearing
the word "nose" and to point at a lamp upon
hearing the word "lamp." The experimenter, who
was clearly visible to the participants, also
pointed at his or her nose or at the lamp upon
hearing the corresponding instruction. After a
while, the experimenter started to make
"mistakes," in that he or she pointed at the
lamp upon hearing the word nose and vice versa.
Interestingly, participants started to make the
same mistakes as well. They spontaneously
imitated the gestures made by the experimenter,
despite the instruction to follow the verbal
cues (i.e., the words "nose" and "lamp") and not
the behavior of the experimenter.
Bernieri (1988; see also Bernieri, Reznick
& Rosenthal, 1988) was the first to provide
truly solid evidence for posture imitation. In
his studies, a somewhat complicated but
nonetheless ingeneous paradigm was used. First,
two participants (A and B) were asked to
interact. While they interacted, they were
videotaped. A little later, both participants A
and B were asked to engage in another
interaction with a different participant, such
that A interacted with C and B would interact
with D. Again, both interactions were
videotaped. Subsequently, two tapes were
constructed on which the gestures and postures
of both participants A and B were displayed. One
concerned the actual interaction between A and
B. The other tape pictured A while interacting
with C, and B while interacting with D.
Subsequently, judges -who were unaware of which
tape displayed the actual interaction between A
and B- estimated the degree of posture
similarity. If the degree of matching is greater
on the first tape (the actual interaction) than
on the second, there is evidence for posture
matching. Bernieri (1988) indeed obtained this
evidence. People do spontaneously mirror the
postures of individuals they interact with.
Chartrand and Bargh (1999) replicated and
extended these effects. Instead of investigating
posture mirroring, they focused on actions such
as foot shaking or nose rubbing. In their first
experiment, a confederate was instructed to
either rub her nose or shake her foot while
working with a participant on a task.
Importantly, the two were strangers and had only
a minimal interaction, greatly reducing the
probability that any imitation as motivational
in nature Ðsuch as part of an attempt to
ingratiate the other person. Their hypothesis,
that participants would mimic the behavior of
the confederate, was confirmed. Under conditions
where the confederate rubbed her nose
participants engaged more in nose-rubbing than
in foot-shaking, whereas the opposite was true
when participants interacted with the
confederate who shook her foot. Chartrand and
Bargh (1999) replicated and extended this
finding in a second study, in which the
confederate purposefully mimicked the body
posture of the participant. This study obtained
clear evidence that mimicry leads to increased
liking of interaction partners. The lack of a
motivational basis for these findings supports
our thesis of an automatic link between social
perception and one's own behavior, in a
naturalistic interaction context.
Speech related variables. Finally, there is
evidence of automatic imitation of various
speech related variables. One phenomena that is
investigated by several researchers is syntactic
persistence, that is, the tendency to use a
certain syntax when this syntax is made
cognitively accessible. This phenomenon supports
the common coding approach to language
comprehension and language production postulated
by Prinz (1990). Prinz argues that we use the
same mental representations for both
comprehension and production of speech.
According to Prinz (see also Studdert-Kennedy,
1987), language comprehension and production
develop at the same time during ontogeny:
"…the ability to produce language is of no
use when there is no one to listen, and the
ability to understand language is of no use when
there is no one to produce it" (pp. 177).
Bock (1986; 1989) reported evidence of
syntactic persistence. In one experiment,
participants would hear and repeat a sentence
such as "The corrupt inspector offered a deal to
the bar owner." Later, participants would see a
picture of, for instance, a boy handing a
valentine to a girl. This picture can be
described as "The boy is handing a valentine to
a girl" or as "The boy is handing the girl a
valentine." As the first sentence has a similar
syntactic form as the priming sentence, this is
the description participants most often gave.
Syntactic structures appear to carry over from
one sentence to another.
Whereas in the studies conducted by Bock
(1986) participants activated a particular
syntax themselves, Levelt and Kelter (1982; see
also Schenkein, 1980) investigated syntactic
persistence in a social context. In one of their
experiments, the experimenter called various
shops and either asked "What time does your shop
close?" or "At what time does your shop close?".
If the former question was asked, shopkeepers
more often answered with "Five o'clock", whereas
the answer to the latter question was "At five
o'clock" in the majority of cases. Importantly,
both Levelt and Kelter as well as Schenkein
obtained such effects of speech imitation for
single words, for clauses as well as for the
structural format of entire sentences. Finally,
Levelt and Kelter showed that cognitive load did
not increase these speech imitation effects
(which were already very substantial under
normal conditions), suggesting that these
effects were automatic in nature.
Recently, Neumann and Strack (2000) obtained
evidence for imitation of tone of voice between
interaction partners. In one of their
experiments, participants listened to an
audiotaped speech given by a stranger. While
they were listening, participants were asked to
repeat what they heard and were audiotaped
themselves. It was found that participants
adopted the tone of voice of the person on the
tape they listened to. A sad tone of voice on
the tape elicited a sad tone of voice in the
participant, whereas a happy voice led to a
happy voice in the participant. These findings
are particularly important as they rule out the
possibility that participants imitated tone of
voice for strategic reasons (e.g., to increase
cohesion). They didn't see the person who
delivered the speech, they didn't even know who
this person was, and no participant was aware of
the actual goal of the experiment. Instead, they
were successfully led to believe that the
experimenters were interested in the
reproduction of speech content.
Are emotion and behavior-matching strategic?
Bavelas and colleagues (Bavelas et al., 1986,
1987) accounted for their findings with a
motivational communicative perspective. They
argue that participants imitate in order to show
the confederate that they are empathizing with
him or her, that they are "feeling their pain."
And if there is more eye contact between the
confederate and the participant, the participant
imitates more because he or she knows that the
confederate is better able to see their
expression. In other words, they interpret the
imitation as a motivated, strategic behavior to
create an empathic bond with the other person.
This model of imitation (that, according to the
division we made earlier between
"facilitator-option" and an "inhibitor-option"
is an example of a facilitator-option) is the
standard account in the field not only of facial
mimicry, but of the related phenomena reviewed
above of "behavior matching" (La France, 1979,
1982) and "rhythmic synchrony" (Bernieri, 1988;
Condon & Ogston, 1966; Condon & Sander,
1974). Most of this research has sought to link
behavioral coordination effects with the
establishment of rapport and liking between the
parties involved, with some researchers viewing
empathy as the cause of mimicry and others
considering mimicry to be the cause of empathy
(see Bernieri & Rosenthal, 1991, and
Chartrand & Bargh, 1999, for reviews).
Although it is true that there tends to be
greater mimicry when the two individuals like
each other than not (e.g., Charney, 1966;
LaFrance & Broadbent, 1976), so that rapport
between the parties is an important moderator of
the effect (see "Moderators" below), this does
not mean that the perception-behavior effect
requires for its occurrence a motivation or
strategy or even positive affect towards the
other person as a necessary condition.
After all, the evidence reviewed above shows
that the only real precondition of imitation of
observable behavior is the perception of the
behavior. We would like to emphasize that our
explanation of an innate express route between
perception and action is supported by this
evidence as our explanation would lead one to
predict all the reviewed effects to be automatic
and non-strategic as opposed to other
explanations that claim these effects to be
strategic and intentional. There is no evidence
at all for the strategic nature of the imitation
effects reviewed above, whereas the support for
the automatic and unintentional nature of
imitation is evident. Meltzoff and Moore (1977)
demonstrated a tendency to imitate among
newborns. O'Toole and Dubin (1968) showed that
mothers tend to imitate their children and there
really is no strategic reason to do so. Although
Bernieri (1988) showed imitation among people
who engaged in an extended interaction
(potentially allowing the interactants to engage
in motivated imitation), Chartrand and Bargh
(1999) showed that even minimal interaction with
a complete stranger led to imitation. Finally,
Neumann and Strack (2000) obtained evidence for
imitation of tone of voice when the person being
imitated was not even present.
