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Emotional Valence is Body-Specific:
Evidence from spontaneous gestures during US presidential debates.
Daniel Casasanto Kyle Jasmin
(daniel.casasanto@mpi.nl) (kyle.jasmin@mpi.nl)
Max Planck Institute for Psycholinguistics
Wundtlaan 1, 6525 XD Nijmegen, The Netherlands
Abstract
What is the relationship between motor action and emotion?
Here we investigated whether people associate good things
more strongly with the dominant side of their bodies, and bad
things with the non-dominant side. To find out, we analyzed
spontaneous gestures during speech expressing ideas with
positive or negative emotional valence (e.g., freedom, pain,
compassion). Samples of speech and gesture were drawn
from the 2004 and 2008 US presidential debates, which
involved two left-handers (Obama, McCain) and two right-
handers (Kerry, Bush). Results showed a strong association
between the valence of spoken clauses and the hands used to
make spontaneous co-speech gestures. In right-handed
candidates, right-hand gestures were more strongly associated
with positive-valence clauses, and left-hand gestures with
negative-valence clauses. Left-handed candidates showed the
opposite pattern. Right- and left-handers implicitly associated
positive valence more strongly with their dominant hand: the
hand they can use more fluently. These results support the
body-specificity hypothesis, (Casasanto, 2009), and suggest a
perceptuomotor basis for even our most abstract ideas.
Keywords: Body-specificity hypothesis; Gesture;
Handedness; Metaphor; Presidential election; Valence
Introduction
Language and culture are two powerful forces that shape our
minds. Where languages and cultures differ from one
another, linguistic and cultural experience gives rise to
language-specific and culture-specific patterns of thinking
and acting, plausibly via ordinary learning mechanisms
(e.g., Casasanto, 2008a; Nisbett, Peng, Choi, & Norenzayan,
2001; cf., Fodor, 1985; Pinker, 1994).
Here we investigate another pervasive force that shapes
our thoughts, feelings, and actions: bodily experience.
According to the body-specificity hypothesis (Casasanto,
2009), people with different kinds of bodies, who interact
with their physical environments in systematically different
ways, should form correspondingly different ‘body-specific’
mental representations.
It is challenging to disentangle the potential contributions
of linguistic, cultural, and bodily experience to the structure
of our minds. Because patterns in language and culture
closely mirror patterns of bodily interactions with the
environment (Clark, 1973), language, culture, and body
generally make the same neural and behavioral predictions.
To overcome this obstacle, the present study tested for a
body-specific association between physical space and
emotional valence that is not encoded in any known
language or cultural artifacts, but which was predicted based
on particulars of our bodies.
In language and culture, Good=Right.
Across languages and cultures, left is conventionally
associated with bad and right with good. English idioms
like the right answer and my right hand man link good
things with rightward space, and complementary idioms like
out in left field and two left feet associate bad things with
leftward space. The Latin words for right and left, dexter
and sinister, form the roots of English words meaning
skillful and evil, respectively. The words for right in French
(droite) and in German (Recht) are closely related to the
words meaning a ‘right’ or privilege accorded by the law,
whereas the words for left in French (gauche) and German
(Links) are related to words meaning distasteful or clumsy.
Left-right idioms are also evident in nonlinguistic
conventions in many cultures. Roman orators were
admonished never to gesture with their left hand, alone
(Quintillian, Institutio Oratoria, Book 11). Actors in the
English renaissance were warned that vigorous left-hand
gesturing was not only vulgar but also dangerous, and could
result in the ‘vital spirits’ exploding out of the left ventricle
(Bulwer, Chironomia, 1644). In modern Ghanaian society,
pointing and gesturing with the left hand is prohibited (Kita
& Essegby, 2001). According to Islamic doctrine, the left
hand should only be used for dirty jobs like cleaning one’s
self, whereas the right hand is used for eating. Likewise, the
left foot is used for stepping into the bathroom, and the right
foot for entering the mosque.
Why does good correspond to right and bad to left,
throughout the world and throughout the ages? One
possible explanation is that this pattern arises from universal
properties of the human brain and mind, perhaps related to
innate hemispheric specialization for approach and
avoidance motivational systems (Maxwell & Davidson,
2007). Once established due to innate neurobiological
factors, conventions in language and culture may reinforce
this implicit preference for the right.
An alternative possibility, however, is that left-right
conventions in language and culture arise as a consequence
of body-specific associations between space and valence.
Bodies are lopsided. Most people have a dominant hand,
usually the right hand (Corballis & Beale, 1976), and
therefore interact with their environment more fluently on
1965
one side of body-centered space than the other. Greater
perceptuomotor fluency has been shown to correlate with
more positive evaluations: People like things that are easy to
perceive and interact with (Oppenheimer, 2008; Reber,
Winkielman, & Schwarz, 1998). For example, expert
typists prefer pairs of letters that can be typed easily over
pairs that are more difficult to type (even when typing is not
relevant to the task), suggesting that motor experience can
influence affective judgments (Beilock & Holt, 2007).
In a sense, we are all ‘experts’ at using our dominant
hands. Perhaps over a lifetime of lopsided perceptuomotor
experience, people come to implicitly associate good things
with the side of space they can interact with more fluently,
and bad things with the side of space they interact with less
fluently? On this possibility, the apparent universality of
the ‘good is right’ mapping suggested by linguistic and
cultural conventions could be a result of right-handers’
predominance in the population, worldwide. Linguistic and
cultural conventions may develop according to the implicit
body-specific preferences of the majority.
Is the ‘right’ side sometimes the left?
If the experience of asymmetrical perceptuomotor fluency
causes people to develop ‘mental metaphors’ (Casasanto,
2008b) linking space to valence, then right- and left-handers
should develop contrasting space-valence associations. For
right-handers, right should be linked with good and left with
bad, but the opposite should be true for left-handers.
To investigate this possibility, a series of experiments
compared right- and left-handers’ preferences for things on
the right or left side of a page. In one study, participants
saw two boxes, one on the right and the other on the left of a
cartoon character (viewed from above). They were asked to
indicate which of the boxes best represented good things
and which best represented bad things. English- and Dutch-
speaking participants showed reliable intuitions about which
was the ‘good’ box, but these intuitions differed strikingly
between right- and left-handers. The majority of right-
handers chose the box on the right, whereas the majority of
left-handers chose the box on the left (Casasanto, 2009).
This pattern was found even when participants were forced
to respond verbally, without writing or pointing with their
hands.
In further experiments, participants were asked to
evaluate pairs of alien creatures based on drawings, or pairs
of job applicants and commercial products based on brief
verbal descriptions. The pictures and descriptions appeared
in columns on the left and right of the page, and the
locations of the members of each pair were counterbalanced.
Right-handed participants tended to attribute more positive
characteristics to the alien creatures who they encountered
in the right column, judging them to be smarter, happier,
more attractive, and more honest on average than the
creatures they saw in the left column. Left-handers showed
the opposite preference. Likewise, right-handers tended to
prefer the person or product they saw described on the right
side of the page, whereas left-handers preferred the ones
described on the left (Casasanto, 2009). Even when the
spatial manipulation was implicit, right- and left-handers’
showed a body-specific pattern of judgments.
Minding the US presidential candidates’ hands.
The goal of the present study was to test for a body-specific
association between handedness and emotional valence in
spontaneous behavior, in the real world. We analyzed a
large and widely available corpus of speech and gesture: the
final US presidential debates from 2004 and 2008.
Serendipitously, both of the candidates from 2004 were
right-handed (John Kerry, Democrat; George W. Bush,
Republican), and both candidates from 2008 were left-
handed (Barack Obama, Democrat; John McCain,
Republican).
The complete transcripts from both debates were parsed
into clauses. All spoken clauses were rated as expressing
ideas with positive, negative, or indeterminate emotional
valence, by raters blind to the gestures that accompanied
them. Gesture strokes during clauses with positive and
negative valence were then coded as having been performed
with the left hand, right hand, or both hands. We then tested
for associations between the hand used to perform each uni-
manual gesture (dominant, non-dominant) and the emotional
valence of the co-occurring spoken clause (positive,
negative).
We considered three possible outcomes. First, there could
be no significant association between hand and valence.
Given that this sample of over 700 gestures provided
considerable power, this result would suggest that people do
not spontaneously associate positive ideas with their
dominant hand, and further that the previously discovered
links between handedness and valence may only be
observable under laboratory testing conditions.
Second, there could be an association of right-hand
gestures with positive valence clauses. This could indicate
that all speakers, right- and left-handers alike, had
internalized the ‘good is right’ mapping in our language and
culture (or alternatively, that the candidates had some
explicit gesture coaching in line with our linguistic and
cultural metaphors).
Finally, the most complex prediction was that the hand
used to gesture would be significantly associated with the
valence of the co-occurring speech, but this association
would differ between right- and left-handers. An
association between dominant hand gestures (whether the
right or left hand) and positive valence would show that the
body-specific mapping found in the previous experiments
(Casasanto, 2009) is not limited to the simplified world of
the laboratory, but also extends to a world as complex as
that of presidential politics.
Methods
Materials
Written transcripts for the final debates preceding the 2004
and 2008 US presidential elections were obtained from the
Commission on Presidential Debates <www.debates.org>.
1966
Videos of the 2004 and 2008 debates were obtained from
<www.archive.org> and <www.msnbc.msn.com>,
respectively. The handedness of candidates was determined
from the online resources listed in the Appendix, and
confirmed by inspection of pictures and videos of the
candidates writing or throwing, from various sources.
Procedure
Analysis of spoken text The goal of the text analysis was
to determine the emotional valence of each spoken clause.
Complete transcripts for both debates were parsed into
clauses by a trained linguist, who served as Coder 1 for
subsequent analyses. All analyses of the spoken text were
conducted based on the written transcripts. The coders were
blind to the gestures that accompanied them.
Coder 1 read each debate in full, classifying the valence
each clause as either positive, negative, neutral, or
indeterminate (i.e., ambiguous or mixed valence). There
were 2998 clauses, in total. Of these, 1566 clauses (52%)
were classified as either negative or positive.
The valence of these clauses was then evaluated by an
independent coder (Coder 2). Coder 2 read the clauses
individually, without reading the full debates, to ensure that
valence judgments for individual clauses were not
influenced by the valence conveyed in larger units of the
discourse. Inter-rater agreement was 82%. Only those
clauses for which both coders agreed were submitted to the
gesture analysis (1279 clauses; 682 with negative valence,
597 with positive valence).
Analysis of gestures The goals of the gesture analysis were
(1) to determine which hand was used for each gesture that
accompanied spoken clauses with positive and negative
valence, and (2) to test for associations of emotional valence
with use of the dominant and non-dominant hand. Coder 1
edited the audio-video recordings of the debates, creating
brief clips corresponding to each of the 1279 clauses that
had been identified as positive or negative: One clause per
clip. Clips lasted from the onset of the first word to the end
of the last word of each clause. Coder 1 performed a non-
blind analysis of the gestures in each clause, viewing the
clips in chronological order and listening to the
corresponding speech, to ensure that the clips contained the
correct verbal material. During 176 of the clauses (14%),
no gestures were observed. During the other 1103 of the
clauses (86%), at least one gesture was observed. The video
clips of these clauses were analyzed further.
Coder 1 determined the number of distinct gestures (i.e.,
gesture phrases) in each clip, according to segmentation
criteria described by McNeill (1992, pp. 82-84), and coded
the hand(s) used for each gesture stroke: left, right, or both
hands. Of the 1103 clips, 395 (36%) contained more than
one gesture, yielding a total of 1731 gestures. Of these, 915
gestures (53%) were bimanual, and therefore could not be
interpreted with respect to the experimental predictions. For
the remaining 816 gestures (47%), the strokes were
performed with either the left or the right hand, only. These
gestures were analyzed further.
Of these 816 gestures, one was excluded (.001%) because
the speaker’s gesture space was substantially occluded due
to the camera angle. An additional 43 gestures (5%) were
excluded because they were highly stereotyped finger-
counting gestures, which people have a strong tendency to
perform with their dominant hand. Finally, 16 pointing or
indicating gestures were excluded (2%) because they made
deictic reference to one of the other people in the room, so
the speakers’ choice of hand may have been influenced by
the locations of their interlocutors. The remaining 756
gestures (93%) comprised a mixture of iconic, metaphoric,
deictic (abstract and self-referential), and most commonly
beat-like gestures. Associations between the valence of the
spoken clause and use of the dominant hand were tested in
these gestures, based on Coder 1’s judgments.
To test the reliability of these judgments, Coder 2
performed a blind (or rather deaf) analysis of the gestures
identified by Coder 1, coding the hand(s) used for each
stroke without listening to the accompanying speech. Of the
1731 gestures observed, 500 (29%) were randomly selected
for analysis by Coder 2, half from 2004 and half from the
2008 debate. Selected video clips were numbered, and non-
consecutive clips were given to Coder 2. The coder did not
know whether gestures were produced during clauses with
positive or negative valence, and could not determine their
content from context. Inter-rater agreement was 97%.
Results
Summary of gestures observed
For each candidate, the number of gestures produced with
the right and left hands during clauses with positive and
negative emotional valence was tabulated (table 1).
Candidates produced more gestures with their dominant
hands (631 dominant hand gestures, 125 non-dominant hand
gestures). Both of the left-handers produced more left-hand
gestures (McCain: 240 left vs. 13 right, p-rep=.991; Obama:
66 left vs. 52 right, p-rep=.80), whereas both right-handers
produced more right-hand gestures (Bush: 39 left vs. 153
right, p-rep=.99; Kerry: 21 left vs. 172 right, p=.99). This
finding is consistent with the general tendency to gesture
more with one’s dominant hand, and corroborates
biographical reports of the candidates’ handedness.
A detailed analysis of the form and function of individual
gestures lies beyond the scope of this report, and is not
directly relevant to our experimental hypothesis, which only
concerns the valence of the spoken clauses and the hands
used for co-speech gesturing.
Tests of association between hand and valence
The association of dominant hand use with valence was
tested using conditional binary logistic regression, stratified
by candidate. Stratification protected against potential
confounds such as Simpson’s paradox (Simpson, 1951) that
could result from combining data across individuals.
1967
Figure 1. Proportion of right- and left-hand gestures during clauses with positive and negative emotional valence. In left-
handers, left-hand gestures were more strongly associated with positive-valence clauses, whereas in right-handers right-hand
gestures were more strongly associated with positive-valence clauses, consistent with the body-specificity hypothesis.
Table 1. Number of right- and left-hand gestures during clauses positive and negative emotional valence.
Candidate Valence of clause Left hand gestures Right hand gestures Total
Obama Negative 29 38 67
(Left-hander, Democrat) Positive 37 14 51
Obama Total 66 52 118
McCain Negative 164 12 176
(Left-hander, Republican) Positive 76 1 77
McCain Total 240 13 253
Kerry Negative 16 108 124
(Right-hander, Democrat) Positive 5 64 69
Kerry Total 21 172 193
Bush Negative 19 59 78
(Right-hander, Republican) Positive 20 94 114
Bush Total 39 153 192
Grand Total 366 390 756
1968
Overall, for all speakers (right- and left-handers), there was
a strong association between the valence of the spoken
clauses (positive, negative) and the hand used for
spontaneous co-speech gestures (dominant, non-dominant;
Wald Chi Square=13.15, df=1, p-rep=.99; figure 1). The
odds ratio for the regression of hand use on valence was
estimated at 2.28 (95% C.I.=1.46-3.57), indicating that
dominant hand gestures were more than two times more
likely to occur during clauses with positive valence, and
non-dominant hand gestures to occur during clauses with
negative valence. The association between hand and
valence was further confirmed by a Cochran-Mantel-
Haenszel test, stratified by candidate (C-M-H
statistic=13.48, df=1, p-rep=.99). This pattern supports the
body-specificity hypothesis.
Of the 756 gestures included in the main analyses above,
499 were the first (or only) gestures produced during the
corresponding spoken clause. Individuating the subsequent
gestures was done systematically (according to McNeill,
1992), but this process is necessarily subjective, and gesture
segmentation choices could, in principle, affect the outcome
of these analyses. Thus, an analysis of the first gestures,
alone, provided the strongest and most objective test of our
hypothesis. This analysis showed a similar association
between hand and valence as was found in the full data set
(Wald Chi square=4.66, df=1, p-rep=.94; odds ratio
estimate=1.80, 95% C.I.=1.06-3.09; C-M-H statistic=4.72,
df=1, p-rep=.94).
To ensure that the observed pattern was not driven
exclusively by right- or left-handers, the association of hand
and valence was tested in each group, separately. Although
the predicted association appears somewhat stronger in the
left-handers, both groups showed a similar pattern as was
found in the full analysis, each group associating gestures
with their dominant hand more strongly with positive
clauses (Left-handers: Wald Chi square=12.71, df=1, p-
rep=.99; odds ratio estimate=3.67, 95% C.I.=1.80-7.51;
Right-handers: Wald Chi square=2.68, df=1, p-rep=.88;
odds ratio estimate=1.62, 95% C.I.=0.91-2.90).
Associations between hand and valence were then tested
in the individual candidates. In both of the left-handed
candidates, left-hand gestures were more strongly associated
with positive-valence clauses, and right-hand gestures with
negative-valence clauses (Obama: Fisher’s exact p-rep=.99;
McCain: Fisher’s exact p-rep=.92). By contrast in both
right-handed candidates, right-hand gestures were more
strongly associated with positive-valence clauses, and left-
hand gestures with negative-valence clauses (Kerry:
Fisher’s exact p-rep=.88; Bush: Fisher’s exact p-rep=.90).
The pattern of gestures observed in each candidate,
individually, supported the body-specificity hypothesis.
A Breslow-Day test for the homogeneity of odds ratios
was conducted to compare the observed pattern across
individuals (Breslow-Day Chi Square=3.30, df=3, p-
rep=.75). Results showed that the strength of the
association between hand and valence did not differ
significantly across candidates.
An additional analysis was conducted to assess the
validity of interpreting John McCain’s gestures in light of
the war injuries he sustained, particularly to his right (non-
dominant) arm. Like the other candidates, McCain
produced fewer non-dominant hand gestures, but the
asymmetry was most pronounced in his case. Still, the
Fisher’s exact test (above) showed a significant association
between hand and valence in McCain’s data, considered
separately. A further analysis showed the predicted effect
when McCain’s more severely wounded arm was tested,
alone. Although he only made 13 uni-manual gestures with
his non-dominant hand, 12 of these gestures were during
negative-valence clauses (sign test on 12 vs. 1, p-rep=.99).
General Discussion
Spontaneous gestures during the final 2004 and 2008 US
presidential debates revealed a previously unattested
pattern: Dominant-hand gestures were more strongly
associated with speech about with good things, and non-
dominant-hand gestures with speech about bad things.
Right- and left-handers use their hands in contrasting ways
when expressing ideas with positive and negative emotional
valence.
The implicit association of handedness and valence
shown previously in laboratory tests was demonstrated here
in spontaneous behavior, confirming that the mental
representation of emotional valence is body-specific
(Casasanto, 2009). Right- and left-handers automatically
activate contrasting associations between action and
emotion when speaking and gesturing. These results were
predicted based on patterns of bodily experience, and show
that people associate good things with the hand they use to
interact with their environment more fluently.
Do gestures follow party lines?
Political affiliations are spatialized along a left-right axis in
linguistic metaphors: Democrats are on the left and
Republicans on the right of the political spectrum. Yet, the
implicit mapping from the left and right hands to valence in
politicians’ gestures does not appear to follow party lines.
Because our sample included a right-hander and a left-
hander from each party, the body-specificity hypothesis
could be tested within Democrats and Republicans,
separately. Both parties showed a similar pattern as was
found in the full analysis (Democrats: Wald Chi
square=10.10, df=1, p-rep=.99; odds ratio estimate=2.82,
95% C.I.=1.49-5.33; Republicans: Wald Chi square=2.68,
df=1, p-rep=.91; odds ratio estimate=1.85, 95% C.I.=0.98-
3.45). Moreover, the overall association of hand and
valence remained significant when the effect of political
party was controlled by conditional logistic regression
(Wald Chi square=4.43, df=1, p-rep=.97; odds ratio
estimate=1.56, 95% C.I.=1.03-2.35). The implicit
association of dominant hand gestures with positive valence
is something that Democrats and Republicans appear to
agree on.
1969
Distinguishing influences of language, culture, and body.
These results cannot be accounted for in terms of idioms in
language or culture. In English-speaking cultures and many
others, linguistic and non-linguistic conventions associate
the right with ideas and actions that are good or allowable,
and the left with those that are bad or prohibited.
Conversely, there appear to be no linguistic or cultural
conventions that link left with good and right with bad
(‘left-wing’ and ‘right-wing’ politics notwithstanding, since
whether liberal or conservative political views are
considered good varies between individuals). Furthermore,
people participate in the same conventions regardless of
their handedness. Left-handers are not allowed to greet
people with left-handed handshakes, or to refer to the
correct answer as ‘the left answer’.
Both enculturation and bodily experience could
potentially explain the ‘good is right’ mapping shown in
right-handers, but only body-specificity can account for the
‘good is left’ mapping found in left-handers, and for the
difference between gesture-valence associations in right- vs.
left-handers. By framing experimental predictions in terms
of the body-specificity hypothesis, we were able to
distinguish the possible contributions of linguistic and
cultural experience from the contributions of bodily
experience to the mental representation of emotional
valence.
These results reveal a previously undiscovered link
between bodily action and emotion. Like research on
linguistic relativity and cultural relativity, research on bodily
relativity (Casasanto, 2009) can elucidate ways in which
particular patterns of experience can give rise to
corresponding habits of thinking, perceiving, and acting.
Acknowledgements
Thanks to R. Staum and P. Staum for statistical
consultation, and to J. van Berkum, L. Casasanto, B.
Tversky, and R. Willems for comments on an earlier draft.
This research was supported in part by a grant from the
Spanish Ministry of Education and Science #SEJ2006-
04732/PSIC, DGI.
Notes
1P-rep indicates the probability of producing a difference
with the sign in the same direction as the observed
difference, given an equipotent replication (Killeen, 2005).
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Appendix
Full URLs for the transcripts of the debates are as follows.
2004 election:
www.debates.org/pages/trans2004d.html
www.archive.org/details/presidential_debate_10_13_04
2008 election:
www.debates.org/pages/trans2008d.html
www.msnbc.msn.com/id/21134540/vp/27207488#2720748
8
Sources consulted to establish the handedness of the
candidates included the following online articles and wikis:
en.wikipedia.org/wiki/Handedness_of_Presidents_of_the_U
nited_States
www.washingtonpost.com/wpdyn/content/article/2008/07/0
3/AR2008070303202.html
www.democraticunderground.com/discuss/duboard.php?az
=view_all&address=273x37442#37482
1970
