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Abstract

Many species use touching for reinforcing social structures, and particularly, non-human primates use social grooming for managing their social networks. However, it is still unclear how social touch contributes to the maintenance and reinforcement of human social networks. Human studies in Western cultures suggest that the body locations where touch is allowed are associated with the strength of the emotional bond between the person touched and the toucher. However, it is unknown to what extent this relationship is culturally universal and generalizes to non-Western cultures. Here, we compared relationship-specific, bodily touch allowance maps across one Western (N = 386, UK) and one East Asian (N = 255, Japan) country. In both cultures, the strength of the emotional bond was linearly associated with permissible touch area. However, Western participants experienced social touching as more pleasurable than Asian participants. These results indicate a similarity of emotional bonding via social touch between East Asian and Western cultures.
royalsocietypublishing.org/journal/rspb
Research
Cite this article: Suvilehto JT, Nummenmaa
L, Harada T, Dunbar RIM, Hari R, Turner R,
Sadato N, Kitada R. 2019 Cross-cultural
similarity in relationship-specific social
touching. Proc. R. Soc. B 286: 20190467.
http://dx.doi.org/10.1098/rspb.2019.0467
Received: 25 February 2019
Accepted: 4 April 2019
Subject Category:
Behaviour
Subject Areas:
behaviour, evolution, neuroscience
Keywords:
social touch, cultural differences, emotion,
bonding
Author for correspondence:
Ryo Kitada
e-mail: ryokitada@ntu.edu.sg
Electronic supplementary material is available
online at http://dx.doi.org/10.6084/m9.
figshare.c.4464836.
Cross-cultural similarity in relationship-
specific social touching
Juulia T. Suvilehto1,4, Lauri Nummenmaa4,5, Tokiko Harada6,
Robin I. M. Dunbar2,7, Riitta Hari3, Robert Turner8, Norihiro Sadato9
and Ryo Kitada10
1
Department of Neuroscience and Biomedical Engineering,
2
Department of Computer Science, and
3
Department
of Art, Aalto University, Espoo, Finland
4
Turku PET Centre, and
5
Department of Psychology, University of Turku, Turku, Finland
6
Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
7
Department of Experimental Psychology, University of Oxford, Oxford, UK
8
Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
9
National Institute for Physiological Sciences, Okazaki, Japan
10
Division of Psychology, School of Social Sciences, Nanyang Technological University, 14 Nanyang Avenue,
637332 Singapore
LN, 0000-0002-2497-9757; RIMD, 0000-0002-9982-9702; RK, 0000-0001-7446-4033
Many species use touching for reinforcing social structures, and particularly,
non-human primates use social grooming for managing their social
networks. However, it is still unclear how social touch contributes to the
maintenance and reinforcement of human social networks. Human studies
in Western cultures suggest that the body locations where touch is allowed
are associated with the strength of the emotional bond between the person
touched and the toucher. However, it is unknown to what extent this
relationship is culturally universal and generalizes to non-Western cultures.
Here, we compared relationship-specific, bodily touch allowance maps
across one Western (N¼386, UK) and one East Asian (N¼255, Japan)
country. In both cultures, the strength of the emotional bond was linearly
associated with permissible touch area. However, Western participants
experienced social touching as more pleasurable than Asian participants.
These results indicate a similarity of emotional bonding via social touch
between East Asian and Western cultures.
1. Introduction
Interpersonal touch is a critical part of human social communication. It contri-
butes to cognitive and socioemotional development in childhood [1,2] and
promotes relational, psychological and physical well-being in adulthood [3,4].
Given its importance, there has been growing interest in the effects of interper-
sonal touch on human social behaviour and in the resulting social relationships.
Non-human primates spend remarkable amounts of time in grooming others,
well beyond the necessity of removing parasites or vegetation debris from the
fur [5]. Social grooming thus plays a particularly important role in social bond-
ing, and the psychological experience of increased social closeness is reflected in
prosocial behaviours [5,6]. In individual female primates, the social grooming
patterns are explained by factors such as attraction to high-ranking individuals,
attraction to kin and competition for grooming partners [7,8], implying that
variations in the relationship specificity of social touch might be correlated
with differences in social structure.
In our previous study, we asked 1368 people from Western countries (Finland,
France, Italy, Russia and the UK) to indicate where on their body they would
allow relatives, friends and strangers to touch them [9]. We also measured the
emotional bond between them since such bonds are the best predictor for
&2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution
License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original
author and source are credited.
engaging in social contact with someone and as they track
the position of different individuals in one’s social network
[10– 12]. In each country, the topographic map of body areas
that one is allowed to touch was associated with the strength
of the emotional bond between the participant and the toucher.
Thus, the relationship-specific patterns of social touch seem
to be related to the establishment and maintenance of social
structures and affective relationships among human adults.
However, these results cannot resolve whether bonding by
social touch is a culturally universal phenomenon or specific to
Western Europe which our previous study was limited to.
Cross-cultural studies have shown that deeply embedded
differences between Western and Eastern cultures strongly
influence emotional processing, together with ideas regarding
experiences such as emotions [13,14], the facially expressed
emotions of others [15–17] and their integration with emotion-
al voices [18]. Indeed, social touch varies according to culture
[19– 21]. For instance, North American students have more fre-
quent physical contact than Japanese students with their
friends and their parents [19]. Moreover, the US students’
social touch patterns in regard to their fathers and mothers
were similar, whereas Japanese students were physically
closer to their mothers than their fathers. However, this
study did not examine the relationship between the touching
pattern and the strength of the emotional bonding. Thus, it
remains unclear to which extent this relationship is culturally
universal and generalizes to non-Western cultures.
Here we compared relationship-specific social touching
patterns between one East Asian and one European culture.
We used a high-resolution self-reporting tool (emBODY) to
quantify relationship-specific maps of bodily regions where
social touch is allowed. Participants in Japan and UK evalu-
ated their emotional bonds with and drew touchable body
regions for different social network members. We hypoth-
esized that patterns of allowed interpersonal touch differ in
Japan and in the UK but vary in a similar way as a function
of social bond in both countries.
2. Material and methods
(a) Participants
Altogether, 309 Japanese individuals and 622 British individuals
participated in the study. The British sample was collected through
Maximiles (data reported in [9]) and the Japanese sample was
collected via MyVoice Communications, Inc., in 2016. As the popu-
lation-leveleffect size wasunknown, we aimed to have the sample
in line with the first study reporting topographies of acceptable
touch (altogether 1368 participants, average 274 per culture, [9]),
which in turn were targeted to double the sample sizes from the
earliest studies using this technology (total of 773 participants
over seven separate experiments, [22]).After cultural background
had been validated and quality control established (described in
detail in the ‘Data analysis’ section), the data of 255 Japanese indi-
viduals (124 male, 40.1 +14.6 years) and 386 British individuals
(214 male, 46.0 +12.6. years) were analysed. The British sample
was chosen for comparison [9], (1) because it was collected via a
paid service similar to the Japanese sample and (2) because the
age distributions were similar in both groups.
(b) Data acquisition
The data were collected online. Before beginning thestudy, partici-
pants gave informed consent online. The Japanese study protocol
was approved by the ethics committee at the National Institute for
Physiological Sciences, Japan. The English version of the online
rating tool (emBODY, [9,22]; https://version.aalto.fi/gitlab/egler-
ean/embody) was first translated into Japanese by a professional
translator (ZENIS Co., Ltd, Tokyo Japan). Then two researchers
(R.K. and T.H.) revised the translated materials by conducting
back-translation and translation until both were satisfied with
the result.
Participants first provided background information about
themselves and members of their social network. They were
given a list of categories of relationship which may be found in
one’s social network (e.g. ‘aunt’, ‘female friend’) and participants
then indicated if they had one or more individuals from these
categories in their own social network. If participants had
multiple individuals in their social network fitting one category,
they were instructed to pick one individual and to answer all
the subsequent questions regarding this individual. We also
added ‘female stranger’ and ‘male stranger’ to the list of social
categories, to probe the acceptable social touch with strangers.
Participants were then asked to give information about the sex
(only for spouses) and ages of the selected members of their social
network, as well as estimates of how long ago they last met them.
We assumed that participants would encounter strangers on a
daily basis and set time since the last meeting to 0 days for the
strangers. We used participants’ own age for the age of the stran-
gers, and in subsequent tasks asked partners to respond with
respect to ‘a woman/man of your age whom you do not know’.
Next, the participants reported theiremotional bond with each net-
work member (scale from 1 representing no emotional bond to 10
representing the strongest possible emotional bond) and gave an
estimate of how pleasant they would find being touched by each
member of their social network (scale from 1, not pleasant at all,
to 10, extremely pleasant).
After completing background questions, the participants were
presented with the colouring task with the emBODY tool. They
were asked to consider where on their bodies they would find it
acceptable for different social network members to touch them
in everyday situations. For each member of their social network,
the participants were shown a body outline in both front and
back view (electronic supplementary material, figure S1a) and
asked to colour the bodily regions where each social network
member would be allowed to touch them. The participants
coloured the bodies using a computer mouse or, if they were com-
pleting the task using a mobile device, using their finger. Painting
was additive so that multiple strokes on the same region increased
opacity; this information was, however, not considered in the
analyses (see below).
(c) Data analysis
(i) Data preprocessing
The datawere first checked for completeness. Data from the colour-
ing tasks were then converted to Matlab (R2015b) two-dimensional
matrices, where each cell represented a pixel on the screen. The size
of the figures was 522 342 pixels (for front and back combined),
out of which 89 129 pixels fell within the body outlines. The diam-
eter of the painting tool was set to 17 pixels. The coloured images
were binarized so that the amount of time a participant spent on
colouring an area would not impact the results. Each participant
completed between two and 15 individual touch area maps
(TAMs), depending on the size of their social network.
As the aim of the study wasto compare data between different
cultures, cultural background criteria were used to exclude some
participants. Japanese participants were asked about their parents’
ethnicity, and whether they had spent an extended period of time
abroad. We excluded any participants who did not report both of
their parents’ ethnicity as ‘Japanese’ or who reported having spent
more than a year abroad. Altogether, 17 Japanese participants were
excluded based on the background questions. In the English
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
2
version, the sample consisted of only British nationals. The partici-
pants were asked about their native (first) language and their
cultural identity. We excluded all participants who did not report
their first language as being English,or who did not identify them-
selves as ‘British’, ‘English’, ‘Irish’, ‘Welsh’ or ‘Scottish’. Altogether,
159 British participants were excluded based on the background
questions. Finally, we visually inspected the TAMs and excluded
38 participants from Japanese dataset and 77 participants from
British dataset due to inappropriate drawing (e.g. doodling or
excessive colouring). The remaining samples, consisting of 386
British and 255 Japanese participants, were used for analysis.
(ii) Comparing the samples using two-proportion z-test
We compared the acceptable touch areas of the two cultural
samples by comparing each pixel in each image using a two-
proportion z-test, with a two-tailed alternative hypothesis, with
a
¼0.05, corrected for false detection rate with no correlation
assumptions. To test the association between emotional bond
and touchable body area, we first calculated a ‘touchability
index’ (TI) as the proportion of coloured pixels within the body
outline for each TAM [9]. To better quantify the differences in
the topographies of acceptable touch, we then defined 13 anatom-
ical regions of interest (ROIs) and calculated ROI-specific TIs as the
proportion of coloured pixels within the ROI. We conducted mul-
tiple linear regression analysis on these TIs for each social network
member in both countries, with the emotional bond and cultural
background as explanatory variables. This analysis was conducted
using group mean data and individual data.
3. Results
(a) Touch area maps for Japanese and British
individuals
Figure 1 shows the mean TAMs for different social members
in Japanese and British samples.
The relationship-specific TAMs in the Japanese and UK
populations were generally consistent. Specifically, the partner
was allowed to touch basicallyanywhere on the body, and clo-
sest acquaintances and relatives were allowed to touch over the
head and upper torso. By contrast, strangers were restricted to
touch only the hands. Direct comparison of TAMs from British
and Japanese participants by two-proportion z-test revealed
that Japanese allowed more touching from their female rela-
tives than did British, especially in the lower extremities and
the bottom (figure 1c). On the other hand, more British partici-
pants allowed their partners to touch their bodies on the torso,
face and legs. Moreover, British participants allowed their
mother, aunt, female cousin and female friend to touch their
heads more and male strangers to touch their hands more.
(i) Emotional bond and pleasantness ratings
In both countries, an individual’s emotional bond was the
strongest with their partner, followed by their closest family
members and relatives. By contrast, participants reported the
least emotional bond with strangers (electronic supplementary
material, figure S2). The strengths of the reported emotional
bonds with friends were between those for primary and
extended family members in both samples. A Mann– Whitney
Utest (after Holm– Bonferroni correction) on emotional
bond yielded a significant difference only for the partner
(U¼13 917, p810
29
, Holm–Bonferroni corrected), such
that the emotional bond with the partner was lower in Japanese
than in British participants.
The participants reported that being touched by their
partner elicited most pleasantness, followed by their close
relatives (electronic supplementary material, figure S3).
Touch pleasantness and emotional bond were significantly
correlated in both cultures, with Spearman correlation coeffi-
cient r
s4402
¼0.69 in the British sample and r
s2977
¼0.74 in the
Japanese sample ( ps,10
210
), The two cultures differed sig-
nificantly in the degree of pleasantness of being touched by
others; with the exception of sister and male stranger, the
British reported finding social touch as more pleasant than
did the Japanese (MannWhitney Utest, ps in range [3
10
216
, 0.015], HolmBonferroni corrected).
(b) The relationship between emotional bond,
pleasantness and touchability index
Figure 2 depicts the correlations between TI, pleasantness and
emotional bond, with TI as the proportion of pixels in the body
that a particular member of the participant’s social network
was allowed to touch (electronic supplementary material,
figure S4). Linear multiple regression analysis with emotional
bond, pleasantness of touch and culture as explanatory vari-
ables revealed that together these variables explained 20% of
the variance in the total touchable body area (adjusted R
2
¼
0.20, F
3,7375
¼626, p,10
210
). Bond (
b
¼0.18, p,10
210
), plea-
santness (
b
¼0.31, p,10
210
) and culture (
b
¼0.16, p,10
210
)
all predicted TI (see also electronic supplementary material,
table S1 for a linear mixed effects model with subject as
random effect). Partitioning R
2
assigned 11.3% of the explana-
tory power to pleasantness of touch, 8.6% to emotional bond
and only 0.4% of explanatory power to the cultural background
(electronic supplementary material, figure S5). For the data
averaged such that each social network member was rep-
resented by the average of responses about that person in
each culture (figure 2), the adjusted R
2
was 0.85, F
3,26
¼58,
p,10
210
.
Due to the high correlation between pleasantness and
emotional bond, we also ran partial correlation tests. When
controlling for pleasantness of the relationship, the association
between emotional bond and TI was still significant, r
s7377
¼
0.15, p,10
210
, 95% CI [0.13, 0.17]. Similarly, when controlling
for emotional bond, the association between pleasantness and
TI remained significant, r
s7377
¼0.22, p,10
210
, 95% CI [0.20,
0.24]. Thus, both pleasantness and emotional bond contributed
independently to the relationship-specific TI.
Altogether, the analysis showed that emotional bond and
perceived pleasantness of touch explained around 20% of the
variance in TI, with only a negligible (0.4%) contribution
from the culture. A supplementary analysis with emotional
bond treated as categorical variable confirmed that emotional
bond explains the variance in the total touchable body area
(electronic supplementary material, figure S8). Finally, we
confirmed this result by conducting the same regression ana-
lyses for both sexes in each culture (mean adjusted R
2
¼0.21,
range [0.17, 0.28]). Patterns of TI as a function of emotional
bond were consistent regardless of the culture or toucher’s
sex (electronic supplementary material, figure S6).
(c) Sex differences
We next examined if sex influences touch acceptance similarly
in the UK and Japan. Figure 3 shows the relationship between
touchable body area and sex of the toucher with respect to male
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
3
and female participants (blue and red dots) in the UK
and Japan. To statistically evaluate the effect of sex on TI,
we conducted an ANOVA on the TIs of male and female par-
ticipants and male and female touchers in both cultures. For
partners, the sex of the partner was determined by whether
the participant was male or female, and hence it was difficult
to compare the effect of sex on TI between them. For this
reason, we excluded the partner data from this analysis.
partner
back front
back frontback front
father
brother
uncle
mother
sister
aunt
acq.
acq.
friend
friend
cousin
cousin
stranger
stranger
partner
father
brother
uncle
mother
sister
aunt
acq.
acq.
friend
friend
cousin
cousin
stranger
stranger
partner
father
brother
uncle
mother
sister
aunt
acq.
acq.
friend
friend
cousin
cousin
stranger
stranger
(a) Japan
(b) UK
(c) difference
proportion of subjects
1.0
0.8
0.6
0.4
0.2
0
proportion of subjects
1.0
0.8
0.6
0.4
0.2
0
10
5
0
–5
–10
UK
Z score
Japan
Figure 1. Relationship-specific TAMs in (a) Japan and (b) the UK. The colouring displays the proportion of the sample reporting that being touched by this person in
this area is acceptable to them. (c) Comparison of the proportion of participants per culture who allow touching in different areas. Red colour in the maps indicates
that Japanese participants reported that area more acceptable, blue colour indicates that British participants reported that area more acceptable. The data in (c)are
thresholded at p,0.05, FDR corrected. After FDR correction, Zthreshold with no correlation assumptions varied from 3.22 to 5.98, depending on the number of
participants who had that particular individual in their social network. Red and blue labels indicate female and male members of the social network, respectively.
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
4
Three-way ANOVA (2 levels of cultures 2 levels of tou-
cher sex 2 levels of participant’s sex) on the TI revealed a
significant main effect of culture F
1,6945
¼12.6, p410
25
,
h
2
¼0.002, such that the TIs in the Japanese sample (M¼
0.17, s.d. ¼0.24) were larger than the TIs in the British
sample (M¼0.15, s.d. ¼0.20, t
5316.8
¼3.38, p¼0.0007, 95%
CI [0.008 0.029], d¼0.085). The main effect of the sex of the
toucher was also significant F
1,6945
¼137.9, p,10
210
,
h
2
¼
0.019, such that the parameter estimates were larger for
female touchers (M¼0.18, s.d. ¼0.24) than for male touchers
(M¼0.12, s.d. ¼0.19, t
6739.3
¼11.7, p,10
210
, 95% CI [0.050
0.071], d¼0.085). Thus, touch by female members of the
social network was generally considered more acceptable
across the whole social network (electronic supplementary
material, figure S7). The effect of participant sex was not
significant (F
1,6945
¼0.72, p¼0.39).
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
12345678910
12345678910 1 2345678910
emotional bond
emotional bond
10
9
8
7
6
5
4
3
2
1
pleasantness
pleasantness
variance in TI explained by
pleasantness 43.5%
bond 36.1%
country 7.4%
total R2 87.0%
touchability index (TI)
touchability index (TI)
UK
Japan
country
Figure 2. Correlations between touchability index (TI), emotional bond and pleasantness. Each dot represents the average response for one member of the social
network in each culture (e.g. mother), with linear regression line and confidence interval for the regression fitted separately for each culture. Bottom right panel
presents the relative importance of regressors in determining the TI in a linear model.
0.3
0.2
0.1
0
female male female
male
female
male
sex of toucher
sex of
subject
mean TI
UK Japan
Figure 3. Interaction plot of the average TI for male and female participants (blue and red dots, respectively) with respect to male and female touchers for each
culture. Error bars depict the 95% confidence interval. Red and blue lines indicate the interaction between toucher sex and the sex of the participant. Note: partners
are excluded from the analyses, as the sex of the partner differs between the male and female participants.
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
5
All interactions were significant at the p,0.05 significance
level. Of the two-way interactions, the interaction between the
toucher sex and participant sex was significant at F
1,6945
¼18.5,
p210
25
,
h
2
¼0.003, such that the difference between TI
for female touchers and male touchers was larger for female
participants (M¼0.08, s.d. ¼0.11) than for male participants
(M¼0.04, s.d. ¼0.09, t
592.61
¼5.7, p210
28
,d¼0.46).
The interaction between the sex of the participant
and the country was significant (F
1,6945
¼22.6, p210
26
,
h
2
¼0.003). The TIs reported by Japanese male participants
(M¼0.18, s.d. ¼0.26) were higher on average than those
reported by Japanese women (M¼0.15, s.d. ¼0.23), British
men (M¼0.14, s.d. ¼0.20), or British women (M¼0.16,
s.d. ¼0.20), two sample t-test t-scores t
2712.5
¼3.8, p¼0.0002,
d¼0.14; t
2329.3
¼5.3, p10
27
; and t
2496.4
¼3.4, p¼0.0006,
d¼0.13 respectively. The interaction between the tou-
cher sex and country was significant (F
1,6945
¼5.0, p¼0.025,
h
2
¼0.001). The TIs for Japanese female touchers (M¼0.20,
s.d. ¼0.26) were on average higher than those for British
female touchers (M¼0.17, s.d. ¼0.22) (t
2758.4
¼3.7, p¼
0.0003, d¼0.13). The three-way interaction was also significant
(F
1,6945
¼25.0, p610
27
,
h
2
¼0.003). This result seems to
be mostly driven by the different responses of Japanese
men and women with respect to male touchers (figure 3). Simi-
lar results were obtained using a mixed-effects model with
subject as a random effect (electronic supplementary material,
table S2).
(d) Region-of-interest analysis
Whole-body TAM analyses revealed cultural differences in
touchability of specific body areas, such as face, hand, and
arm. To further examine for area-specific cultural differences,
we next conducted linear regression analyses on the regional
TIs for each culture, with emotional bond as the explanatory
variable (figure 4). Adjusted R
2
values of fitted linear func-
tions averaged across body regions ranged between 0.04
and 0.15. Comparing linear models fitted to ROI-wise TI
data showed significantly higher baseline acceptability (inter-
cept) of touch on hair (
b
¼20.02, t
7376
¼22.96, p¼0.003),
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
1.0
0.8
0.6
0.4
0.2
0
12345678910
12345678910
12345678910 12345678910
emotional bond
Japan
UK
hair face shoulder (front) shoulder (back)
shoulder (back)shoulder (front)
torso (back)torso (front)arm
hand crotch bottom
foot leg (front) leg (back)
a b
a ba ba b
a b
a b
a b
a b
a b
a b a b
a ba b
ROI definitions
hair
arms
face
torso
(front)
torso
(back)
crotch bottom
hands
legs (front)
legs (back)
feet
differences in
a (intercept) and b (slope):
greater in Japan
greater in the UK
no difference
country
touchability index per ROI
Figure 4. Visualization of ROI-specific cultural differences in TI versus emotional bond. Linear regression lines were fitted to each culture separately. Blue and red
colours depict UK and Japan, respectively. Each dot represents the average response for one member of the social network (e.g. ‘British partner’ or ‘Japanese
mother’). The grey intercept and slope terms mean no significant difference in the regression lines between the cultures. The coloured terms signal which culture
had higher intercept (
a
) or slope (
b
) values, with blue and red colours indicating the British and the Japanese, respectively. The visualization is presented with
averaged data in the interest of clarity, but the significance of intercept and slope are calculated from the full (un-averaged) data.
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
6
feet (
b
¼20.05, t
7376
¼27.3, p,10
210
), legs (both front,
b
¼20.03, t
7376
¼25.3, p910
28
, and back,
b
¼20.03,
t
7376
¼25.7, p210
28
), crotch (
b
¼20.01, t
7376
¼23.0,
p¼0.003) and bottom (
b
¼20.03, t
7376
¼25.1, p3
10
27
) in the Japanese sample. The same test showed higher
baseline acceptability of touch on arms (
b
¼0.06, t
7375
¼3.4,
p¼0.0006), hands (
b
¼0.14, t
7375
¼7.2, p,10
210
) and face
(
b
¼0.07, t
7376
¼9.3, p,10
210
) in the British sample. The
same test showed a different rate of increase in TI for each
unit of emotional bond (slope) on the arms (
b
¼20.01,
t
7375
¼23.5, p¼0.0004) and hands (
b
¼20.02, t
7375
¼27.3,
p,10
210
). In both of these ROIs, the TI was more responsive
to changes in emotional bond (steeper slope) in the Japanese
sample.
4. Discussion
The results show that although the touchable areas differed
between the UK and Japan, they were similarly dependent
on the strength of the emotional bond. Emotionally close
individuals in the inner layers of the social network
were allowed to touch larger bodily areas, whereas touching
by strangers was primarily limited to the hands. The ROI
analyses confirmed that most of the ROIs were similarly
sensitive to emotional bond in both countries. This result
suggests that the use of social touch for bonding purposes
serves a similar function in East Asian and European
cultures, rather than being merely culture-based normative
behaviour. This interpretation accords with previous
studies [9,19,23] suggesting cultural invariance in social
touching.
We have previously reported consistentsocial touching pat-
terns in a large sample of European cultures [9]. Additionally,
American and Japanese college students were asked where
they had touched and been touched by their parents, a same-
sex friend and an opposite-sex friend [19]. The relative
frequencies of touch by these different members of the social
network followed the same pattern in both cultures [19].
One possible explanation for the cross-cultural similarities
in social touching is the effect of globalization. For instance,
Japanese culture may be influenced by social customs in
e.g. Western movies that are shown widely in Japan. How-
ever, the relationship specificity of touchable areas (found
here in European and Japanese cultures) is consistent with
both our earlier study with Western cultures [9] as well as
an older study looking at Japanese and North American
cultures [19]. Thus, it is unlikely that the role of recently
shared cultural elements plays a major role in the cross-cultu-
rally similar association between social touch and emotional
bond.
Social touch induces positive feelings and improves
interpersonal evaluation [24– 27]. For example, participants
evaluate even a stranger more positively, if that person
has inconspicuously touched them during an interaction
[25,27– 29]. This close connection between social touching and
preference toward the source of touch suggests a causal role
of touch on social bonding. There is some evidence of touching
causally impacting bonding in romantic relationships [30].
However, it is not clear if this extends to other relationships
and this cannot be directly addressed from the current cross-
sectional data. We also found that emotional bonds are
correlated with experienced pleasantness of social touch.
However, a cross-sectional design cannot reveal whether
pleasure derived from being touched by someone enhances
the emotional bond to the toucher, or whether liking someone
makes their touch feel more pleasant.
Social touch is important for group cohesion of non-human
primates, and grooming relationships predict the level of
support during conflict situations and when in need of help
[8,31– 34]. It is hypothesized that grooming-induced relaxed
and pleasurable feelings could constitute the psychological
mechanism for an individual’s willingness to offer subsequent
help, thus forming the basis of mutual exchanges of social sup-
port [5,34]. Because social touching increases prosocial
behaviour [35– 37], it is possible that human social touch
increases emotional bonding with the individual being
touched, enhancing their prosocial behaviour.
Neurophysiological studies have revealed that the un-
myelinated afferent c-tactile nerve fibres are selectively
responsive to light and slow touch [38– 40]. The signals car-
ried out by these fibres are indirectly transmitted to the
insula [38], a part of the neural network responsible for affec-
tive tactile interactions [40,41]. This pathway could thus
support culturally universal hedonic nature of interpersonal
touch. However, as shown in the present study, relationship
information imposes top-down influences on this circuitry
(e.g. how the individuals are touched and by whom they
are touched, electronic supplementary material, figure S3).
It is also known that physical contact with members of
one’s social network attenuates brain activity associated
with both the threat of physical pain stimulus [42] and aver-
sive images [43]. Processing interpersonal aspects of touch
may recruit additional brain networks [44,45], including the
action observation network (AON) [46]. Thus, the positive
and calming effect of interpersonal tactile interchanges may
be generated by the interaction of these brain networks, med-
iating the relationship between touchable area and emotional
bonding, regardless of the different cultural norms.
(a) Gender difference in both cultures
Participants in both cultures allowed women to touch their
bodies more than men, which accords with prior findings in
Western cultures [9,47]. The preference to touch by women
was comparable in British men and women. By contrast,
responses of the Japanese participants showed a clear gender
difference: Japanese men did not show a statistically significant
preference for touch by women, whereas Japanese women
showed a remarkably strong preference.
Earlier studies have found opposite-sex touch to be prefer-
able to same-sex touch [19,23,48–50]. Preference for female
touch in the female participants might therefore seem to con-
tradict earlier findings. On closer inspection, this seeming
contradiction is caused by a difference in terminology. Most
of the earlier studies discussing gender effects have inspected
the difference of body accessibility for ‘same-sex friend’ and
‘opposite-sex friend’. Unfortunately, most of the older exper-
iments [23,48– 50] use the euphemism ‘opposite-sex friend’ to
indicate a romantic partner (a usage made explicit in [51]),
whereas ‘same-sex friend’ seems to refer to a platonic friend.
This practice biases the comparison, as touching romantic part-
ners is both qualitatively and quantitatively different from
touching other people [9].
Taking this difference of nomenclature into account, our
findings would in fact seem to be in line with earlier studies.
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
7
For example, a similar preference for female touch has pre-
viously been found with respect to parents: participants
touch and are touched more by their mothers than fathers,
both in the United States [23,52] and in Japan [19]. Similar
to the current findings, both male and female Japanese
participants touch and are touched by their mothers more
than by their fathers, but the difference is greater for female
participants [19]. Conversely, in the American sample, the
preference for mother over father was of comparable size
between male and female participants [19].
(b) Cultural differences between the Japanese
and the British
While the overall association of touching and social bonding
was concordant across cultures, some differences were also
found. First, the Japanese participants reported the overall
pleasantness of being touched to be lower than the British
did (electronic supplementary material, figure S3), although
both cultures showed similar changes in emotional bond
across different touchers (figure 2). This difference may be in
part due to differences in wording (‘kokochiyoi’ in Japanese
versus pleasant in British), but it can also reflect differences
in daily non-verbal communication: Japanese conduct social
touching (e.g. handshakes and hugs) much less frequently
than Americans [19] and they do likely less than British.
Second, we also observed three notable differences in the
topographies of acceptable touch. The British participants
allowed their partners to touch their bodies more than the
Japanese (figure 1). This finding accords with previous research
showing that touch between partners is more frequent in most
body areas in the Western (North American) culture than in
Japan [19]. The British participants in the present study also
reported stronger emotional bonds with their partners than
did the Japanese participants, suggesting that the difference
between touch allowances for the partner might not be merely
a cultural norm in behaviour but indicative of awider difference
in the intimate relationships in the two cultures.
Moreover, British participants allowed female family mem-
bers and female friends to touch their faces more than did the
Japanese participants. A previous study demonstrated that
the British tend to touch their own faces more frequently than
the Japanese do [53]. It is possible that such ‘accessibility’ to
face may originate from gestures that are more specific to British
than Japanese and their self-touching behaviour. By contrast,
more Japanese participants reported that their female relatives
are allowed to touch them on their legs and bottoms. Female
members in the Japanese culture often take care of children in
their network and have physical contact with them. It is con-
sidered that British culture is more individualistic than Japan
and that individuals in such culture assume responsibility
only for themselves and their immediate family [54]. Thus,
the observed difference may be explained by the roles of the
female relatives in child rearing in the two cultures.
We also observed cultural differences in the relationship
between the emotional bond and the touchable area in
specific body parts such as the arms and hands. In these
regions, the strength of the emotional bond with a social net-
work member increased touchability more in the Japanese
versus British sample, i.e. the Japanese had a steeper slope
in the fitted linear function (figure 4). This difference might
be explained in terms of cultural difference in daily
gestures. For instance, gestures involving physical contacts,
such as handshakes and hugs, are more common in Western
countries than in East Asian countries, such as Japan. This is
supported by the higher intercepts in arm and hand for the
UK sample in the ROI-wise analysis. Thus, more emotional
closeness may be necessary for the Japanese to engage in
this type of social touching.
Finally, the difference between the touch allowances for
female touchers and male touchers was larger for Japanese
women than for Japanese men or British participants of
either sex (culture sex of toucher sex of participant inter-
action, figure 3). This culture-specific gender difference can
be also associated with the above-mentioned points. More
specifically, Japanese women had much smaller TIs for all
males in their social network than for women with similar
formal relationship (e.g. mother and father, see electronic sup-
plementary material, figure S7). Collectively, although we
found some differences, the associations between emotional
bond, pleasantness and TI were concordant in both cultures.
(c) Limitations
Our study was conducted online. Because the participants did
not meet the experimenter, they could answer the questions
without the sense of invasion of privacy (e.g. feeling embar-
rassed that experimenters in front of them know their
touching behaviour). While there is some experimental evi-
dence suggesting that attitudes towards touch impact
touching behaviour [55], it is possible that the data may not
directly translate to real-life touching behaviour. Therefore, it
will be important to validate the current findings by conduct-
ing observational research of real-life touching in the future.
Second, although the currently available evidence suggests
that social touching is concordant across a wide range of Wes-
tern, Orthodox and Japanese cultures (see also [9]), these data
do not generalize to the other major cultures of the world [56].
However, already the present data demonstrate marked cross-
cultural consistency in touch-dependent bonding across a wide
range of cultures and geographical locations.
5. Conclusion
Relationship-specific emotional bonds account for the magni-
tude of social touching from social network members
similarly between Western and East Asian (Japanese) cul-
tures. Pleasure derived from touch, however, depended on
the culture. Because the relation-specific social touching pat-
terns of Japanese and Western respondents are consistent,
the relationship between emotional bonding and touchable
body area may be largely biologically determined. Human
social touch, like social grooming of non-human primates,
may provide a scaffold for social bonding with the members
of one’s social network. This supports the role of somatosen-
sation and emotional feelings in the maintenance of social
bonds in humans [57].
Data accessibility. The data are available from the Dryad Digital Reposi-
tory: https://doi.org/10.5061/dryad.f0f2642 [58] and the code to
produce all the figures and numbers are available at https://ver-
sion.aalto.fi/gitlab/jtsuvile/cultural-similarity-touch.
Competing interests. The authors declare no conflict of interest.
Funding. This work was supported by Emil Aaltonen Foundation grant
and Alfred Kordelin Foundation grant to J.T.S.; by Academy of
Finland grant (no. 294897) to L.N. and European Research Council
grants to L.N. (no. 313000) & R.I.M.D. (no. 295663), by MEXT/JSPS
royalsocietypublishing.org/journal/rspb Proc. R. Soc. B 286: 20190467
8
KAKENHI (grant no. 26244031; 15H01846) to N.S. and ( grant no.
16H01680; 25135734) to R.K.; and by an NAP start-up grant of
Nanyang Technological University to R.K.
Acknowledgements. We thank Enrico Glerean for his help in collecting
the data. We acknowledge the computational resources provided
by the Aalto Science-IT project.
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Chapter
Kapitel enthält: emotionale, soziale und ethische Aspekte von Berührungen; Placeboeffekte; Embodiment; Haus- und Therapietiere; Einsamkeit. - Abstract: Im medizinischen Kontext können von erforderlichen Berührungen, die einem medizinischen oder pflegerischen Zweck dienen, soziale Berührungen unterschieden werden. Diese, oft spontan auftretenden Berührungen, erfüllen soziale oder emotionale Funktionen. Soziale Berührungen können beruhigend, tröstend, angst-, schmerz- oder stressreduzierend wirken. Es besteht somit die Möglichkeit, soziale Berührungen im medizinischen oder pflegerischen Kontext gezielt zu diesen Zwecken einzusetzen.
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Across a plethora of social situations, we touch others in natural and intuitive ways to share thoughts and emotions, such as tapping to get one's attention or caressing to soothe one's anxiety. A deeper understanding of these human-to-human interactions will require, in part, the precise measurement of skin-to-skin physical contact. Among prior efforts, each measurement approach exhibits certain constraints, e.g., motion trackers do not capture the precise shape of skin surfaces, while pressure sensors impede direct skin contact. In contrast, this work develops an interference-free 3D visual tracking system using a depth camera to measure the contact attributes between the bare hand of a toucher and the forearm of a receiver. The toucher's hand is tracked as a posed and positioned mesh by fitting a hand model to detected 3D joints, whereas the forearm is extracted as a detailed 3D surface. Based on a contact model of point clouds, the spatiotemporal contact changes are decomposed as six high-resolution time-series attributes, i.e., contact area, indentation depth, absolute velocity, and three orthogonal velocity components, together with contact duration. To examine the system's capabilities and limitations, two experiments were performed. First, to evaluate its ability to discern human touches, one person delivered cued social messages, e.g., happiness, anger, sympathy, to another using their preferred gestures. The results indicated that messages, gestures, and the individual touchers, were readily discerned from their contact attributes. Second, the measurement accuracy was validated against independent devices, including an electromagnetic tracker, pressure mat, and laser sensor. While validated here in the context of social communication, this system is extendable to human touch interactions such as maternal care of infants and massage therapy.
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Past research has shown consistent benefits associated with and resulting from affectionate touch, though past research is based almost exclusively on highly satisfied and otherwise non-representative samples. The current research used two nationally representative samples to test correlates (Study 1) and anticipated consequences (Study 2) of affectionate touch in romantic relationships. In Study 1, greater kissing frequency was associated with greater individual well-being, and these links were especially pronounced in the most satisfying relationships. In Study 2, participants who were randomly assigned to imagine receiving affectionate touch from their spouse anticipated greater individual well-being (less stress and greater life satisfaction) and relational benefits (greater perceived partner affection, state security, cognitive interdependence, and relationship quality). These benefits were stronger among people with moderate or high relationship satisfaction but observed even for the subset of individuals (approximately one-third of the sample) who rated their relationships as “distressed.” Theoretical and practical implications are discussed.
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In this study, touch behavior was monitored via live-feed webcams in 18 bars, spread across 5 continents (North America, South America, Europe, Australia, and Asia) for 213 hours. Our findings offer support for a link between equatorial proximity (measured by latitude) and cultural indulgence with more tactile communication. In cultures where indulgence versus restraint was more normative, those perceived as females initiated more touch in both opposite- and same- sex dyads. Moreover, in cultures closer to the equator, there was an increase in touch frequency and the number of body locations touched. Housed within these findings is the idea that geographical location may play a predictable role in motivating the development of cultural communication norms and behaviors. We consider the influence of sunlight, topography, history, and other culture-specific forces on the development of touch norms.
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Dementia is an ever-increasing health and social problem, with a growing number of people being affected worldwide. As dementia progresses, dependency on others increases, requiring the presence of caregivers. Caregivers tend to focus on the diagnosis itself – dementia – which makes it difficult to see the person in their uniqueness. The person is there, and can be seen by listening, which requires time and communication skills. The voices of older adults living with several types of dementia, collected while working as a psychologist in a nursing home, are presented in the first person to bring forward the person they are. These excerpts of interactions illustrate the basic psychological need of relatedness, which is built through interaction, stories, and touch, and the needs of competence and autonomy. The framework of this paper encompasses validation therapy, person-centered care, and self-determination theory. Two conclusions emerge: Seeing the person through the dementia enables an adequate psychological assessment and a helpful supportive psychotherapy, and it also makes us acknowledge and help satisfy the three basic psychological needs of relatedness, competence, and autonomy.
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In mammals, and especially primates, group size and social complexity are typically correlated. However, we have no general explanation why this is so. I suggest that the answer may lie in one of the costs of group living: mammalian reproductive endocrinology is extremely sensitive to stress, and forms one of the hidden costs of living in groups. Fertility declines with group size widely across the social mammals, including primates, and will ultimately place a constraint on group size. However, some species seem to have been able to mitigate this cost by forming bonded relationships that reduce the impact of experienced aggression, even if rates of aggression remain high. The downside is that they reduce network connectivity and hence risk fragmenting the group by providing fracture lines for group fission. To explore this, I compare network indices and fertility patterns across the same range of group sizes for two species of Old World monkeys, Colobus guereza and Theropithecus gelada: the former relatively unsocial, the latter intensely social with frequent use of grooming-based alliances. Compared to those of the guereza, gelada social networks lose density more slowly, maintain connectedness more effectively and are less likely to fragment as they increase in size. Although fertility declines with group size in both species, in gelada the impact of this effect is deferred to larger group sizes. The differences in fertility and network structure both predict the very different maximum group sizes typical of these two species, as well as the typical sizes at which their groups undergo fission. This finding may explain aspects of wider mammalian sociality.
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This paper examines social network size in contemporary Western society based on the exchange of Christmas cards. Maximum network size averaged 153.5 individuals, with a mean network size of 124.9 for those individuals explicitly contacted; these values are remarkably close to the group size of 150 predicted for humans on the basis of the size of their neocortex. Age, household type, and the relationship to the individual influence network structure, although the proportion of kin remained relatively constant at around 21%. Frequency of contact between network members was primarily determined by two classes of variable: passive factors (distance, work colleague, overseas) and active factors (emotional closeness, genetic relatedness). Controlling for the influence of passive factors on contact rates allowed the hierarchical structure of human social groups to be delimited. These findings suggest that there may be cognitive constraints on network size.
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Throughout the life span, individuals engage in affectionate touch with close others. Touch receipt promotes well-being in infancy, but the impacts of touch in adult close relationships have been largely unexplored. In this article, we propose that affectionate touch receipt promotes relational, psychological, and physical well-being in adulthood, and we present a theoretical mechanistic model to explain why affectionate touch may promote these outcomes. The model includes pathways through which touch could affect well-being by reducing stress and by promoting well-being independent of stress. Specifically, two immediate outcomes of affectionate touch receipt—relational-cognitive changes and neurobiological changes—are described as important mechanisms underlying the effects of affectionate touch on well-being. We also review and evaluate the existing research linking affectionate touch to well-being in adulthood and propose an agenda to advance research in this area. This theoretical perspective provides a foundation for future work on touch in adult close relationships.