=Paper=
{{Paper
|id=Vol-2524/paper13
|storemode=property
|title=Being like you improves my comfort space: social human-virtual confederates interactions
|pdfUrl=https://ceur-ws.org/Vol-2524/paper13.pdf
|volume=Vol-2524
|authors=Gennaro Ruggiero,Francesco Ruotolo,Tina Iachini
|dblpUrl=https://dblp.org/rec/conf/psychobit/RuggieroRI19
}}
==Being like you improves my comfort space: social human-virtual confederates interactions==
https://ceur-ws.org/Vol-2524/paper13.pdf
BEING LIKE YOU IMPROVES MY COMFORT
SPACE: SOCIAL HUMAN-VIRTUAL
CONFEDERATES INTERACTIONS
Ruggiero, G.,1 Ruotolo, F., 1 and Iachini, T. 1
1 Laboratory of Cognitive Science and Immersive Virtual Reality (CS-IVR),
Department of Psychology, University of Campania L. Vanvitelli (Caserta, Italy)
Abstract. This study aims to explore how the comfort distance between a person
and a virtual avatar (interpersonal comfort-space, IPS) is modulated by body
characteristics during a social interaction. Once immersed in a virtual scenario,
participants could either see virtual agents approaching them (passive condition)
or moved towards them (active condition). In both conditions, participants had to
press a button as soon as they felt that the distance between them and the avatar
was uncomfortable. Importantly, participants could have similar or different (i.e.
smaller) body-size compared to the avatar. Results showed that participants with
different body size preferred larger distances as compared to those with similar
body size, particularly in the passive condition. Finally, the different body size
participants in the passive condition showed a gradual increase of comfort-dis-
tance with the decrease of their arms’ length. These results suggest that the pos-
sibility of control modulates IPS: people prefer a larger comfort-distance when
can only observe virtual agents with a big body size approaching them. There-
fore, the IPS increase may reflect an evolutionary mechanism of self-protection
that determines an automatic avoidance reaction to a potential violation of the
near body space.
Keywords: interpersonal comfort-space, avatar, body-size.
1 Introduction
In the last decades, the Immersive Virtual Reality (IVR) systems are becoming in-
creasingly popular in clinical and research fields [1]. The concept of “presence” or “the
feeling of being there” describes the quality of our subjective experience in IVR [2; 3].
When the virtual environments are populated by virtual agents, we may have the feeling
of interacting with them as if we were together with other individuals in actual contexts,
a feeling referred to as ‘social presence’ [4-6].
The capacity of IVR to convince a user to be in reality can represents a viable solu-
tion for medical, rehabilitative, social and psychological purposes [3]. The presence of
naturalistic virtual agents is useful to help users, particularly elderly and clinical popu-
lations, to perform the assigned task [1]. Therefore, it is important to understand in
which way the characteristics of virtual agents may affect the quality and the efficacy
of virtual social interactions.
Copyright © 2019 for this paper by its authors. Use permitted under
Creative Commons License Attribution 4.0 International (CC BY 4.0).
Proxemics studies have shown that the use of space during interactions is a good
measure of the quality of social interactions [7]. The “interpersonal comfort-space”
(IPS) represents the optimal distance between ourselves and others, that is our emo-
tional ‘private space’ [8]. Typically, people increase IPS in uncomfortable/threatening
situations and reduce IPS in comfortable/safe situations [8-9]. Recent studies using IVR
have demonstrated that IPS is modulated by the socio-emotional characteristics of the
virtual confederates such as age, gender and facial expressions [4; 6; 10-12]. The phys-
ical characteristics of interactants (e.g., height) may also modulate IPS. Pazhoohi et al.
[13] found, for example, that comfortable IPS was positively associated with height of
male participants. Body size can represent a signal of threat/weakness provoking avoid-
ance behaviors or dominance/competition provoking approach behaviors [14].
In sum, individuals’ body size could represent a key factor in modulating the exten-
sion of IPS during interactions with virtual agents. To our knowledge, no study has
addressed this issue so far. Here, we tested the effect of body size similarity on IPS
during virtual interactions by dividing male participants in two groups: similar body
size as virtual confederates (Similar Body Size group), different body size from virtual
confederates (Different Body Size group). Participants determined comfort-distance
from virtual agents under two approach conditions: while standing still (passive) or
walking toward the virtual confederates (active).
We expected that comfort-distance should be shorter with similar than different body
size. Since when we can actively control the spatial behavior we feel safer [10], we
hypothesized comfort-distance should be smaller in the active than passive condition.
However, the passive condition should determine an expansion of distance especially
within the dissimilar body size group.
2 Method
2.1 Participants
Thirty-one right-handed male participants, aged 18-26 years (Mean= 21.5; SD= 2.2),
participated in the study. Seventeen participants with similar body’ size as the virtual
confederate (h.= 1.78m, arms’ length= 76cm) were assigned to the “Similar Body size
group” (h.= 1.77m; arms’ length=75.2cm); 14 participants with shorter body’ size from
the virtual confederate were assigned to the “Different Body size group” (h.= 1.70m;
arms’ length= 71.7cm). Participants had common experience with digital technology
but no one with virtual reality devices. Nobody claimed discomfort or vertigo during
the IVR experience.
2.2 Settings and apparatus
The IVR equipment was installed in a 5x4x3 m room of the Laboratory of Cognitive
Science and Immersive Virtual Reality (CS-IVR, Dept. Psychology). The equipment
included the 3-D Vizard Virtual Reality Software Toolkit 6 (Worldviz, LLC, USA)
with the head mounted display (HMD) HTC VIVE. A glove with 14 tactile-pressure
sensors allowed the participants to ‘‘see’’ and ‘‘feel’’ their arm movements (Data Glove
Ultra; WorldViz, USA).
2.3 Virtual stimuli
The virtual room consisted of green walls, white ceiling and grey floor. Twelve realistic
confederates with neutral facial expressions were used [10-11].
Virtual humans represented male adults aged about 26 years, wearing similar casual
clothes and looking like Italians (Fig. 1). Their gaze was kept looking straight ahead
through-out the trials.
Fig. 1. The figure depicts a) a virtual confederate approaching frontally participants; b) the virtual
confederate (1) compared to participants had similar (2) or different (3) physical characteristics.
2.4 Procedure
After wearing the HMD and the Data Glove participants were immersed in the vir-
tual scenario and could perform extensive exploratory movements. Next, they were led
to the starting position where they held a keypress device in their dominant hand. The
experimental session comprised two Passive and Active blocks in a counterbalanced
order. The comfort-distance instruction for both approach conditions was: ‘‘press the
button as soon as the distance between you and the confederate makes you feel uncom-
fortable’’. After button press, virtual confederates disappeared. Each virtual confeder-
ate appeared 4 times (quasi-randomized order) resulting in 24 per block (tot. 48 trials).
3 Results
The mean participant-virtual confederate distances were analyzed through a 2x2
ANOVA with terms Groups (between) and Approach (within). A main effect of Groups
emerged (F(1,29)= 17.498, p=.001, η²p = .38) due to Different body size group
(M=61.34cm, SD=38.23cm) preferring a larger distance than Similar body size group
(M=29.33cm, SD=13.29cm). A main effect of Approach condition emerged (F(1,29)=
22.906, p < .001, η²p = .44) due to a larger distance in the passive (M=59.51cm,
SD=33.81cm) than active (M=28.06cm, SD=20.25) approach. A significant Groups x
Approach interaction was found: F(1,29)= 8.566, p < .01, η²p = .23 (see Fig. 2). The
Scheffè post-hoc test revealed that within the Different body size group, passive ap-
proach was larger than active one (p< .001); whereas within the Similar body size
group, no difference emerged. Finally, a negative Pearson correlation (see Table 1) be-
tween arms’ length and Different body size group in the passive approach emerged by
demonstrating a gradual increase of comfort-distance with the decrease of the length of
participants’ arms. No other significant correlations emerged.
Fig. 2. The graph shows mean comfort distance (cm) for each group as a function of passive and
active approach conditions. Error bars represent standard errors.
Table 1. Descriptive statistics and correlations between arms’ length of both groups (N=31)
and the IPS distance for passive and active approach conditions; ^p= .12; *p< .05.
Groups Arms’ length Passive approach Active approach
(M:Sd)
Similar Body Size 76.0; 1.8 .40^ .21
Diff. Body Size 71.1; 2.8 -.50* -.31
4 Conclusions
The results confirmed that comfort-distance was larger when participants had a
shorter instead of similar body size as compared to virtual agents. The passive approach
provoked a general enlargement of the IPS with respect to the active one. This is in line
with previous evidence showing an increase of IPS when we do not have the full motor
control of spatial behavior, thereby reflecting a low feeling of safety [6; 10]. Im-
portantly, IPS was increased only in the passive approach condition when participants
had a different rather than similar body size as compared to the virtual agents. The
correlational analysis demonstrated that different body size participants in the passive
condition reported a gradual increase of comfort-distance with the decrease of their
arms’ length.
Therefore, body size is an important factor in the modulation of IPS [13]. Along with
social-emotional factors, the body size of a smaller individual can represent an element
of weakness during social interactions with taller interlocutors. By contrast, being phys-
ically similar to our interlocutors gives us the possibility to manage the interaction in
terms of competition at par, thus allowing behaviors of approach [14].
In line with an evolutionary perspective, these findings are consistent with the fun-
damental defensive function of the near body space representation [15]. The need of
maintaining a feeling of safety is crucial when the person who enters in our space is
perceived as potentially harmful, and this provokes an automatic avoidance reaction [6;
9-10].
The current study focused only on male dyadic interactions and this can be a limita-
tion. Further studies should investigate whether the interactions between women of
similar or different body sizes can replicate the same findings reported here.
In sum, if we want to improve the quality and efficacy of virtual social interactions
it is particularly interesting the finding that IPS is shorter when individuals and virtual
agents are physically similar. This is in line with the evidence that when other persons
are perceived as similar to us, we tend to approach them to facilitate the social interac-
tion [13-14].
References
1. Morganti, F., Riva, G.: Conoscenza, comunicazione e tecnologia: aspetti cognitivi della
realtà virtuale. LED Edizioni Universitarie (2006).
2. Slater, M.: Place illusion and plausibility can lead to realistic behaviour in immersive virtual
environments. Philosophical transactions of the Royal Society B 364(1535), 3549–3557
(2009).
3. Riva, G., Waterworth, J., Murray, D.: Interacting with Presence: HCI and the Sense of Pres-
ence in Computer-mediated Environments. Walter de Gruyter GmbH & Co KG (2014).
4. Iachini, T., Pagliaro, S., Ruggiero, G.: Near or far? It depends on my impression: Moral
information and spatial behavior in virtual interactions. Acta Psychologica 161, 131-136
(2015).
5. Nowak, K. L., Biocca, F.: The effect of the agency and anthropomorphism on users' sense
of telepresence, copresence, and social presence in virtual environments. Presence: Tele-
operators and Virtual Environments, 12(5), 481-494 (2003).
6. Ruggiero, G., Frassinetti, F., Coello, Y., Rapuano, M., Schiano di Cola, A., Iachini, T.: The
effect of facial expressions on peripersonal and interpersonal spaces. Psychological Re-
search 81, 1232-1240 (2017).
7. Hall, E. T.: The hidden dimension. New York: Doubleday (1966).
8. Hayduk, L.A. Personal space: Where we now stand. Psychological Bulletin, 94, 293–335
(1983).
9. Kennedy, D. P., Gläscher, J., Tyszka, J. M., Adolphs, R.: Personal space regulation by the
human amygdala. Nature Neuroscience, 12, 1226–1227 (2009).
10. Iachini, T., Coello, Y., Frassinetti, F., & Ruggiero, G.: Body space in social interactions: A
comparison of reaching and comfort distance in immersive virtual reality. PLoS ONE, 9(11),
e111511 (2014).
11. Iachini, T., Coello, Y., Frassinetti, F., Senese, V. P., Galante, F., Ruggiero, G.: Peripersonal
and interpersonal space in virtual and real environments: Effects of gender and age. Journal
of Environmental Psychology, 45, 154–164 (2016).
12. Ruggiero, G., Rapuano, M., Iachini, T.: Perceived temperature modulates peripersonal and
interpersonal spaces differently in men and women. Journal of Environmental Psychology
63, 52-59 (2019).
13. Pazhoohi, F., Silva, C., Lamas, J., Mouta, S., Santos, J., Arantes, J.: The effect of height and
shoulder-to-hip ratio on interpersonal space in virtual environment. Psychological research,
1-10 (2018).
14. Ellis, L.: The high and the mighty among man and beast: How universal is the relationship
between height (or body size) and social status. In L. Ellis (Ed.), Social Stratification and
Socioeconomic Inequality, Vol. 2 (pp. 93–112). Westport, Praeger (1994).
15. Graziano, M.: The Spaces Between Us: A Story of Neuroscience, Evolution, and Human
Nature. 1st ed. Oxford University Press, Oxford (2018).