envelopes.

######  Proposition 5.3.

Let $X$ be a $\mathbb{G}\text{-}C^{*}$-operator system. There exists a
$\mathbb{G}\text{-}C^{*}$-injective envelope $(S,\iota)$ for $X$. If
$(\widetilde{S},\tilde{\iota})$ is another $\mathbb{G}\text{-}C^{*}$-injective
envelope, there exists a unique $\mathbb{G}\text{-}C^{*}$-unital order
isomorphism $\theta:S\to\widetilde{S}$ such that the diagram

${S}$${\widetilde{S}}$${X}$$\scriptstyle{\theta}$$\scriptstyle{\iota}$$\scriptstyle{\tilde{\iota}}$

commutes. Moreover, $(S,\iota:X\to S)$ is a $\mathbb{G}$-$C^{*}$-injective
envelope if and only if $(S,\iota)$ is $\mathbb{G}$-$C^{*}$-injective and
$\mathbb{G}$-$C^{*}$-rigid.

###### Proof.

If $(S,\iota)$ is a $\mathbb{G}$-$C^{*}$-injective and
$\mathbb{G}$-$C^{*}$-rigid extension of the $\mathbb{G}$-$C^{*}$-operator
system $X$, then $(S,\iota)$ is a $\mathbb{G}$-$C^{*}$-injective envelope of
$X$. Indeed, if $\iota(X)\subseteq T\subseteq S$ where $T$ is a
$\mathbb{G}$-$C^{*}$-injective operator subsystem of $S$, there is a
$\mathbb{G}$-$C^{*}$ ucp map $\theta:S\to T$ such that
$\theta|_{T}=\operatorname{id}_{T}$. Viewing $\theta$ as a map $S\to S$ and
noting that $\theta\iota=\iota$, the $\mathbb{G}$-$C^{*}$-rigidity shows that
$\theta=\operatorname{id}_{S}$. Thus, $S=\theta(S)\subseteq T\subseteq S$ and
$S=T$.

We now use this fact to show that $\mathbb{G}$-$C^{*}$-injective envelopes
exist. We may assume that $X\subseteq B(\mathcal{H})$. Let
$Y:=\mathcal{R}(B(\mathcal{H})\mathbin{\overline{\otimes}}B(L^{2}(\mathbb{G})),\operatorname{id}\mathbin{\overline{\otimes}}\Delta)$
which is a $\mathbb{G}$-$C^{*}$-injective operator system and consider the set
$\mathcal{G}$ of all $\mathbb{G}$-$C^{*}$-equivariant ucp maps $\varphi:Y\to
Y$ such that $\varphi\circ\alpha=\alpha$. Viewing $\mathcal{G}$ as a subset of
the ucp maps $Y\to B(\mathcal{H}\otimes L^{2}(\mathbb{G}))$, we observe that
$\mathcal{G}$ is closed in the topology of pointwise $\sigma$-weak
convergence. Indeed, assume that $\\{\varphi_{i}\\}_{i\in I}$ is a net in
$\mathcal{G}$ that converges to the ucp map $\varphi:Y\to B(\mathcal{H}\otimes
L^{2}(\mathbb{G}))$ in this topology. If $y$ is in the algebraic core of the
$\mathbb{G}$-$C^{*}$-action
$\operatorname{id}\mathbin{\overline{\otimes}}\Delta:Y\curvearrowleft\mathbb{G}$,
then

$\displaystyle(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)\varphi(y)=\lim_{i\in
I}(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)\varphi_{i}(y)=\lim_{i\in
I}(\varphi_{i}\odot\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)(y)=(\varphi\odot\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)(y)\
,$

and we conclude that $\varphi(Y)\subseteq Y$ and
$(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)\varphi=(\varphi\otimes\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\Delta)$.
Moreover, if $x\in X$, then

$\varphi(\alpha(x))=\lim_{i\in I}\varphi_{i}(\alpha(x))=\alpha(x)\ ,$

so $\varphi\in\mathcal{G}$. By [HHN22, Proposition 2.1], it follows that there
exists an idempotent $\varphi\in\mathcal{G}$ such that
$\varphi=\varphi\phi\varphi$ for all $\phi\in\mathcal{G}$. Since
$\varphi\alpha=\alpha$, we see that $\alpha(X)\subseteq\varphi(Y)$. We claim
that $(\varphi(Y),\alpha:X\to\varphi(Y))$ is a $\mathbb{G}$-$C^{*}$-injective
envelope of $X$. Consider the action
$\beta:=\operatorname{id}\mathbin{\overline{\otimes}}\Delta:Y\to Y\otimes
C_{r}(\mathbb{G})$, which by $\mathbb{G}$-$C^{*}$-equivariance of $\varphi$
restricts to a map $\widetilde{\beta}:\varphi(Y)\to\varphi(Y)\otimes
C_{r}(\mathbb{G})$. In this way $(\varphi(Y),\widetilde{\beta})$ becomes a
$\mathbb{G}$-$C^{*}$-operator system. Indeed, note that

$\widetilde{\beta}(\varphi(y))(1\otimes\lambda(g))=(\varphi\otimes\operatorname{id})(\beta(y))(1\otimes\lambda(g))=(\varphi\otimes\operatorname{id})(\beta(y)(1\otimes\lambda(g))$

so the Podleś condition for $\varphi(Y)$ follows from the Podleś condition for
$Y$.

Since $\varphi\circ\varphi=\varphi$, we see that $\varphi$ is the identity on
$\varphi(Y)$. Hence, $\varphi(Y)$ is $\mathbb{G}$-$C^{*}$-injective.

Let $\psi:\varphi(Y)\to\varphi(Y)$ be a ucp $\mathbb{G}$-$C^{*}$-equivariant
map with $\psi\circ\alpha=\alpha$. Then $\psi\varphi\in\mathcal{G}$ and
$\varphi\psi=\psi$, so that

$\varphi=\varphi(\psi\varphi)\varphi=\psi\varphi\ ,$

which means that $\psi=\operatorname{id}.$ This establishes the
$\mathbb{G}$-$C^{*}$-rigidity of the extension. The statement about uniqueness
of the $\mathbb{G}$-$C^{*}$-injective envelope follows immediately from the
definitions of $\mathbb{G}$-$C^{*}$-injectivity and
$\mathbb{G}$-$C^{*}$-rigidity.

Finally, if $(S,\iota)$ is a $\mathbb{G}$-$C^{*}$-injective envelope, then by
the uniqueness it is canonically isomorphic to $(\varphi(Y),\alpha)$, which
has the required equivariant rigidity and injectivity properties. ∎

In view of the preceding proposition, we can speak about _the_ injective
envelope of a $\mathbb{G}$-$C^{*}$-operator system $X$, which we will denote
by $I_{\mathbb{G}}^{C^{*}}(X)$. The $\mathbb{G}$-$C^{*}$ action on this space
is implicitly understood.

######  Remark 5.4.

A similar result is of course true for $\widehat{\mathbb{G}}$-operator
systems. In this case, starting from a $\widehat{\mathbb{G}}$-operator system
$(X,\alpha)$ with $X\subseteq B(\mathcal{H})$, one applies [HHN22, Proposition
2.1] to the set $\mathcal{G}$ of all $\widehat{\mathbb{G}}$-equivariant ucp
maps
$\varphi:B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})\to
B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})$
satisfying $\varphi\circ\alpha=\alpha$ to find a minimal idempotent
$\varphi\in\mathcal{G}$. One then checks that

$(\varphi(B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})),\alpha:X\to\varphi(B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})))$

is a $\widehat{\mathbb{G}}$-injective envelope for $X$.

The only thing that may not be entirely obvious is that $\mathcal{G}$ is
closed in the topology of pointwise $\sigma$-weak convergence. But suppose
that
$\varphi:B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})\to
B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})$
is a ucp map and that $\\{\varphi_{i}\\}_{i\in I}$ is a net in $\mathcal{G}$
that converges to $\varphi$ in this topology. If
$\omega\in\mathscr{L}^{\infty}(\widehat{\mathbb{G}})_{*}$ and $y\in
B(\mathcal{H})\mathbin{\overline{\otimes}}\mathscr{L}^{\infty}(\widehat{\mathbb{G}})$,
we see that

$\displaystyle(\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)((\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})\varphi(y))$
$\displaystyle=\lim_{i\in
I}(\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)((\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})(\varphi_{i}(y)))$
$\displaystyle=\lim_{i\in
I}(\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)((\varphi_{i}\mathbin{\overline{\otimes}}\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})(y))$
$\displaystyle=\lim_{i\in
I}\varphi_{i}((\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})(y))$
$\displaystyle=\varphi((\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})(y))$
$\displaystyle=(\operatorname{id}\mathbin{\overline{\otimes}}\operatorname{id}\mathbin{\overline{\otimes}}\omega)((\varphi\mathbin{\overline{\otimes}}\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})(y))\
,$

so we conclude that
$(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})\varphi=(\varphi\mathbin{\overline{\otimes}}\operatorname{id})(\operatorname{id}\mathbin{\overline{\otimes}}\hat{\Delta})$,
i.e. $\varphi$ is $\widehat{\mathbb{G}}$-equivariant and thus
$\varphi\in\mathcal{G}$.$\mbox{}\hfill\Diamond$

The $\widehat{\mathbb{G}}$-injective envelope of a
$\widehat{\mathbb{G}}$-operator system $X$ will be denoted by
$I_{\widehat{\mathbb{G}}}(X)$ and the $\widehat{\mathbb{G}}$-action on
$I_{\widehat{\mathbb{G}}}(X)$ is implicitly understood.

After our work, the following result comes for free:

######  Theorem 5.5.

Let $X$ be a $\widehat{\mathbb{G}}$-operator system. Let $(Y,\iota)$ be a
$\widehat{\mathbb{G}}$-extension of $X$. Then $(Y,\iota)$ is the
$\widehat{\mathbb{G}}$-injective envelope of $X$ if and only if
$(Y\rtimes_{r}\widehat{\mathbb{G}},\iota\rtimes_{r}\widehat{\mathbb{G}})$ is
the $\mathbb{G}$-$C^{*}$-injective envelope of
$X\rtimes_{r}\widehat{\mathbb{G}}$. In particular,

$I_{\widehat{\mathbb{G}}}(X)\rtimes_{r}\widehat{\mathbb{G}}=I_{\mathbb{G}}^{C^{*}}(X\rtimes_{r}\widehat{\mathbb{G}}).$

###### Proof.

Immediate from Theorem 4.3, Proposition 5.2 and Proposition 5.3. ∎

Recall that the $C^{*}$-algebra $C(\partial_{F}\widehat{\mathbb{G}})$ of the
Furstenberg boundary $\partial_{F}\widehat{\mathbb{G}}$ can be realised as the
operator system $I_{\widehat{\mathbb{G}}}(\mathbb{C})$ [KKV22]. In view of
this, the following is obvious:

######  Corollary 5.6.

$I_{\mathbb{G}}^{C^{*}}(C_{r}(\mathbb{G}))=C(\partial_{F}\widehat{\mathbb{G}})\rtimes_{r}\widehat{\mathbb{G}}$
as $\mathbb{G}$-$C^{*}$-operator systems.

Acknowledgments: Both authors would like to thank Kenny De Commer for valuable
input throughout the entire project. The authors also want to thank Sergey
Neshveyev for a useful discussion and Stefaan Vaes for sharing the proof of
Proposition 3.22 and allowing us to write it down in this paper.

The first named author would like to thank Adam Skalski for hospitality and a
useful discussion related to this project during a research visit to IMPAN in
the framework of the FWO–PAS project VS02619N “von Neumann algebras arising
from quantum symmetries”. This author is supported by Fonds voor
Wetenschappelijk Onderzoek (Flanders), via an FWO Aspirant-fellowship, grant
1162522N. The second author is supported by the NFR project 300837 “Quantum
Symmetry”.

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E-mail address:
---

.0pt


0 ©2024 IEEE. This is the author’s preprint version of the article. Final
version to appear in IEEE Transactions on Visualization and Computer Graphics.
Research please specify Tiffany D. Do is with The University of Central
Florida. E-mail<EMAIL_ADDRESS>Camille Isabella Protko is with The
University of Central Florida. E-mail<EMAIL_ADDRESS>Ryan P. McMahan is
with The University of Central Florida. E-mail<EMAIL_ADDRESS>
# Stepping into the Right Shoes: The Effects of User-Matched Avatar Ethnicity
and Gender on Sense of Embodiment in Virtual Reality

Tiffany D. Do0000-0003-3323-4586  Camille Isabella Protko  and Ryan P.
McMahan0000-0001-9357-9696

###### Abstract

In many consumer virtual reality (VR) applications, users embody predefined
characters that offer minimal customization options, frequently emphasizing
storytelling over user choice. We explore whether matching a user’s physical
characteristics, specifically ethnicity and gender, with their virtual self-
avatar affects their sense of embodiment in VR. We conducted a $2\times 2$
within-subjects experiment (n=32) with a diverse user population to explore
the impact of matching or not matching a user’s self-avatar to their ethnicity
and gender on their sense of embodiment. Our results indicate that matching
the ethnicity of the user and their self-avatar significantly enhances sense
of embodiment regardless of gender, extending across various aspects,
including appearance, response, and ownership. We also found that matching
gender significantly enhanced ownership, suggesting that this aspect is
influenced by matching both ethnicity and gender. Interestingly, we found that
matching ethnicity specifically affects self-location while matching gender
specifically affects one’s body ownership.

###### keywords:

Virtual reality, sense of embodiment, avatars, diversity.

This example shows an Asian female participant. In our study, we investigated
the embodiment effects of matching a self-avatar to the user’s ethnicity and
gender through four conditions: A) Complete: Both ethnicity and gender are
matched; B) Ethnicity: Ethnicity is matched, but gender is not; C) Gender:
Gender is matched, but ethnicity is not; D) None: Neither ethnicity nor gender
are matched.

Introduction

In many virtual reality (VR) applications and games, users embody characters
that act as their representation within the virtual world. However, these
applications frequently offer limited customization options, prioritizing
narrative cohesion over user choice. This constraint becomes apparent in well-
known VR titles such as Half-Life: Alyx, Resident Evil Village, and Batman:
Arkham VR, where users find themselves restricted to embodying predefined
white characters, with no option for gender and ethnicity customization. This
raises a fundamental question: does this limitation affect a user’s degree of
embodiment?

The study of sense of embodiment in VR, which describes the combination of
sensations experienced while immersed in and controlling a virtual body, [23],
has garnered increased attention in recent years. We hold a particular
interest in this phenomenon because one’s sense of embodiment can play a
crucial role in shaping a user’s experience within VR, as highlighted by prior
research [33]. For example, prior work has shown that the level of embodiment
can exert influence over various facets, including distance perception [17]
and cognitive performance [21]. Additionally, an increased sense of embodiment
can significantly moderate the outcomes of embodiment illusions, such as the
Proteus effect [22, 28]. However, research investigating similarities between
a user and their avatar is sparse [7], and there is further limited
understanding of how specific factors, such as matched ethnicity and gender,
may impact the sense of embodiment.

One of the central challenges in embodiment research is the lack of diversity
in avatar representations. For instance, while numerous studies have examined
the influence of various factors like avatar appearance and fidelity [25, 4,
8, 44], they have frequently used white avatars as the default. This
limitation extends to research exploring the similarities between a user and
their avatar, including factors like avatar ethnicity and gender. For
instance, prior investigations into the effects of embodying avatars of a
different gender have predominantly relied on white avatars [27, 26, 51]. On
the other hand, studies exploring the impact of embodying avatars of a
different ethnicity [35, 22, 3, 42] have typically employed gender-matched
avatars and limited their participants to mostly individuals of white
ethnicity, thus limiting generalizability. Our research goes beyond these
prior studies by thoroughly examining the design space of both matched gender
and ethnicity to assess how these factors interact and influence one’s sense
of embodiment in VR.

As VR games and applications continue to gain global traction, it becomes
increasingly important to investigate how the similarity between a user’s
characteristics and their self-avatar can influence their sense of embodiment
within the virtual environment. Our research explores the intricate
relationship between user ethnicity, gender, and self-avatar in shaping
embodiment in VR. We answer the following research questions:

  * •

RQ1: How does matching or not matching a user’s ethnicity and their avatar’s
ethnicity impact sense of embodiment in VR?

  * •

RQ2: How does matching or not matching a user’s gender with their avatar’s
gender impact sense of embodiment in VR?

  * •

RQ3: In which ways do matching gender and ethnicity interact with each other?

We conducted a $2\times 2$ within-subjects study involving 32 participants (17
women, 15 men) to investigate the effect of the avatar’s ethnicity (matched or
not matched) and gender (matched or not matched). In an effort to address the
conventional limitations related to participant diversity in embodiment
studies, our participant pool encompassed individuals from diverse ethnic
backgrounds, including Asian, Black/African-American, Hispanic/Latino, and
White populations. Participants engaged in a standard embodiment task [40]
using four avatars: Complete (same ethnicity, same gender), Ethnicity (same
ethnicity, different gender), Gender (different ethnicity, same gender), and
None (different ethnicity, different gender).

Table 1: An overview of avatar embodiment studies investigating the impact of
matching user characteristics with their avatar’s characteristics.

| Avatar Factors | Participant Factors | Measures
---|---|---|---
| Gender | Ethnicity | Avatar Ethnicity | Other | Gender | Ethnicity | Sense of Embodiment
Fribourg et al. [16] |  |  | Unspecified | Realism, Control | M, F | Unspecified | $\checkmark$
Maselli and Slater [30] |  |  | White | Realism | M, F | Unspecified | $\checkmark$
Eubanks et al. [11] |  |  | Obscured | Tracking level | M | Unspecified | $\checkmark$
Bartl et al. [4] |  |  | White | Realism, Clothing | M, F | Unspecified | $\checkmark$
Latoschik et al. [25] |  |  | White | Realism | M, F | Unspecified | $\checkmark$
Dewez et al. [8] |  |  | White |  | M, F | Unspecified | $\checkmark$
Fribourg et al. [15] |  |  | Unspecified | Second avatar | M | Unspecified | $\checkmark$
Waltemate et al. [48] |  |  | White, Personalized | Personalization, Immersion | M, F | Unspecified | $\checkmark$
Roth and Latoschik [40] |  |  | White, Personalized | Personalization, Realism | M, F | Unspecified | $\checkmark$
Jo et al. [20] |  |  | White, Personalized | Personalization, Quality, Clothing | Unspecified | Unspecified | $\checkmark$
Fiedler et al. [13] |  |  | White, Personalized | Personalization | M, F | Unspecified | $\checkmark$
Dollinger et al. [10] |  |  | White, Customized, Personalized | Personalization, Fidelity | M, F | Unspecified | $\checkmark$
Salagean et al. [41] |  |  | White, Personalized | Realism | M, F | Unspecified | $\checkmark$
Ries et al. [38] |  |  | Black | Tracking level, Fidelity | Unspecified | Unspecified |
Kim et al. [24] |  |  | Asian | Similarity | M, F | Asian | $\checkmark$
Radiah et al. [37] | $\checkmark$ |  | White, Matched | Personalization | M, F | Unspecified | $\checkmark$
Peck et al. [34] | $\checkmark$ |  | Matched |  | M, F | 83 White, 42 Other | $\checkmark$
Peck et al. [32] | $\checkmark$ |  | Matched |  | F | White* | $\checkmark$
Lugrin et al. [27] | $\checkmark$ |  | White | Realism | M, F | Unspecified | $\checkmark$
Lopez et al. [26] | $\checkmark$ |  | White |  | M | White | $\checkmark$
Wu and Chen [51] | $\checkmark$ |  | White |  | M, F | Unspecified | $\checkmark$
Schulze et al. [43] | $\checkmark$ |  | White |  | M, F | Unspecified |
Chang et al. [5] | $\checkmark$ |  | White |  | M, F | White* |
Schwind et al. [44] | $\checkmark$ |  | White | Realism | M, F | Unspecified |
Peck et al. [35] |  | $\checkmark$ | Black, White, Alien | Avatar perspective | F | White | $\checkmark$
Kilteni et al. [22] |  | $\checkmark$ | Black, White, Obscured | Clothing | M, F | White | $\checkmark$
Marini and Casile [29] |  | $\checkmark$ | Black, White | Mirror presence | F | White | $\checkmark$
Ash [3] |  | $\checkmark$ | Black, White |  | M, F | White* | $\checkmark$
Ambron et al. [1] |  | $\checkmark$ | Black, White, Alien |  | M, F | Black, White | $\checkmark$
Salmanowitz et al. [42] |  | $\checkmark$ | Black, White |  | M, F | White |
Chen et al. [6] |  | $\checkmark$ | Asian |  | M, F | Asian |
Ours | $\checkmark$ | $\checkmark$ |  | Asian, Latino,
---
Black, White
| M, F |  | Asian, Latino,
---
Black, White
$\checkmark$

*Marked studies reported majority White participants (75%+), but also included participants of other ethnicities.

##  1 Related Work

###  1.1 Virtual Embodiment

Virtual embodiment, a key aspect of VR, has gained considerable attention as
self-avatars become more popular. Embodiment describes the phenomenon where
users are co-located with a virtual avatar and view it from a first-person
perspective [33]. Embodiment research delves into how users perceive and
interact with their self-avatars [46], and prior research shows that
embodiment can impact various aspects of the user experience, such as distance
perception [17], self-enfacement [18], performance [21], and cognitive load
[32]. Roth et al. [40] emphasize that embodiment is a part of self-
consciousness, primarily driven by the processing of multi-sensory
information. We find the degree of embodiment to be important due to its
potential to shape the overall user experience in VR. For instance, prior
research by Gonzalez-Franco et al. [17] revealed that a higher degree of sense
of embodiment can reduce distance underestimation within VR, while Juliano et
al. [21] found that a higher degree of sense of embodiment were correlated
with increased neurofeedback performance in brain-computer interfaces.

Several scholars have reported that sense of embodiment comprises various
facets. For instance, seminal work by Kilteni et al. [23] describes how
embodiment can be broken down into three components: body ownership, defined
as “implications that the body is the source of the experienced sensations"
[23]; agency, characterized as “the feeling of controlling one’s own body
movements, and, through them, events in the external environment" [47]; and
self-location, representing “a determinate volume in space where one feels to
be located" [23].

###  1.2 Avatar Personalization

Our research primarily focuses on examining the influence of the resemblance
between a user’s personal characteristics and those of their self-avatar on
the sense of embodiment. In recent years, there has been increased interest in
the study of how similarity to one’s self avatar impacts sense of embodiment,
particularly for photorealistic scanned avatars. For example, Kim et al. [24]
found that a personalized avatar boosted users’ sense of embodiment in
comparison to a random avatar of the same race and gender. Of particular
relevance to our study is foundational work on personalization conducted by
Waltemate et al. [48] and Salagean et al. [41]. Both studies discovered that a
personalized avatar created using photogrammetry elicited a stronger sense of
body ownership compared to a generic gender-matched avatar of similar quality.
Yet, some studies have reported that personalized avatars may interact with
avatar realism. For example,  Jo et al. [20] found that participants felt more
embodied in a generic avatar with similar clothing to their own in comparison
to a realistic point-cloud based representation. Similarly, a recent study by
Dollinger et al. [10] found that participants embodying a personalized
photorealistic avatar had increased sense of embodiment compared to customized
and generic avatars, but resulted in higher eeriness and reduced body
awareness. However, these approaches to avatar personalization are not
feasible for consumer applications or even some research labs.

Notably, the generic avatars in most of these previously mentioned studies
([48, 41, 20, 10]), were depicted as White. This aspect raises important
questions about the potential impact of matching or not matching both
ethnicity and gender, particularly in the context of generic avatars. For
example, would generic avatars of the same ethnicity as the participant induce
any differences in sense of embodiment? Our research expands upon this
understanding by specifically investigating how the interaction of matching
ethnicity and gender affects embodiment for generic avatars, which have been
commonly employed in consumer VR applications and previous embodiment
research.

###  1.3 Matching Avatar Ethnicity

Numerous studies have delved into the influence of virtual embodiment on users
(e.g., [35, 45, 3]). Table 1 provides an overview of avatar embodiment
research examining matching or not matching avatar ethnicity. Many
investigations have centered on how embodying avatars of a different race can
impact racial biases (e.g., [35, 29]), or influence actions within VR
(e.g.,[45, 42]). However, our primary focus centers on examining how avatar
ethnicity specifically impacts the degree of the sense of embodiment.

Early studies conducted by Peck et al. [35] and Kilteni et al. [22], employing
between-groups designs, revealed that White participants who embodied a dark-
skinned avatar did not have significant differences in body ownership and
sense of embodiment compared to participants who embodied a light-skinned
avatar. Ambron et al. [1] also found that that both Black and White
participants reported comparable ownership levels for light-skinned and dark-
skinned hands. It is important to note that these studies did not employ
comprehensive standardized questionnaires to assess embodiment, primarily due
to their early nature. Our research advances upon these initial findings by
utilizing more extensive and validated questionnaires, including multiple
subscales, to precisely investigate the impact of matching race on embodiment.
Furthermore, we employ a within-subjects design to assess differences at the
individual level.

A more recent study conducted by Marini and Casile [29], which employed a
validated questionnaire [33], revealed a significant effect of matching the
avatar’s race on the "appearance" subscale. This subscale includes questions
that investigate whether users perceive a connection between their real body
and virtual body in terms of appearance. However, it is important to note that
Marini and Casile’s study exclusively focused on white female users and only
provided avatars of white and black ethnicity. This limited scope highlights
the direction of our research, as we aim to explore a more diverse participant
pool and corresponding avatars.

Freeman and Maloney conducted an interview-based study [14] and uncovered that
users, particularly non-white individuals, regarded the presentation of
ethnicity, including skin tone and facial features, as pivotal for self-
presentation within VR. Given the importance of ethnicity in shaping the
experiences of non-white users, we anticipate that our study, which
encompasses participants from various ethnic backgrounds, may yield results
that differ from those observed in studies conducted on more homogeneous
participant groups (e.g., [35, 22, 29]).

###  1.4 Matching Avatar Gender

Table 1 provides an overview of avatar embodiment research examining matching
or not matching avatar gender. Of particular relevance to our study is work by
Peck et al. [32, 34], which explored the manipulation of avatar gender in a
race-matched context across two studies. Although they found that gender
matching induced different responses in stereotype lift, it did not yield
significant effects for embodiment. It is important to note that Peck et al.
[34] acknowledged low reliability in their embodiment questionnaire and
recommended the use of more validated measures in future studies. Similarly,
in a study investigating how gender can affect implicit bias, Lopez et al.
[26] reported that gender matching did not significantly affect a user’s sense
of embodiment. However, their study did not employ validated embodiment
questionnaires, and instead individually analyzed the responses of five Likert
scale questions. Our contribution builds upon these previous investigations by
employing robust and validated embodiment questionnaires [33, 12], which offer
more comprehensive measurements.

In contrast to the findings of Lopez et al. [26] and Peck et al. [32, 34],
Lugrin et al. [27] reported that individuals who used generic white avatars of
the same gender experienced heightened levels of virtual body ownership
compared to those who embodied avatars of a different gender during VR fitness
training. Similarly, Radiah et al. [37] found that participants felt more
embodied in a same-gender avatar, but only when they could personalize it.
Overall, they reported that participants did not exhibit any significant
differences between generic white male and female avatars. However, both
studies did not provide information about the ethnicity of the participants,
raising questions about whether matching ethnicity may interact with matching
gender (i.e., whether a generic avatar that matches the user’s ethnicity would
have effects of gender). Our study extends this line of research by
investigating the combined effects of gender and ethnicity to provide a more
comprehensive understanding of their influence on virtual embodiment.

Figure 1: Headshots of the avatars employed in our study, from the Virtual
Avatar Library for Inclusion and Diversity (VALID) [9], by ethnicity and
gender. The top row features Asian avatars, followed by Black/African-
American, Hispanic/Latino, and White avatars in subsequent rows. Female
avatars are depicted on the left, while male avatars are shown on the right.
For each unique ethnicity and gender combination, there were three distinct
avatars for participants to choose from.

##  2 Methods

We conducted a $2\times 2$ within-subjects study to evaluate the effects of
matching user ethnicity and gender to their self-avatar. Participants embodied
four distinct avatars, which had varying characteristics depending on their
self-reported ethnicity and gender: Complete (same ethnicity, same gender),
Ethnicity (same ethnicity, different gender), Gender (different ethnicity,
same gender), and None (different ethnicity, different gender). Participants
were able to choose from three avatars for each condition (see Figure 1 for
all avatars).

We used avatars from the Virtual Avatar Library for Inclusion and Diversity
(VALID) [9], which provides avatars that are statistically validated to be
perceived as specific ethnicities and genders (see Figure 1 for examples of
the avatars). For “different gender" avatars, participants embodied an avatar
of the opposite gender (man or woman). Our study encompassed participants from
diverse ethnic backgrounds, including Asian, Black/African-American,
Hispanic/Latino, and White individuals. To ensure that participants perceived
different-ethnicity avatars as distinct from their own ethnicity, we selected
avatars that were the least representative of the participants’ respective
ethnicity. This decision was informed by the agreement rates provided by the
VALID library. For instance, Asian participants embodied Black avatars as
their “different ethnicity" avatars, as these avatars were perceived as the
least representative of Asian ethnicity. For an overview of the selected
different-ethnicity avatars corresponding to each participant’s ethnicity,
please refer to Table 2. All avatars wore a gray shirt and black shorts.

Table 2: Selected different-ethnicity avatars based on the participant’s ethnicity. Agreement rate is the average rate at which the avatar is identified as the participant’s ethnicity, as informed by the Virtual Avatar Library for Inclusion and Diversity (VALID). [9] | Participant
---
Ethnicity
| Different-Ethnicity
---
Avatar
| Average Agreement
---
Rate
Asian | Black | 0.02
Black | White | <0.01
Hispanic/Latino | Asian | 0.05
White | Black | <0.01

###  2.1 Research Hypotheses

We had the following hypotheses for our research questions:

H1: Participants will have an increased sense of embodiment in an ethnicity-
matched avatar, considering prior results indicating that presentation of
ethnicity is is important for a user’s sense of identity in VR [14, 1].

H2: Participants will have an increased sense of embodiment in a gender-
matched avatar, based on previous findings suggesting that same-gender avatars
induce higher levels of sense of embodiment [27].

H3: Participants will experience the greatest sense of embodiment when
provided an ethnicity-matched, gender-matched avatar than simply the
combination of their individual effects. Due to the lack of prior research in
this area, we based this hypothesis on feedback from participants that piloted
our study design.

###  2.2 Dependent Variables

After each condition, we administered two standardized embodiment
questionnaires, as described below. We additionally administered an exit
survey after all of the conditions to obtain qualitative information from our
participants.

####  2.2.1 Standardized Embodiment Questionnaire (SEQ)

To assess virtual embodiment, we employed the 2021 Standardized Embodiment
Questionnaire (SEQ) developed by Peck and Gonzalez-Franco [33]. We opted for
this questionnaire due to its comprehensive and validated nature, encompassing
elements from various previous questionnaires. The SEQ consists of 16
questions, each rated on a 7-point Likert scale. The SEQ generates a main
Embodiment score, which is further divided into four subscales: “Appearance”,
“Response”, “Ownership”, and “Multi-Sensory”.

####  2.2.2 Preliminary Embodiment Short Questionnaire (pESQ)

We additionally employed the Preliminary Embodiment Short Questionnaire (pESQ)
[12] to gain further insights into responses, particularly as it separates
"Ownership" into "Self-Location" and "Body Ownership" and encompasses the
three aspects of embodiment as outlined by [23]. We chose to also administer
this questionnaire as it is relatively short and measures "Self-Location",
which is not measured by other validated questionnaires such as the SEQ [12].
The pESQ consists of five questions, each rated on a 5-point Likert scale.
Similar to the SEQ, the pESQ generates an Embodiment score, which is further
divided into three subscales: "Agency", "Body Ownership", and "Self-Location".

####  2.2.3 Exit Survey

Upon concluding the experiment, participants participated in an exit survey,
allowing them to express their thoughts and insights regarding the avatars.
These qualitative responses served as a valuable resource for obtaining deeper
context to complement our quantitative findings. Participants were prompted
with two key questions: 1) Which avatar(s) did you feel most embodied by? Why?
and 2) Which avatar(s) did you feel least embodied by? Why?

###  2.3 Apparatus

Participants used an HTC Vive Pro and three additional VIVE trackers (2018) on
the participants’ feet and lower back. To track their hands, participants used
Valve Index controllers, which affords basic finger tracking (see Figure 2 for
an example). All movements, including finger tracking, were transferred from
these devices to the participants’ avatars using FinalIK 111http://root-
motion.com/ and SteamVR.

Figure 2: An example of the apparatus. Participants wear a Vive Pro headset,
two Valve Index controllers, and three Vive trackers. The Index controllers
afford basic finger tracking.

The embodiment simulation was implemented in Unity (2021.3.6f1), featuring a
virtual bedroom equipped with a mirror simulation. The virtual environment was
illuminated by a soft white directional light (intensity 1.0). The virtual
mirror emulated the behavior of a physical mirror by using a secondary virtual
camera and a render texture. The secondary virtual camera was positioned on
the opposite side of the mirror along the Z-axis, based on the user’s head
position, and rotated based on the user’s forward direction reflected across
the mirror plane (see Figure 3). The mirror and wall objects were hidden from
this secondary virtual camera to produce the appropriate reflected image
within the mirror’s render texture. Users were initially positioned
approximately 1.5m away from the mirror.

Figure 3: A depiction of our virtual mirror implementation. A secondary
virtual camera is positioned across the Z-axis from the user’s head position
and rotated based on the user’s forward direction reflected across the mirror
plane to provide the proper reflection in the mirror.

###  2.4 Procedure

The study procedure received approval from an Institutional Review Board (IRB)
before implementation. The study consisted of one in-person session that
lasted approximately 45 minutes. Before arriving to the lab, participants
completed a background survey that captured their demographics, ethnicity,
gender, education, VR experience, and gaming experience.

Upon arrival to the lab, participants were assigned to one of four Latin
squares ordering cohorts for counterbalancing. Subsequently, they were
instructed to choose four characters, each corresponding to one of the
experimental conditions, using an avatar selection interface displayed on a
computer (see Figure 4). The selection screen was dynamically tailored based
on each participant’s ethnicity and gender, which ensured that participants
were presented with avatars that precisely matched the conditions (Complete,
Ethnicity, Gender, and None). For example, a participant who identifies as an
Asian man would exclusively see avatars representing Asian men when selecting
their Complete avatar and avatars representing Black women when choosing their
None avatar. Participants were only given the instructions, “Choose an avatar
that you would use to represent yourself in virtual reality" for each
selection.

Figure 4: Our avatar selection interface enabled participants to customize
their four conditions.

Participants proceeded by entering VR and embodying the first avatar, adhering
to the Latin squares ordering assigned to them. They were then instructed to
stand straight in order to calibrate the avatar’s height (using FinalIK’s
SteamVR calibration), with the avatar remaining concealed from their view
until after calibration. The FinalIK calibration system scales the avatar to
match the height of the headset. Subsequently, participants engaged in a
standard embodiment procedure, adapted from the protocol developed by Roth and
Latoschik [40] (see Figure 5). During these tasks, participants executed
actions in front of a virtual mirror, such as “Hold your right arm forward
with your palm facing down" and “Look at the same hand in the reflection" (see
Appendix A). Since our questionnaires encompassed questions concerning feet
and object interaction, we included an additional set of six instructions
pertaining to feet and object interaction (see Appendix A, Instructions
32-37). After the final task, participants exited VR.

After each embodiment task, participants filled out the SEQ and pESQ on a
computer. This process was then repeated for the remaining three conditions.
After the last condition, participants took our short exit survey on a
computer. Participants were then thanked for their time and were compensated
with a $15 USD gift card.

Figure 5: An example of several key tasks from the adapted embodiment
procedure. A) Hold your right arm straight forward with your palm facing down.
B) Put your left hand with some distance in front of your chest, the palm is
facing downwards. C) Take two small steps forward. D) Bend down and place the
cube on the floor.

###  2.5 Participants

A total of 32 participants were recruited from our university via listservs.
They provided self-reported demographic information, including gender (17
women and 15 men), ethnicity (7 East Asian, 6 Black/African-American, 11
Hispanic/Latino, and 8 White), and age (M=21.03, SD=3.70). All participants
reported normal or corrected vision and indicated the absence of disabilities.
Among the participants, 10 reported owning a consumer VR system, while 21
reported playing video games at least weekly.

Figure 6: We present mean measurements from the SEQ for all statistically
significant results, accompanied by standard error bars (1 SDE). An asterisk
(*) denotes significantly different conditions. We display plots grouped by
ethnicity conditions for overall Embodiment, Appearance, and Response, given
the significant main effects observed for these scales based on ethnicity. For
the Ownership scale, which exhibited significant main effects for both
ethnicity and gender, we provide plots grouped by both ethnicity and gender.
Notably, there were no significant effects identified for the Multi-Sensory
subscale.

###  2.6 Data Analysis Approach

Following the guidelines provided by [33] and [12], we computed the averages
of all subscale questions and the total embodiment score. Subsequently, we
conducted a Shapiro-Wilk test to determine the normality of the score
distributions. Given that this test revealed non-normal distributions for
several measures, we opted to employ the Aligned Rank Transform (ART) method
[50] for 2 x 2 factorial analysis of variance. Using this procedure, we tested
for interaction and main effects of matched avatar ethnicity and gender.

##  3 Results

The means and standard deviations for all measures can be found in Table 3. We
first describe results for the SEQ, and then the pESQ.

Table 3: An overview of the means (M) and standard deviations (SD) of
standardized questionnaire results. A red asterisk (*) indicates a significant
difference for ethnicity matching, while a red plus (+) sign indicates a
significant difference for gender matching.

|  | Complete
---
Same Ethnicity
Same Gender
M (SD)
| Ethnicity
---
Same Ethnicity
Diff. Gender
M (SD)
| Gender
---
Diff. Ethnicity
Same Gender
M (SD)
| None
---
Diff. Ethnicity
Diff. Gender
M (SD)
SEQ
Embodiment* | 3.48 (0.86) | 3.27 (0.88) | 3.18 (0.97) | 3.15 (1.05)
Appearance* | 3.21 (0.94) | 3.11 (1.04) | 2.99 (1.07) | 2.98 (1.11)
Response* | 2.92 (0.90) | 2.72 (1.07) | 2.56 (1.04) | 2.62 (1.22)
Ownership*+ | 3.92 (0.84) | 3.54 (0.78) | 3.40 (0.98) | 3.24 (1.03)
Multisensory | 3.87 (1.07) | 3.69 (0.99) | 3.77 (1.11) | 3.76 (1.19)
pESQ
Embodiment | 3.74 (0.61) | 3.52 (0.72) | 3.52 (0.72) | 3.40 (0.74)
Self-Location* | 3.86 (0.66) | 3.75 (0.88) | 3.48 (1.08) | 3.54 (1.06)
Agency | 4.28 (0.72) | 4.22 (0.58) | 4.28 (0.58) | 4.08 (0.88)
Body Ownership+ | 3.06 (1.07) | 2.59 (1.06) | 2.78 (1.16) | 2.56 (1.08)

###  3.1 SEQ

Our analysis of the SEQ data [33] did not reveal any significant interaction
effects between matched ethnicity and gender for overall embodiment or any of
its subscales. However, we did identify a significant main effect of matched
ethnicity on the overall “Embodiment” score ($F(1,31)=7.35$, $p<0.01$,
$\eta_{p}^{2}=0.07$). This finding indicates that participants reported higher
levels of “Embodiment" when their ethnicity matched that of their avatar,
regardless of matching gender. Conversely, we did not find any main effects of
gender matching on the overall “Embodiment" score.

Upon further examination of the three subscales within the SEQ, we found a
significant main effect of matched ethnicity for the “Appearance" subscale
($F(1,31)=4.10$, $p=0.04$, $\eta_{p}^{2}=0.04$), but not for matched gender.
Similarly, there was a significant main effect of matched ethnicity for the
“Response" subscale ($F(1,31)=8.50$, $p<0.001$, $\eta_{p}^{2}=0.08$), but not
for matched gender. Hence, participants reported higher levels of “Appearance"
and “Response" when embodying avatars of the same ethnicity, regardless of the
avatar’s gender. Interestingly, we also found significant main effects of both
matched ethnicity ($F(1,31)=17.87$, $p<0.001$, $\eta_{p}^{2}=0.16$) and
matched gender ($F(1,31)=8.31$, $p<0.001$, $\eta_{p}^{2}=0.08$) for the
“Ownership" subscale.

Figure 7: Mean measurements from the pESQ for all significant results,
presented alongside standard error bars. An asterisk (*) indicates
significantly different conditions. We show scores for Self-location and Body
Ownership. There were no significant effects for overall Embodiment or the
Agency subscale.

###  3.2 pESQ

Our analysis revealed no significant interaction effects between matched
ethnicity and gender for overall embodiment or any subscales of embodiment
when using the pESQ [12]. We did observe a significant main effect of matched
ethnicity on the “Self-Location" subscale, indicating that participants
reported feeling more self-located when their avatar matched their ethnicity
($F(1,31)=4.74$, $p=0.03$, $\eta_{p}^{2}=0.05$). However, we did not observe a
significant main effect of matched gender on the “Self-Location" subscale
($F(1,31)=0.03$, $p=0.86$).

Additionally, there was a significant main effect of matched gender on the
“Body Ownership" subscale, with participants reporting a higher degree of body
ownership when the avatar matched their gender ($F(1,31)=6.06$, $p=0.01$,
$\eta_{p}^{2}=0.06$). However, we did not observe a significant main effect of
matched ethnicity on the “Body Ownership" subscale ($F(1,31)=1.45$, $p=0.23$).

###  3.3 Exit Survey

Additionally, we conducted an exit survey to gather qualitative insights from
participants beyond the quantitative measures. Specifically, we inquired about
which avatars they felt the most and least embodied by and the reasons for
their choices. Table 4 presents the selections made by participants.
Participants were allowed to choose multiple avatars in their responses.
Notably, most participants felt most embodied in the Complete avatar, and
least embodied in the None avatar.

Table 4: Responses from the exit survey regarding which avatars participants felt most and least embodied by. | Complete | Ethnicity | Gender | None
---|---|---|---|---
Most embodied | 27 | 5 | 2 | 1
Least embodied | 1 | 5 | 6 | 25

##  4 Discussion

In this section, we first discuss implications for embodiment research based
on our results, and then implications for self-avatar design and development.
We conclude the section by discussing the limitations of our work and paths
for the future. We found that participants experienced heightened levels of
sense of embodiment when they used avatars matching their own ethnicity,
irrespective of gender matching. This effect extended across multiple
dimensions of embodiment, encompassing aspects pertaining to "appearance",
"response", and "ownership" [33]. Furthermore, we observed that gender had a
significant effect on feelings of "ownership", suggesting that this aspect of
embodiment was influenced by both matching ethnicity and gender.

###  4.1 Matched Avatar Ethnicity Affects Sense of Embodiment

Our findings suggest that matching a user’s ethnicity with their virtual
avatar enhances their overall sense of embodiment. These outcomes contrast
with previous research by Peck et al. [35], Kilteni et al. [22], and Radiah et
al. [37], where participants did not report significant differences in sense
of embodiment when their ethnicity was not matched with their avatar. Several
factors may contribute to these differences, including our use of validated
questionnaires and a more diverse user population. Whereas these earlier
studies exclusively focused on White participants, our research encompassed
participants of Asian, Black/African-American, Hispanic/Latino, and White
ethnicities, and featured corresponding avatars.

Furthermore, discrepancies in results might also be attributed to the level of
tracking involved. In these prior studies, participants were typically seated
during the embodiment task and did not engage in interactions involving their
feet or lower back. Eubanks et al. [11] have noted that including these body
parts in the embodiment experience significantly enhances the sense of
embodiment. Consequently, the influence of matched ethnicity on embodiment may
become more evident when a broader range of body parts is actively tracked in
the virtual experience.

Our findings highlight the significance of ethnicity in sense of embodiment.
In the exit survey, a Latino participant noted, “I felt that the [same-
ethnicity avatars] embodied me the most because they resemble physical
features of myself…even for the avatar of a different gender, their face
looked most closely to mine." Notably, three participants (2 Asian, 1
Hispanic/Latino) explicitly emphasized that skin tone was the most important
factor for their sense of embodiment. These responses echo the sentiments from
Freeman and Maloney’s interviews [14], highlighting the particular
significance of ethnic facial features and skin tone for non-white users in
VR.

###  4.2 Ethnicity and Gender Affect Ownership Differently

We found that gender significantly affected ownership, as indicated by the
SEQ, thus partially supporting H2. Interestingly, the pESQ unveiled further
nuanced findings. Eubanks et al. [12] note that the SEQ combines self-location
and body ownership into a single factor called “Ownership". However, these
factors can be separated to represent “Body Ownership" and “Self-Location",
respectively. While the SEQ showed that “Ownership" was affected by both
ethnicity and gender matching, further investigation by the pESQ shows that
“Body Ownership" specifically is affected by gender matching, while “Self-
Location" is affected by ethnicity matching.

Our study revealed that participants experienced a stronger sense of self-
location within the virtual environment when their avatar matched their
ethnicity, while they reported a greater feeling of body ownership when their
avatar matched their gender. These findings align with the insights gathered
from our exit surveys, where participants provided comments that reinforced
these observations. For instance, one participant remarked, "I felt like I
could picture myself there since [the same-ethnicity avatars] looked similar
to me," emphasizing the importance of ethnicity in creating a sense of feeling
located in the body within the virtual environment. Conversely, another
participant stated, "I felt my body was more true to the proportions that a
[same-gender avatar] would have," highlighting the role of gender matching in
enhancing feelings of body ownership.

###  4.3 Implications for VR Research

Our study holds important implications for the field of VR research.
Traditionally, research into the effects of matching or mismatching ethnicity
and gender has predominantly focused on white users (e.g., [35, 22, 42, 26])
or generic white avatars [4, 25, 8, 27, 51, 5]), which limits the
generalizability of findings and may introduce biases into results. For
example, requiring an Asian participant to use a White avatar may disrupt
their sense of embodiment, potentially leading to unintended consequences in
other aspects, such as depth perception [17] or overall cognitive performance
[21]. In previous research by Aseeri and Interrante [2] and Herrera and
Bailenson [19], participants were given the opportunity to choose the skin
tone of their self-avatar’s hands. We suggest that future studies adopt
comparable methodologies, and resources such as the VALID Avatar Library [9]
and Hafnia Hands [36] may help with diverse representations. Additionally,
there is a growing recognition that non-white users may place greater
importance on the representation of their ethnicity in virtual avatars,
considering it a vital aspect of their identity [14]. As VR continues to gain
global popularity, it is imperative for research to embrace more diverse user
populations and corresponding avatars to ensure a more comprehensive
understanding of virtual embodiment.

Our research shows that matching ethnicity is especially important for overall
embodiment. We strongly recommend that VR researchers provide users with the
option to customize the ethnicity of their self-avatars, as it can profoundly
influence sense of embodiment and various facets of embodiment. Additionally,
we also found that matching avatar gender can also play a role specifically in
body ownership. Research in which body ownership is important, such as
perspective-taking research, should also allow participants to choose a gender
that matches their identity. This customization can enhance the quality of the
VR experience and promote a stronger sense of embodiment. We found the Virtual
Avatar Library for Inclusion and Diversity (VALID) [9] very helpful for this
purpose.

###  4.4 Implications for VR Developers

Our findings carry important implications for VR application and game
developers. We recommend that developers provide players with the option to
customize their self-avatar’s ethnicity and gender, especially for games that
have generic avatars. Striking a balance between narrative cohesion and
personalization is crucial for maximizing feelings of embodiment and body
ownership. For instance, in games where a character’s race or gender is non-
essential to the storyline, players should be afforded the ability to
customize the main character’s characteristics to enhance their sense of
connection with the avatar.

Our results found that matching self-avatar ethnicity is especially important
for a sense of embodiment, and we thus urge developers to take this into
account when designing characters for their applications. While gender
matching may only affect body ownership, it may still be important for
applications where it is important for users to feel like they "own" their
avatar body, such as games with physical combat. This approach can contribute
to a more inclusive and engaging VR experience, catering to a wider and more
diverse audience.

###  4.5 Limitations and Future Work

While our study included a more diverse range of ethnicities than previous
research, it is important to note that our sample size was relatively small
($n=32$). As a result, we could not explore potential differences in
embodiment experiences among various ethnic groups, which might interact with
matched avatar ethnicity or gender. In our future research, we plan to recruit
a larger participant sample and conduct statistical analyses to explore
potential interactions between user ethnicity and matched avatar
characteristics. Our participants were also mostly comprised of students from
a single university and may not reflect the diversity of the larger more
international VR userbase. Additionally, we only recruited participants
identifying as male or female, and we provided only binary avatars for
selection. This limitation was partly due to the lack of nonbinary avatars
available. However, it is crucial to understand how nonbinary users perceive
embodiment in VR and which avatars they feel most connected to.

In our study, we employed generic avatars, which is a common practice in many
previous virtual embodiment studies, sourced from the VALID library [9]. We
opted for this library due to its extensive collection of validated avatars
that encompass diversity in terms of ethnicity. However, it is important to
note that these avatars were not personalized to each individual user, a
factor that has been shown to potentially enhance the levels of embodiment
[49]. To delve deeper into this aspect, future research should explore how
personalization, in conjunction with matched ethnicity and gender, may
interplay to influence the phenomenon of virtual embodiment.

The within-subjects design employed in our study may have been susceptible to
demand characteristics [31], where participants discern the study’s objectives
over time. We utilized Latin Square ordering to counterbalance the sequence of
avatars among participants, which may help mitigate some characteristics of
demand characteristics [39]. To further validate our findings and address this
concern, we conducted a supplementary between-subjects analysis focusing only
on participants’ initial avatar embodiment. This analysis yielded trends
consistent with our within-subjects findings for the SEQ (see Supplementary
Materials for additional analyses). However, to ensure the reliability of
between-subjects responses, a larger sample size would be necessary for future
investigations. Deeper exploration of between-subjects responses with a larger
participant pool could validate and refine these outcomes.

Furthermore, our decision to include both the SEQ and the pESQ aimed to ensure
a comprehensive evaluation of the sense of embodiment, encompassing
measurements for ’Self-Location’ in addition to the detailed assessments
provided by the SEQ. However, employing multiple questionnaires introduces the
potential for statistically significant differences to arise purely by chance.
We acknowledge that while our results showed significance across both
questionnaires, these outcomes might not solely be due to our experimental
factors. We suggest that future studies may benefit from employing a single
questionnaire to assess the sense of embodiment. This approach could mitigate
the likelihood of chance findings due to multiple assessment tools and offer a
more focused examination of the experimental variables.

###  4.6 Conclusion

Our study investigated matching user characteristics, specifically ethnicity
and gender, with their self-avatar in VR impacts sense of embodiment. Through
a study involving a diverse group of participants, we gained valuable insights
into the effects of matching or mismatching these factors on users’ sense of
embodiment. We found that matching the ethnicity of the user and their self-
avatar significantly enhances overall sense of embodiment, extending across
various aspects, including appearance, response, and ownership. On the other
hand, matching gender also significantly affected feelings of ownership,
suggesting that this aspect is influenced by both ethnicity and gender
congruence. Interestingly, we observed that matching ethnicity significantly
affects the self-location aspect of ownership, while matching gender
significantly impacts the sense of body ownership.

Our research has important implications for the field of VR embodiment.
Historically, VR studies investigating the effects of embodiment have
primarily involved limited populations or avatar representations, which may
have biased results. We strongly recommend that VR researchers allow users to
customize the ethnicity of their self-avatars, as this customization can
significantly influence sense of embodiment. Furthermore, we encourage
researchers to embrace more diverse user populations and corresponding avatars
to ensure the generalizability and inclusivity of their findings. In summary,
our study provides a step forward in understanding the dynamics between user
characteristics and their virtual self-avatar in VR environments. As VR
technology continues to advance and becomes more globally popular, it is
important that research in this field keeps pace by considering the diverse
identities of its users.

## Supplemental Materials

All supplemental materials are available on OSF at
https://doi.org/10.17605/OSF.IO/R7V9C, released under a CC BY 4.0 license. In
particular, they include (1) full paper with appendices, (2) full videos of
the applications that participants used, (3) additional plots of all data, and
(4) additional preliminary analysis of between-subjects data.

###### Acknowledgements.

The authors wish to thank Asma Ahmed for her feedback on early drafts. This
work was supported in part by the Doctoral Research Support Award from the
College of Graduate Studies at The University of Central Florida.

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