Facial expressions of avatars promote risky decision-making
The amygdala plays a key role in driving increased risk-taking
National Institute of Information and Communications Technology (NICT)
image:
Figure 1 Example scenario
How expressing opinions in an online meeting may feel different depending on whether a supervisor’s face is shown directly or represented as an avatar.
view moreCredit: National Institute of Information and Communications Technology (NICT)
Highlights
- Humans take more risks when interacting with facial expressions shown on avatars rather than real human faces.
- This shift in risk-taking behavior is linked to activity in the amygdala.
- The findings offer new insights into both the advantages and the cautionary aspects of communication via avatars.
Abstract
A research team led by Dr. TANAKA Toshiko and Dr. HARUNO Masahiko at the National Institute of Information and Communications Technology (NICT, President: TOKUDA Hideyuki Ph.D.), investigated how avatar-mediated communication affects human decision-making. They discovered that participants were more likely to take risks when facial expressions (such as admiration or contempt) were displayed by avatars than when the same expressions were shown on real human faces. This increase in risk-taking was found to result from a more favorable valuation of the "uncertainty" of facial feedback in the avatar condition. Furthermore, fMRI analysis revealed that this valuation of uncertainty depends on activity in the amygdala.
These results offer important insights into how avatar-based social communication, such as in virtual and augmented reality, can affect human decision-making, and highlight the amygdala's critical role in this process. The findings were published in the April 22, 2025 issue of the journal PLOS Biology, which features high-impact research in the life sciences.
Background
In recent years, avatar-mediated communication has rapidly spread in contexts such as online meetings and customer service. However, scientific studies on how avatars influence human cognition and decision-making are still in their early stages. In particular, little is known about how behavior changes when a communication partner's facial expressions are shown via avatars rather than real faces. For example, situations such as expressing opinions during online meetings or shopping in virtual stores increasingly involve avatars as communication partners. Understanding how avatars' facial expressions influence risk-related decisions in such settings is crucial.
Achievements
In this study, participants performed a risk decision-making task while undergoing fMRI scanning. In each trial, they were presented with two options and asked to choose their preferred one:
- A "safe" option: a guaranteed small reward (e.g., 80 yen with 100% probability)
- A "risky" option: a larger reward with lower probability (e.g., 300 yen with 33% probability)
Before the task, participants had a face-to-face meeting with a same-gender observer. During the task, when participants selected the risky option:
- Success was followed by the observer showing an admiring facial expression
- Failure was followed by a contemptuous expression
These expressions were shown either using the observer's real face (Human condition) or an avatar face (Avatar condition), switching every 6 to 13 trials (see Figure 2, left).
Results showed that participants made more risky choices in the Avatar condition than in the Human condition, particularly when the risky option had only a slightly higher expected value (see Figure 2, right).
The increase in risky decision-making was explained by a more favorable valuation of the uncertainty of which facial expression would be shown. This valuation was more positive in the Avatar condition.
fMRI analysis further revealed that this valuation of uncertainty was associated with activity in the amygdala (see Figure 3).
Future Prospects
This study demonstrates that avatar-mediated communication influences human risk-taking behavior and that this effect is linked to the amygdala. The researchers plan to further investigate how factors such as the avatar's gender or age, individual personality traits, and other types of decision-making tasks are influenced by avatars.
They also aim to explore how avatars can be effectively used to support decision-making in real-world settings such as education and interpersonal support, while also identifying potential risks associated with avatar use.
Article information
Authors: Toshiko Tanaka, Masahiko Haruno
Title: Feedback from an avatar facilitates risk-taking by modulating the amygdala response to feedback uncertainty
Journal: PLOS Biology
DOI: 10.1371/journal.pbio.3003122
URL: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003122
This research was supported in part by the following programs: JST Moonshot R&D Program “Realization of a society where people are free from limitations of body, brain, space, and time by 2050,” project: “Realizing a society where avatars coexist and empower all individuals”, JST CREST Program “Exploration and application of multi-sensing systems in biological environments,” project: “Decoding multi-world predictive coding in cyber society” (Principal Investigator: HARUNO Masahiko) and Grant-in-Aid for Transformative Research Areas (A) “Decoding and manipulating brain dynamics that induce early behavioral changes, opening up multi-layered biology.”
All experiments in this study were approved by the NICT ethics committee. Informed consent was obtained from all participants after explaining the procedures of the study.
Illustrations in the background section were adapted from images generated using Microsoft Copilot.
Figure 2. (Left) Risk decision-making task. (Right) Increase in risk-taking under the avatar condition.
Figure 2. (Left) Risk decision-making task. Participants chose between a "safe" and "risky" option. While making choices, they were observed via camera by an on-screen face—either a real human or an avatar. If they selected the risky option, the outcome (win or no win) was followed by the observer displaying a facial expression: admiration for wins, contempt for losses. The avatar and human face conditions alternated every 6 to 13 trials. When the safe option was selected, the participant received the reward and moved on to the next trial. Reward values and probabilities changed each trial, with one option always being 100%.(Right) Increase in risk-taking under the avatar condition. The red line shows the average risk-taking rate under the Avatar condition, and the blue line under the Human condition. The x-axis represents the expected value difference between the two options. When the risky option was only slightly better (moderate expected value differences), participants were more likely to choose it under the Avatar condition.
Figure 3 Amygdala activity reflecting valuation of feedback uncertainty. The amygdala encoded individual differences in how uncertain facial feedback was interpreted, explaining variations in risk-taking behavior across participants.
Credit
National Institute of Information and Communications Technology (NICT)
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
People
Article Title
Feedback from an avatar facilitates risk-taking by modulating the amygdala response to feedback uncertainty
Article Publication Date
22-Apr-2025
Listening to an avatar makes you more likely to gamble
The amygdala plays a key role in driving increased risk-taking
PLOS
image:
Participants performed a gambling task in the presence of a human observer, choosing between a safe (certain) option and a gamble (probabilistic) option. They were instructed to look at the observer’s face, which was presented either as an avatar or as a real human. Participants were informed that the avatar’s facial expressions and movements mirrored those of the real human observer. The authors found that participants made more gambling choices in the avatar condition than in the human condition.
view moreCredit: Toshiko Tanaka (CC-BY 4.0, https://creativecommons.org/licenses/by/4.0/)
Expecting feedback from an avatar compared to a real human facilitates risk-taking behavior in a gambling task, and a brain region called the amygdala is central to this facilitation, according to a study published April 22nd in the open-access journal PLOS Biology by Toshiko Tanaka and Masahiko Haruno from the National Institute of Information and Communications Technology, Japan.
In virtual-reality environments, individuals can adopt various forms of avatars, projecting their behaviors into a virtual realm where their interaction partners also appear as avatars. With this shift in communication style, it is essential to understand how the use of avatars influences our behavior and brain functions. While the behavioral effects of using avatars for oneself have been extensively investigated, fewer studies have focused on behavioral changes caused by the communication partner’s avatar. Given the gap between the current scientific understanding of avatars and growing commercial applications of avatar-based communication, there is a need for a systematic investigation of how an interaction partner’s avatar affects behavior and brain function, particularly in risk-taking scenarios.
To address this need, Tanaka and Haruno designed a task to examine how risk-taking behaviors and underlying neural computations change when a human communication partner's appearance alternates between an avatar and a real person. Specifically, the participants received dynamic facial-expression feedback from either a human observer presented as an avatar or a real human face based on the outcome (win or no-win) of each gambling trial. A total of 28 individuals participated in the behavioral experiments, and 51 individuals underwent functional magnetic resonance imaging (fMRI) scanning.
The results showed that expecting avatar feedback increased gambling behavior in both behavioral and fMRI settings. The computational model-based analysis revealed that the increased gambling rate in the avatar condition was driven by increased valuation of uncertainty regarding facial-expression feedback. Notably, a negative amygdala response to feedback uncertainty contributed to increased risk-taking behavior in both the avatar and human conditions.
In addition, individual differences in behavioral and neural sensitivity to feedback uncertainty were linked to a personality trait score that reflects emotional consideration for others. Taken together, these findings suggest that the amygdala’s response to feedback uncertainty plays a key role in driving increased risk-taking behavior in the avatar condition and that this function is closely linked to individual differences in interpersonal (emotional) reactivity. According to the authors, the results provide valuable insights into human communications and social interactions using avatars that are becoming increasingly more common in our world.
Coauthor Masahiko Haruno adds, “We found that people tend to take more risks when their partner responds through an avatar rather than showing their real face. This seems to be driven by a change in how they process uncertainty—and interestingly, that change is reflected in the amygdala.”
Coauthor Toshiko Tanaka adds, “Using the same confederate and having them pass as just another participant every time wasn’t easy—it took a lot of effort to keep things feeling real for each new person.”
In your coverage, please use this URL to provide access to the freely available paper in PLOS Biology: https://plos.io/43MGr63
Citation: Tanaka T, Haruno M (2025) Feedback from an avatar facilitates risk-taking by modulating the amygdala response to feedback uncertainty. PLoS Biol 23(4): e3003122. https://doi.org/10.1371/journal.pbio.3003122
Author countries: Japan
Funding: This work was supported by JST Moonshot R&D (JPMJMS2011, https://projectdb.jst.go.jp/grant/JST-PROJECT-20339237/), JST CREST (JPMJCR22P4, https://projectdb.jst.go.jp/grant/JST-PROJECT-22712882/), and KAKENNHI (22H05155, https://kaken.nii.ac.jp/ja/grant/KAKENHI-PLANNED-22H05155/) to MH. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
Journal
PLOS Biology
Method of Research
Experimental study
Subject of Research
People
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