Ioku Tomohiro
Kobe Women’s University, Department of Psychology
The University of Osaka, Graduate School of Engineering Science
Email : t_ioku[at]outlook.com
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Research
I am interested in how people make judgments and interact with other people, artificial intelligence, and social institutions across a range of social domains, including consumer behavior, law, healthcare, and media. Human decision-making is shaped not only by individual values and emotions but also by interpersonal relationships, the ways in which information is communicated, interactions with AI, and social norms and institutions. From this perspective, I am working on the following research projects.
Consumer choices are shaped not only by price and performance but also by trust in companies and products, ethical values, and relationships with others. Our project examines what consumers prioritize in their decision-making and how their choices affect their relationships with others.
In particular, I have examined how the performance, transparency, and environmental impact of AI assistants shape consumer preferences (Ioku, Song, & Watamura, 2024), as well as how using AI to select gifts affects both gift givers and recipients (Ioku & Watamura, 2026). I have also studied the altruistic motives underlying consumers’ negative word-of-mouth on social media, including a desire to prevent other consumers from experiencing similar harm (Ioku et al., 2027, in press). More recently, using large-scale social media data and survey experiments, I have been investigating how people’s linguistic expressions and forms of communication converge through online interaction.
How do people determine the appropriate severity of punishment for a crime, and how do they justify that decision? This project examines how people perceive crimes and offenders and how those perceptions shape judgments about punishment and the justice system.
For example, my colleagues and I have studied how the purposes of punishment—such as retribution, incapacitation, deterrence, and rehabilitation—shape sentencing decisions, as well as differences between the judgments of professional judges and laypeople (Watamura, Ioku, & Wakebe, 2022; Watamura, Wakebe, & Ioku, 2022; Watamura & Ioku, 2022). We have also examined attitudes toward the death penalty, the acceptability of wrongful convictions, and cross-cultural differences in punitiveness (Watamura, Ioku, & Mukai, 2023; Watamura & Ioku, 2023; Mukai et al., 2025). In addition, my research addresses how members of the public recognize and decide whether to report signs of child maltreatment (Ioku et al., 2025a; Ioku et al., 2025b) and how defendants’ gender and gender-role attitudes influence sentencing judgments in child maltreatment cases (Mukai et al., 2024a; Mukai et al., 2024b).
In healthcare, an important challenge is how to incorporate individuals’ values into decisions about future treatment and end-of-life care. The central question of this project is how people think about medical treatment and care at the end of life and how their decisions are shaped by psychological and social factors.
In this project, we have studied people’s readiness for advance care planning (ACP) and the factors that facilitate or inhibit discussions about future medical treatment and care (Watamura et al., 2026). Our studies have also examined the reassurance and anxiety associated with the legalization of euthanasia (Watamura, Ioku, & Yamamoto, 2025), as well as how perceived burdensomeness and attitudes toward death affect people’s willingness to choose euthanasia (Ioku & Watamura, 2025). Additionally, we have investigated, from an international perspective, the foundations of attitudes toward euthanasia that cannot be explained by cultural values alone (Watamura, Hunt, & Ioku, 2025).
People’s attitudes and behavior are shaped by their relationships with others and by how information is communicated and received. My colleagues and I examine how people perceive other individuals and society and how those perceptions influence interpersonal relations, social judgments, and communication.
Particularly, I have investigated how the feeling that one’s group is understood by others influences attitudes, emotions, and behavior toward them (Ioku & Watamura, 2022a; Ioku & Watamura, 2022b; Ioku & Watamura, 2024a). Together with my colleagues, I have also examined public support for reporting the real names of juvenile offenders and how such disclosure affects discrimination and social evaluations of those offenders (Watamura & Ioku, 2023a; Watamura & Ioku, 2023b). Another strand of this research examines individual differences in sensitivity to social and environmental stimuli. Specifically, I have investigated how sensory processing sensitivity, often discussed in relation to Highly Sensitive Persons (HSPs), is associated with occupational stress and empathy among employees (Ioku & Watamura, 2024b).
Artificial intelligence is becoming more than a technology for processing information: it is increasingly an entity to which people delegate decisions, place trust, and sometimes relate as a social partner. This project examines how people perceive AI’s capabilities and judgments and how those perceptions shape trust in and acceptance of AI, as well as human decision-making.
For instance, we have studied the role of perceived empathy in trust in and acceptance of AI judges (Watamura et al., 2023) and how judgments made by human judges and AI influence citizens’ sentencing decisions (Watamura, Liu, & Ioku, 2025). I have also examined how AI performance, transparency, and environmental impact shape consumer preferences (Ioku, Song, & Watamura, 2024) and how delegating choices to AI affects interpersonal relationships (Ioku & Watamura, 2026). In addition, I have extended this work to the acceptance and use of generative AI in higher education, including how universities frame AI in their policy guidelines (Ioku, Kondo, & Watanabe, 2024a) and how people understand the capabilities and limitations of AI (Ioku, Kondo, & Watanabe, 2024b).