Frontier Research Institute for Interdisciplinary Sciences
Tohoku University

As an only child and an indoor type, I often drew pictures. When drawing, I felt that the faces of others I saw might not look the same to everyone else, leading me to think, “What we see might be different for each person.” Since around that time, I vaguely became interested in the individual differences in ways of thinking, perception, and expression.

I study how a person’s so-called “character” is formed. Among the mental functions inherent to humans, characteristics that remain relatively stable regardless of time and situation are called psychological traits (such as conscientiousness, empathy, concepts often referred to as “personality” or “noncognitive skills”). These psychological traits are thought to be formed as genes, and the developmental environment influences brain development, but the complex mechanisms involved are not yet fully understood.

Researchers have examined the relationship between an individual’s genetic sequence or developmental environment and their brain and psychological traits. However, genes are inherited from parents, and caregivers are deeply involved in shaping the developmental environment. The life experiences of caregivers are likely reflected in the construction of a child’s developmental environment. To fully understand the basis of psychological trait formation, it is essential to closely examine the impact of parental genes, life experiences, and psychological traits on their children.

Therefore, I focus on biologically related parents-child trios, consisting of father, mother, and child, collecting and analyzing data regarding genes, MRI brain images, developmental environment information, and psychological traits (project name: Transmit Radiant Individuality to Offspring [TRIO] study). How do parents’ childhood experiences relate to their children’s brains and psychological traits? What are the neuroscientific bases for similarities in personality and the propensity to develop the same mental disorders between parents and children? It is known that parents and children have similar brain functions and structures, but what significance does this hold in human development? By exploring these questions, I aim to elucidate the mechanisms behind the formation of psychological traits (individuality) that make a person “who they are.”

In graduate school, I analyzed brain images of elementary and junior high school students to understand how a mother’s praise and warm attitude affect the child’s brain development. I believed that understanding how parent-child relationships impact a child’s brain would help us understand the mechanisms that shape human personality. However, parents were once children themselves, and their childhood experiences likely play a role in shaping parent-child relationships.

I came to think that to fully understand these dynamics, we need to investigate what parents experienced, how they developed before becoming parents, and how these experiences impact the development of their children—the next generation. Moreover, research on parent-child relationships and child development often focuses on mothers and children, with less emphasis on fathers, which I saw as a problem. These realizations led me to initiate my current research, focusing on father-mother-child trios.

As an undergraduate, I majored in linguistics in the Faculty of Letters and belonged to a lab that investigated linguistic phenomena through psychological experiments. I studied how people generate language, specifically how they formulate sentences according to Japanese grammar when they want to say something.

Initially, I did not intend to become a researcher, so I job hunted during my third year. I naively believed I could follow in the footsteps of my seniors, who received job offers from well-known companies. However, reality hit hard when I failed miserably in the first round of interviews. This experience made me realize that perhaps I did not want to work in a corporate environment. That was the first time I considered graduate school as an option. Although I could have continued with linguistics in the Graduate School of Letters, I wanted to change my environment and grow further. Additionally, I felt that my interest lay not in specific functions, such as language and emotion, but in the brain, the organ that governs all these functions. Therefore, I decided to advance to a medical graduate school that had labs where I could study the brain using MRI imaging.

In research aimed at understanding human development, studies focusing solely on children or mother-child pairs have been conducted worldwide. However, studies involving trios including fathers are rare, and projects that obtain MRI images of the brain are almost nonexistent. Therefore, the exciting aspect of my research is the ability to address questions that cannot be addressed with data from only children or mother-child pairs, such as whether the findings observed in mother-child pairs are also seen in father-child pairs, whether there are completely different results between father-child and mother-child pairs, and whether there are synergistic effects of both parents’ life experiences on the child’s development. This unique approach distinguishes my research and allows us to explore these questions.

I believe the insights gained from my research could help maintain and promote mental health by providing new perspectives for counseling and psychotherapy. My findings can offer explanations for identity-related concerns often experienced during adolescence, such as “Why am I the way I am?” By biologically explaining that certain experiences of previous generations have led to one’s current self through specific processes, it may help individuals distinguish between factors they can and cannot change. This understanding could help people shift their focus to aspects they can change.

However, although it might be said that parental life experiences affect a child’s development, children cannot change their parents’ life experiences. Depending on how this information is conveyed, it could lead to negative messages, such as feeling unlucky with their parents. It is crucial to find ways to communicate these findings in a way that does not negate anyone and promotes a positive societal impact.

My research relies heavily on the cooperation of parents-child trios as samples. However, when I first recruited participants in 2021, I was only able to gather eight trios. With about 2 million yen in research funding from the lab, I initially planned to recruit around 30 trios, but even after rallying my relatives and acquaintances, I ended up with only eight. Such a low turnout made me worry about the feasibility of continuing my research, and I felt quite disheartened.

At that point, I realized how little benefit the general public sees in participating in research. It’s inconvenient, uncertain, and something they don’t need to do. To increase participation, I had to create a system that made it easy for anyone to join. This involved selecting only essential tests to shorten the time required, providing as much information as possible about the tests beforehand, widely advertising the call for participants, and being thoughtful about the incentives offered. Thanks to these efforts, now, whenever we advertise, dozens of families sign up, allowing us to continue our research.

I didn’t have a firm determination to pursue a Ph.D. and become a researcher. However, during my master’s program, a professor who mentored me once told me, while quite inebriated, “You have talent.” That moment made me think, “Really? Maybe I should become a researcher then.” And that was the turning point.

I enjoy the tension in academia, where you must stay sharp to survive. Research requires not just focusing on immediate tasks but also taking a broad view to understand your role and continuously seeking new things that only you can do. Although I don’t think I’ve mastered this balance, I find it fascinating and engaging.

Yes, that’s right. Many researchers have a strong conviction to “absolutely uncover this in their lifetime,” and I envy them. I feel I haven’t yet found such a conviction for myself. However, I believe that to understand human nature, we must study the human brain. Therefore, I want to cherish my current research theme and produce high-quality results.

I was attracted by the fact that FRIS has produced many young researchers who are making remarkable strides in their fields. I applied for an assistant professor position at FRIS because of this appeal. Now that I am a part of FRIS, I still feel that it is an organization that respects young independent researchers and seriously considers how to create systems that make research easier to pursue.

I often have discussions with Dr. Yuka Fujiki (complex systems and network science: assistant professor), who joined FRIS at the same time as I did. Because my research generates a large amount of data, I have long believed that integrating it with fields such as information science and mathematical sciences is necessary. To fully utilize the information contained in the data, more complex mathematical models are required. Therefore, I am considering conducting collaborative research using the statistical causal discovery methods that Dr. Fujiki is working on. Additionally, there are many other researchers at FRIS who are outstanding even from the perspective of different fields, which is very stimulating for me.

First and foremost, I want to carefully nurture the current parents-child trio research project, “Family Neuroscience.” I aim to be a researcher who continuously delivers fundamental tasks, such as consistently publishing papers, securing research funding, and ensuring that if I receive a research fund of 10 million yen, I produce data that is worth that amount. My current research may not immediately save lives or directly contribute to disease treatment. Therefore, I intend to conduct my research as sincerely as possible, focusing on accumulating knowledge that is as high-quality as possible.

(Interview conducted in May 2024)