Cognitive Evaluation Theory and Organismic Integration Theory are particularly relevant to Rintaro Okabe’s motivation. For Cognitive Evaluation Theory, this theory focuses on intrinsic motivation and the role of three psychological needs: competence, autonomy, and relatedness. Cognitive Evaluation Theory posits that individuals feel motivated to engage in activities that enhance their sense of mastery (competence), allow them the freedom to make choices (autonomy), and foster a sense of connection with others (relatedness). For Organismic Integration Theory, on the other hand, deals with different forms of motivation, which includes external regulation (where behavior is controlled by external rewards or demands) and integrated regulation (where behavior is fully aligned with one’s sense of self and personal values). Organismic Integration Theory describes how individuals move from being externally motivated to more self-determined forms of motivation as they internalize and integrate behaviors into their sense of identity.

Rintaro’s motivation is aligned with cognitive evaluation theory. For Competence, in the story of Steins;Gate, Rintaro’s perceived competence is linked to his success in discovering the secrets of time travel and his ability to affect change in the timelines. His alter characteristic, Hououin Kyouma, is an expression of his need to feel competent and capable in the face of incredible challenges. The "mad scientist" persona acts as a shield and also as a motivating force that helps him maintain confidence, especially during moments of doubt or failure. As he succeeds in understanding how D-Mail (messages sent to the past) works, Rintaro’s sense of competence grows, which further motivates him to continue his experiments. For Autonomy, Rintaro’s actions are motivated by his desire to retain autonomy. When faced with the dangers presented by SERN (an “evil” mysterious organization which holds a prototype of time machine) and the possibility of a dystopian future, he decides to act independently to change the course of events. He takes on the challenge of changing timelines repeatedly, because he believes in his power to alter outcomes. This sense of control and autonomy and being the only one who can make a difference drives his persistence even when things seem bleak. The need for relatedness is an important motivative factor for Rintaro. His relationships with Mayuri, Kurisu, and other lab members form the emotional core of his journey. His motivation to continue his time-travel experiments becomes particularly intense when the lives of those he loves are at stake. Mayuri’s repeated deaths across timelines deeply affect Rintaro, motivating himself to find a world line where she survives. His intrinsic motivation is supported by his sense of connection to the people around him, as he wants to protect them from harm.

The combination of these three needs supports Rintaro's motivation throughout the series. His perception of being competent in using time travel, having autonomy over his decisions, and being connected to his friends allows him to persist in the face of almost impassable obstacles. This persistence ultimately leads to his success in finding the Steins Gate world line where both Mayuri and Kurisu are saved.

Rintaro Okabe’s motivation also aligns with Organismic Integration Theory. In the beginning of the story, Rintaro’s motivations are partly driven by external rewards, such as reputation and recognition, and his desire to outwit SERN. He sees himself as a "mad scientist" who wants to expose conspiracies and prove his genius. However, as the story progresses, his motivation shifts to become more personal and meaningful. He internalizes the value of his actions because they align with his held belief that it is his responsibility to protect his loved ones. By the end of the series, he no longer acts simply for external rewards or a sense of obligation, instead, his actions are driven by an internalized commitment to protect both Mayuri and Kurisu. The "mad scientist" persona becomes less of a performance and more a genuine part of who he is, as he embraces his role as the one capable of changing destiny. His shift in motivational reasons impacted his ultimate success. The early motivation does not provide the resilience needed when he encounters setbacks. It is only when his motivation evolves, when his actions become an integrated part of his identity and align with his core values of love, friendship, and responsibility, that Rintaro finds the strength to overcome the repeated trauma of witnessing Mayuri's death and the daunting task of saving Kurisu.

Rintaro Okabe’s motivation throughout "Steins;Gate" are aligned with both Cognitive Evaluation Theory and Organismic Integration Theory. His intrinsic motivation is supported by his need for competence, autonomy, and relatedness, while his progression from externally regulated behavior to fully integrated regulation marks his journey towards a more self-determined and resilient form of motivation. Ultimately, it is this internalization of his purpose, moving beyond the superficial motivations of fame and ego towards a deeper connection to his friends and their well-being, that allows Rintaro to succeed in reaching the Steins Gate world line and saving the people he loves.