One of his primary research topics is mapping the regions of the brain to faculties such as emotion, language, memorization, and cognition.

His other primary topic involves applying this information to aid children to develop, aging people to retain, and patients to recover their learning facilities.

He reportedly refused royalty payments in the region of €15,000,000 (about US$21,000,000) from Nintendo, the games' publisher, on the grounds of a belief that one should only get such an amount of money when one has worked for it.

[3] In 2001, Ryuta Kawashima conducted a study at Tohoku University in Japan, claiming that frontal lobes are not stimulated during video game playing sessions.

However scientists widely dismissed his study after he claimed that the lack of stimulation could potentially stunt brain development and negatively affect people's ability to control their behaviour.

In February 2011, Dr. Kawashima released the video game Body and Brain Connection for Microsoft's Kinect peripheral on Xbox 360.

In 2014, Super Smash Bros. for Nintendo 3DS and Wii U was released and included a summonable "Assist Trophy" based on Dr. Kawashima's appearances in the Brain Age series, the only character appearing in the Super Smash Bros. series to be directly based on a real person's likeness.