In a unique study, researchers have now shown that the essence of on individual remains largely stable over the years. "In our study, we tried to answer the question of whether we are the same person throughout our lives," said study author Miguel Rubianes from the Complutense University of Madrid (UCM) in Spain.

"In conjunction with the previous literature, our results indicate that there is a component that remains stable while another part is more susceptible to change over time," Rubianes added. The 'continuity of the self' -- the capacity for self-awareness and self-recognition-- remains stable whereas other components such as physical aspects, physiological processes and even attitudes, beliefs and values are more liable to change.

Even components such as personality traits tend to change slightly over the years, but "the sense of being oneself is preserved, improving our understanding of human nature," Rubianes said. The study, published in Psychophysiology, also determined how long it takes the brain to recognise our own personal identity as distinctive compared to others: around 250 milliseconds.

To carry out this study, the brain activity and event-related brain potentials of twenty participants were recorded by electroencephalography (EEG) when presented with stimuli and performing identity and age recognition tasks. The research has revealed that the essence of our being remains largely stable over the years. "This study demonstrates the importance of basic and clinical research alike in the study of the role of personal identity, and may play a fundamental role in psychological assessment and intervention processes," Rubianes noted.