How do our hormones contribute to our personality?

Investigating saliva hormones and finger sizes in relation to personality traits

How do our hormones contribute to our personality?

Researchers from the University of Wollongong (UOW) Schools of Medicine and Education, the Illawarra Health and Medical Research Institute (IHMRI), and Northumbria University are conducting a landmark study looking at the link between hormones and personality.

PhD candidate Alex South is recruiting for a study that measures hormones such as testosterone, oxytocin, dopamine and cortisol against individuals’ personality traits.

“We know that early life experiences can shape personality, but personality traits are also partly inherited and we don’t fully understand the underlying biology. Personality traits also differ between males and females, so we are wondering if there is a hormone basis to that,” Ms South said.

Ms South is currently recruiting 60 healthy male participants over 18 to take part in the study. Female participants have already been recruited.

Participants will be asked to provide a saliva sample and complete some personality questionnaires covering a full range of personality traits, from agreeableness and conscientiousness, to social dominance and impulsivity.

“Previous research has linked some personality traits to hormone concentrations, particularly testosterone and cortisol which are closely related to social dominance, status-seeking behaviour and stress responses,” Ms South said.

“However, previous studies were limited and we are examining a wider range of traits and greater number of hormones.”

Participants will also undergo a finger ratio examination, which measures the difference in size between the second and fourth finger.

“The difference in length between the second and fourth fingers provides a window into the prenatal environment during the person’s early development, revealing the amount of hormones, mostly testosterone, they were exposed to in the womb,” Ms South said.

“The more testosterone, the more the ring finger grows.

“Previous research has found that longer ring fingers are related to many physical and psychological characteristics, however, we have much to learn about their potential relationship to personality characteristics.”

Trial participants must be available to come into the IHMRI lab, which will be subject to COVID-safe measures.

To express your interest in this study, contact Ms South at ajs546@uowmail.edu.au.

Ms South’s PhD research is supervised by Dr Susan Thomas and Dr Emma Walter of UOW and Dr Emma Barkus of Northumbria University.

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