New research suggests that simple increases in a man's height and age makes them appear more dominant.

The new study from Carlota Batres, Daniel Re, and Professor David Perrett of the Perception Lab at the University's School of Psychology & Neuroscience sheds light on why Hollywood directors might choose certain actors to play leading roles, The Daily Mail reported.

"Understanding what influences dominance perceptions is important since a dominant appearance in male faces is associated with a variety of social outcomes, ranging from high rank attainment of cadets in the military to high levels of sexual activity in teenage boys," Batres, who led the study, said in a statement. "Dominant people are also favored as leaders during times of intergroup conflict and are more successful leaders in the business world. Hence, understanding what it is that makes someone look dominant is important given its influence on a variety of social outcomes."

For the study, researchers used computer graphic manipulations to make subtle alterations to images of men's faces. Participants in the study were asked their opinions on the men, based on how tall, masculine and old they appeared to be.

When the researchers made 25-year-old men look 8 cm taller, up to a decade older, or made their faces more masculine, by for example increasing the prominence of their eyebrows, the onlookers thought the men looked more dominant.

"Such perceptions may also follow reality: taller men being more formidable opponents and strength increasing with age until a man gets to his mid-thirties," Perrett said in a statement.

The researchers say the study also provides some insight into casting choices made by film directors, since male leading roles are often played by actors who fit the dominance description in the study.

For example, Channing Tatum is often cast to play strong and dominant characters, from the interplanetary warrior Caine Wise in "Jupiter Ascending" to the experienced male dancer "Magic Mike."

The findings are detailed in the SAGE journal Perception.