The researchers hypothesize that the facial hair "may signal men's age and masculine social dominance."
RELATED: The best celebrity beards
Our favorite celebrity beards
Our favorite celebrity beards
WAILEA, HI - JUNE 04: (EDITORS NOTE: Image was shot in black and white. Color version not available.) Actor Scott Eastwood, recipient of The Maui Film Festival Rising Star Award poses for a portrait at the Taste of Summer Opening Night Party during the 2015 Maui Film Festival at Grand Wailea on June 3, 2015 in Wailea, Hawaii. (Photo by Jonathan Leibson/Getty Images for Maui Film Festival)
BEVERLY HILLS, CA - JANUARY 08: Actor Chris Pine attends the 74th Annual Golden Globe Awards at The Beverly Hilton Hotel on January 8, 2017 in Beverly Hills, California. (Photo by Frazer Harrison/Getty Images)
BEVERLY HILLS, CA - JANUARY 14: Actor John Krasinski announces the nominees during the 88th Oscars Nominations announcement at the Academy of Motion Picture Arts and Sciences on January 14, 2016 in Los Angeles, California.(Photo by Jeffrey Mayer/WireImage)
Canadian actor Ryan Reynolds poses for photographers during a photocall for the film 'Woman in Gold' presented as Berlinale Special at the 65th Berlin International Film Festival Berlinale in Berlin, on February 9, 2015. AFP PHOTO / ODD ANDERSEN (Photo credit should read ODD ANDERSEN/AFP/Getty Images)
TORONTO, CANADA - NOVEMBER 25: Drake performs before the game between the Toronto Raptors and the Cleveland Cavaliers on November 25, 2015 at the Air Canada Centre in Toronto, Ontario, Canada. NOTE TO USER: User expressly acknowledges and agrees that, by downloading and or using this Photograph, user is consenting to the terms and conditions of the Getty Images License Agreement. Mandatory Copyright Notice: Copyright 2015 NBAE (Photo by Ron Turenne/NBAE via Getty Images)
BEVERLY HILLS, CA - SEPTEMBER 24: Joe Manganiello attends the go90 Sneak Peek held at the Wallis Annenberg Center for the Performing Art on September 24, 2015 in Beverly Hills, California.(Photo by JB Lacroix/WireImage)
LOS ANGELES, CA - AUGUST 10: Actor Ben Affleck attends the Project Greenlight Season 4 Winning Film premiere 'The Leisure Class' presented by Matt Damon, Ben Affleck, Adaptive Studios and HBO at The Theatre at Ace Hotel on August 10, 2015 in Los Angeles, California. (Photo by Angela Weiss/Getty Images)
BEVERLY HILLS, CA - JANUARY 16: Actor Aziz Ansari arrives at the 2011 InStyle/Warner Brothers Golden Globes Party at The Beverly Hilton hotel on January 16, 2011 in Beverly Hills, California. (Photo by Jon Kopaloff/FilmMagic)
NEW YORK, NY - SEPTEMBER 13: Actor Hugh Jackman attends the Men's Singles Final match between Roger Federer of Switzerland and Novak Djokovic of Serbia on Day Fourteen of the 2015 US Open at the USTA Billie Jean King National Tennis Center on September 13, 2015 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)
LONDON, ENGLAND - SEPTEMBER 03: Tom Hardy attends the UK Premiere of 'Legend' at Odeon Leicester Square on September 3, 2015 in London, England. (Photo by Dave J Hogan/Getty Images)
HOLLYWOOD, CA - NOVEMBER 14: Actor Idris Elba attends the 7th annual Governors Awards at The Ray Dolby Ballroom at Hollywood & Highland Center on November 14, 2015 in Hollywood, California. (Photo by Jason LaVeris/FilmMagic)
BEVERLY HILLS, CA - JANUARY 10: 73rd ANNUAL GOLDEN GLOBE AWARDS -- Pictured: Actor Steve Carell arrives to the 73rd Annual Golden Globe Awards held at the Beverly Hilton Hotel on January 10, 2016. (Photo by Kevork Djansezian/NBC/NBCU Photo Bank via Getty Images)
SINGAPORE - DECEMBER 06: English former professional footballer, David Beckham watches the Men's Team Football 5-a-Side match between Singapore and Thailand during the 8th ASEAN Para Games 2015 at the Marina Bay Sands Hall on December 6, 2015 in Singapore. (Photo by Suhaimi Abdullah/Getty Images)
DUBAI, UNITED ARAB EMIRATES - DECEMBER 16: (EDITORS NOTE: This image has been digitally altered) Actor Jake Gyllenhaal poses during a portrait session on day eight of the 12th annual Dubai International Film Festival held at the Madinat Jumeriah Complex on December 16, 2015 in Dubai, United Arab Emirates. (Photo by Gareth Cattermole/Getty Images for DIFF)
Discover More Like This
BACK TO SLIDE
As such, it could indicate "formidability among males and the potential to provide direct benefits, such as enhanced fertility and survival, to females."
For the experiment, 8,520 women were asked to rate a variety of images of male faces for physical attractiveness through the perspective of a "short-term liaison or a long-term relationship."
As a news release about the research states, "Stubble was judged as most attractive overall and received higher ratings for short-term relationships than full beards, which were more attractive for long-term relationships. Extremely masculine and extremely feminine-looking males were least attractive, irrespective of relationship context."