Many LinkedIn users invest hours into making their profiles look professional. They scour the thesaurus looking for a verb to describe their work experience and they tediously list every professional accomplishment they've ever achieved.

Yet, many of those same people put little effort into their profile pictures. They use a candid shot from a smartphone or recycle a professional headshot from a previous position.

If that sounds familiar, you may have your priorities mixed up. Research says your profile picture could be the biggest factor in determining whether you'll land a new job.

First Impressions Stick

A 2016 study published in Social Psychological and Personality Science found that the first impression you make in your photograph will stick. Even after you meet someone face-to-face, it's hard to change someone's initial impression of you.

In the first phase of the study, participants looked at photographs of four women. Each woman was smiling in one picture and had a neutral expression in the other.

The participants were then asked to comment on the woman's personality. They judged how likely she was to be agreeable emotionally stable, extroverted, conscientious, and open to new experiences.

They were also asked whether they'd likely want to be friends with that woman.

Then, between one month and six months later, the participants met one of the women. They were not given any reminders about the scores they had given during phase one of the study.

Participants were told to play a trivia game with the woman for 10 minutes. Then, they were instructed to spend another 10 minutes getting to know one another as well as possible.

After each interaction, participants evaluated how likable the woman was and they offered assessments about her personality.

Remarkably, participants' evaluations of the woman remained consistent with their impressions from the photograph in phase one of the study.

Those who had said she looked like a nice person in the picture viewed her as a positive person during their face-to-face interactions.

Participants who had said she looked disagreeable, close-minded, and emotionally unstable in the photographs maintained those same judgments after meeting in-person.

Why First Impressions Remain Consistent

The authors of the study offer two reasons why the impressions we form from a picture remain unchanged after an in-person meeting:

  1. The halo effect - A positive first impression increases the chances that you'll attribute other positive characteristics to that individual. For example, if you think someone looks kind, you are more likely to assume that individual is also socially competent, has a healthy marriage, and is a good parent.
  2. Self-fulfilling prophecy - If you expect someone to be likable, you'll behave in a friendlier manner. That increases the chances you'll have a positive interaction. On the other hand, if you deem someone to be unlikable, you may be more standoffish, which increases the chances you'll have a negative interaction.

What This Means for Your LinkedIn Photo

Hiring managers and recruiters will develop a specific impression of you based on your LinkedIn profile picture. And that impression is likely to remain constant throughout the interview process.

You certainly can't control how everyone will perceive you. Perhaps you resemble a neighbor one hiring manager never liked. Or maybe a cynical recruiter will conclude your smile is phony.

But, you can take steps to ensure your picture portrays you in a positive manner most of the time. Your makeup, hairstyle, clothing, body language, and facial expression create a lasting first impression.

So it's important to think about what judgments people may make based on your profile picture. What are people likely to conclude about your personality and your competence by looking at you?

Of course, it's nearly impossible to subjectively evaluate your own picture. In fact, researchers say if you want to pick the best profile picture, you should ask a stranger to do it for you.

So while it might be awkward to ask strangers on social media for their input, it could be the key to making a great impression and landing the job of your dreams.