Although it is difficult to definitively label someone as a psychopath, there are certain behavioral patterns that can help you can identify one.

A psychopath is one who lacks empathy, and finds it difficult to understand why people have feelings. This can be spotted in several less obvious ways, including the type of drinks someone orders, reports CheatSheet.

The following scientifically explained behavioral attributes could be a warning sign that someone might be a psychopath if the person exhibits them, and interestingly, men are more likely to exhibit such behaviors.

Here are three things to watch out for if you suspect someone to be a psychopath:

1. They're immune to yawning stimuli

People who rate highly on psychopathic traits are less likely to be affected by the contagious yawning stimuli that most of us fall prey to when we see another person yawn. Photo taken from YouTube

According to a study that was published in the journal Individual and Personality Differences, it has been found that people who rate highly on psychopathic traits are less likely to be affected by the contagious yawning stimuli that most of us fall prey to when we see another person yawn.

The study was conducted with 135 undergraduates who were asked to complete a questionnaire meant to assess their levels of psychopathic traits. Later, they were shown three videos in a random order- one had a person with a neutral face, one was of a person laughing, and the third was of a person yawning. The faces of the participants were closely monitored for minute facial muscle activity while they were watching the videos.

The findings were very interesting. The participants with high score on the psychopathy-related trait of coldheartedness, often described as an emotional detachment combined with an overall disagreeable disposition, were less affected by the contagious stimuli of yawning back in response of watching someone yawn, in this case in the third video.

According to Psychology Today, people who exhibit psychopathic traits tend to be insincere, selfish, overconfident, and uncaring. Due to their lack of empathy, they often fail to connect by responding back when they see someone yawn, which seems to fall within the psychopathic personality trait.

2. They tend to take a lot of selfies

Posting a lot of selfies on social media can be an indication of a psychopathic personality trait. Photo taken from fyuoh.com

Research suggests that posting a lot of selfies on social media can be an indication of a psychopathic personality trait.

In another study published in Personality and Individual Differences, researchers at Ohio State University studied people's personality traits and how they present themselves on social media.

The researchers surveyed a nationally-representative sample of 800 men aged between 18 and 40 with the purpose of testing their selfie-taking habits in relation to their functional levels of narcissism, Machiavellianism, and psychopathy, the tree traits which are collectively known as the 'Dark Triad' and have become a new focus in the study of personality psychology.

The survey focused on personalities, asking them questions such as how attractive they considered themselves, how much they desired others to pay attention to them, how concerned they were with morality, and whether they had an affinity toward manipulating people. The participants were then asked about the frequency of their social media usage; for instance, how often they posted pictures and the degree to which they would edit their photos before posting them.

The findings revealed that those men who showed high levels of self-objectification (or who valued themselves solely based on appearance) and narcissism spent greater amounts of time on social media and networking sites. The researchers also found that men who were more narcissistic and psychopathic were more likely to post selfies more frequently and edit their posted photos the most.

It is noteworthy that these levels of narcissism are "subclinical" and do not imply that the person exhibiting these constitute someone as having a full-blown psychopathic disorder, rather it was the traits that qualify as such that were present.

3. They order black coffee

A person who prefers to have black coffee may have psychopathic tendencies. Photo taken from NDTV.com

A study published in the journal Appetite suggests that a person who prefers to have black coffee may have psychopathic tendencies.

The study, conducted by researchers at Innsbruck University in Austria over almost 1000 people, found that those who preferred bitter foods and beverages were more likely to exhibit characteristics of Machiavellianism, psychopathy, narcissism, and sadism.

Besides black coffee, the other bitter foods included in the study were radishes, celery and tonic water.

It should be noted that the answers were self-reported by the subjects. However, trying to identify someone having psychopathic traits based on whether the person orders black coffee can be confusing because someone who wants to cut out dairy and sugar from their diet, or just wants to have a strong cup of coffee, would have preferred the same!