Theories Personality Psychology Print 10 Fascinating Facts About Personality By Kendra Cherry Updated August 23, 2019 More in Theories Personality Psychology Myers-Briggs Type Indicator Behavioral Psychology Cognitive Psychology Developmental Psychology Social Psychology Biological Psychology Psychosocial Psychology Personality makes us who we are. It influences nearly every aspect of our lives including what we choose to do for a living, how we interact with our families, and our choices of friends and romantic partners. But what factors influence our personality? Can we change our personalities, or do our overall traits remain constant throughout life? Since personality is such a fascinating topic, it has become one of the most heavily researched subjects within psychology. Thanks to all this research, psychologists have learned a great deal about the things that influence personality as well as how personality influences our behaviors. Continue reading to discover more about what researchers have learned in these ten fascinating facts about personality. 1 Birth Order Can Influence Your Personality Cultura/JFCreatives / Cultura Exclusive / Getty Images You've probably heard of this concept before. Firstborn children are often described as "bossy" or "responsible," while last-born children are sometimes described as "irresponsible" and "impulsive." But how true are these common stereotypes? For decades, pop psychology books touted the effects of birth order on personality, but hard evidence on the phenomenon remained elusive until quite recently. A few empirical studies have found that such things as birth order and family size may indeed have an impact on personality. One study even found that birth order can influence your choices of friends and romantic partners; first-borns tend to associate with other first-borns, middle-borns with other middle-borns, and last-borns with last-borns. Another recent study published in the journal PNAS suggested that many of the stereotypes associated with birth order, such as first-borns being bossy or last-borns being irresponsible, don't necessarily hold water. The study looked at more than 5,000 American subjects, almost 4,500 British subjects, and more than 10,000 German participants. While the researchers did find that first-born children tended to score better on intelligence tests, they also looked at how birth order influence self-reported information on the five broad dimensions of personality: extroversion, neuroticism, agreeableness, conscientiousness, and openness. The study found little evidence supporting any connection between birth order and character. While this research does not mean that birth order has no impact on personality, it does suggest that further investigation is needed. 2 Your Personality Is Relatively Stable Throughout Life Lucia Lambriex / Taxi / Getty Images Do you think that personality can change over time or is your basic temperament set in stone? In long-term studies of personality, some of the most core parts of personality remain stable throughout life. Three aspects that do tend to change as we age are anxiety levels, friendliness, and eagerness for novel experiences. According to researcher Paul T. Costa Jr., there is no evidence our overall personalities change as we grow older. "What changes as you go through life are your roles and the issues that matter most to you. People may think their personality has changed as they age, but it is their habits that change, their vigor and health, their responsibilities and circumstances—not their basic personality," he suggested in a New York Times article. 3 Personality Traits Are Linked to Certain Illnesses JPM / Image Source / Getty Images In the past, a number of different personality traits have been suspected of contributing to particular illnesses. For example, hostility and aggression were often linked to heart disease. The difficulty was that while some studies would reveal a link, other studies demonstrated no such connection. Recently, researchers have used a statistical technique known as meta-analysis to reevaluate previous research on the connection between personality and disease. What they discovered were some previously unnoticed connections between neurotic personality traits and five illnesses; headaches, asthma, arthritis, peptic ulcers, and heart disease. Another study suggested that shyness might be linked to a shorter lifespan. 4 Animals Have Distinctive Personalities Cultura RM/Grace Chon / Cultura / Getty Images Does it ever seem like your beloved pet has a personality that makes him utterly unique? Animal researchers have found animals from nearly every species of animal (from spiders to birds to elephants) have their own personalities with preferences, behaviors, and quirks that persist throughout life. While some critics suggest that this represents anthropomorphism, or ascribing human traits to animals, animal personality researchers have been able to identify consistent behavioral patterns that can be empirically measured and tested. 5 Current Research Suggests That There Are Five Core Personality Traits JGI/Jamie Grill / Blend Images / Getty Images In the past, researchers have debated exactly how many personality traits exist. Early researchers such as Gordon Allport suggested that there were as many as 4,000 distinct personality traits, while others such as Raymond Cattell proposed that there were 16. Today, many personality researchers support the five-factor theory of personality, which describes five broad personality dimensions that compose human personality: ExtraversionAgreeablenessConscientiousnessNeuroticismOpenness 6 Personality Influences Personal Preferences Hill Street Studios / Blend Images / Getty Images It may come as no shock to learn that your personality can have a profound effect on your personal preferences, but you just might be surprised by how far reaching these effects may be. From your choice of friends to your taste in music, your unique personality can influence nearly every choice you make in your daily life. For example, while you might pride yourself on carefully considering the issues before choosing a candidate to support, research suggests that personality may play a strong role in political preferences. One study conducted by researchers at the University of Toronto found that individuals who identified themselves as conservatives were higher in a personality trait called orderliness, while those who self-identified as liberal were higher in empathy. Researchers suggest that these underlying personality needs to either preserve order or express empathy can have a strong influence on political preferences. 7 People Can Accurately Judge Your Personality Based on Your Facebook Profile Justin Lewis / Stone / Getty Images When you think about people's online identities, you might imagine that most people try to present an idealized version of their real selves. After all, in most online situations you get to pick and choose the information you want to reveal. You get to select the most attractive photos of yourself to post and you can edit and revise your comments before you make them. Surprisingly, one study discovered that Facebook profiles are actually quite good at conveying your real personality. In the study, researchers looked at the online profiles of 236 U.S. college-aged individuals. The participants also filled out questionnaires designed to measure personality traits including extroversion, agreeableness, conscientiousness, neuroticism, and openness. Observers then rated the personalities of the participants based on the online profiles, and these observations were compared to the results of the personality questionnaires. The researchers found that observers were able to get an accurate read on a person's personality based on their Facebook profile. "I think that being able to express personality accurately contributes to the popularity of online social networks in two ways," explained psychologist and lead author Sam Gosling. "First, it allows profile owners to let others know who they are and, in doing so, satisfies a basic need to be known by others. Second, it means that profile viewers feel they can trust the information they glean from online social network profiles, building their confidence in the system as a whole." 8 Numerous Factors Can Contribute to Personality Disorders Kevin Dodge / Blend Images / Getty Images An estimated 10 to 15% of adults in the United States experience symptoms of at least one personality disorder. Researchers have identified a number of factors that may contribute to the onset of different personality disorders such as obsessive-compulsive disorder and borderline personality disorder. These factors include: GeneticsRelationships with peersHigh sensitivityVerbal abuseChildhood trauma 9 Cardinal Traits Are Rare Hulton Archive / Getty Images Psychologist Gordon Allport described cardinal traits like those that dominated an individual's life to the point where that person is known and often identified specifically by that trait. These traits are considered rare, however. In many cases, people become so known for these traits that their very names become synonymous with that type of personality. Consider the origins of these often-used terms: Freudian, Machiavellian, narcissistic, Don Juan, and Christ-like. For most people, personality is instead composed of a mixture of central and secondary traits. Central traits are those that make up the core foundation of personality, while secondary traits are those related to preferences, attitudes, and situational behaviors. 10 Your Pet May Reveal Information About Your Personality Kathrin Ziegler / Cultura Exclusive / Getty Images Would you consider yourself more of a "dog person" or a "cat person"? According to one study, your answer to this question might actually reveal important information about your personality. In a study of 4,500 people, researchers asked participants whether they considered themselves to be more dog people or cat people. These individuals also completed a personality survey that measured a number of broad traits including conscientiousness, openness, neuroticism, and agreeableness. The researchers discovered that people who identified themselves as dog people tended to be more extroverted and eager to please others, while those who described themselves as cat people tended to be more introverted and curious. According to researcher Sam Gosling, a psychologist at the University of Texas-Austin, the results might have important implications in the field of pet therapy. By using personality screenings, therapists might be able to match people in need with animals that are best suited to their personality. Was this page helpful? Thanks for your feedback! Have you ever wondered what your personality type means? Or maybe you wanted to know whether you’re left-brained or right-brained? Sign up to get these answers, and more, delivered straight to your inbox. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Angier, N. Even Among Animals: Leaders, Followers and Schmoozers. The New York Times; 2010. Friedman HS, Booth-Kewley S. The "Disease-Prone Personality": A Meta-Analytic View of the Construct. American Psychologist. 1987;42:539–555. Goleman, D. 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