Lesson 9: Personality and Individual Differences
Transcript
Welcome back to The Introduction to Psychology Series. I’m RJ Starr.
At this point in the series, we’ve explored the foundations—how we learn, how we remember, how we feel, and how we change over time. But there’s one question that sits underneath a lot of those ideas, and it’s the focus of today’s lesson: What makes people different from each other?
Why does one person love being the center of attention while another avoids eye contact? Why do some people thrive in chaos and others shut down? Why do you feel like yourself in one setting and like a stranger in another?
Today we’re talking about personality and individual differences. How psychologists define personality, what factors influence it, and whether or not it’s really as stable as we think.
Let’s start with the big picture. What is personality?
In psychology, personality refers to the consistent patterns of thoughts, feelings, and behaviors that make a person distinct. It’s what tends to be stable across time and situations. Not just how you act—but how you respond, what you notice, what you value, and how you interpret the world.
Personality isn’t just behavior. It’s the lens you use to filter experience.
There are a lot of ways to describe personality. Some systems are formal, like the Five-Factor Model. Others are more pop-cultural, like the Myers-Briggs Type Indicator or astrology. Some are rooted in empirical research. Some are more introspective. We’ll focus here on the science-backed frameworks that help us make sense of individual differences—without reducing people to fixed categories.
The most widely accepted model in modern psychology is called the Big Five, or the Five-Factor Model. It describes personality in terms of five broad traits. These aren’t types—they’re dimensions. You’re not in one box or another. You fall somewhere on a continuum for each trait.
Let’s go through them.
The first is openness to experience. This trait describes how curious, imaginative, and open-minded you are. People high in openness tend to enjoy novelty, art, ideas, new experiences. They’re often creative and reflective. People low in openness tend to prefer routine, familiarity, and practical thinking. Neither is better. They’re just different ways of relating to the world.
The second is conscientiousness. This is about organization, self-discipline, and dependability. High-conscientiousness individuals are planners. They meet deadlines. They set goals and follow through. Low-conscientiousness individuals may be more spontaneous, flexible, or disorganized. Again, this isn’t good or bad—it depends on the context.
The third is extraversion. This one gets the most attention, but it’s often misunderstood. Extraversion isn’t just about being outgoing. It’s about where you get your energy. High-extraversion people tend to feel energized by social interaction, stimulation, activity. They enjoy being around others and often speak or act quickly. Low-extraversion—often called introversion—doesn’t mean shy. It means a preference for calm, quiet environments. Introverts tend to feel drained by too much stimulation and often recharge alone. Both styles have value. The culture just tends to favor one over the other.
The fourth trait is agreeableness. This measures how cooperative, compassionate, and warm a person is. High-agreeableness individuals tend to prioritize harmony, empathy, and kindness. Low-agreeableness individuals may be more skeptical, competitive, or blunt. In some settings, high agreeableness is a strength. In others, especially when negotiation or tough feedback is required, low agreeableness may be more adaptive.
And finally, the fifth trait is neuroticism. This refers to emotional stability—or instability. People high in neuroticism are more prone to anxiety, mood swings, and emotional reactivity. People low in neuroticism tend to be more calm, resilient, and even-tempered. This doesn’t mean high neuroticism is a flaw. It may simply mean someone is more sensitive to emotional cues or internal discomfort.
These five traits—openness, conscientiousness, extraversion, agreeableness, and neuroticism—have been studied across cultures and age groups. They tend to hold up well over time, although that doesn’t mean they’re set in stone. Personality can shift, especially in response to major life events, therapy, personal growth, or intentional change.
That’s important to say. Because sometimes personality is treated like a sentence. People say, “That’s just how I am,” and use it as a way to avoid growth. But the truth is, while personality traits may be relatively stable, they are not fixed. You can become more conscientious with effort. You can build emotional regulation. You can learn to take up space—or learn to listen more carefully—depending on what’s needed.
Psychologists have studied this. Personality change can and does happen—especially when people are motivated and supported. But it’s gradual. It’s not a makeover. It’s more like sculpting. Shifting the weight of traits slowly over time.
Now let’s talk about what influences personality in the first place.
The age-old question is nature versus nurture. How much of who we are is inherited? And how much is shaped by experience?
Twin studies have provided a lot of insight here. Identical twins, who share 100% of their DNA, tend to have more similar personalities than fraternal twins, who share about 50%. Even when raised apart, identical twins often show surprising similarities—in temperament, interests, even quirks. That suggests a strong genetic component.
But genetics isn’t destiny. Environment matters deeply. The family you grow up in. The culture you live in. The opportunities you have—or don’t have. The trauma you’ve experienced. The relationships that shaped your trust, confidence, or fear. All of that influences personality.
It’s not nature or nurture. It’s both. And they’re always interacting. Genetics may provide a blueprint, but environment writes the story.
Temperament, which shows up early in life, is often seen as the biological foundation of personality. Some babies are more reactive than others. Some are easily soothed. Some are more sensitive to stimulation. These early differences can shape how a child relates to their world—and how their world responds to them.
Over time, those interactions get reinforced. A shy child who’s encouraged gently may grow into a confident introvert. A shy child who’s constantly told to “speak up” or teased for being quiet may develop anxiety. Same temperament—different environment, different outcome.
Culture also plays a huge role in shaping how personality traits are expressed, valued, or suppressed. What counts as assertive in one culture may be seen as aggressive in another. What counts as respectful in one family may look like passivity in another. The same person might be seen as warm in one context and weak in another, depending on what traits are expected.
So when we talk about personality, we have to be careful not to oversimplify. Labels can be helpful—but they can also limit. You are not your trait score. You are not your type. You are a living system of patterns, shaped by biology, history, relationship, and context.
That’s part of what makes people so fascinating. Two people can respond to the same situation in completely different ways—not because one is right and the other is wrong, but because their personalities filter the world differently.
This is especially important in relationships—romantic, professional, or otherwise. Personality differences can create conflict, yes, but they can also create balance. One person sees the big picture. Another notices the details. One wants to process out loud. Another wants to think it through internally. Neither is wrong—they’re just different.
The trouble starts when we assume our way is the only way. Or when we pathologize difference. Just because someone feels more than you, or less than you, doesn’t mean they’re unstable or detached. Just because someone needs alone time, or stimulation, or control, or clarity—it doesn’t mean they’re difficult. It just means they’re wired differently.
Personality psychology invites us to take a step back. To ask not just, “Why are they like that?” but “What’s shaping their response?” and “How can I meet them where they are?”
It also invites us to ask that of ourselves. What patterns do I fall into? Where do I feel most like myself? What situations bring out my best? What environments bring out my worst? And what’s within my power to shape?
Because while some aspects of personality may be outside our control, others are up for negotiation. We can practice self-regulation. We can develop patience. We can learn to communicate better. We can stretch. And in stretching, we don’t become someone else. We just become more flexible.
In the final lesson of this series, we’re going to turn toward something that affects nearly everyone at some point: psychological distress. We’ll talk about mental health and human struggle—not as pathology, but as part of what it means to live in a complex, emotional body. We’ll explore how psychology understands mental illness, stress, and healing—and what it looks like to meet suffering with insight and compassion.
Thanks for listening. I’ll see you in Lesson Ten.