7 | Individual Differences and Similarities
Anna Sofia Caruso and Alison Heinhold Melley
Key Theme: Psychology explains general principles that govern behavior while recognizing individual differences.
Here, we’re talking about individual differences and general patterns of behavior. Remember:
Psychology deals with probability, not certainty.
Taking apart the ideas in our key theme, think about the “general principles” as the high probability of what humans will do or what humans are like, based on empirical evidence. Then, the “individual differences” are the ways that people differ from each other and the unlikely (but possible) ways some people differ from those general principles.[1] To determine whether those general principles even exist for any particular trait or behavior, we need many different kinds of research studies with many different kinds of people.
Some examples:
Development: Human babies begin to walk around 12 months old, on average, but the range is from 6 to 18 months – a child who begins to walk at 18 months is not “delayed” any more than a child who walks at 6 months is “advanced.” The “general principle” is the average age for walking, the individual difference is the wide range of ages at which this develops. It is less likely but very possible that a healthy developing child does not walk until 19 months.
Cognition: The quick-thinking tools our brains develop to help with making sense of the world (called heuristics) can sometimes lead us to see the world in a biased way. This is a general principle. For example, we are all susceptible to confirmation bias. This happens when we hold a particular belief, we more easily see evidence that *supports* that belief and it is difficult to see evidence that does not support it. So, if I believe someone does not like me, I will see all the things they do that confirm that “truth” – but ignore any action that debunks my belief. The individual differences come in how susceptible people are to this bias, and how much they consciously work against this human tendency to keep their mind open to possibilities. Just believing that something is true does not make it true!
Health: There are individual differences in how we respond to stress. For example, some people automatically take a problem-focused approach (methodical, somewhat detached, looking for solutions) while others take an emotion-focused approach (paying attention to the feelings around the situation). Of course, this does not mean that people always respond in the same way – in fact they may begin with one approach and move onto another as the stressful situation continues.
Understanding Individual Differences in Personality
One way you differ from other people is your unique patterns or dispositions of thought, feeling, and behavior that you bring to each situation. In other words, your personality. The ways we think about, influence, and relate to other people (dispositions) is the focus of study in personality psychology. The concept of individual differences refers to the variations in dispositions among people. These differences shape our behavior in general, and especially our interactions with each other. These differences help explain why people may react differently to the same situation or patterns of behavior over time.
When we talk about personality, we often use trait words. For instance, we might describe how introverted a person is or how conscientious they are. These trait words help us understand broad patterns of behavior but we need to be careful to avoid using them as distinct categories or labels. Describing how much of a trait a person displays is much more accurate than saying they are “an introvert.” We can describe a person’s unique personality profile, but this is just one part of the puzzle – description does not tell us why someone developed those traits, whether they have always show these traits, or how they might change in the future. This involves considering the genetic and environmental factors that shape our personalities over time.[2]
Describing Personality
Personality description focuses on identifying and measuring consistent patterns in how people think, feel, and behave. For example, the widely used Five Factor and HEXACO Models describe personality along five broad dimensions: Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. Research shows that these traits are prominent across diverse cultures, suggesting a genetic influence the expression of these traits can vary widely depending on environmental factors. For example, a person high in openness might thrive in a creative environment but feel stifled in a rigid, structured setting.
Explaining Personality
Explaining the development of personality traits requires us to consider both genetic and environmental influences. Behavior genetics research, including twin and adoption studies, has demonstrated that personality traits are moderately heritable. However, genes don’t directly code for personality traits. Rather, they influence our biology in ways that make patterns of thinking, feeling, and behaving likely.
The concept of epigenesis refers to how genes and environment interact throughout development to shape an individual’s characteristics. Environmental factors like parenting, culture, and life experiences can influence how our genetic predispositions are expressed. Genetic factors such as infant temperament or appearance can influence how caregivers and others respond to us, and us to them. This cycle continues throughout the lifespan, with constant interaction.
For example, a person might have a genetic predisposition for high intelligence, but without a stimulating environment, this potential might not be realized. The interaction between genes and the environment is dynamic. For instance, identical twins reared together share both their genes and environments, making them more similar in personality traits compared to fraternal twins. However, even identical twins reared apart show significant similarities,demonstrating the strong genetic component of personality.
Consider two siblings, both inheriting a genetic predisposition for high neuroticism (the tendency to experience negative emotions). One sibling experiences a stable, supportive environment in childhood while the other is exposed to chronic stress and trauma. This could happen within the same family or in different families (in the case of adoption or other separation). These siblings will likely end up with quite different personality profiles in adulthood. The sibling with the supportive upbringing may learn effective coping skills that moderate their tendency toward anxiety and emotional instability. In contrast, the sibling with the stressful environment may develop heightened neuroticism as their genetic vulnerability interacts with environmental risk factors.
Practical implications:
As you can see, Individual differences in personality arise from complex interactions between genetic (nature) and environmental (nurture) influences. As you continue your studies in psychology, you’ll encounter many examples of how our shared human nature interacts with our unique experiences to make each of us distinctly individual. Understanding these individual differences is key to gaining insight into human behavior and mental processes, and the ways in which each person navigates the world.
This kind of understanding can have impacts in all areas of our lives. For example:
Personal Development: Self-awareness and personal growth. Individuals can identify strengths and challenges that may hinder their progress.
Interpersonal Relationships: Understanding personality differences can improve our relationships. We can adjust communication styles, manage expectations, and foster empathy towards others’ perspectives and behaviors.
Education: An appreciation for the complexity of personality and behavior can help educators with classroom management and expectations.
Workplace Efficiency: In the workplace, understanding personality differences can aid in team building, conflict resolution, and leadership, maximizing productivity and job satisfaction.
Clinical: In therapeutic settings, an understanding of personality can inform treatment plans and interventions. Clinicians can better comprehend their clients’ behaviors and tailor their approach to suit individual needs.
Consumer Behavior: Marketers and businesses predict consumer preferences and behaviors, leading to more effective advertising and product development strategies.
In essence, the study of individual differences in personality is not just an academic exercise; it has real-world applications that can lead to more harmonious social interactions, more effective educational and work environments, and better mental health outcomes.
Religion and Social Psychology
Religion is an important part of many people’s lives, so psychologists study how it affects the way people think and behave. While religion involves many areas of psychology – like how children develop religious beliefs (developmental psychology), or how religion affects mental health (clinical psychology) – this section will focus on in-groups and prosocial behavior (social psychology).
The psychology of religion as an area of study understands that religion is also a cultural issue that cannot fully be explained by psychology alone[3]. While there is a lot to discuss (and discover) about religiosity in the context of thought and behavior, this section will focus on the effects of religiosity in two contexts: how religious groups form, and how religion affects helping behavior (social psychology).
Understanding Group Identity
Have you ever noticed how people often divide themselves into groups? In psychology, we call the group you belong to your “in-group” and groups you’re not part of “out-groups.” These groups can form around many things:
- The sports teams you support or schools you went to
- Your nationality, ethnicity, or your home country
- Physical features such as eye color (like in Jane Elliott’s famous classroom experiment where she divided students by eye color)
“In-group favoritism” is a term used for when you have a bias towards other members of the group you are in. It means that you favor your in-group – it is not about disliking another group.
Religion is another way people form these groups.[4] Researchers Dunkel and Dutton[5] wanted to understand how in-group favoritism works among religious people felt about others who shared their religion. They studied 1,627 people who were Catholic, Baptist, Methodist, or Jewish. To keep things simple and focus just on religion (not race), they only included white participants in their study.
The researchers asked questions like:
“How strongly do you identify with your religious group?”
“Do you prefer spending time with people from your own religion?”
These questions were intended to measure “religiosity” with a score.
What did they find? There was a correlation between religiosity and in-group favoritism. The higher someone scored on religiosity, the more they preferred being around others from their religion. This was true for all four religious groups in the study. However, it’s important to note that since it is a correlational study, based on self-reports of both in-group favoritism and religiosity, which means we cannot make strong conclusions, rather we can build on this research to learn more.
Religion and Helping Behavior
Researchers Kelly, Kramer, and Shariff[6] looked at the relationship between religiosity and another important social psychology concept: prosocial behavior. This means helpful behaviors such as:
Giving to charity
Volunteering
Being generous
As well as harmful behaviors like:
Cheating
Crime
Violence
Religiosity was the other primary variable of interest, and the meta-analysis included papers that measured They did not confine their search to any one religious group, but the majority were some sect of Christianity.
The research question was “Does being religious make people more likely to help others?” They conducted a meta-analysis, which is often considered the “gold standard” of research: combining the results from 234 different studies done between 1964 and 2020. These studies measured religious affiliations, behaviors, and beliefs.
Most studies focused on Christian religions, but they looked at other religions too. After examining all the studies containing those measures, they found there was a positive correlation (r = .13) between religiosity and prosociality. Interestingly, that relationship was stronger when people reported their own behavior (self-report) compared to when researchers measured actual behavior.
Key Terms:
In-group: A group you belong to
Out-group: A group you don’t belong to
Correlation: When two things are related, but we don’t know if one causes the other
Meta-analysis: A study that combines results from many other studies
Conclusion
In this chapter, we learned about how people can be both similar to and different from each other. Psychology helps us understand both the general patterns that most people follow and the ways that individuals might be unique. This is the heart of our key theme.
We explored how personality develops through a mix of our genes and our experiences. Think about it like this: we might be born with certain tendencies, but our environment – including our family, friends, and life experiences – helps shape who we become. This is why even identical twins, who share the same genes, can develop different personalities. We also looked at how understanding individual differences matters in real life. This knowledge can help us:
- Become more aware of our own strengths and challenges
- Get along better with people who are different from us
- Learn and work more effectively
- Understand why people might join religious or social groups
The research on religion showed us how being part of a group can influence our behavior, like how religious beliefs might affect whether people help others. However, it’s important to remember that these patterns are just general trends – they don’t predict exactly how any one person will behave.
Understanding individual differences helps us appreciate what makes each person unique while also recognizing what we have in common. This knowledge can help us better understand ourselves and others, leading to stronger relationships and more successful experiences at school, work, and in our personal lives.
- Neufeld, G. (2022) Understanding Psychology’s Integrative Themes - YouTube https://youtu.be/YoDJFOH6G8w?si=G3OvfmwA1AJMkOh4 MacMillan Learning ↵
- Gray, K. (2012) Introduction to Psychology, Cognella Academic Publishing. ↵
- Paloutzian, R. F., & Park, C. L. (2021). The psychology of religion and spirituality: How big the tent? Psychology of Religion and Spirituality, 13(1), 3–13. https://doi.org/10.1037/rel0000218 ↵
- Preston, J. L., & Ritter, R. S. (2013). Different Effects of Religion and God on Prosociality with the Ingroup and Outgroup. Personality and Social Psychology Bulletin, 39(11), 1471–1483. https://doi.org/10.1177/0146167213499937 ↵
- Dunkel, C. S., & Dutton, E. (2016). Religiosity as a predictor of in-group favoritism within and between religious groups. Personality and Individual Differences, 98, 311–314. https://doi.org/10.1016/j.paid.2016.04.063 ↵
- Kelly, J. M., Kramer, S. R., & Shariff, A. F. (2024). Religiosity predicts prosociality, especially when measured by self-report: A meta-analysis of almost 60 years of research. Psychological Bulletin. ↵