Is This Just Who We Are: Unpacking Personality, IQ, and Psychometric Testing

Before exploring personality, it’s important to recognize that psychometric testing began with cognitive assessments, making IQ (Intelligence Quotient) a foundational concept in understanding human behavior. This post examines the significance of both IQ and personality in shaping how we perceive and navigate the world.

The Origins of Cognitive Testing and IQ

Cognitive testing and the concept of IQ emerged in the early 1900s when Alfred Binet and Théodore Simon developed the first intelligence test to assess children’s learning potential. Later, William Stern introduced the term IQ as a ratio of mental age to chronological age, which was standardized by Lewis Terman in the Stanford-Binet Intelligence Scale.

IQ scores follow a normal distribution, often referred to as the bell curve, with most people clustering around the average (mean) score of 100 and fewer individuals at the extremes. The standard deviation is typically 15 points, meaning that:

IQ percentiles give a clearer picture of how an individual ranks relative to the population:

IQ 70 (2nd percentile) – Borderline intellectual functioning.
IQ 85 (16th percentile) – Below average intelligence.
IQ 100 (50th percentile) – Average intelligence.
IQ 115 (84th percentile) – Above average intelligence.
IQ 130 (98th percentile) – Gifted intelligence.
IQ 145+ (99.9th percentile) – Highly gifted/genius level.

In 1904, Charles Spearman demonstrated that cognitive abilities are interconnected. Using factor analysis (a statistical method that identifies underlying patterns by grouping related variables), he found moderate to strong correlations (ranging from 0.3 to 0.6) between different cognitive tasks, leading to the concept of general intelligence (g). This foundational idea in intelligence research was further expanded by Raymond Cattell in 1963, who distinguished between:

Fluid intelligence (Gf): The ability to solve novel problems and adapt to new situations.
Crystallized intelligence (Gc): Acquired knowledge and skills, such as vocabulary and factual information

The Emergence of Personality Testing

While cognitive testing focused on intelligence, the study of personality began to take shape in the early 20th century. The first modern personality test, the Woolworth Personal Data Sheet, was created in 1917 during World War I to identify soldiers susceptible to shell shock (now PTSD). This marked the beginning of using personality assessments in practical contexts.

In the decades that followed, personality testing evolved significantly, leading to models like the Myers-Briggs Type Indicator (MBTI) (1944), DISC (1956), and the Enneagram (1970s). While these tests gained popularity for personal and professional use, they often lacked consistent scientific validation. This changed in the 1980s with the emergence of the Big Five Personality Traits, which provided a robust, research-backed framework for understanding human behavior.

Most of these personality tests typically consist of 100 or so questions, often using a Likert scale (e.g., 1–5), asking respondents to rate how accurately a statement describes them. For example:

"Do you enjoy deep philosophical discussions?"
"Are you someone who keeps your workspace organized?"
"Do you feel energized after socializing with a large group of people?"

By analyzing responses, these tests generate a detailed profile of an individual’s personality, highlighting strengths, weaknesses, and behavioral tendencies. This data can be used for personal development, career guidance, team building, and even clinical applications.

Multiple Intelligences and the Hierarchy of Intelligence

In 1983, Howard Gardner proposed his Theory of Multiple Intelligences, challenging the idea that intelligence is a single, general factor. He argued that people excel in different areas, categorizing intelligence into eight modalities: linguistic, logical-mathematical, musical, spatial, bodily-kinesthetic, interpersonal, intrapersonal, and naturalistic abilities. While this theory resonated with educators, many of these intelligences align more with specific cognitive abilities or personality traits rather than general intelligence.

John Carroll's Three-Stratum Theory of Intelligence (1993) provided a hierarchical model that synthesized decades of intelligence research:

Stratum III: General intelligence (g) at the top, influencing all cognitive tasks.
Stratum II: Broad abilities such as fluid intelligence, crystallized intelligence, memory, and processing speed.
Stratum I: Narrow, specific abilities like vocabulary and arithmetic skills.

This model reconciled previous theories by demonstrating how intelligence operates across multiple levels, with g serving as the overarching cognitive factor. Notably, Gardner’s interpersonal and intrapersonal intelligences align more closely with personality traits than traditional cognitive abilities:

Interpersonal intelligence relates to social skills, empathy, and the ability to understand others, overlapping with traits like Agreeableness and Extraversion in the Big Five.
Intrapersonal intelligence involves self-awareness, introspection, and emotional regulation, connecting with traits like Neuroticism (emotional stability) and Openness (self-reflection).

While g remains the most reliable predictor of cognitive performance, the interplay between intelligence and personality underscores the complexity of human behavior.

IQ, Life Outcomes, and the Limits of Intelligence

Today, IQ remains one of the most heritable psychological traits, with studies estimating its genetic influence to be as high as 80% in adulthood. While there is little evidence that IQ can be significantly increased through external interventions, unhealthy lifestyle habits, such as poor nutrition or inadequate sleep, can negatively impact cognitive performance. As demonstrated in The Bell Curve: Intelligence and Class Structure in American Life, IQ is a strong predictor of life outcomes beyond family socioeconomic status, including higher income, job performance, and social status.

Beyond economics, IQ is also correlated with life stability, including:

Marriage longevity and lower divorce rates
Better parenting outcomes
Reduced likelihood of incarceration
Improved overall health and longevity

Given these broad implications, IQ is the most reliable measure in psychology but doesn’t determine rationality, wisdom, or life satisfaction. Rationality and wisdom involve making optimal decisions in a scenario by combining logic, emotional insight, and ethical considerations while minimizing cognitive biases and thinking long-term.

These qualities extend beyond raw cognitive ability, involving experience, emotional intelligence, and personality traits like Openness and Conscientiousness from the Big Five. Fulfillment and life satisfaction are shaped by a wider set of personal and social factors, including relationships, purpose, and individual temperament.

The Big 5 or Five Factor Model (FFM)

The Big Five Personality Traits, or the Five-Factor Model (FFM), is the most scientifically validated framework for understanding personality. Its roots date back to the 1930s when Gordon Allport and Henry Odbert identified thousands of words describing personality traits in the English language. Through factor analysis, researchers like Raymond Cattell narrowed these down, and in the 1940s and 1960s, studies by Donald Fiske and others consistently identified five core dimensions. These traits were later refined and popularized by Robert McCrae and Paul Costa in the 1980s, who developed tools like the NEO Personality Inventory (NEO-PI) to measure them.

The five traits—Openness, Conscientiousness, Extraversion, Agreeableness, and Neuroticism (OCEAN)—are universal and apply across cultures and languages, making the model widely applicable. Research has demonstrated its empirical reliability, stability over time, and correlations with biological and genetic factors. Neuroimaging studies have linked traits to specific brain functions, and studies show the model is highly consistent across diverse populations. It also shows strong predictive power for life outcomes like job performance, academic success, relationships, and mental health. For example, Conscientiousness is linked to productivity, while Neuroticism is associated with mental health challenges.

Since the 1990s, researchers have expanded on the Big Five personality traits. In 2002, Colin DeYoung, Jordan Peterson, and Daniel Higgins introduced two overarching meta-traits, building on John Digman’s (1997) earlier work:

Stability (associated with being well-socialized, combining low Neuroticism and high Agreeableness and Conscientiousness).
Plasticity (linked to personal growth, associated with high Extraversion and Openness).

These meta-traits provide a higher-order structure that captures broader patterns within personality.

Additionally, in 2007, DeYoung, Peterson, and Lena Quilty introduced the 10 aspects within the Big Five, offering a more detailed breakdown of personality traits. This two-level hierarchy—meta-traits and aspects—offers a more comprehensive framework for understanding personality structure and behavior.

The Big 5 Traits	Aspect 1	Aspect 2
Neuroticism:	Volatility	Withdrawal
Conscientiousness:	Industriousness	Orderliness
Agreeableness:	compassion	Politeness
Extraversion:	Enthusiasm	Assertiveness
Openness:	Intellect	Openness

Stability and Plasticity:

Stability refers to the regulation of behavior, emotions, and impulses to maintain consistency and social harmony. It encompasses the Big Five traits of Emotional Stability (low Neuroticism), Conscientiousness, and Agreeableness, all of which contribute to predictability and reliability in personality. Stability is rooted in the brain’s serotonergic systems, which promote inhibition of impulses and emotional control. This meta-trait ensures individuals adhere to social norms, manage stress effectively, and remain committed to long-term goals. By fostering self-discipline, trustworthiness, and emotional resilience, Stability helps maintain order both internally and in interpersonal relationships.
Plasticity reflects the tendency to explore, adapt, and innovate, enabling individuals to respond effectively to new challenges and opportunities. It encompasses the Big Five traits of Extraversion and Openness to Experience, which drive curiosity, enthusiasm, and intellectual engagement. Plasticity is associated with the brain’s dopaminergic systems, which govern motivation and reward sensitivity, encouraging exploration and creativity. This meta-trait allows for learning, personal growth, and the ability to thrive in dynamic environments. By fostering flexibility, spontaneity, and openness, Plasticity helps individuals break free from routine and embrace novelty.

Together, these meta-traits create a dynamic system:

High Stability and High Plasticity:
- Ideal for personal mastery. The individual maintains self-regulation, emotional resilience, and social harmony while embracing creativity, exploration, and growth.
- Example: A disciplined yet creative leader who balances structure with innovation.
Low Stability and High Plasticity:

May result in impulsivity or chaos. A lack of emotional regulation or order undermines the ability to channel exploration into meaningful outcomes.
Example: A highly imaginative but emotionally volatile artist who struggles with consistency.

High Stability and Low Plasticity:
- May lead to rigidity or resistance to change. A focus on consistency inhibits growth and adaptation.
- Example: A reliable but overly rigid manager who struggles to adapt to new ideas.
Low Stability and Low Plasticity:
- Often associated with instability and a lack of growth. Difficulty maintaining emotional control or direction results in disorganization and unfulfilled potential.
- Example: A disorganized individual struggling to find direction in life.

This framework does not suggest that being high in all domains is better in every scenario. Instead, a balance between Stability and Plasticity is key to social cohesion and personal development. Flexibility—the ability to adapt one’s behavior and mindset to different situations continues to be representative of a healthy psyche.

Neuroticism: Stability of Emotion

Neuroticism is the personality trait associated with negative emotion, encompassing a wide range of experiences such as frustration, disappointment, grief, pain, threat, uncertainty, and anxiety. The trait is composed of two aspects:

Withdrawal: Measures the freeze response, which involves physiological hyper-preparation (e.g., increased heart rate, muscle tension) coupled with paralyzing fear. This response is adaptive in dangerous situations but can be maladaptive in everyday life.
Volatility: Reflects reactive and impulsive behaviors, such as a driver cursing in traffic or leaving a negative online comment. Volatility is characterized by emotional outbursts and difficulty regulating anger or frustration.

Agreeableness: Stability of Social Interactions

Agreeableness helps us balance our interests with the interests of others. Agreeable individuals are often described as kind, warm, polite, and accommodating, while disagreeable individuals may be seen as selfish, ruthless, or vengeful. The trait consists of two aspects:

Compassion: Reflects empathy, care, and concern for others.
Politeness: Involves respect for authority, social norms, and the avoidance of conflict.

Conscientiousness: Stability of Motivation

Conscientious individuals are careful, reliable, organized, self-disciplined, and persevering, while unconscientious individuals are often carefree, laid-back, and inattentive. The trait is divided into two aspects:

Orderliness: Associated with a preference for structure, routine, and cleanliness. Interestingly, orderliness is linked to higher disgust sensitivity, which helps maintain hygiene and avoid harmful substances.
Industriousness: Reflects diligence, discipline, and the ability to stay focused on long-term goals

Extraversion: Exploration of Social Behavior

Extraversion is associated with positive emotion and the pursuit of rewarding experiences. The more extraverted an individual is, the more pleasure they tend to feel in response to success. The trait consists of two aspects:

Assertiveness: Reflects directness, confidence, and the ability to take charge in social situations.
Enthusiasm: Characterized by sociability, warmth, and a lively, outgoing demeanor.

Openness to Experience: Exploration of Cognitive Ability

Openness is the Big Five trait most closely linked with IQ and is associated with exploration, creativity, and intellectual engagement. The trait is divided into two aspects:

Openness: Describes individuals who are original, imaginative, creative, complex, curious, and have broad interests. Those low in openness are often conventional, concrete, and prefer routine.
Intellect: Reflects the ability to understand abstract ideas, solve complex problems, and engage in philosophical discussions. Intellect is considered the personality reflection of IQ.

The Difference Between Males and Females

Traits tend to be relatively even between the sexes, although one sex often leads in the mean percentile. At the extremes (the top 100 for a given trait), a specific sex typically dominates, pointing to a biological foundation. The most significant differences are observed in Agreeableness and Neuroticism, with females scoring higher around 60% of the time reflecting historically nurturing and caregiving roles. Males, on the other hand, tend to score higher in Assertiveness, Industriousness, and Intellect.

Despite these trends, individual differences within each sex are often greater than the differences between them, as personality is influenced by both biological and social factors. This relationship is bidirectional, where genetics can influence lifestyle choices, and epigenetics shows how lifestyle factors can impact gene expression. However, studies have shown in the gender-equality paradox that egalitarian societies with greater gender equality (like Scandinavia) show the largest sex differences, suggesting a stronger biological foundation.

The biggest difference between males and females, outside of personality, is their interests, which are often reflected in their career choices. Males tend to gravitate toward technical fields like engineering and machinery, while females are more likely to pursue people-centered roles, such as nursing and education. This pattern suggests that when individuals are free to pursue their genuine interests, biological drives—shaped by evolutionary factors—tend to reassert themselves. This highlights the complex interplay between biology, personality, and the environments in which people thrive.

Personality Traits and Adaptation

Each personality trait has its pros and cons, and the benefits of being higher or lower in a particular trait depend on the situation. Our personalities are shaped by genetic predisposition and environmental factors, adapting as we progress through different life stages. Traits that were essential in childhood may no longer serve us as we mature, requiring adaptation to better suit our current environment.

Personality tends to remain stable over time due to our natural resistance to change. As we age, the traits we've developed become ingrained, and altering our behaviors may seem unnecessary, especially if they still serve our survival needs. Many people don't prioritize change, but it’s easier to adjust when we're in environments that actively encourage it—such as having a supportive social network, engaging in personal growth experiences, or gaining exposure to new educational opportunities.

Some Pros and Cons of Each Personality Trait

1. Neuroticism

Pros: High neuroticism is beneficial in high-stress, risky, or unpredictable environments, where sensitivity to threats can be advantageous.
Cons: In stable, low-stress contexts, it may lead to overthinking, emotional turbulence, or unnecessary stress.

2. Agreeableness

Pros: High agreeableness fosters harmony, cooperation, and trust, making it ideal for social or team-oriented situations.
Cons: In competitive or corrupt environments, agreeableness can become a disadvantage, leading to vulnerability or exploitation.

3. Conscientiousness

Pros: This trait is excellent for achieving long-term goals, maintaining organization, and excelling in disciplined pursuits.
Cons: It can cause excessive stress in chaotic or unpredictable circumstances where flexibility is more important than order.

4. Extraversion

Pros: High extraversion thrives in dynamic, social, and high-energy environments, fostering strong interpersonal connections.
Cons: It can lead to burnout in solitary, deeply focused, or introspective settings that require long periods of quiet concentration.

5. Openness to Experience

Pros: Encourages creativity, innovation, and exploration, making it ideal for roles requiring novelty and adaptability.
Cons: In environments that rely on routine, structure, or tradition, high openness may result in dissatisfaction or a lack of focus.

Practical Takeaways

Career and Success

Understanding an individual’s Big Five traits can predict career success by identifying roles that align with their natural inclinations, talents, and cognitive abilities, including IQ. People tend to thrive in environments that complement both their personality and cognitive strengths, whether that’s a hands-on role for someone with high industriousness or a more intellectually driven career for those with higher openness and intellect. When personality traits and cognitive abilities align with the demands of a job, productivity and job satisfaction improve, reducing burnout and promoting long-term success. For instance, a person with high conscientiousness might excel in structured environments, while someone with higher openness may do better in innovative or creative fields, even if their IQ is average.

Relationships and Compatibility

The Big Five also plays a pivotal role in relationship compatibility. Research suggests that partners with similar personalities—excluding high levels of neuroticism—tend to have more harmonious relationships. While exact alignment isn’t necessary, significant disparities in traits can lead to miscommunication and conflict, making negotiations within the relationship more challenging. Cognitive factors, like IQ, also play a role in how partners relate and communicate, with some individuals preferring intellectual discussions while others prioritize emotional connection. Shared values, temperaments, and goals create a foundation for trust, cooperation, and mutual understanding.

Family Dynamics and Child Development

In family settings, diverse personalities among children often reflect a healthy, well-balanced home environment. A mix of traits allows for varied interactions, encouraging each child to develop according to their unique temperament and cognitive abilities. This diversity can also apply to IQ, as some children may excel in problem-solving or creativity, while others shine in emotional intelligence or physical tasks. In societies with egalitarian values, where opportunities and rights are equally accessible, innate natural differences—especially between males and females—are more likely to emerge. These differences foster specialization and diversity in skills, benefiting both individuals and society as a whole.

Conclusion

IQ, rooted in general intelligence (g), is a strong predictor of material success, career performance, and life stability. Yet, it is only one piece of the puzzle. Personality, shaped by the Big Five traits and their higher-order meta-traits (Stability and Plasticity), influences how we regulate emotions, interact with others, and adapt to challenges. Together, IQ and personality provide a deeper understanding of human potential, helping us navigate both personal growth and social dynamics—revealing why engaging with diverse perspectives promotes further development.

However, these results do not define our limits; rather, they offer insights into how we engage with the world. Tests can serve as useful tools for self-discovery, but they are unnecessary for those with strong self-awareness. Our lives are shaped by the interplay of our innate traits, cognitive abilities, emotional intelligence, life experiences, and the environments we immerse ourselves in.

IQ may indicate our ability to gain knowledge, and while knowledge may provide us power, it is wisdom—developed through our internal journeys—that leads to peace.

MICHAEL FARAH