The Flynn Effect: Why IQ Scores Have Been Rising

A Startling Discovery

In the 1980s, political scientist James Flynn made a remarkable discovery: IQ scores have been rising approximately 3 points per decade throughout the 20th century.

This means that someone who scored 100 (average) in 1950 would score around 115 on today's tests — or conversely, someone scoring 100 today would have scored 85 in 1950.

Are we actually getting smarter, or is something else going on?

What Is the Flynn Effect?

The Flynn Effect refers to the substantial and sustained increase in intelligence test scores across generations, observed in many countries worldwide.

Key facts:

• Rate: Approximately 3 IQ points per decade
• Duration: Observed throughout most of the 20th century
• Geographic Spread: Documented in over 30 countries
• Test Type: Strongest on fluid intelligence (abstract reasoning) tests

The Scale of the Effect

To put this in perspective:

If this were a real intelligence increase, the average person today would be considered "gifted" by 1900 standards, and someone of average intelligence in 1900 would be considered below average today.

What's Driving the Flynn Effect?

The causes are complex and likely involve multiple factors:

1. Improved Nutrition

Better childhood nutrition, especially in the first years of life, supports brain development:

• Reduction in malnutrition and deficiency diseases
• Better access to essential nutrients (iodine, iron, protein)
• Improved maternal nutrition during pregnancy
• Elimination of many childhood infectious diseases

2. Education Expansion

Dramatic increases in educational access and duration:

• More years of formal schooling
• Universal primary education in most countries
• Earlier exposure to abstract concepts
• Standardized curricula emphasizing reasoning

3. Environmental Complexity

Modern life is more cognitively demanding:

• Abstract thinking is required for everyday tasks
• Technology requires complex problem-solving
• Work increasingly involves analytical thinking
• Visual media trains pattern recognition

4. Test Sophistication

Familiarity with test-taking:

• People are more experienced with standardized tests
• Educational systems teach test-relevant skills
• Abstract reasoning is practiced more frequently

5. Smaller Family Sizes

Research shows negative correlation between family size and IQ scores:

• More parental attention per child
• Greater resource investment per child
• More adult verbal interaction

Which Skills Are Improving Most?

Interestingly, the Flynn Effect is not uniform across all types of intelligence:

This pattern suggests we're getting better at abstract thinking specifically, not necessarily "smarter" in all ways.

Is the Flynn Effect Reversing?

Recent research suggests a concerning development: the Flynn Effect may be slowing or even reversing in some developed countries.

The Reverse Flynn Effect

Studies from Norway, Denmark, France, and other countries show:

• IQ scores peaked around 1990-2000
• Scores have been declining since, especially for younger cohorts
• The decline is approximately -0.2 to -0.3 points per year

Possible Explanations

• Environmental Changes: Increased screen time, decreased reading, changing family dynamics
• Immigration Patterns: Demographic shifts in some countries
• Educational Changes: Shifts in teaching methods or curricula
• Test Ceiling Effects: Modern populations may be hitting the upper limits of what these tests can measure
• Selection Effects: Changes in who takes standardized tests

What the Flynn Effect Tells Us About Intelligence

The Flynn Effect reveals important insights:

1. Intelligence Is Not Fixed

If IQ scores can rise 30 points in a century, intelligence is clearly responsive to environmental factors. This challenges the idea of intelligence as purely genetic or fixed at birth.

2. Environment Matters Enormously

Nutrition, education, cognitive stimulation, and living conditions have measurable impacts on cognitive development.

3. Different Types of Intelligence Are Affected Differently

The fact that fluid intelligence improves more than crystallized intelligence suggests these are distinct (though related) capacities.

4. Cultural Context Shapes Cognition

Modern technological societies emphasize abstract, hypothetical thinking in ways that agricultural societies did not. Our cognitive skills adapt to what our environment demands.

The "Grandparent Problem"

Here's a thought experiment that highlights how puzzling the Flynn Effect is:

If your grandparents scored average (IQ 100) in 1950, and you score average (IQ 100) today, one of you should be significantly "smarter" than the other — but that doesn't match our real-world experience.

This suggests that:

• IQ tests measure specific cognitive skills, not overall "smartness"
• Different eras require different cognitive strengths
• Practical intelligence and wisdom don't necessarily correlate with IQ test scores
• Context matters enormously in how intelligence manifests

Implications for Understanding IQ

The Flynn Effect has profound implications for how we interpret IQ scores:

IQ Tests Are Not Measuring "Pure" Intelligence

If scores can rise this dramatically without genetic changes, tests are clearly measuring something affected by education, culture, and experience — not just innate cognitive capacity.

Comparing Across Generations Is Problematic

An IQ of 100 in 1950 is not equivalent to an IQ of 100 in 2025. The meaning of the score changes as the population changes.

Environmental Interventions Work

The fact that population-level IQ can rise so dramatically shows that improving education, nutrition, and cognitive environments produces real, measurable gains.

The Modern Cognitive Environment

Today's world demands abstract thinking in unprecedented ways:

• Technology: Computers, smartphones, and software require navigating abstract systems
• Visual Literacy: We process complex visual information (graphs, diagrams, interfaces) daily
• Hypothetical Thinking: Planning, scenario analysis, and "what if" reasoning are routine
• System Thinking: Understanding networks, relationships, and complex interactions

Our ancestors were equally intelligent but lived in environments that emphasized different cognitive skills — practical knowledge, social intelligence, navigation, and hands-on problem-solving.

The Bottom Line

The Flynn Effect — the sustained rise in IQ scores across the 20th century — reveals that:

• Intelligence test performance is highly responsive to environmental factors
• Nutrition, education, and cognitive complexity matter enormously
• Abstract reasoning skills are particularly trainable
• IQ scores reflect both cognitive capacity and cultural adaptation

Rather than proving we're "smarter" than our grandparents, the Flynn Effect shows that cognitive abilities adapt to the demands of the times.

Challenge Your Abstract Reasoning

The tests that show the largest Flynn Effect gains are abstract reasoning tests like Raven's Matrices. Challenge yourself with IQ Ladder's pattern recognition puzzles — the same type of abstract thinking that has improved most dramatically over the past century.