Smarter

"Are there truly ways to boost your intelligence, or is it hardwired into you from birth?" This book explores whether cognitive potential is malleable and how actions like learning music or physical exercise might make a difference.

1. Intelligence is not easily defined, but it comes in two forms.

Intelligence often feels like a vague concept; we know it’s important, but defining it remains a challenge. Psychologists have categorized it into two types: fluid intelligence and crystallized intelligence. Fluid intelligence is your ability to think logically and solve unfamiliar problems. Crystallized intelligence is the accumulated knowledge and skills you’ve gained throughout life.

Fluid intelligence helps you when reasoning through novel situations without relying on prior knowledge. For instance, solving a new form of a logic puzzle taps into fluid intelligence. Unfortunately, this type of intelligence tends to peak in early adulthood and decline with age, once seen as unchangeable.

On the other hand, life experiences constantly build crystallized intelligence. Remembering facts for trivia or recalling how to drive a car relies on this store of information. What’s intriguing today is the growing belief that fluid intelligence, contrary to past assumptions, might also be trainable with the right methods.

Examples

• Fluid intelligence enables identifying patterns in a logic puzzle you’ve never seen before.
• Crystallized intelligence is at play when solving a history quiz using previously learned dates and facts.
• Historically, fluid intelligence was associated with brain structure, such as the size of certain brain regions.

2. Measuring fluid intelligence is complex and indirect.

You can’t see or directly observe intelligence, which makes it difficult to measure. Psychologists use constructs—conceptual ideas that are measured indirectly—to assess intelligence. Like dark matter in physics, fluid intelligence is assessed by measuring its effects rather than observing it directly.

Traditional IQ tests estimate intelligence using latent variable analysis. By combining responses across various questions or tasks, psychologists analyze patterns in how people perform to gauge intelligence levels. However, IQ tests themselves have limits and are criticized for their narrow focus.

More recent attempts to measure fluid intelligence have turned to brain scans, such as functional magnetic resonance imaging (fMRI). By observing which parts of the brain receive more blood flow during a task, scientists can infer which regions are more active. This process helps to connect physical brain structures, like the prefrontal cortex, to aspects of cognitive performance.

Examples

• IQ tests combine questions about numbers and spatial reasoning to estimate intelligence.
• fMRI scans reveal that the left lateral prefrontal cortex is highly active during working memory tasks.
• Studies show a direct relationship between brain gray matter and fluid intelligence, but it only accounts for a portion (around 6.7%).

3. Brain games target working memory to boost fluid intelligence.

Games designed to stretch your cognitive capacity might sound like marketing hype, but some research supports their impact. A popular example is the N-Back game, where players remember sequences of letters or images and identify patterns from a certain distance (or “N”) back.

Psychologist Susanne Jaeggi published groundbreaking research in 2008, showing that just four weeks of N-Back training improved participants’ fluid intelligence scores by 40%. This was a significant challenge to the traditional belief that such intelligence couldn’t be improved. Alongside working memory improvements, brain games are also valued for their potential in helping kids with ADHD.

Brain-training programs like Lumosity capitalize on these findings by transforming scientific cognitive exercises into engaging games. However, while some results have been positive, debates persist about whether gains transfer to broader real-world tasks.

Examples

• N-Back requires players to spot patterns two or three steps back in a sequence.
• Jaeggi’s 2008 study linked N-Back training to measurable gains on fluid intelligence tests.
• Over 40 million members signed up for Lumosity, hoping to sharpen their minds.

4. Exercise can make you smarter, especially resistance training.

Physical exercise doesn’t just keep your body fit; it’s also tied to a healthier brain. Research dating back to the 1960s connected fitness to improved cognitive performance. More recent studies have focused on understanding which kinds of exercise have the most significant effects.

A 2012 study led by Teresa Liu-Ambrose divided women into groups practicing aerobic exercise, resistance training, or toning exercises. Only the resistance training group improved their cognitive performance on memory and focus tests. These improvements were further confirmed by changes seen in brain scans.

Exercise doesn’t just enhance cognitive tests—it also helps brain plasticity, or the ability to adapt and create new neural connections. Whether it’s lifting weights or playing a sport, physical activity engages the body and brain alike, making it an accessible way to sharpen intelligence.

Examples

• Elderly tennis players showed better cognitive scores compared to those who remained sedentary.
• Liu-Ambrose’s study demonstrated resistance training improves both memory tests and brain activity.
• Aerobic training aids brain plasticity but does not improve test scores as effectively as resistance training.

5. Music training may enhance intellectual skills.

Learning music has long been associated with cognitive growth, and research confirms its benefits. A 2004 study by Glenn Schellenberg found that children who took music lessons experienced IQ increases compared to those who had acting lessons or no lessons at all.

Music education improves skills like memory, spatial reasoning, and creative problem-solving. For example, playing an instrument requires mastering hand-eye coordination while interpreting sheet music, an exercise in multitasking that fine-tunes your mental processing.

Notably, different types of lessons yielded varying results. Schellenberg discovered that voice students improved the most, followed by keyboard lessons. Even drama lessons boosted IQ to some degree, showing how structured artistic activities shape the brain’s cognitive framework.

Examples

• Schellenberg’s study revealed dramatic IQ gains among music students over 36 weeks.
• Voice lessons contributed the strongest improvements in intellectual measures.
• Learning sheet music sharpens memory and logical processing capabilities.

6. Critics question brain-training transfer effects.

Despite claimed benefits, the scientific debate remains. A meta-analysis by Charles Hulme and Monica Melby-Lervåg examined 23 studies on brain-training effects. While small gains were observed, critics question the real-world significance.

Far transfer—the idea that brain games improve unrelated abilities like math or reading—is controversial. While gains in tasks like problem-solving were recorded, whether they extend to practical skills is less certain.

Though skeptics abound, many remain optimistic about brain-training’s effects. Continued studies aim to clarify these issues, especially for applications like educational settings or ADHD therapy.

Examples

• Hulme’s analysis showed measurable gains in reasoning but questioned broader impacts.
• Far transfer refers to whether solving puzzles improves unrelated real-world skills.
• Gains in non-verbal reasoning haven’t conclusively improved outcomes in reading performance.

7. The military places high value on brain training.

The U.S. military invests heavily in brain training to boost analysts’ decision-making abilities. Agencies like the Intelligence Advanced Research Projects Activity (IARPA) aim to sharpen cognitive skills through structured programs.

In 2014, IARPA announced a $12 million initiative to explore how training affects intelligence. The focus isn’t just on intelligence tests but real-world scenarios, where quick thinking and clear judgment are essential.

Such investments underscore the military's belief in the practical value of cognitive improvement, even while research debates its limits.

Examples

• IARPA funds projects designed to improve analysts’ ability to manage complex data.
• Brain training improves decision-making in high-pressure environments.
• The military focuses on practical applications beyond theoretical IQ scores.

8. Not all claims about intelligence enhancement hold up.

Supplements promising cognitive boosts—like Omega-3 oils or B vitamins—lack strong evidence for real benefits. Placebo effects often explain perceived improvements.

Likewise, “smart drugs” like Ritalin can stimulate focus but don’t necessarily create long-term intelligence gains. Overuse may even harm natural brain functions.

The lesson: Be wary of quick fixes and focus instead on scientifically supported methods, like physical exercise and music.

Examples

• Omega-3s are commonly marketed for brain health, but studies show inconsistent results.
• Pills like Ritalin temporarily improve focus but don’t increase raw intelligence.
• Short-term “hacks” often miss the broader picture of sustainable intellectual growth.

9. Intelligence isn’t static but changing it takes effort.

Emerging evidence suggests fluid intelligence might be more flexible than once thought. Gains are possible through purposeful actions, but they’re neither quick nor guaranteed.

Whether through brain games, music lessons, or weightlifting, incremental improvements are supported. However, attention to lifestyle factors, like sleep and stress management, also plays a role in mental sharpness.

The future of intelligence enhancement remains promising, but critical thinking and persistence are needed to uncover effective paths.

Examples

• Fluid intelligence was previously believed unchangeable; now we see potential for growth.
• Lifestyle factors like stress directly affect mental clarity and focus.
• Continued research will clarify how much of intelligence is adaptable over a lifetime.

Takeaways

1. Incorporate resistance training into your weekly routine to support memory and attention.
2. If you’re curious about music, commit to learning an instrument or joining a singing group—it may boost your brainpower.
3. Approach brain-training games with measured expectations; combine them with lifestyle changes like exercise and mental rest for a fuller benefit.