DEBUNKED: Your IQ is Fixed

Figure 1: Artistic illustration of the human brain surrounded by geometric shapes and patterns, symbolizing neural connections and the brain’s adaptability through neuroplasticity.

For decades, IQ scores have been treated as permanent labels, suggesting that intelligence is a fixed trait determined early in life. Students were often told they had a set capacity for learning, while workplaces relied on test results to define potential. But neuroscience reveals a very different story: intelligence is not static—it is dynamic, flexible, and shaped by experience.

In this blog, we will break down where the myth of a “fixed IQ” comes from, explain why it is biologically impossible, and uncover the real harm caused when society accepts it as truth. Let’s dive in and challenge this misconception head-on.

The Origin 

Click Here to View Figure 2: Portrait of Alfred Binet (1857–1911), the French psychologist who developed the first intelligence tests to identify children needing academic support.

The belief that intelligence is fixed began with the misuse of early intelligence tests. Alfred Binet originally developed IQ tests in the early 1900s to help identify children in need of academic support, not to permanently label their intelligence. When the test was adapted in the United States as the Stanford-Binet, however, it was reframed as a single score that supposedly reflected an individual’s lifelong capacity. This narrow interpretation transformed IQ into a rigid label rather than a tool for guidance [1].

By the middle of the 20th century, IQ was widely compared to physical traits like height—unchangeable and inherited. Education systems began sorting students into tracks, and employers used test scores in hiring, embedding the idea that intelligence could not change. Over time, the myth spread beyond science and into classrooms, workplaces, and the media. Research in educational neuroscience has since shown that this assumption is a neuromyth, a false belief that misrepresents how the brain works and how intelligence develops [4].

Why the Myth Is Biologically Impossible

Click Here to View Figure 3: Illustration comparing fluid intelligence—abstract reasoning, problem-solving, and the ability to learn new things—with crystallized intelligence, which relies on prior knowledge, experiences, and tends to increase with age. 

Let’s be clear: intelligence is not a fixed trait encoded at birth. Modern neuroscience reveals that the brain is adaptive, constantly reshaping itself in response to experience and learning. Here’s why the “fixed IQ” myth falls apart under real science:

1. Your Brain Rewires Itself. Neuroscience research shows that the brain constantly adapts through neuroplasticity. Every time you learn a new skill, solve problems, or practice something challenging, neurons form new pathways. This proves intelligence is not locked in place but can change across the lifespan [3].

2. Fluid vs. Crystallized IntelligencePsychologist Raymond Cattell’s model distinguishes between fluid intelligence (problem-solving and reasoning in new situations) and crystallized intelligence (knowledge and experience). While fluid intelligence can decline with age, it can also be trained, and crystallized intelligence usually increases over time. Together, they show intelligence is flexible rather than fixed [2].

   
   

3. Cognitive Fitness Can Be StrengthenedResearch on “cognitive fitness” demonstrates that engaging in puzzles, learning languages, playing instruments, or adapting to new challenges keeps the brain agile. Just like physical exercise improves the body, mental training enhances the brain’s capacity to adapt [5].

Click Here to View Figure 4: Graphic showing “Effective Strategies for Cognitive Training,” listing methods.

Why the Myth Is Harmful (Beyond Just Being Wrong)

At first glance, the idea that IQ is fixed might seem harmless—just a number from a test taken once in childhood. But believing this myth has serious consequences:

1. It limits potential.If students are told their IQ defines their future, many may stop challenging themselves. Those labeled “average” or “below average” might avoid difficult subjects or give up on higher education. These labels restrict opportunities rather than expand them [4].

2. It reinforces inequality.Education systems that track students by IQ scores often deny access to advanced resources for those with lower scores. This deepens social and economic gaps, creating a cycle where opportunities are limited by a number rather than effort or growth [1].

3. It creates a false sense of destiny.Believing intelligence is set in stone encourages a fixed mindset. Instead of seeing ability as something to strengthen through practice and strategy, people resign themselves to a “ceiling” that doesn’t actually exist [4].

4. It discourages investment in growth.In workplaces and schools, the myth can prevent institutions from providing training, mentoring, or enrichment programs. If intelligence is “unchangeable,” then resources for development are seen as wasted—when in fact they are essential for growth and innovation [1].

By exposing the myth of a fixed IQ, we affirm that intelligence can be cultivated, expanded, and strengthened. This shift in perspective opens new pathways for academic success, workplace innovation, and personal growth—empowering millions of people to pursue their potential without limits.

Sources:

1. Can You Increase Your IQ? The Truth, the Science, and What You Can Actually Do. https://iqfreetests.com/can-you-increase-your-iq

2. Cherry, K. (2020). Fluid vs. Crystallized Intelligence: What’s the Difference? https://www.thoughtco.com/fluid-crystallized-intelligence-4172807

3. Gilkey, R., & Kilts, C. (2007). Cognitive Fitness. Harvard Business Review, 85(11), 53–58. PMID: 18159786

4. Centre for Educational Neuroscience. Intelligence Is Fixed?  https://www.educationalneuroscience.org.uk/resources/neuromyth-or-neurofact/intelligence-is-fixed

5. Exercise can boost your memory and thinking skills https://www.health.harvard.edu/mind-and-mood/exercise-can-boost-your-memory-and-thinking-skills