You can calculate mental age using the historical IQ formula by multiplying a person’s IQ score by their chronological age (actual age in years) and then dividing the result by 100.
For example, if a 10-year-old has an IQ of 120, their mental age is 12 (120 * 10 / 100 = 12). This suggests their cognitive abilities are similar to that of an average 12-year-old.
The Mental Age Formula Explained
The concept of mental age was developed to compare a person’s intellectual performance to the average performance of others. It was a key part of the original intelligence quotient (IQ) formula.
To find someone’s mental age, you need two pieces of information:
- Chronological Age (CA): Their actual age in years.
- IQ Score: Their score from a standardized intelligence test.
The formula is:
Mental Age (MA)=100IQ Score×Chronological Age (CA)
Real-Life Examples of Calculating Mental Age
Seeing the formula in action makes it easier to understand. This calculation is most relevant for children, as the concept doesn’t apply well to adults.
Example 1: A child with a higher-than-average IQ
- Scenario: An 8-year-old child takes an IQ test and scores 125.
- Input:
- Chronological Age (CA) = 8
- IQ Score = 125
- Calculation:
(125 × 8) / 100 = 1000 / 100 = 10 - Output: The child’s mental age is 10. This means they are performing at a cognitive level typical for a 10-year-old.
Example 2: A child with an average IQ
- Scenario: A 10-year-old child scores 100 on an IQ test.
- Input:
- Chronological Age (CA) = 10
- IQ Score = 100
- Calculation:
(100 × 10) / 100 = 1000 / 100 = 10 - Output: The child’s mental age is 10, which matches their actual age.
Why the Mental Age Concept Is No Longer Used
While the mental age formula is historically important, it has significant limitations and is not used in modern psychological assessments.
The main issue is that cognitive development isn’t linear and slows significantly in adulthood. The formula falsely implies that a 40-year-old is intellectually twice as capable as a 20-year-old.
Modern tests, like the Wechsler Adult Intelligence Scale (WAIS), use a deviation IQ. This score compares your performance to the standardized average of your own age group, not the average of a different age. A score of 100 is always the average for any age group.
Frequently Asked Questions (FAQ)
- What is mental age?
Mental age is a measure of a person’s intellectual functioning based on the age at which an average individual reaches the same level. For instance, if you have a mental age of 10, you are functioning at the cognitive level of a typical 10-year-old.
- Can I calculate my own mental age at home?
Not accurately. The formula requires a valid IQ score, which can only be obtained from a standardized test administered by a qualified psychologist. Online quizzes are not reliable and should not be used for a real assessment of your cognitive ability.
- Why don’t modern IQ tests use mental age anymore?
Modern tests don’t use mental age because it’s not a valid measure for adults. Cognitive development isn’t linear and slows down after adolescence. Today’s tests use a “deviation IQ,” which compares your score to others in your specific age group, providing a more accurate result.
- What is the difference between mental age and chronological age?
Chronological age is simply how old you are in years. Mental age is a measure of your intellectual abilities compared to the average abilities of different age groups. When your mental age matches your chronological age, your IQ is considered average (100).
- Is a high mental age a sign of being gifted?
Yes, historically, having a mental age significantly higher than your chronological age was considered an indicator of giftedness. For example, an 8-year-old with a mental age of 12 would likely have a high IQ score and be considered intellectually gifted.
- How does the mental age formula work for adults?
It doesn’t work well for adults at all. The concept was designed for children whose cognitive abilities are still developing. An adult’s intelligence is stable, so comparing a 30-year-old to a 40-year-old using this formula is meaningless and provides inaccurate results.
- What is a “normal” or “average” mental age?
An “average” mental age is one that is the same as your chronological age. This corresponds to an IQ score of 100 on the historical scale. It means your intellectual functioning is right on track for your age group.