What Age Does IQ Stop?

IQ, as measured by standard tests, doesn't actually "stop" increasing at a specific age. Instead, the ability itself that IQ tests measure, which we can think of as raw intelligence, follows a slightly different pattern. According to the provided information, while the average IQ remains around 100 across different ages (like 5 and 50), the underlying intelligence itself generally increases until somewhere between the ages of 20 and 50, before it begins to decrease. The peak age of this increase varies among people and depends on the specific type of intelligence.

Understanding IQ Development

Here's a breakdown of how intelligence changes with age based on the reference information:

• Early Years: While children have a baseline IQ, they are still developing intellectually.
• Growth Phase (approximately 20-50): This is when most individuals experience the greatest increase in their raw intellectual ability. The reference highlights that the specific age at which peak intelligence is reached varies.
• Decline: After peaking sometime between 20 and 50, intelligence gradually declines.

Key Factors Influencing Peak Intelligence

The reference mentions that both the peak age and the level of intelligence reached are affected by these factors:

• Individual Differences: Some people reach their peak intelligence earlier or later than others.
• "Type of Intelligence": Different types of intelligence, such as fluid (problem-solving) and crystallized (accumulated knowledge), might peak at different times.

Table Summarizing IQ and Age

Summary

The provided information indicates that IQ scores remain relatively stable across a person’s lifespan, while the intelligence capacity increases until the age of 20–50 years old, and declines after that. Therefore, rather than an age where IQ stops, the raw intelligence rises till its peak and then it decreases.