Introduction
The question of whether our IQ remains consistent over time has long intrigued researchers and individuals alike. This article explores the evidence and insights from various assessments and studies to provide a comprehensive understanding of IQ stability.
IQ Testing in Educational Settings
In past educational systems, particularly for special education (sped) students, IQ tests were conducted every three years to monitor and adjust support services. However, these tests often produced varying results, sometimes differing significantly by as many as ten points. Despite the variations, the core issue was whether these fluctuations were significant enough to impact the provision of services.
One case mentioned herein involved a student who scored 128 on an IQ test at age 12 and then scored 124 just a few years later. The decision in such cases often hinges on whether these changes are reflective of actual cognitive development or merely temporary interest and motivation fluctuations. Eventually, the practice of retesting every three years was discontinued as it was found to be unnecessary and potentially disconcerting.
Perspectives from Individual Experiences
From personal anecdotes, we see that repeated testing can lead to different results, often due to varying levels of engagement. An individual noted that they scored 122 on an IQ test at age 6 and then scored the same 122 on a college-aged IQ test, despite a period where they "totally goofed off" in middle school but excelled in college. This example suggests that IQ can be somewhat stable, but external factors like interest and motivation significantly influence test results.
Longitudinal Studies of IQ
Longitudinal studies like the Scottish Mental Health survey provide valuable insights into the consistency of IQ scores over long periods. This survey involved assessing the IQ of 11-year-olds and then re-assessing about 101 of these individuals 77 years later. The correlation between the two IQ scores was approximately 0.67, indicating a significant degree of stability in IQ. This correlation suggests that while there is some variability, there is also a consistent base measure of intelligence that persists over decades.
Individual Variations and Personal Stories
Other individuals share personal stories of fluctuations in their IQ scores over time. One person took two Mensa entrance tests at age 19, with scores of 103 and 118, and then took an official IQ test at age 36, scoring 140. The significance of these results is that even with a gap of 17 years, the individual's measured IQ significantly improved, suggesting that IQ can be affected by life experiences and achievements.
Online Test Validation and Improvement Effects
One source of questionable reliability in IQ testing comes from online tests. According to one individual, multiple administrations of a valid online IQ test led to progressively higher scores, peaking around 140. This improvement is likely due to practice effects rather than genuine increases in IQ. The conclusion is that retaking the test several times can lead to higher scores, but this is not indicative of actual cognitive growth. Other studies suggest that with proper preparation, the increase in scores can be as high as 20 points, but this too is a testament to improved test-taking skills rather than a growth in intelligence.
Conclusion
While the fluctuation in IQ scores can be influenced by various factors, including interest, motivation, and life experiences, the stability of IQ over time, especially in the absence of these changes, is demonstrated through longitudinal studies and personal accounts. IQ tests remain valuable tools for understanding cognitive abilities, but it is crucial to recognize the limitations and practice effects inherent in repeated testing.