According to a recent study conducted by researchers at the University of California (UC) Davis Health, human brain sizes have grown by a significant 7% since the 1930s. The study, which compared brain sizes of individuals born from the 1930s to the 1970s, found that the brains of Generation X were 6.6% larger than those of the Silent Generation.

The increase in brain size may have positive implications for younger generations, as it could potentially reduce the risk of age-related dementia, such as Alzheimer's disease. The researchers theorized that external influences, such as improvements in health, social, cultural, and educational factors, could be contributing factors to this growth.

However, despite the larger brain sizes, recent studies have indicated a concerning trend in IQ levels among younger generations. The study found that both Generation Z and Generation Alpha have the lowest IQ scores compared to previous generations. Factors such as overreliance on phones and the internet have been linked to this decline in IQ levels.

The study, conducted over a span of 75 years, involved MRI scans of more than 3,000 participants born between the 1930s and the 1970s. The research showed a consistent increase of 6.6% in brain size among people born in the 1970s compared to those born in the 1930s. On average, the brain volume of today's generation measures around 1,400 milliliters, while individuals born in the 1930s had an average brain volume of 1,234 milliliters.

It is important to note that brain size does not necessarily determine intelligence. Research has shown that there is only a slight relationship between brain size and intelligence. Extra brain mass primarily serves to allow individuals to store more lifetime memories, according to neuroscientists.

Despite this, the larger brain sizes observed in younger generations may have long-term benefits for brain health. The researchers suggest that larger brain structures could act as a buffer against age-related brain diseases like Alzheimer's and related dementias.

The increase in brain connectivity among younger generations could also lead to more accurate and efficient performance on cognitive tasks. However, these findings raise questions about the decreasing IQ levels observed among Generation Z and Generation Alpha. Studies conducted in various countries, including Finland, France, and the UK, have reported a decline in IQ scores.

Factors such as disruptions to in-person learning during the Covid-19 pandemic and increased use of social media have been suggested as explanations for this decline. Skills like verbal reasoning, visual problem-solving, and numerical series tests have all seen a decline in performance.

While the findings of increased brain size contradict previous beliefs that the human brain hasn't evolved, the discrepancy between brain growth and declining IQ levels among younger generations remains a topic of further research. As scientists continue to investigate the complexities of the human brain, understanding the correlation between brain size, intelligence, and cognitive development will be crucial in addressing these concerns.