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Aspects of intelligence may be declining

New King’s College London research suggests that some aspects of intelligence may be declining. 

Previous research has shown than since the middle of the last century, human intelligence has been increasing, this is termed the ‘Flynn Effect.’ This new research used data from around 140,000 participants in 1754 independent studies from across the world and found this increase may be slowing down or going into reverse, depending on what aspects of intelligence are measured.

Specifically, an ‘Anti-Flynn Effect’ has been found for working memory - the ability of an individual to hold information in memory for processing, reasoning and decision making - which is a key intellectual ability.

Dr Peera Wonguppuraj, who began the research at IoPPN and finished it at Burapha University in Thailand, says:

‘Working memory forms the basis for many everyday activities from just thinking about what you are about to say, to mental arithmetic or solving ‘on the spot’ problems. We are intrigued that this ability has decreased significantly over the last 43 years. One theory is that people are living longer and, perhaps, this aspect of intelligence is more vulnerable to the effects of ageing.

‘Another more speculative theory is that there are biological reasons for working memory decline, for example, the fact that people are having fewer children, which could mean over a longer period the genetic basis for working memory is made marginally less robust.’

Professor Robin Morris, Professor of Neuropsychology at the IoPPN concludes:

‘Despite the decline not being huge and there being considerable individual variation, this does challenge assumptions about the nature of intelligence, including the notion that intelligence is a simple entity. Other aspects of intelligence may continue to rise.’

Paper reference: Wongupparaj, P., Wongupparaj, R., Kumari, V., & Morris, R. G. (2017). The Flynn effect for verbal and visuospatial short-term and working memory: A cross-temporal meta-analysis. Intelligence, 64, 71-80.