Working memory capacity and processing efficiency predict fluid but not crystallized and spatial intelligence: Evidence supporting the neural noise hypothesis

Working memory and processing speed are related to intelligence. This study measures concurrently working memory, processing speed and processing efficiency along with fluid, crystallized and spatial intelligence. Two hundred sixty five participants took part in the study. The findings show that working memory and processing efficiency predict fluid, but not crystallized and spatial intelligence. These results are consistent with the neural noise hypothesis based on the empirical observation of synchronous activity of neurons in the brain. Higher scores on fluid intelligence are thought to be related to smaller levels of neural noise-oscillations, as well as to greater levels of processing efficiency and working memory.