Before the twenty-first century, we used to think dreams only occurred during rapid eye movement (REM) sleep, but more recent research shows people sometimes recall dreams even when they are woken from non-REM stages of sleep.
Whether these two types of dreaming are inherently different is something neuroscientists are still trying to figure out.
Researchers in Brazil have now developed a high-speed analysing tool that can take… qualitative reports and display them in a more objective graph form, taking into account biases for both length and language.
“We know REM dreams are longer and more like movies,” says neuroscientist Sidarta Ribeiro from the University of São Paulo in Brazil.
“Automating the process of analysis, as we did in the study, made possible the first-ever quantitative measurement of this structural difference.”
Compared to traditional methods, which rely on parsing out the meaning of words, this non-semantic graph analysis was able to instead focus on the overall tone of what was said.
While non-REM sleep is suspected of having some restorative function, we’re still not really sure why REM sleep exists. If dreaming during this stage is truly of a different quality, as this new research suggests, then REM and non-REM dreaming might be driven by distinct underlying mechanisms that could play differing roles in our biology.