Researchers have mapped out the way our brains process visual data that falls below the threshold for conscious perception, indicating that neuronal encoding and maintenance of subliminal stimuli (such as flashing a brand logo for less than a second during a movie) is more substantial than previously thought.
“Our results indicate that what is “invisible” to the naked eye can, in fact, be encoded and briefly stored by our brain,” observes Jean-Rémi King, a postdoctoral fellow at the Department of Psychology at NYU.
In the study, King and fellow researchers Niccollo Pescetelli from the University of Oxford, and Stanislas Dehaene from Collège de France, had participants look at a series of quickly flashed images and report which ones they saw and which ones they did not, while being monitored by a magnetoencephalograph (MEG), which makes multiple measurements of the tiny magnetic fields generated by neuronal activity in the brain at every millisecond.
Decoding the complex data by using a custom-built machine learning algorithm has helped the team confirm a series of theoretical predictions. Most importantly, the study shows a striking dissociation between the dynamics of “objective” (concerning visual data that reaches the eyes) and “subjective” neural representations (concerning what is consciously perceived and reported).
Contrary to predictions, however, results also showed that invisible images can be partially maintained within the higher processing stages of visual perception, which lines up with recent evidence for unconscious working memory (i.e. usable information obtained without any conscious participation).
“Undoubtedly, these results suggest that our current understanding of the neural mechanisms of conscious perception may need to be revised,” notes King, who also holds an appointment at the Frankfurt Institute for Advanced Studies (FIAS). “However, beyond our empirical findings, this study demonstrates that machine learning tools can be remarkably powerful at decoding neuronal activity from MEG recordings – a preview of what we can uncover about the workings of the brain.”
Sources: study abstract, sciencedaily.com.