The sensation of experiencing the present moment is actually a memory, according to a new perspective published in the Journal of Cognitive Neuroscience.
Researchers from Boston University, Queensland University of Technology, and the University of Toronto argue that because neural processing involves delays, our intuitive feeling of “now” cannot be a direct mirror of the external world. Instead, the brain employs unconscious perceptual mechanisms to construct a timeline that is then consciously remembered.
The paper suggests that the same neural circuitry responsible for remembering the past and predicting the future is also used to generate the conscious perception of the present.
The best estimate theory
The new framework synthesises theories from the fields of memory, perception, and neurology. It posits that the brain’s “default mode network” — along with control and salience networks — handles the simulation processes required for consciousness.
“The same simulation processes are used whether we are consciously remembering the past, experiencing the present or imagining the future,” says Andrew Budson, professor of neurology at Boston University Chobanian & Avedisian School of Medicine.
Budson explains that because of the time lag in processing sensory data, the brain must simulate reality rather than record it in real-time.
“Perceptual mechanisms represent an ongoing, editable, ‘best estimate’ of our past, present, and future. There is no hard boundary between conscious perception and memory at milliseconds to seconds timescales,” says Budson.
The purpose of consciousness
The collaborators — including Hinze Hogendoorn of Queensland University of Technology and Donna Rose Addis of the University of Toronto — suggest that this theory resolves long-standing questions regarding the biological function of consciousness.
By linking consciousness directly to explicit memory systems, the researchers argue that its primary function is evolutionary planning.
“If our synthesis is correct, then we now know the purpose of consciousness, which is the purpose of explicit memory — to use prior information to understand the present moment, imagine possible futures, and plan accordingly,” says Budson.
