Recently, I have witnessed a discussion during one of the talks in our department. The issue was about the study of motor imagery. The experiment went as follows: participants imagined a movement; their brain signal was measured with an EEG during this imagination exercise; after, participants performed actual movements. It turned out that the performance on the subsequent movement task correlated with the brain signal during the imagination task. In contrast, the performance was not correlated with the self-evaluation of imagery, i.e., participants who claimed they imagined movement vividly and in detail didn’t improve their performance. The conclusion was made that participants are not reliable, their reports are not reliable, but the brain signal is veridical, it is genuine, and should be trusted. It felt to me inappropriate and even mistaken to trivialize subjective experience in such a way, to classify it as noise. Fortunately, some neuroscientists have chosen subjective experience as their research program. This is a review of the book by Hakwan Lau, a prominent contemporary researcher in the field of subjectivity and consciousness. The book, titled “In Consciousness We Trust: The Cognitive Neuroscience of Subjective Experience”, is his opinion on where we should move in this field.

There are a gazillion theories of consciousness (or subjective experience), but only some of them can be empirically tested. One is the global workspace theory (GWT). Another is the recurrent processing theory (RP).

GWT (Baars and later Dehaene) is usually described with the theater metaphor. The audience sits in the dark; these are unconscious processes, such as memory, emotional systems, language, sensory analyzers, and motor planners. On the backstage, signals compete to get to the stage; these are sensory inputs and internal thoughts. The spotlight selects the signal from backstage; the spotlight is attention. When the signal enters the stage, it enters conscious awareness. The audience “sees” what’s on the stage and incorporates this information. In this theory, consciousness is the global availability of information across the brain. The key element of the theory is the stage. It has been proposed that the distributed fronto-parietal network (prefrontal, parietal, and cingulate cortex) may function as the stage, while signals that compete to enter the stage come from sensory cortices (for instance, the primary visual area). 

The problems surfaced when it turned out that the prefrontal areas are substantially activated only when participants are required to respond. In other cases, the activation was small or absent completely. While evidence about fronto-parietal network engagement remains mixed, it is almost impossible that the brain, passively observing something, is unconscious.

RP theory (Lamme) posits that consciousness arises from recurrent processing loops within sensory cortices. To arrive at a conscious visual percept, the signal from the primary visual cortex should be propagated to higher visual areas and back to the primary visual cortex. The prefrontal cortex, under RP theory, is not involved. Feasibly, it means that perception is rich; we experience much more than we can report and/or remember. 

However, the empirical evidence for richness is debated. The perception may only appear to be rich, while the brain seems to be filling the gaps: the world is perceived as sharp, although the quality of vision on the periphery is known to be worse than in the center; during eye movement, the world doesn’t look distorted, although it should be. Although it may subjectively feel that the perception is rich, it might be a carefully constructed imitation.

Therefore, it seems that experimental evidence favours neither exclusive involvement of sensory areas nor overwhelming functional significance of the prefrontal cortex.

Since neither view is satisfactory, the author proposes a somewhat unified view:  Perceptual Reality Monitoring (PRM). PRM posits that both higher-order and first-order states are needed for conscious perception. The author explains PRM with GAN metaphor. GAN, or generative adversarial networks, is a deep learning framework that includes two networks: a generator and a discriminator, which compete to create realistic images. In the brain, generators are sensory signals, and discrimination is a high-order state. Discriminator uses prior beliefs and momentary predictions to decide whether sensory signals are of use. In other words, conscious experience occurs when perception is self-recognized. The author argues that only this kind of unifying theory may account for all of the empirical evidence.

The narrative was clear, and the book was easy to read. However, I cannot say I agree with everything. Firstly, the author speaks annoyingly about philosophers. Yes, they don’t produce any empirical evidence; their ideas are often untestable; sometimes they take neuroscientific experiments and interpret them as they need. It may all be true, but this feedback is crucial for us, neuroscientists. The worst place that the scientist may find themself is in their own bubble. Secondly, I have a hard time comprehending functionalist theories. I also don’t see how functionalist theory can be a neuroscientific theory. For instance, all action potentials are similar. How could it be that some action potentials elicit conscious perception? If consciousness arises on the level of networks, which qualities do those networks have that set them distinct from non-conscious networks? If there is a network for the first-order process and for the higher-order process, when exactly does consciousness appear? Thirdly, what was not clear to me is where the border between the subconscious and the conscious is in the PRM. The author says that consciousness is the way (process?) of how perception affects cognition, i.e., “the interface”. Clearly, subconscious processing influences cognition, and clearly, subconscious processes feel different from conscious processes. At the same time, the author doubts that primitive animals possess consciousness. However, for an animal that is capable of movement, there should be some kind of signal that feeds back, informing the animal about success or failure or the movement. Is it already perceptual reality monitoring?

There are, of course, things that I wholeheartedly agree with. The author argues that we should continue empirical studies even though the theories are not all-encompassing. Agree. And that we should understand that we have the same goal, and should cooperate more. Agree. Lastly, I do find the proposed theory interesting, whilst not all-encompassing and satisfactory.

Favorite quote 

“Consciousness is the gating mechanism by which perception impacts cognition; it selects what perceptual information should directly influence our rational thinking.”

February, 2026