Rapid Recurrent Feedback and the Rise of Consciousness
Recurrent Neural Processing and the Path to Subjectivity
In this article
Abstract
Neural processing in the human brain consists entirely of biological mechanics, yet consciousness presents itself as subjective experience arising from within. How such experience could emerge from purely physical processes is the dilemma historically known as the hard problem of consciousness (Chalmers, 1995).
This article proposes that recursive neural processing produced by rapid recurrent feedback systems may provide the physical foundation for resolving the mystery. It is argued that, similar to how stereoscopic depth emerges from the combination of slightly different 2D images, subjective experience emerges from a combination of two successive neural moments.
When information generated by a neural response returns to its source soon enough to participate in the response still developing, the system processes its activity in relation to its own immediate past. This internally generated, temporal reference is proposed to be the foundation for both an intrinsic point of view and subjective experience, itself.
The View from Within
We do not merely process information about the world. We experience it. We see color, hear music, feel pain and experience the passage of time. All of these experiences have distinctly different feelings attached, but all have one thing in common. There is always someone who experiences them from an internal point of view. This subjective perspective is the dilemma that lies at the heart of the hard problem. Why should physical processing produce something that is seen from within the system doing the processing?
The theory presented here begins, however, with a more concrete question. Instead of asking how neural activity somehow creates subjective experiences, we ask what physical organization could establish an internal point of view.
The answer to that question is argued to lie in an ordinary but remarkable feature of the brain's circuitry known as rapid recurrent feedback.
Rapid Recurrent Feedback
When a rapid recurrent network reacts to the world, it sends a burst of information towards multiple downstream targets, but a portion of that information loops quickly back to the input side of the network from which it came, a process first examined in accounts of vision (Lamme & Roelfsema, 2000).
By the time the feedback returns to its network of origin, however, the network has already begun processing new input. So the returning signal simply joins the ongoing process.
Each new response, then, incorporates both newly incoming sensory input plus information about the network’s preceding response. Each new neural moment, in this way, ends up containing information from two different times.
The effect of this combination of moments can be illustrated by analogy to stereoscopic vision. Our eyes view the world from slightly different positions. Neither image alone contains stereoscopic depth, but when the brain integrates the two views, their relationship provides something neither view possesses independently: the dramatic, and emergent perception of depth—a property that could not have been predicted from either image alone.
Something analogous to this is argued here to occur between successive neural states linked by sufficiently rapid recurrence—only it happens in the dimension of time instead of space. The possibility being considered is that the relationship between neural moments generates a new, emergent property that, like stereopsis, could not have been predicted from either of its components considered independently.
A Physically Embedded Reference Point
In the relationship considered above, prior activity does more than precede present activity. Information generated by the earlier response returns through an identifiable pathway and helps determine what the network does next. The earlier response then serves as an internal reference affecting the ongoing processing.
The emergent property of subjectivity is suggested to be the network's response to an event that occurred but failed to vanish into the past. Information from the prior response has circled back and is now physically embedded in the present response. The network responds differently than it otherwise would precisely because information about its own preceding response is participating anew. In this purely physical sense, the network is responding to the world subject to its own prior response to the world.
This unique relationship is renewed with each new cycle through the network’s own internal activity. Each response contributes something to the one that follows and thereby establishes an ongoing, internally generated relationship between successive states.
The past is not merely stored and remembered. It remains alive and active in creating each present moment.
This oddly intertwined relationship is argued here to constitute the physical foundation for the intrinsic point of view from which subjectivity emerges. Although the relationship has a close structural similarity to that of stereopsis it does not necessarily show that the emergent property must be subjectivity, specifically. It shows only that some sort of emergent property might be expected—and subjectivity is simply the one that emerges, arising as a totally new and unpredictable property of the neural network.
An Internal Point of View Examined
A point of view requires a relationship between two states. In ordinary physical descriptions, the relationship may be external—a position relative to a coordinate system, for example, or motion relative to another object.
Rapid recurrent processing, on the other hand, introduces something fundamentally different. It produces an internal reference generated by the system's own immediately prior activity. The network's preceding response becomes part of an ongoing relationship which enables that prior response and the new response to be presented, side by side within each new moment.
In a physically meaningful sense, the network is responding to the world shaped by its own prior response to the world; creating a structure that can only be interpreted by the network as an internal point of view—an arrangement strongly implying a physical underpinning for consciousness.
From Perspective to Experience
This combination of two time intervals is not just another brief interval containing successive neural events. It is a particular causal organization in which the system's past is physically included in its present.
This organization is proposed to be a physical structure able to support an internal point of view because it establishes the two components required for such a relationship.
Perhaps more importantly, it is not merely a relationship imposed by an outside observer describing the system. It establishes the relationship to be a function of the network's own internal machinery. It exists within the system's own causal organization.
It is further argued that this organization ultimately provides the crucial step from merely processing information to experiencing information.
Subjective experience need not require the brain to create a separate internal observer that somehow manufactures consciousness. Subjectivity may instead reside simply in the organization of the activity itself—specifically in the ongoing, cyclic relationship between what the system is doing now and what it just did.
Felt qualities are consequently understood to arise from sensory responses simply because those responses occur within a causal organization that presents them from an intrinsic, internal point of view.
Putting the Idea to the Test
Any proposal about consciousness must be capable, first of all, of being wrong and it must lead to questions that can be investigated.
Testing this proposal requires research methods that can distinguish rapid recurrent activity from incoming sensory processing and determine whether disrupting that recurrence changes conscious perception.
If conscious experience can be shown to occur while the system's immediately preceding response is blocked from participating, the theory cannot be a necessary foundation for consciousness.
Conclusion
Rapid recurrent processing offers a concrete candidate for the physical organization underlying an intrinsic point of view and emergent subjectivity. Its proposed contribution is that information about a system's preceding response returns soon enough to help form its developing response, presenting the immediate past as an active internal contribution to the present.
The central hypothesis is that this continuing relationship constitutes the temporal foundation of a felt perspective. Its appeal lies in locating the proposed basis for subjectivity directly within the causal organization of neural activity.
Consciousness need not depend upon some mysterious additional ingredient being added to neural activity. Subjectivity may simply emerge automatically when neural activity becomes organized so that the system's own past provides an internally updated contribution to the system as it unfolds into the present.
All of this suggests a direct physical bridge between mechanistic processing and experience that can be stated surprisingly simply:
Subjective experience can emerge automatically when a system's present state is formed containing an embedded, physical relationship to its own immediately preceding state.
References
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Chalmers, D. J. (1995). Facing up to the problem of consciousness. Journal of Consciousness Studies, 2(3), 200–219. https://consc.net/papers/facing.html
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