The nature of conscious perception
When consciously viewing the world, we perceive its many spatial elements together with their associated properties (e.g., location, size, brightness). All those elaborate spatial details are perceived, simultaneously and in parallel. As I show elsewhere (Gur Reference Gur2015), it is the neural activity in the primary visual cortex (V1) with its veridical depiction of the spatial elements comprising the visual image (a V1 “map”) that is the basis of object representation, perception, and recognition. A second process evident in our conscious perception is the integration of the neural activity occurring in disparate V1 loci into holistic objects. The ability of the brain to generate perceived objects is quite remarkable; a small number of dots that individually carry no information of orientation, size, or length can be easily recognized as meaningful shapes (Gur Reference Gur2015). Even when flashed for a mere 50 microseconds or less (Greene & Ogden Reference Greene and Ogden2012; Greene & Visani Reference Greene and Visani2015), during which time visual cells fire just one or two spikes (Gur & Snodderly Reference Gur and Snodderly1997), it is possible to successfully detect the shapes represented by the dots. Our conscious perception of raw, acute, holistic objects can be modified by processes implemented in many visual and non-visual areas that provide auxiliary information regarding, size, tilt, distance, and so forth. This spread-out activity interacts with the V1 activity patterns to allow the comparison of the acute, ever-varied consciously observed object with a memory – a stored prototype, leading to object recognition (Gur Reference Gur2015).
We can thus see that there are two conscious processes that are essential for our visual perception: detail preservation and details-onto-objects integration, which, together with non-conscious information extraction, enable space perception and object recognition. Needless to say, those conscious processes have nothing to do with motor activity but, among other functions, provide an understanding of our world without which no meaningful motor activity is possible.
It is in the conscious state, particularly the low-level one, that the unique ability of the brain to combine simultaneously occurring discrete local activity patterns into a unified entity is expressed. This instant transformation from the particular to the whole is performed without sending the information elsewhere to a comparator or integrator. Let us consider two points of light that generate two activity loci in V1. These two loci are perceived as two points of light, but, in addition, we can compare their properties: point A is oval, small, and bright, whereas point B is circular, large, and dim. Such comparisons are done instantly and in parallel. This ability to retain the identity and spatial properties of individual elements and at the same time compare or correlate, in parallel, many individual inputs, is easily performed during conscious perception, but it is something that no physical devise, computers included, can achieve.
Finally, to demonstrate how essential consciousness is to our functioning, let us look at the “creature in the cave” example in some detail: For the organism to react to the noxious odor and move towards the cave's opening, it must understand that there is an opening out there. But the light information falling on its retina is a collection of light intensities of various contrasts and sizes; some stem from the edge of the opening, and some do not. To decide which of the disparate light sources should be combined, and then perceived as a holistic entity that differs from the rest of the cave, is not a trivial achievement. As discussed above, all spatial elements are perceived, some are integrated into the “cave opening object,” and some are not. To understand that it is an opening to the outside world requires repeated conscious exposures, interactions, and learning to secure the knowledge that the series of contrast gradients signifies an opening tying the cave to the outside world. All of this and more must happen in the conscious field before the organism can plan any motor activity.
Although appreciating the interesting and original thesis presented by Morsella et al., I argue that their depiction of consciousness as merely binding “incompatible skeletal muscle intentions” (sect. 2.4, para. 5) is extremely narrow. Consciousness is first and foremost a state in which information about the world is made available to us. Information originates from many disparate sources, and it is only within the conscious field that the many inputs create a cohesive, integrative percept. In what follows I present examples showing how consciousness informs us about the world and how complex motor activity is possible while consciousness is engaged elsewhere, and I conclude by using the visual system to discuss the unique nature of consciousness.
Morsella et al.'s description of the “creature in the cave” reaction to the noxious odor takes for granted a highly developed capacity of understanding the world that must precede any meaningful motor reaction. The organism has to understand that its body is an object in a three-dimensional world containing many objects; that its body is an independent object separated from the cave; that there is a world outside the cave; and that the cave has certain spatial properties. It must also be able to estimate distances and sizes that change as it moves. All those consciously gained pieces of information are not necessarily precursors to action and do not represent “competition for control of the skeletal muscles.” Calling such consciously gained scene-understanding “encapsulated” is avoiding the issue; the major, fundamental role of consciousness is dismissed to emphasize a minor one.
Driving a car provides a useful example of a complex motor activity that is unrelated to the concomitant conscious field. Occasionally, we may drive while our conscious attention is completely engaged elsewhere; all motor-related decisions, including those involving conflict resolutions (whether to switch lanes now, whether to increase speed), are performed outside our active conscious state. We can find ourselves coming out of a lengthy day-dreaming, realizing that we have been driving 10 kilometers without any memory of what happened on the road but with a clear memory of the content of our conscious ruminations.
The nature of conscious perception
When consciously viewing the world, we perceive its many spatial elements together with their associated properties (e.g., location, size, brightness). All those elaborate spatial details are perceived, simultaneously and in parallel. As I show elsewhere (Gur Reference Gur2015), it is the neural activity in the primary visual cortex (V1) with its veridical depiction of the spatial elements comprising the visual image (a V1 “map”) that is the basis of object representation, perception, and recognition. A second process evident in our conscious perception is the integration of the neural activity occurring in disparate V1 loci into holistic objects. The ability of the brain to generate perceived objects is quite remarkable; a small number of dots that individually carry no information of orientation, size, or length can be easily recognized as meaningful shapes (Gur Reference Gur2015). Even when flashed for a mere 50 microseconds or less (Greene & Ogden Reference Greene and Ogden2012; Greene & Visani Reference Greene and Visani2015), during which time visual cells fire just one or two spikes (Gur & Snodderly Reference Gur and Snodderly1997), it is possible to successfully detect the shapes represented by the dots. Our conscious perception of raw, acute, holistic objects can be modified by processes implemented in many visual and non-visual areas that provide auxiliary information regarding, size, tilt, distance, and so forth. This spread-out activity interacts with the V1 activity patterns to allow the comparison of the acute, ever-varied consciously observed object with a memory – a stored prototype, leading to object recognition (Gur Reference Gur2015).
We can thus see that there are two conscious processes that are essential for our visual perception: detail preservation and details-onto-objects integration, which, together with non-conscious information extraction, enable space perception and object recognition. Needless to say, those conscious processes have nothing to do with motor activity but, among other functions, provide an understanding of our world without which no meaningful motor activity is possible.
It is in the conscious state, particularly the low-level one, that the unique ability of the brain to combine simultaneously occurring discrete local activity patterns into a unified entity is expressed. This instant transformation from the particular to the whole is performed without sending the information elsewhere to a comparator or integrator. Let us consider two points of light that generate two activity loci in V1. These two loci are perceived as two points of light, but, in addition, we can compare their properties: point A is oval, small, and bright, whereas point B is circular, large, and dim. Such comparisons are done instantly and in parallel. This ability to retain the identity and spatial properties of individual elements and at the same time compare or correlate, in parallel, many individual inputs, is easily performed during conscious perception, but it is something that no physical devise, computers included, can achieve.
Finally, to demonstrate how essential consciousness is to our functioning, let us look at the “creature in the cave” example in some detail: For the organism to react to the noxious odor and move towards the cave's opening, it must understand that there is an opening out there. But the light information falling on its retina is a collection of light intensities of various contrasts and sizes; some stem from the edge of the opening, and some do not. To decide which of the disparate light sources should be combined, and then perceived as a holistic entity that differs from the rest of the cave, is not a trivial achievement. As discussed above, all spatial elements are perceived, some are integrated into the “cave opening object,” and some are not. To understand that it is an opening to the outside world requires repeated conscious exposures, interactions, and learning to secure the knowledge that the series of contrast gradients signifies an opening tying the cave to the outside world. All of this and more must happen in the conscious field before the organism can plan any motor activity.