IV. The Psychological Basis of Perception

Our knowledge of the physical and physiological bases of perception must not allow us to lose sight of the fact that perception is a conscious process.  Consciousness is not a passive state at the end of a physiological chain of events.  Consciousness plays a causal role in the final achievement of perception.  In order to understand this role, let us first identify the biological nature of consciousness.

Action Regulation as the Biological Function of Consciousness

The function of consciousness, for any living organism possessing this capacity, is the acquisition of knowledge and the control of behavior in accordance with that knowledge.  Cognitive control of behavior, therefore, requires an integration of behavioral and sensory processes.  At the physiological level, the nervous system is primarily responsible for this sensory-motor integration.  Consciousness acts (through the nervous system) as the central regulator of the organism’s life.  Conscious control of behavior and conscious control of the acquisition of knowledge, therefore, are and must be a joint and integrated process.

The capacity to perceive objects is a necessary precondition for purposive, life-serving behavior.  The perception of objects as potential sources of value or of danger makes possible anticipation and preparation for action.  The capacity for perception has evolved in parallel with the capacity for self-generated movement.  The capacity for cognitive control and anticipation has necessarily developed in parallel with the repertoire of self-generated actions.  The enormous versatility of self-generated, self-regulated action is the most obvious fact differentiating “sentient” from “vegetative” life forms, i.e., animal forms from plant forms. {55}

From the start, perception requires conscious control of behavior.  In order to perceive, the organism must act.  He must direct his behavior.  He must control the orientations of his receptor organs.  He must apply his receptor organs to his environment.  He must “reach out” in order to “pick up” information.

Perception then is not a passive mechanical process, nor is it a vegetative or homeostatic process.  Perception is not an effect passively received but rather is an effect actively aimed at by the organism.  Perception is goal-directed and purposive.  The goal of perception is, in the widest sense, the same as the goal of all conscious processes: maintenance of the organism’s cognitive contact with reality by the active acquisition of knowledge.  When I say that perception is a goal-directed process, I mean it in the literal and non-metaphorical sense.  The concept of goal or purpose implies and presupposes the existence of consciousness.  Purpose, in perception, is to be thought of as a causal antecedent, not merely as a functional consequent.  The goal of perception may be innately determined, as it is for animals and human infants, but it is none-the-less a goal.  I will define a goal as: a state or condition that a living entity seeks to bring about or alter by conscious action.  In the case of perception, the conscious action under the organism’s control is the act of attention.

Perception and Attention

Attention is the process of mentally isolating some aspect, component, or attribute of that portion of existence within ones immediate range and scope of awareness.   The faculty of attention is the organism’s means for maintaining autonomous control over its sensory input.  Such control enables the organism to {56} (A) Maintain a sensory effect, and (B) Repeat and intentionally bring about a sensory effect.  These latter are necessary for the mental isolation of sensory effects and, therefore, as we shall see, are necessary for perception.

The process of attention is necessitated by two facts:  The first is that the information available to the sensory system is virtually limitless, whereas the capacity of a cognitive system to process information is quantitatively restricted in terms of the number of units of information the process can handle per unit of time.  The available information contains both an enormous range (in terms of diversity) and scope (in terms of hierarchical structure).  Attention accordingly involves selective control over the available modality, the available content, and the possible levels of focus.  (Control of mental focus consists of control over the level of detail, precision, or specificity attended to within the selected content.)

The second fact necessitating the faculty of attention is that cognition is a life process.  An organism born instantly able to extract and utilize a huge amount of vital information is a biological impossibility if only because of the tremendous versatility and complexity required for the appropriate, i.e., life-serving, contextual application of any unit of know- ledge.  Knowledge is not, biologically, an end in itself.  Its end is to serve the-life of the organism by proper contextual application.  Cognitive organs and processes are designed to enable the organism to optimize the extraction of maximally vital, i.e., contextually relevant, information, and are not designed to merely make possible the extraction of the maximum quantity of information.  Knowledge of facts about the environment is a survival need, but not all facts have equal survival relevance in any {57} concrete context.  Therefore, cognition must, of necessity, be a selective process.

Attention, Self-Initiated Movement, and Perception of the External world.

 In terms of its importance for perceptual development, the most critical differentiation achieved is the propriospecific / exterospecific distinction.  The hypothesis that I offer here is that this perceptual achievement is intimately dependent upon the perceiving organism’s capacity to notice and attend to the sensory effects accompanying self-initiated movement.  According to this hypothesis, during the very early stages of perceptual development, a series of “discoveries” take place.  What are discovered are several categories of ordered sensory effects, which are differentiated, based upon their connection to self initiated movement.  By attending to certain sensory effects, the young organism discovers that some effects are controllable by him, while others are independent of his control.  This represents the earliest form of an awareness of the difference between propriospecific and exterospecific sensory effects.  This stage represents the earliest awareness, therefore, of an external world, i.e., a world independent of the perceiver.  The capacity for self-initiated movement is an essential precondition for the segregation of these propriospecific and exterospecific sensory effects.  The perceiver discovers, by attending to their differences: (1) That some sensory changes are under his control and can be started, repeated, reversed and stopped by self-initiated movements of his receptor organs; (2) That some sensory changes are not controllable by self-initiated movements, but are independent of changes in the orientation of his receptor organs; (3) That there are constraints in the ways that sensory effects {58} change under categories (1) and (2), and that these constraints are independent of movement as such.  Effects under category (1) are propriospecific.  Effects under category (2) are exterospecific.  And constraints under category (3) specify external object stability or coherence.  Without awareness of propriospecific/exterospecific differences, no perception is possible.   Without the capacity for self-initiated movement, I submit that no awareness of propriospecific/exterospecific difference is discoverable.  Therefore, the capacity for self-initiated movement is a precondition for perception as such.

By attending to the sensory effects accompanying self-movement, perception of the external world emerges, as the organism simultaneously discovers: 1.  That he can control some of these sensory effects, by moving; 2.  That, reciprocally, he can use these sensory effects to control his movements 3.  That these effects specify self-movement, 4. How to know when he is moving, viz., from the fact that he can control these effects, 5.  That those effects uncontrolled by his movement specify external independent existence, 6.  That constraints in the formal changes (transformations) under self-movement or external movement specify stable external existents, i.e., objects.

This solution to the problem of how the distinction between ego and world is initially discovered was first suggested to me by a passage I read in one of Helmholtz’s chapters in his Treatise on Physiological Optics, entitled, {59} Concerning the Perceptions in General (reprinted in Warren and Warren, 1968):

In this sort of experimentation with objects some of the changes in the sense-impressions are found to be due to our own will; whereas others, that is, all that depend on the nature of the object directly before us, are urged upon us by a necessity which we cannot alter as we like, and which we feel most when it arouses disagreeable sensations or pain.  Thus we come to recognize something independent of our will and imagination, that is, an external cause of our sensations.  This is shown by its persisting independently of our instantaneous perception; because at any moment we like, by suitable manipulations and movements, we can cause to recur each one of the series of sensations that can be produced in us by this external cause.  Thus this latter is recognized as an object existing independently of our perception.  (p.  200)

Helmholtz concluded that from these sensory impressions we unconsciously infer the existence of an external world which is the cause of our sensations: But if we ponder over the basis of this process, it is obvious that we can never emerge from the world of our sensations to the apperceptions of an external world, except by inferring from the changing sensation that external objects are the causes of this change.  (p.  200)

Helmholtz believed that there is operative an innate “law of causation” which forces upon us the belief that our changing sensations are caused by the existence of external objects.  Helmholtz’s auxiliary hypotheses of unconscious inference and the innate law of causation are entirely unnecessary if we merely assume that the organism will notice, and automatically perceive, in different forms, sensory effects that are self-movement dependent and sensory effects that are self-movement independent.

According to the View that I offer here, the awareness of an external world of stable and moving objects is neither a mental construction nor an unconscious inference nor a conditioned response, nor is it a purely physiological achievement.  This awareness is the automatic form in which the differentiation between the three categories of sensory effects are noticed, {60} retained and integrated.  The perceiver does not “conclude” (consciously or subconsciously) that the cause of the difference he notices between exterospecific and propriospecific sensory effects must be “a world outside of a perceiving me.” Rather, the perception of an external world is the automatic form in which relationships between changing sensory features are integrated and retained.  We do not conclude that the external world exists; we perceive that it exists.  At this stage of cognition we are not aware of the world in the form of an inferential abstraction, we are aware of the world in the form of a perceptual concrete.  The perceptual world is neither a construction nor an abstraction, it is an extraction and integration from sensory givens.  It is a discovery that springs into awareness.  It is the form in which we experience the products of the automatic integration of the differences we have isolated mentally by controlled attention to sensory contents.

For the final form of my thesis that self-initiated movement is the key to the achievement of the propriospecific/exterospecific distinction I am fully indebted to J.  J.  Gibson who is the first to explicitly state that proprioception consists of “the detecting of those variants of stimulation that can be controlled,” (Gibson, 1967, p.  166).  A recent body of data dealing with visual prosthesis (Bach-y-Rita, 1972, 1975) clearly reveals the crucial importance of self-initiated movement in the development of prosthetic visual perception.  Subjects, who are congenitally blind, are fitted with a special apparatus consisting of a miniature “TV camera interfaced electronically to a 32 x 32 array of electrocutaneous stimulators.  The TV “image” is electronically transferred to the array of skin stimulators, producing an electrocutaneous pattern of stimulation {61} mapping the pattern of the TV image.  The perceptual experiences produced under conditions in which the subject did not control the TV camera, were dramatically different with respect to perceptual spatial localization, than were the perceptual experiences produced under conditions in which the camera was under the subject’s control.  Bach-y-Rita (1972), reports:

Using a fixed camera, subjects report experiences in terms of feeling on the skin, but when they move the camera their reports are in terms of externally localized objects.  Self-induced camera motion appears to be analogous to eye movements.  We suggested (B.  W.  White et al., 1970) that external localization of percepts depends critically on such movements and suggested that a plausible hypothesis is that a translation of the input that is precisely correlated with self-generated movement is the necessary and sufficient condition for the experienced phenomena to be attributed to a stable outside world.  . Conversely, in the absence of such a correspondence, the origin is perceived as being within the observer.  (Bach-y-Rita 1972, p.  100)

Given that a perceiver is capable of self-initiated action and given that the perceiver is able to notice the differences between sensory effects that are correlated with self-initiated movement and sensory effects that are independent of self-initiated movement, we have the basis for categorically differentiating these two classes of effects.  This differentiation is experienced in the form of “perceived subject vs. perceived object.” In other words, a perceived object is the form in which we automatically integrate and mentally retain the noticed sensory effects that are independent of our control.  Conversely, the perception of our selves is the form in which we automatically integrate and mentally retain the noticed sensory effects that are dependent upon our control, i.e., which are correlated with self-initiated movements.

Perception of self is not merely experienced as a center of geometrical convergence.  Self is, and biologically must be, perceived as a causally {62} efficacious center, i.e., as a controllable center, in a stable world.  This view of perception, therefore, links proprioception with self-control over sensory transformations.  The self is a causal center, not merely a geometrical center of sensory transformations.  This view connects perception of reality with perception of self as an active, i.e., behaving or potentially behaving, being.  The acquisition of perceptual data on the one hand and the regulation of behavior in accordance with that data on the other hand do not, in this view, have to be somehow brought together; they are already intimately united in the very act of perceiving.

Proprioception and the Autonomy of Self-Generated Movement

If self-generated movement is a necessary condition for the perception of external objects, it is reasonable to ask, how does an individual know that his movements are self-generated? The answer cannot lie in any of the attributes of the energy patterns stimulating the receptor organs, because all changes in these energy patterns which can be brought about by self-generated movement, can also be brought about by passively imposed movement, and yet, the experimental evidence indicates that the same energy patterns will produce different perceptual effects depending upon whether these patterns are caused by passive movement of the perceiver or by self-generated movements of the perceiver.

The experimental work on visual prosthesis, discussed earlier, is a dramatic illustration of this fact.  When a changing electrocutaneous pattern is controlled by the experimenter moving the prosthetic sensor (the TV camera), the subject reports contact stimulation, but when the same changing pattern is controlled by the subject moving the sensor, the perception of externally localized objects is produced.  There are other more familiar phenomena {63} illustrating the dependence of enteroception upon self-generated movement.  For example, when the eye is moved actively, the world appears to remain stable while our gaze is perceived as shifting.  But if the eyeball is moved passively, by applying pressure to the corner of the eye, the visual field appears to swing or rock in the same direction as that of the ocular movement.  Or consider another example: if we observe a strong after-image produced by a light flash in a totally dark room, it is found that when the eye is passively moved by the application of external mechanical pressure, the after image appears to remain stationary; but if the eye is moved voluntarily, the image appears to move, after a slight delay, in the same direction as the movements of the eye.

One seemingly plausible explanation of the differences in these perceptions is that during self-generated movement, there occurs a sensory “feedback” from the muscles and/or joints being moved, and that this feedback is somehow processed as self-generated movement.  This, however, is not an adequate explanation, if only for the reason that self-initiated and self-controlled limb movements, for example, can be carried out without any afferent feedback from the moving limb.! This fact is revealed by the results of an in-depth clinical study carried out and reported by Karl Lashley (1917), working with a patient suffering from partial anesthesia of both legs brought about as a result of a spinal injury.  Lashley’s clinical examinations and tests clearly established that this patient was totally unable to perceive the position of his lower leg or the direction or extent or movement of his leg, so long as these were controlled by the experimenter, and so long as these movements did not cause forces to be applied to other parts of the patient’s body, such as might occur during extreme or rapid displacements of the limb.  (Of course {64} the patient’s leg was visually shielded from him by means of a screen.) Although the patient was able to move his leg, he was unable to reproduce any movement of his leg manually induced by the experimenter.  Furthermore, even though the patient could briefly hold his leg in any position set by the experimenter, the patient could not tell what position his leg was occupying.  Yet, in spite of this total lack of sensitivity to movement or position of his leg, the patient was able, with almost normal accuracy, to bring his own leg into any requested position and to move his leg in any requested direction for any requested distance.  From the results of these tests and performances, Lashley concludes:

We are rather forced to the conclusion that the phenomena observed are independent of afferent excitations from the moving organ.  The experiments have shown that the subject is able to control the extent of his movements with almost normal accuracy, to vary the speed and extent of movement independently, and to make rhythmic alterations of flexion and extension.  The evidence for anesthesia makes it necessary to assume that all these activities may be carried out in the absence of excitation from the moving organ.  (p.  70)

The results of Lashley’s investigation strongly suggest that consciously initiated and controlled movements do not necessarily depend upon and are not necessarily guided by proprioceptive afferance, and that consciously initiated sensory-independent movement is possible.  The meaning of this last statement is that our awareness that our movements are self-generated is not itself a sensory awareness, nor-is it caused by our sensory awareness.  In the light of the foregoing, I will suggest that our awareness of the fact that an act is self-generated is an irreducible psychological primary the datum for which is an internal psychical event.  Sensory effects may provide us with knowledge that we are moving, but only the direct awareness of the internal psychical event of “intending” can provide us with knowledge {65} that we are acting.  Our perceptions do not cause our awareness of ourselves as self-generated movers, but it is our awareness of our selves as movers that determines how sensory patterns will be perceived.  We saw, for example, in the case of the after-image viewed in a dark room, that moving the eye passively results in no perceived change in the position of the after-image, whereas voluntarily moving the eye results in the perception of the image as moving with the eye.  Conversely, if the eye muscles are paralyzed, mechanical movement of the eye produces the perception that the visual field is moving in the opposite direction from that of the eye; whereas, “every intended but unfulfilled eye movement results in the perception of a quantitative movement of the surroundings in the same direction,” (Von Holst, 1954, p.  501).  Thus it is possible for our intentions-to-act to affect our perceptions when there has been no change in the energy patterns stimulating our receptors.

These conclusions about the nature of self-generated movement are both consistent with and demanded by the view of perception that is offered here.  For if the awareness of self-generated movement is a precondition for proprioception/exteroception, as I hold it to be, then proprioception cannot itself be a precondition for the awareness of self-generated movement.

As to how the propriospecific/exterospecific breakthrough is achieved, I can only speculate that by some process of directed attention, the newly conscious individual discovers (1) that he can cause certain sensory patterns to change, and (2) that some of the attributes in these changing patterns are under his control, whereas others are independent of his control.  These discoveries are automatically integrated and experienced in the form of the propriospecific/exterospecific distinction.  Only after this latter integration {66} is achieved, however, can the individual discover that what he is doing to control the changing sensory patterns is moving his receptors relative to his external surroundings.  In other words, awareness of himself as a non-specific causal agent is prior to and a precondition for proprioception, i.e., awareness of himself specifically as a being moving about in an external world.  In conclusion, autonomous self-generated motor action must precede and provide the basis for the perceptual discovery of self-generated movement and the perceptual guidance of self-generated movement.

Perceptual Learning

The Automatization of Attention and Receptor Movements

Because perception depends upon conscious focus and selective attention, and because the conscious mind is severely limited in terms of the number of units which can be simultaneously held in conscious focus; perceptual development can only progress when the conscious mind is freed from the necessity of repeatedly controlling the attentional processes responsible for past perceptual achievements.

The means by which the conscious mind is freed is by making automatic the attentional procedures underlying past perceptual achievements.  The process of automatizing consciously acquired methods and products is called learning.  The degree to which a conscious process is automatized is measured by the degree to which it is no longer consciously initiated, directed, controlled, or maintained.  In the case of perceptual learning, the conscious process that is automatized is the control of attention.

In part, attention is a sensory-motor skill, insofar as perceptual learning involves learning to control the movements of ones receptor apparatus so as to increase ones perceptual clarity of the isolated content.  This I will call, the process of optimization of perceptual clarity through {67} motor control of the receptor apparatus.  Note that according to this concept sensory learning and motor learning are not separate skills, but are two aspects of any perceptual learning and always develop hand-in-hand.  They are joint determinants of perceptual development.  Increased motor efficiency depends upon increased sensory efficiency, and vice versa.  The senses are sharpened by increased motor control and motor control is increased by sharpened senses.

Perceptual learning consists of “streamlining” the process of attention.  By “streamlining” I mean the systematic and progressive elimination of in- essential procedures.  Or, stated positively.  the progressive isolation of essential procedures for making differentiations and integrations.  Perceptual learning consists, in part, of learning to make finer as well as faster discriminations.  It is the learning of faster discriminations that frees the mind to learn to make still finer discriminations.  Learning to make faster discriminations means learning to quickly differentiate between objects and between parts or attributes of objects.  This is achieved by gradually learning the essential features of objects.

Virtually every object in the environment contains a tremendous amount of perceptible detail.  Because the number of units of information one can hold in conscious focus is limited, however, we cannot perceive every perceptible feature of every entity in our sensory field at the same time.  In order to deal with the enormous amount of available data, we learn to identify the critical or essential features of objects and learn to pay little attention to non-essential and redundant features.  Perceptually, an essential” object feature is one which is critical for the making of a perceptual discrimination or integration in a particular perceptual context. {68}

Please note that this process of streamlining requires that we first laboriously attend to many details of many objects, and therefore, presupposes object perception.  Attending for essential features is an advanced stage of perceptual development.  Its function is to free the conscious mind to make new differentiations.

We learn not only the features of objects, we also learn how objects look under different conditions of observation, i.e., in different perceptual contexts.  This skill allows us to make rapid differentiations and integrations, even under conditions of deficient stimulation.  For example, we learn how objects “look” under static monocular conditions of observation.  If we were forced to View the world exclusively under such conditions from birth, of course perceptual development would never occur, indeed perception as such would be impossible, we can learn to deal with the world perceptually under deficient stimulus conditions only after we have discovered the world under adequate conditions.

Perception and conceptualization

It is undeniable that higher-level cognitive processes, particularly the process of concept formation, can be of immense value in facilitating the perceptual learning of fine differences and the perceptual integration of complex patterns.  This is because conceptualization makes it possible to deal with actualities in terms of there mere potentialities and to consciously deal with perceptual givens in terms of abstract knowledge about facts which are not perceptually given.  As a consequence, conceptualization makes it possible to set as the aim and purpose of perception the search for merely possible differences or relationships.  In this way the process of perceptual attention can be conceptually regulated. {69}

Since attention is regulated by purpose, the more highly differentiated the purpose, the more precise the attention.  Conceptualization makes possible the direction of attention that is not “stimulus bound” (i.e., direct, in terms of perceptual givens).  For this reason conceptualization extends the range of possible perceptions.  Although conceptualization can control what one attends to or notices, it cannot determine the content of perception.  This is limited by the givens in the available energy gradients.

Developmentally, conceptualization, i.e., concept formation, genetically depends upon the prior development of sense perception.  The givens of concept formation are the objects perceived by means of our sense organs.  Concept formation cannot begin until the perceptual level of cognition has been achieved.  Concept formation makes it possible to classify and categorize objects to treat objects as members of a class, i.e., as units; to generalize from knowledge of one member of a class to all others in that class; to deal with objects in terms of principles and rules; to make inferences from what is given to what is not given; to make assumptions about facts not given in terms of perceptual givens; to move beyond actualities and treat the world in terms of its potentialities or possibilities.  All of these conceptual processes can be, to some degree, automatized and made to operate subconsciously, but before they can be automatized, they must first be acquired consciously, and, as I have said, being conceptual processes, they all rest upon and presuppose the prior achievement of the perceptual level of awareness.  Perception, therefore, cannot depend upon these processes.   Any theory that holds that conceptual processes are necessary for perception is invalidated by that premise alone.  Any theory that holds that our perceptions are the product of “unconscious inferences,” “unconscious assumptions,”{70}”unconscious betting, wagering, probabilistic weighing,” etc., cannot be correct.    For such theories can never explain how perception betting takes place.  All such theories either fail to grasp the genetic priority of perception, or they entirely misconceive the nature of conceptualization.

Both perception and conceptualization involve processes of differentiation and integration.  But the principles underlying the processes of perceptual differentiation and integration are fundamentally different from those underlying conceptual differentiation and integration.  The goal of perceptual differentiation is the achievement of increased discriminations and identifications of individual, concrete, particular entities and attributes of individual concrete entities.  To achieve this end, the organism attends to order and structure in changing energy gradients.  When a sequence of sensory events occurs, the organism notices that there is an order or “structure in the changing sequence.  The particular components of this sequence are integrated in terms of their detected order.

The goal of conceptualization is “cognitive expansion by unit reduction,” (Rand, 1966).  Concept formation consists of (1) grouping entities in terms of their common attributes, (2) disregarding the magnitude differences in the shared attribute, and (3) treating each entity in the group equally as an instance of a higher order unit, viz., as a particular kind of entity.  Conceptualization treats entities as units, i.e., as entities of  kind.  In concept formation entities are differentiated in terms of their differences,  i.e., in terms of their non-commensurables, and integrated into mental units, called concepts, in terms of their similarities, i.e., in terms of their commensurable attributes (Rand, 1966).

Magnitude differences are crucial for perceptual differentiation, but {71} are treated as inessentials for concept formation, on the implicit learned premise that the magnitude of a property does not affect the essential nature of that property.  Furthermore, perceptual components are integrated on the basis of internal detected order; whereas, conceptual components are integrated on the basis of an external commensurable “common denominator.” Of course, perceptual awareness is the precondition for conceptual categorization, but categorization is not a perceptual process.  It is a process that moves beyond sense perception and requires a volitional consciousness capable of mentally detaching entities and attributes from particular concrete situations (Rand, 1966).  It is a process requiring the capacity to assume the abstract attitude toward perceptual concretes (see Goldstein & Scheerer, 1941).

Latest page revision: April 19, 2014 4:00 pm

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