Discuss the six broad classes of perceptual phenomena

Perception is the state of being aware of something through senses, it is therefore an image that reflects on mind and stimulates memory. The phenomena of perception can be classified for our present purpose under six heading. The six broad classes of perceptual phenomena are below-

1. Sensory quality and dimension
2. Figural or configuration aspects
3. Perceptual constancy
4. Dimensional Frame of Reference
5. Concrete objective character
6. The prevailing set or state

Sensory quality and dimension
First a small paper disc is shown on a white background. We notice that it appears red. Another disc is shown which looks blue and so on. A certain experienced quality. The tone we hear, the smell of a rose, a taste, a pain, an experience of pressure, warmth or cold are other familiar examples. We also observe that the quality has associated with it certain quantities or dimension. In vision, at lease the quality is spread out or extended, it seems to occupy space. Related to quality we have also the experience of intensity or of strength.

One gray disc looks brighter or darker then another, one red is stronger than another. Qualitative experiences also endure through time. Sensory qualities and dimension, therefore, constitute one general aspect of the way things appear to us. It is true that these qualities and dimension are often modified by the conditions or surroundings under which they are observed, such for example, as background and illumination. They may interact with one another in many ways, but the existence of qualities can never be fully accounted for by this interaction.

There has been some difficulty with classification and terminology in this field. Looking at the matter from the standpoint of pure conscious awareness Titchener regarded sensation as elements of consciousness and quality, intensity, extensity, duration and clearness as attributes of sensation. It seems better, perhaps, to-regard not sensation but the experience of quality as a basic fact in our awareness of our world, a fact contributed by the process of the organism itself to the energies received from the stimulus.

Figural or configuration aspects
Our second class of perceptual phenomena contrasts sharply with the first. Though like those in the first they are experiences arising from things in the environment, they seem even less determined by the stimulus and more determined by processes inside the organism. They exhibit strongly the effect of one thing upon another in the perceptual manifold, an effect which frequently produces optical of other illusions. They are concerned mainly with the formal properties of the thing we perceive, such as shape, outline, grouping, and the like. Looking at a circle drawn with ink on a white card, we note that the appearance of its size is altered if it is placed between parallel lines or enclosed in an angle. It can be made to appear distorted into part of a spiral by a twisting line along its course and by special features in the background. A square turned up on one of its corners looks quite different fro the way it appears when its upper and lower edges are in a horizontal position. Looking at the drawing of the circle again, but without accompanying lines or angles, we see that it encloses an area that is segregated from the surroundings, and that the line of the circle itself is a contour that seems to belong to the circle as its edge and not to be the edge of a circle hole in the background. We see that circle appears as a definite “figure” standing forward clearly and that the rest of the card seems to extend beneath it as a less vivid ground.

Figure and ground are ubiquitous aspects of perceptions. In every sense modality our word consists of figures appearing against grounds and where other aspects are not in control there are a number of rules that determine which part shall be figures and which ground. In drawings in which either portion may serve as figure or ground there is usually a shift of the percept back and forth from one figure-ground experience to the opposite.

Perceptual constancy
Suppose now there is presented a circular disc, first directly before us in the frontal plane where it is of course seen as circular, and then in a position titled away from us so that the image it produces on our retinas is elliptical in shape. We still tend under the latter conditions to see the disc as circular, not as elliptical. We do not however, see it as perfectly circular, but as a compromise that favors the circular more than the elliptical form. This is the phenomenon of perceptual consistency. It preserves for us consistency of appearance and thus the means of recognizing and identifying objects when they are seen at different angles or in different distances and of colors and brightnesses under differing conditions of illumination. Cues given by the object and surroundings enter intimately into perceptual constancies. There cues seem to be utilized in agreement with past experience and for the most part they give us fairly veridical perceptions.

Dimensional Frame of Reference
A fourth class of aspects appears when we are faced by the problem of giving absolute dimensional judgments concerning the members of a series of stimuli. This feature is not to be confused with sensory dimensionality as it was discussed in our first category where for example, brightness or loudness were estimated with reference to some objective standard. The aspects we are now considering refers, rather to the question of what we call bright or dull light or heavy loud or faint and the like with respect to stimuli that we experience. Suppose for example, that we are presented with a lot of circular discs of the same size, one after the other. Let the discs, however, be in the form of spots of light thrown on a screen and differing over a fairly large range in brightness. We are to judge for each disc whether we consider it to be bright or dim or medium. Though no standard of reference is given, there will probably be determined, after series of stimuli has been presented, a degree of brightness that looks to the observer as neutral that is a degree above to be dim. The individual, in other words, forms his own subjective scale of judgment. We shall call this phenomenon the dimensional frame of reference.

Concrete objective character
It is a universal aspect of perception that will seem almost too obvious to mention. It is quite distinct from any of the aspects we have described, though it is related to them. Though it is not necessary to do so, let us approach the matter by beginning with sub threshold conditions. Suppose we are looking at some object, with a view to identifying it, under very brief exposures in a series of trails are then gradually lengthened or the illumination is gradually increased. We see at first a kind of reddish blur having a roundish form, but identification of the objects does not come. Exposure or illuminations are further increased and we try again. A number of trails without success or with misperceptions may occur. Then all at once, we recognize it. It is an apple. It is not a red circular disc, it not a beet or round red ball- but an apple. We can not say it is just color experience. It is not adequately characterized by its configurational or wholeness properties alone.

This aspect of perception is so universal and characteristic that it would be hard to find anything regarding the appearances of things that is more significant. Things and event appear to us not as mere qualities, dimensions or forms but as things and event. Concrete object character as we shall call it is a fundamental property of practically all our perceptions.

The prevailing set or state
It is an aspect of perception in which individual differences as well as differences in the state of an individual at different times, play an important role. It has long been known that particular sets of the individual or attitudes, either long standing or momentary affect the selection of the objects that will be perceived. Phenomenologically they also result in a greater attentive clearness or vividness of those objects. To this aspect of perception the concrete object character of the stimulus is especially relevant, for when we take the character and meaning of the object into account we can often see a relation between it and the state the individual is in. The phenomenon is most clearly shown with respect to objects that we are looking for or meaning that we are seeking to realize from stimulus-situations that are undetermined or vague.

Perceptual sets or readinesses induced by needs are both common and important. Emotional states may also determine perceptual readiness or the manner in which we perceive certain objects or relation. An illusion in which, on a dark night, one sees a tombstone in a cemetery as a ghost is a timeworn example. The way in which indefinite or ambiguous things are perceived may to some extent be influenced by the individual characteristics of the perceiver, a fact implied by the use of the Rorschach test for personality diagnosis. However, overlook the fact that the set to perceive may often be based not upon any strong motivating, emotional o personality edition, but upon nothing more dramatic that the frequency and familiarity of the object in the observers experience.