Bob Davis
Mar 31, 201913 min
Perception - Ronald .H. Forgus
“Neither the whole truth nor the whole of good is revealed to any single observer although each observer gains a partial superiority of insight from the peculiar position in which he stands”
The field of perception would make a greater contribution to the emerging identity of psychology if it were related to the broader context of the cognitive processes. This conviction is discussed in detail in this book., where it is strongly held that a course or a book on perception should extend itself to complete the treatment of what seems to be a unified whole, namely , the developing integration of perception, learning, and thinking in the processing of information. The book does not seem to include every known area or publication, which seems relevant to the task. The present approach has therefore been to select a set of guiding principles that appear to be directing our understanding about the nature of information extraction and its contribution to general behavior.
The style of perception is intended to be instructive rather than argumentative. By this statement I do mean to imply that instruction excludes arguing. On the contrary, sophisticated instruction necessitates a certain amount of critical debate. The main concern in the present volume, however, is to transmit a body of meaningful knowledge about perception and thinking without spending much time on controversial issues, the status of which seems unclear at present. This choice was based on the fact this text is intended primarily for the students interested in cognition and perception.
Having developed the basic thesis that perception is the superset of information extraction, with learning and thinking as subsets, I go on to discuss why I think, on both logical and experimental grounds, that an exclusive or empirical theory of perception is untenable. Perception is organized in an ordinal hierarchy, beginning with built- in programs and developing by increasing degrees to modified programs. First psychophysical functions and problems of methodology, and then the principles organized around each level of the hierarchy are analyzed, from brightness through form to social perception and conceptualization. Since the concept of information extraction was used to analyze and conceptualize the process of perception, this analysis is extended to the area of thinking in the last four chapters, although technical language is held to a minimum.
There are many ways that a book on perception can be organized. This one has placed the process of perception within the context of man’s general need to adapt to his environment if he is to cope effectively with the demands of life.
Definition of Perception: In this quest for adaptive behavior the way the individual gains knowledge about his environment is of prime importance. The gaining of such knowledge necessities the extraction of information from the vast array of physical energy, which stimulates the organism’s senses. Only those stimuli, which have, cue value, which trigger some kind of reactive or adaptive action from the individual, should logically be called information.
For our purposes, perception will be defined as the process of information extraction.
When we compare the higher mammals and especially man with the lower animals, we are tremendously impressed with the fact that the adaptive perceptual processes of the latter are largely completed through genetic evolution. That is to say, their perceptual programs are built in, wiredin, or prewired at birth.
Can you count the Number of Black Dots?
Information regarding structure and lightness based on phenomenal transparency influences the efficiency of visual search
Phenomenal transparency reflects a process, which makes it possible to recover the structure and lightness of overlapping objects from a fragmented image. This process was investigated by the visual-search paradigm. In three experiments, observers searched for a target that consisted of gray patches among a variable number of distracters and the search efficiency was assessed. Experiments 1 and 2 showed that the search efficiency was greatly improved when the target was distinctive with regard to structure, based on transparency. Experiment 3 showed that the search efficiency was impaired when a target was not distinctive with regard to lightness (ie perceived reflectance), based on transparency. These results suggest that the shape and reflectance of overlapping objects when accompanied by transparency can be calculated in parallel across the visual field, and can be used as a guide for visual attention.
Are the lines straight?
The book further covers the physical factors, which causes perception. The most common among them are Light, Mathematics, People and art. The author emphasizes that perception becomes the core process in the acquisition of knowledge or cognition. He thus conceives of Perception as the superset, with learning and thinking as subsets subsumed under the perpetual process.
The author than takes us further defining relationship between perception, learning, and thinking. The thesis is that perception is a superset, which subsumes the subsets of learning, and thinking in the total act of information extraction may seem too novel or strange for some individual
Perception, learning, and thinking have traditionally been referred to as the cognitive processes since they all deal, to some extent, with the problem of knowledge. Perception can generally be defined as the process by which an organism receives or extracts certain information about the environment. Learning is defined as the process by which this information is acquired through experience and becomes part of the organism’s storage of facts. Thus the results of learning facilitate the further extraction of information since the stored facts become models against which cues are judged. The most complex of these cognitive processes, namely, thinking, is an activity that is inferred to be going on when an organism is engaged in solving problems, which also involves the use of models.
Further the author discusses the four stages involved in producing the final product of perception. These sequential stages were stimulation by energy; sensory transduction of this energy; brain reception, selection, and, modification of this energy; and the perceptual response or experience. An attempt was made to define the nature of the information-extraction process in man. A discussion and an illustration of the importance of considering the two-way interaction between perception, learning, and thinking in an understanding of this process were presented. The problem of information extraction, ending with our conviction that modern psychology subscribes to an approach to psychophysical correspondence which believes that perceptual patterns or organizations begin with an intrinsic structure based on built-in programs and that these become modified through the specific effects of learning and practice.
Is the circle round?
Further the hierarchical organizations of perceptual segregation were discussed in details.
The order, listed from the simplest to the most complex task, conforms to the following sequence:
· The detection of the stimulus energy (light) and a discrimination of change in
Stimulus energy.
· The discrimination of a unified brightness or figural unity as separate from the
background.
· The resolution of finer details, which gives rise to a more differentiated figure.
· The identification or recognition of a form or pattern.
· The manipulation of the identified form; this happens, for example, in problem
solving and social perception.
The book illustrates many experiments by Wever and Bridgen (1933) to find the trend of the quantitative thresholds. Also other experiments by Hebb(1937), Drury(1933).
By using such criteria, as the amount of energy required, the relative importance of sensory and central functions, the influence of experience, and ontogenetic and phylogenetic development, the author has established an order of perceptual segregation.
This hierarchical order consists of the following subtasks:
· Detection of light and change in light energy.
· The gross discrimination of a figural unity.
· The resolution of a more clearly differentiated figure.
· The identification of form.
· The manipulation or modification of form, as in social perception and problem
solving.
Through various experiments the author finally concluded that tasks 1 and 2 are more strongly determined by sensory factors, while the progression from task 3 to task 5 requires the increasing involvement of the brain, learning and experience.
The determination of how small a stimulus a person could detect and how small a change he could discriminate raised the question of what kind of measuring scale one could construct in perception The author has not discussed in details the basic psychophysical methods assuming that it will have been encountered in standard courses and texts dealing with experimental psychology, rather he gave attention to objections or challenges for classical methods on methodological grounds and to the suggested alternatives which have been proposed.
The author first described briefly the classical psychophysical determination of thresholds and single- dimensional scales. Then he discussed some modified methods designed to study the same problems investigated by traditional approaches.
Finally, he mentioned the fact that recent innovations in methodology now give us an approach to the measurement of more elusive subjective variables, such as beauty and familiar identities.
The author further discusses some of the visual data, which have been collected and systematized by using psychophysical methods. The book does not discuss the physics and physiology of the visual process. The author further discusses some of the major variables, which determine the precision with which the eye as a sensory receptor can perform perceptual task1 i.e., the detection of light or change in light. These variables were then grouped affecting threshold into three classes, which, of course, have interacting effects. Under the heading ‘State of Organism’ effects of retinal locus and receptor adaptation. Under” Nature of the Stimulus” the factors of spatial area, temporal duration, and wavelength composition were discussed. Under “Patterning” the phenomenon of spatial acuity and a kind of temporal acuity measured by the CFF were discussed.
Which is the lowest step?
The world that we see does not consist simply of collection of scattered light intensities and nuances of hue. Rather it is organized into certain units and patterns, which we call attributes and which seem reliable, orderly, and dependable. The author further defines more fully the nature of brightness, size, and shape constancy .The author describes various experiments and concludes that the studies reviewed, which used primarily the psychophysical methods of adjustment and constant stimuli, suggest that whiteness constancy operates because the organism responds innately to differences between the intensity of reflected light relative to the intensity of pooled reflected light coming from a common background or frame of reference. If the common background is missing or illumination conditions are such as to preclude this relative perception, then illumination matches based on the absolute differences are made.
The theory offered to explain these facts is based on the ratios of reflected light; taking into account albedo and absolute intensity .It also subsumes color-contrast phenomena.
Whiteness constancy is a sensory fact, not appreciably affected by learning; that is the organism does not have to learn to respond to relative differences between the reflectance of each object and its background. Although the observer responds innately to this relation between the object and background reflectance the accuracy with which the ratio is matched is affected by field experiences in the natural world.
The author attempts to point out the ways in which whiteness, shape constancies differ.
Cue gradient and cue density interact in the detection and recognition of objects defined by motion, contrast, or texture. The human visual system is able to extract an object from its surrounding using a number of cues. These include foreground/background gradients in disparity, motion, texture, colour, and luminance. We have investigated normal subjects' ability to detect objects defined by motion, texture, or luminance gradients. The effects of manipulating cue density and cue foreground/background gradient on both detection and recognition accuracy were also investigated. The results demonstrate a simple additive relationship between cue density and cue gradient across forms defined by motion, luminance, and texture. The results are interpreted as evidence for the notion that form parsing is achieved via a similar algorithm across anatomically distinct processing streams.
Are the holes on the inside or the outside?
Although most illusory figures published in scientific articles are very simple and abstract, visual illusions are not confined to vision laboratories. They also occur in nature
and our daily life (Gregory and Gombrich 1973). The facet of human culture that takes advantage of visual illusions most actively is probably clothing. Clothes manufacturers and fashion magazines keep touting dresses that make you look slender, boots that make Your legs look longer; jackets that make you look younger, and so on. One well-known. Flattering effect is the apparent lengthening of legs by high-cut bathing suits . It is obvious that, when viewed from the side, a high-cut bathing suit exposes a larger area of the hip, which looks like an extension of the leg thus making the leg appear longer. However, there is a possibility that a high-cut bathing suit makes the legs look longer even when the actual length of the legs is clearly visible in a frontal view.
How many rods does the fork has?
The change-detection results correlated well with the oddity data. They confirmed that face inversion had little effect upon detection of changes in eye color, a moderate effect upon detection of eye-position or mouth-color changes, and caused a drastic reduction in the detection of mouth-position changes. An experiment in which uncued and fully cued subjects were compared showed that cueing significantly improved detection of feature color changes, but there was little difference between upright and inverted faces. Full cueing eliminated all effects of inversion. Compared to partial cueing, changes in mouth color were poorly detected by uncued subjects.
One can conclude that uncued subjects encode the spatial relations of features more than the colors of features that mouth color in particular is not considered a relevant dimension for encoding, and that familiarization redistributes attention from more to less salient facial regions. Inversion effects are not simply an exaggeration of the salience effects revealed by withdrawing cueing, but represent an interaction of spatial encoding with salience, in that the greatest inversion effects occur for spatial shifts in less salient facial regions, and can be eliminated through the use of focused attention.
Can you spot the dog?
Aging and the perception of speed
Two experiments were conducted to explore the potential effects of aging upon the perception and discrimination of speed. In the first experiment, speed difference thresholds were obtained for younger and older observers for a variety of standard speeds ranging from slow to fast. The second experiment was designed to evaluate the observers' ability to discriminate differences in the speed of moving patterns in the presence of significant amounts of noise (the noise was manipulated by limiting the lifetimes of individual moving stimulus elements). The results of both experiments revealed a significant deterioration in the ability of the older observers to perceive or detect differences in speed. While the presence of noise was found to affect the observers' discrimination performance, it affected both younger and older observers' thresholds in a proportionally equivalent manner -- the older observers were no more affected by noise than the younger observers.
Inversion effect: Rabbit or Duck?
Inversion has a disproportionate disruptive effect on the recognition of faces. This may be due to the disruption of holistic or configural encoding employed to recognize upright faces. The paradigm developed by Tanaka and Farah (1993 Quarterly Journal of Experimental Psychology, Section A 46 225 - 246) was used to investigate the effect of 90°(or orthogonal) rotation on configural encoding. Faces learnt in the orthogonal condition were not recognized as well as upright faces, but a whole-face advantage was found in both cases. This whole-face advantage did not occur for inverted faces. It appears that 90° rotation affects recognition but not specifically configural encoding. It is concluded that rotating a face can have at least two different effects on face processing depending on the range of rotation. Implications for the nature of facial dimensions and the expertise account of the inversion effect are considered.
Are the red lines straight?
The brain transforms sensory messages into conscious perceptions almost instantly Chaotic, collective activity involving millions of neurons seems essential for such rapid recognition.
When a person glimpses the face of a famous actor, sniffs a favorite food or hears the voice of a friend, recognition is instant. Within a fraction of a second after the eyes, nose, ears, tongue or skin is stimulated, one knows the object is familiar and whether it is desirable or dangerous. How does such recognition, which psychologists call preattentive perception, happen so accurately and quickly, even when the stimuli are complex and the context in which they arise varies?
Social Perception:
The perception of motion and kinetic events is determined by relation existing between elements of time space and brightness .Moreover certain configurational events , such as figure –ground ,radius and action and common fate , also influence the perception of motion and phenomenal events .The analysis of the configurational aspects of kinetic events are used to begin the study of social perception. The author states that the social perception studies can be fitted into two descriptive classes Whether we respond to social aspects innately or whether we do so in an open .There is also a third kind of perceptual learning designated as the influence of learning on the development of differential –reaction sets .Thus factors such as values , anxiety and the like influence our ability to perceive by affecting our discrimination or judgment of already perceived stimuli through making us more or less sensitive to certain attributes of the stimulus complex or by accentuating certain parts of errors when the stimulus is unclear. Through learning individuals can respond differently to the potential cues or information carried by unclear or impoverished stimulus complexes, and so on. By exploring the field this way, i.e,. by realizing that emotions, motivation , or personality factors can only influence the reaction to already perceived things, we shall clear away a lot of the mystery and mysticism which tend to be prevalent in the area of social perception.
Sets in cognitive behavior and thinking:
The author further describes an experiment which was followed by a detail analysis of the influence of set, defined as a perception which is structured within the narrow bounds that facilitate a certain specific type of activity or thinking. The major advance which began an ended with the gestalt research was that the investing of thinking moved away from analyzing the content of thought to studying the act of thought as the process of thinking .This was more desirable because of the greater objectivity which became possible.
Concept formation and Language:
A critical analysis of the principles of cognitive behavior indicates that concept formation is the process which bridges the gap between perception, learning, and thinking. The author further describes how these three are co-related for adequate treatment of cognition. The author begins by postulating that successful thinking depends largely on the individual’s ability to group or reorganize problem material into a more meaningful relationship .Concept formation , therefore , becomes the most important basis for problem solving since it provides the categories which the individual will have available for grouping the elements presented in a problem statement. Finally the author points out that there is some impairment of the conceptual thinking of individuals who have suffered organic brain damage.
Problem Solving:
The author begins with brief description of the stages and purposes of problem solving .He then proceeds to a discussion of how effectively information is transmitted and assimilated from such varying stimulus conditions as positive and negative instances in concept attainment. Next he looked at sequential effects in problem solving in the work of such people as H.H.Kendler on reversal-shift learning and Harlow on learning sets .He finally ended with a discussion of some problem-solving strategies which come from the work of Bruner, Goodnow, and Austin. A theoretical starting point, based on information theory and decision theory, was described as a framework for further research in the field of problem solving.
Conclusion:
The book has dealt with the processing and utilization of information by humans. The author first described the nature of built in programs that exist in all humans. He further describes how this built- in programming ability proceeds up a hierarchy to a more complex programming which is modified by experience and learning’s. The author has added details of many experiments to explain the complex process of perception. But, he concentrates more only on the visual effects and motion effects and does not discuss in details the social aspects of perception. Though in the later part the author has highlighted the important conceptualization in current cognitive work and has aided in developing an appreciation for the broad area of human behavior. One is impressed by the tremendous flexibility and modifiability of man’s ability to deal with information.
Samir Bahirat