[vinnomot] Humanism and Psychology: ( Comp 7): Human Information Processing

 

Understanding Ourselves and Our Universe: How Psychology Can Turn the "Mysteries of Human Nature" into Useful Tools for Self Improvement and Success in Life

 

Part 7: More details about human information processing (receiving and processing information about our world)
Making sense of sensations The basic neuropsychology of sensation and perception
As is true of all animal organisms, humans have specialized organs for receiving stimuli and translating those stimuli into processable form for use by the central nervous system (CNS). Contrary to the "common ancient wisdom" that we have only five senses, humans in fact have at least twelve different sensory input systems. While our sensory systems have obviously served us well enough -- since human adaptation constitutes one of the great success stories in all of evolution -- human senses are not the best in the animal kingdom (except with the aid of technical extentions like microscope, telescope, internet, phone, radio, video, camera, car, aeroplane, ultrasound etc.). Other animals have much more acute senses (e.g., vision, hearing, and smell), and some even have sensory systems humans don't possess (e.g., the "echo location" sensory system of dolphins, and sharks' ability to detect small electrical fields over relatively large distances). Worse still, humans don't even possess all the senses necessary for survival; e.g., although oxygen respiration is absolutely necessary for life, we have no sense that tells us when there is no oxygen in the air we breathe! Given any odorless, colorless gas to breathe, humans will quietly and happily fall asleep and suffocate without ever having a clue that anything is wrong, as in most accidental carbon monoxide and carbon dioxide deaths. Incidentally, for those who believe humans were perfectly created by a divine designer-maker, this little sensory inadequacy poses a major problem in their explanation; i.e., either that "designer-maker" made a big mistake, or that "designer-maker" didn't know that humans need oxygen to live! The much more useful theory of evolution, in contrast, simply says that the lack of an oxygen-sensing receptor hasn't yet proven sufficiently deadly to keep us from breeding and continuing our species. Should there be a serious oxygen depletion event or gradually worsening oxygenation condition on earth, however, human evolution could take a sharp turn for the worse some time in our future. Our 12 Sensory Systems start with the "familiar five" -- which everyone is aware of, but are really eight senses, not five: vision, hearing, smell, taste, "touch" (which is actually made up of four different sensory systems: the two temperature senses of cold and warm, plus two contact senses of light and heavy pressure). In addition to those basic eight, we also have four other sensory systems: the vital sense of pain (which warns us of bodily dysfunctions), the proprioceptive or kinesthetic sense (that provides feedback from our muscles and joints to allow us to determine the orientation of our body parts in space), our sense of balance or equilibrium (located in our inner ears), and somatic senses located in various organs and glands (to give our brains feedback on internal bodily functions, often via the Autonomic Nervous System). The sole function of each of our sense organs is exactly the same: to translate stimulus energy into neural impulse energy (energy transduction) via specialized neurons called sensory receptors. (All 12 of our sensory systems have different sensory receptors.) Until our sense organs transduce an energy source external to the CNS into neural impulses, we cannot be aware of that stimulus. Sensory experience is actually a CNS function, since if visual stimuli are never transduced into neural impulses, we will not see that stimulus, regardless of how well our eyes are functioning, and the same is true for all 12 senses. In intact nervous systems -- i.e., a person with all the necessary neurological components functioning normally -- all our sensory experiences are produced by neural activities in those 12 sensory systems and combinations thereof. For example, the proper combination of "warm and cold" receptors is sensed as "hot;" the proper combination of "pressure" and "pain" receptors is sensed as an "itch." Thus, our universe is really made up only of what our receptors can sense. Aspects of our universe that we cannot sense -- such as important elements like infrared light, ultraviolet light, and the microscopic and sub-microscopic universe of the very small, must be mechanically translated into visible light for us to see them, and therefore to know they existat all. People who rely on "revealed evidence" or "self-evident religiouss knowledge" are prisoners of their own faith and not of their sensory and cognitive limitations. Humanists, on the other hand, welcome new information provided to us by science and technology on all aspects of the universe (our senses plus their technological extentions), including on ourhuman potentials and capabilities, and benefit ourselves and others by keeping up with such progress.
Making "sense" of sensations - human perception
What we usually think of as "sensation" (e.g., seeing, hearing, itching, hunger) is not the sole function of our sensory organs (eyes, ears, skin, stomach) at all. Sensory experience is actually a CNS function called perception; i.e., attaching meaning to the neural impulses carrying the transduced sensory stimulus. Vision, hearing, and all the other sensory experiences which we so take for granted actually occur in areas of the brain specialized for that purpose. Seeing a ball, for example, requires that the light from the ball be received and transduced into neural impulses by the retina in the eye (the sense organ); then those neural impulses must be carried up toward the brain, where other neurons specialized for visual reception register the visual image, and still other neurons in the brain recognize that visual pattern from memory as "a ball." Thus, to perform even a simple perceptual experience like seeing a ball requires four related but separate neural functions: 1.  energy transduction (in the retina) 2.  energy transmission (from the eye to the CNS, via the optic nerve) 3.  sensory reception (in the visual reception area of the occipital cortex of the brain) 4.  sensory association (from visual association and memory areas in other regions of the brain). Given for the moment that the simplest and most complex sensory-perceptual experiences are all products of these four sequential neural steps, let's address the key question: What is "meaning," and where does "meaning" come from? This topic can be addressed in much greater depth, but for now we can say that all such meaning comes from two sources: genetically pre-programmed perceptual instincts, and previous learning experiences stored in memory. In the ball example, your brain will automatically interpret the shape and depth cues of the ball to perceive it as a sphere. It takes previous experiences with such shapes and language to recognize it and label it a "ball," or to recall that such a shape with light rays in a certain range of the color spectrum is "white," or to recall that such spheres of a certain size with darker angled patterns (the stitches) are of a type called "baseball," and to tell that the absence of other marks on the sphere means it is a "new baseball." In an intact nervous system, our instincts and memory operate quickly and apparently seamlessly to produce the CNS perceptual experience of "seeing a new baseball." Without the sensory experience's "meaning" provided by instincts and memory, all we could "see" is a meaningless sphere (if even that); we would know nothing about what it was, or what it was used for, or what to call it, nor could we communicate our perceptual experience to anyone else. Thus, what we usually think of as a simple sensory experience is actually a fairly complex integration of genetically pre-programmed energy transduction, genetically pre-programmed and experientially programmed and re-programmed energy transmission, genetically pre-programmed and experientially programmed and reprogrammed sensory reception, and predominantly experientially programmed and re-programmed sensory association. In other words, the neural equipment and its basic operation is almost all genetic, the all-important "meaning" aspect of perception is mostly learned, and each and every step of this stimulus processing sequence can be disordered or destroyed by ill-learning or trauma (to the sense organ, the sensory transmission neurons, the sensory reception neurons, and/or the memory storage and retrieval neurons). "Murphy's Law of Neuropsychology" states that for every function, there can be an equal and opposite dysfunction, ranging from 0% to 99.999%. 100% destruction would equal a total disability.
The basic neuropsychology of sensation and perception
In order to understand how we actually receive and process information, and to then be able to improve some of our own information processing, we must learn a bit more about the neurological functions that determine sensation and perception. We will use the running analogy of a computer to illustrate each component and its basic functions and dysfunctions in recognizing a familiar face. There are other models and theories, but we think this one is the best for both accuracy and ease of understanding. [This is basically a five-step information processing model, incorporating a three-store model of memory, based on the work of Peterson and Peterson (1965), Atkinson and Shriffrin (1971), Klatzky (1980), and Koon (1991), among many others. And there are other SciPsy models; but I like this one best.] Before exploring the way humans process cognitively mediated information, let's briefly dispense with the simplest stimulus -> response, the aforementioned reflex arc. As with all other animals, humans have a genetically pre-programmed repertoire of instinctive responses triggered by a particular stimulus. Examples are kicking when struck just below your knee with a rubber hammer (the patellar tendon reflex), blinking when a puff of air hits your eye (the eye blink reflex), feeling angry when frustrated (the frustration-aggression response), or a baby smiling when its cheek is tickled (the cute and cuddly reflex. All humans with intact nervous systems have exactly the same human information processing sequence. To ease into some of the higher cognitive functions not included in the first basic S -> R sequence example, let's consider the information processing (IP) steps in viewing a familiar face. The brightness of the face stimulus are encoded by the number of sensory neurons simultaneously firing; the colors of the face are encoded by the frequency of sensory neuron firings; and the color saturation (shadings and features) is encoded by the particular pattern of sensory neurons firing. If the sense organ misses any of the face's key features, or the sensory neurons do not perfectly encode any of the stimulus characteristics, this could produce sensory misinformation (an unrecognizable code for the face, or a code which is more likely to be interpreted as being that of a different face). Although almost automatic, this step is considerably more complex than we are routinely aware. (For a fascinating account of a severe disorder exemplifying the importance of this IP step, read the true and poignant biography called The Man Who Mistook His Wife for a Hat by Dr. Oliver Sacks.)range of instinctive reflexes. Human newborns' repertoires are almost entirely instinctive, but as we develop into maturity, instincts represent an increasingly small fraction of our psychological repertoire. In fact, one of the main factors that put humans highest on the phylogenetic ladder is our relatively small proportion of instincts compared to all other animal species, which have a much higher percentage of instincts in their adult psychological repertoire. Thus, if you want to be correct well over 90% of the time when asked, "Why did [insert anyone here] do [insert any behavior here]?", the answer is "He/she learned to do it that way!" The vast majority of thoughts, feelings, and behaviors we exhibit as adults are learned from environmental experience by the previously studied principles of learning. The cognitively mediated phenomena we'll study next is another example of the basic Once all the facial characteristics are successfully encoded, the sensory transmission fibers simply have to carry the same codes to the CNS for perception. In this case, the sensory transmission fibers begin with the optic nerve, which transmits two reversed, inverted images of half the visual field through a major neural junction called the optic chiasm, then through other specialized nerve centers in the subcortical thalamus, and finally up to the visual reception area of the occipital lobe in the back of one's brain. We won't go into the details of neural transmission here, but suffice to say that if there were any "short circuits" in the neurons that either blocked transmission or changed its codes, we would perceive either a greatly changed face, or perhaps no face at all. If somehow the visual transmission fibers were not connected up correctly to the visual perception area of the brain's occipital cortex, but went somewhere else instead, we could actually "hear" the visual stimulus (if it were connected to the specialized auditory reception area in the brain's parietal lobe), or even "feel" it (if it were connected to the specialized somatosensory reception area elsewhere in the parietal lobe). There are unfortunate people with cross-wired, "non-intact" central nervous systems who can "smell" sights and "see" sounds. Further evidence of this phenomenon is found in numerous experiments using electrical stimulation of the brain (ESB), where researchers can artificially stimulate sensory transmission fibers or sensory reception neurons with tiny electrical charges -- imitating who knows what exact neural codes -- and routinely produce a sensory experience. Note that with sense organ stimulation alone there is no sensory experience. But sensory transmission fiber or CNS visual reception neuron stimulation alone does create sensory experience. So we don't really see with our eyes; we actually see with our brains!

 

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