Reflex action

“ Imagine my efforts at teaching the training class psychology! The other day we were struggling with the subject of reflex action, and one of the girls handed in this definition as she had understood it from me! "Reflex action is of a activity nervous. It is sometimes the don't understand of what it is doing and stops many messages to the brain and sends the motion to the legs." ”

“ The higher function of nerve action, which we call the intellect, as distinguished from simple reflex action and from instinct, is the choice among different responses to the stimulus of external realities. As conditions of life become more complex, the demands of external realities become more exacting. ”

“ Reflex action is non-mental neuro-muscular adjustment, due to the inherited mechanism of the nervous system, which is formed to respond to particular and often recurring stimuli, by giving rise to particular movements of an adaptive though not of an intentional kind. ”

“ That a reflex action is determined by the sensory mechanism, no one disputes;468 whether the reaction of a sensory mechanism shall be called a sensation or not, is a question of terms. I have shown why it must be so called if anything like coherence is to be preserved in physiological investigations; and I have more than once suggested that the fact of intellectual processes taking place at times with no more consciousness than reflex actions, is itself sufficient to show that a process does not lapse from the mental to the mechanical sphere simply by passing unconsciously. ”

“ Reflex action is earlier established than voluntary action. In a child most activity is reflex—unconscious. It may be complex, modified by many contradictory stimuli, but whatever else modifies it, a clear personal determination seldom does. ”

“ Secondary Reflex Action.—Everyday experience teaches that any voluntary action becomes easier by repetition. A given act performed a number of times under conscious direction establishes a condition in the nervous system that enables it to occur without that direction and very much as reflex actions occur. ”

“ The conception of reflex action is surely one of the best conquests of physiological theory; why not be radical with it? Why not say that just as the spinal cord is a machine with few reflexes, so the hemispheres are a machine with many, and that that is all the difference? The principle of continuity would press us to accept this view.
But what on this view could be the function of the consciousness itself? Mechanical function it would have none. The sense-organs would awaken the brain-cells; these would awaken each other in rational and orderly sequence, until the time for action came ”

“ Most people know something of what is meant by reflex action. The nerves which pass from the various organs to the brain convey with, great rapidity messages to its various parts, which are answered by reflected waves of impulse. ”

“ When a stimulus promptly arouses a reaction, and that ends the matter, we speak of reflex action--provided, of course, the connection between stimulus and response is native. But when a stimulus sets up a tendency to a reaction that cannot be immediately executed, or towards an end-result which cannot immediately be reached, and when the tendency so aroused persists for a time in activity, and gives rise to preparatory reactions, then we speak of instinct. ”

“ Supposing also that emotions, desires, sensations, and "motives" in general, occupy the same relation to the volition, which they precede, as the stimulus of reflex action, and are also the effect determined solely by an external stimulus, we have action in every respect like the reflexes. We are prepared to admit that a great many actions are so mediated. ”

“ Diagram of the nerve path of a simple reflex action.
Reflex Actions; their Meaning.—If through disease or for other reasons the cerebrum does not function, no will power is [Pg 354] exerted, nor are intelligent acts performed. All acts performed in such a state are known as reflex actions. The involuntary brushing of a fly from the face, or the attempt to move away from the source of annoyance when tickled with a feather, are examples of reflexes. In a reflex act, a person does not think before acting. The nervous impulse comes from the outside to cells that are not in the cerebrum. ”

“ In the reflex action we find all that constitutes in some sort the very groundwork of an intelligent act—that is to say, the same series of stages, in the same order, with the same relations between them. ”

“ III Just above our unconscious mental modifications appear the reflex actions, or instincts. Here experience is translated into action before it reaches consciousness; that is, though the actions accomplish intelligent ends, there is no previous knowledge of the ends to be accomplished. A flash of light falls on my eye, and the lid closes. It seems a wise act. The brilliant light is too fierce. ”

“ Reflex action is the effect produced by an impression made upon a sensory nerve, transmitted by that nerve to a nerve-center, and reflected or thrown back along a motor nerve in much the same way as we may imagine the force to be which is applied to one end of a string running over a pulley and transmitted in a different direction by the other end to produce a certain effect. ”

“ The Uses of the Reflex Action.—The reflex activity of the cord is exhibited in the healthy body in many ways, but since it is never accompanied with sensation, we do not readily recognize it in our own bodies. Reflex movements are best studied in the cases of other persons, when the conditions enable us to distinguish between acts that are consciously, and those that are unconsciously performed. For example, if the foot of a person soundly asleep be tickled or pinched, it will be quickly withdrawn from the irritation. ”

“ Reflex action is generally acknowledged to be clearly related to instinct. Reflex acts are products of evolution even more highly organised than the instincts. It is therefore quite in accordance with the function of suppression in relation to instinct that this process should come into action in connection with the reflexes. ”

“ Now the moment an emotion is causally accounted for, as the arousal by an object of a lot of reflex acts which are forthwith felt, we immediately{382} see why there is no limit to the number of possible different emotions which may exist, and why the emotions of different individuals may vary indefinitely, both as to their constitution and as to the objects which call them forth. For there is nothing sacramental or eternally fixed in reflex action. Any sort of reflex effect is possible, and reflexes actually vary indefinitely, as we know. ”

“ The other element, beginning with that immediate passage of a single stimulus into a single motion, called reflex action, presently comes to be a set of associated discharges of stimuli producing associated motions; constituting instinct. Step by step arise more entangled combinations of stimuli, somewhat variable in their modes of union, leading to complex motions, similarly variable in their adjustments ”

“ Meanwhile, we can already see one consequence and one point of connection with the reflex-action theory of mind. Any mind, constructed on the triadic-reflex pattern, must first get its impression from the object which it confronts; then define what that object is, and decide what active measures its presence demands; and finally react. The stage of reaction depends on the stage of definition, and these, of course, on the nature of the impressing object. When the objects are concrete, particular, and familiar, our reactions are firm and certain enough,—often instinctive. ”

“ Simple reflex action is an instinctive expression, manifesting an intuitive perception, almost intelligent, as shown by the contraction of the stomach upon the food, simply because it impinges upon the inner coats, and thus excites them to action. A better illustration, because it displays sympathy, is when the skin, disabled by cold, cannot act, and its duties are largely performed by the kidneys. ”

“ Certain acts repeated again and again have established conditions in the nervous system which enable definite forms of action to be excited, somewhat after the manner of reflex action. On account of habits, therefore, the actions of the individual are more or less predisposed. What he will do under certain conditions may be foretold from his habits. Habits simply represent, a higher order of secondary reflexes—those more closely associated with the mental life and character than are the lower forms. ”

“ These activities are at first entirely voluntary, but by repetition they gradually become reflex, requiring only the stimulus to start them.
The advantages to the body of its acquired reflexes are quite apparent. The mind does not have to attend to the selection and direction of stimuli and, to that extent, is left free for other work. A good example of this is found in writing, where the mind apparently gives no heed to the movements of the hand and is only concerned in what is being written. The student will easily supply other illustrations of the advantages of secondary reflex action. ”

“ The formation of sudden, irreversible conclusions on the slenderest evidence is less distant from reflex action than is the formation of deliberate and modifiable conclusions after much evidence has been collected. And similarly, the quick passage of simple emotions into the particular kinds of conduct they prompt is less distant from reflex action than is the comparatively-hesitating passage of compound emotions into kinds of conduct determined by the joint instigation of their components. ”

“ It is true that the resulting compound psychical changes do not take place with the same readiness and automatic precision as the simple reflex action instanced; it is true that some individual experiences seem required to establish them. ”

“ Thus we see the ordinary movements of the animal continuing to be repeated with only that part of the nervous system in operation which is capable of producing reflex action. What the entire creature has been accustomed to do, the separate parts continue to do when cut off from the guiding influence of the sensorium. ”

“ By reflex nervous action is meant, action which one part of the nervous system exerts over another part, without any intermediate action on the brain, and consequently without consciousness; or which, if it does pass through the brain, at least produces its effects independently of the will. ”

“ A vast amount of our activities are reflex, and in such action an efferent stimulus follows an afferent promptly and quite mechanically. It is only where efferent stimuli do not immediately become entirely transmuted into outwardly moving impulses that mental action comes in and an animal feels. ”

“ I see an example of it in the way in which many of them account for our thoughts and resolutions: they call them reflex action. The discovery of the nature of automatic motion was one of the most important discoveries of the last age. An action goes along a nerve to the centre of a ganglion, and comes out in motion by another nerve: thus, if a frog's foot is pricked, it is immediately drawn in. Of much the same kind is the reflex action of the sensori-motor system. ”

“ The central process which initiates a reflex action may be excited by the external stimulation of a peripheral nerve, by the internal stimulation of a peripheral nerve, or by the irradiation from some other part of the central tissue. ”

“ In other words, they are reflex acts.
'The reflex actions proper to the spinal cord itself are NATURAL, and are involved in the structure of the cord and the properties of its constituents. By the help of the brain we may acquire an affinity of ARTIFICIAL reflex actions. That is to say, an action may require all our attention and all our volition for its first, or second, or third performance, but by frequent repetition it becomes, in a manner, part our organisation, and is performed without volition, or even consciousness. ”

“ Our flesh shrinks from what it dreads and responds to the stimulus of what it desires by a purely reflex action of the nervous system. Our eyelid closes before we are aware that the fly is about to enter our eye. ”

“ The nervous system of man, inherited from that of the lower animals, may be regarded as primarily a means of making locomotion safe. The reflex action of the nerve center is the type of all mental processes. ”

“ It also indicates how such nervous relations may be complicated by other connections of [Pg 41] the nerve-cells involved in the reflex action. It will be seen that they make many upward connections with the brain, in consequence of which consciousness may be involved. Ordinarily one is more or less conscious of reflex action, though the will is not involved; in fact, a willed or voluntary action is usually considered the reverse of a reflex or involuntary action. But for a reflex action the brain is not essential. ”

“ Is there not here much more than what our modern physiologists are prone to call [Pg 247] automatic movements, the results of reflex sensorial action? The more I study the lower animals, the more firmly am I persuaded of the existence in them of psychical faculties, such as consciousness, intelligence, will, and choice! ”

“ Grasping for your hat when you feel the wind taking it from your head is an example. These acquired reactions never reach the extreme speed of the quickest reflexes, but at best may have about the speed of the simple reaction. Though often useful enough, they are not so fundamentally necessary as the reflexes. The reflex connection of stimulus and response is something essential, native, closely knit, and always ready for action. ”

“ Any agency, such as heat or pressure, which, by acting on the neurons of the body, is able to produce a sensation, may be called a sensation stimulus. It has perhaps already been observed that the stimuli that lead to voluntary action, as well as those that produce reflex action of the muscles, cause sensations at the same time. ”

“ Big movements, such as the combined action of all four legs of an animal in walking, require cord and brain stem to work together, and throw into relief what is really true even of simpler reflexes, namely that a reflex is a coordinated movement, in the sense that different muscles cooperate in its execution. ”