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ESSAY: Motivation, the Pleasure Response and the Evolution of the Survival Instinct
Posted By Robert DePaolo On December 5, 2010 @ 12:19 pm In Psychology | 1 Comment
This article discusses the biological roots of the survival instinct and offers speculation on the origin of motivation and the perception of pleasure. The point is made that these phenomena can be viewed as adaptations to increased systemic biological/cellular complexity.
The Anthropomorphic Barrier
One of the problems inherent in describing natural phenomena is that we – the describers – are prone to viewing nature through the lens of human experience. We tend to define processes such as the survival instinct, motivation and pleasure in emotional and cognitive terms; for example, with phrases like the “will to live”, or “a fear of death,” despite the fact that all organisms, including those without the neurological software that ostensibly provide cognition and emotion also behave in ways driven by survival, pleasure and motivation.
For example, many creatures with little or no brain display very sophisticated and purposeful behavior patterns. The spider, without a frontal lobe and therefore without (in human terms) executive functioning capacities is able to plan ahead in its pursuit of prey by weaving a web as resilient as steel without need of any materials other than those spun out of its own body. Leaf cutter ants are able to store mulch in the earth until it reaches the point of fermentation, at which time they eat those materials in what amounts to an agricultural behavior pattern. Some wasps paralyze spiders with venom, then lay eggs in the spider’s abdomen. When the eggs hatch, a ready-made meal awaits the offspring, who dine on the innards of the spider. Such parental planning over a long period of time is reminiscent of the human parent who buys savings bonds for his son’s college education. Yet the wasp and spider brains are miniscule compared to ours. As Fetzer (2005) suggested, there are numerous examples of behavior typically attributed to higher intelligence that do not in fact required higher intelligence.
In this paper a similar concept is applied to basic functions that compel organisms to survive, prompt behavior and provide the perception of pleasure. We can begin by discussing the earliest stages of evolution.
The Epoch of Movement
The first life forms appeared roughly 4.5 billion years ago. These were the prokaryotes; single cell structures with organelles floating inside an osmotic membrane in a symbiotic but minimally integrative manner. They were not capable of movement. Several billion years later, the more advanced eukaryotic (nucleated) cells evolved. They differed from the earlier version because they were more integrative. All the genetic material, including ribosomes, organelles etc were encased in a central part of the cell – the nucleus. The first task of both organisms was to remain intact and they did so by extracting from and exchanging energy with the external environment (Allen 2010). But this was not a function of “will” or any other psychic process. Their internal resilience was simply related to the fact that the elements within the cell were housed within a membrane and were interactively congruent.
The eukaryotes were arguably the forerunners of a process known as biological complexity. Not only did they contain more genetic material than their predecessors, the prokaryotes, they also developed a layered anatomy with a nucleus separate from, yet integrated functionally with the cell body. Having a nucleus helped insulated some of the fundamental elements of the cell from outside contact and also led to a regulatory system by which internal monitoring could ensue. That is significant, because for any complex biological system to endure, it must have some capacity for internal regulation. That is because a complex system without some sort of homeostatic or regulatory mechanism could not keep all its various parts cohesive. If the separate parts clashed, or operated in a manner completely detached from one another it would create chaos, interference, and entropy, leading to an evolutionary dead end.
Thus, as cells began to become more complex, their sub-components began to communicate. To illustrate: If cellular component A exhibited a certain behavior, cellular component B would have to exhibit a certain behavior to hold the process together. That balancing act, which typifies all psychological and physiological aspects of the biological world, might have led to phenomena we now refer to as the survival instinct, motivation and the perception of pleasure.
Stasis and Survival
The question of how and why motivation, the perception of pleasure and a penchant for survival came about has not been answered definitively. Therefore the question remains as to why all organisms, large and small, cephalic and a-cephalic have an innate resistance against termination.
Use of the term “survival instinct” is not terribly helpful in making that determination. It suggests some sort of neural configuration, either in a brain or primitive nerve net that creates fear and entails a preference for life over death, as implied in Darwin’s writings; or perhaps a trait enabling organisms to in effect “wager” their way through life (Hamilton (2010) or the existence of “selfish genes” that govern all behavior from the outset (Dawkins 1976) – the last of which would require, ironically, an a-cephalic intellectual capacity on the part of simple genes.
For humans death is an analytic process – the word “analytic” referring generally to cognitive, perceptual and emotional appraisals regarding life and death. We fear leaving this earth, worry what will happen to our children, ponder questions about past accomplishments, deeds undone, goals unmet, fences un-mended. However since such thoughts and are not available to other creatures and since they too behave in ways to avoid death we must look for some other explanation. Thus remains the question of how and when did the survival instinct and phenomena such as pleasure and motivation originate.
A Possible Model
It might have begun with the advent of complexity. More specifically, as soon as cell conglomerates became more complex, monitoring mechanisms became essential to maintain the overall integrity of the cell complex. A signal system was needed to provide information regarding the moment to moment physical and dynamic integrity of the complex. The signal could not have arisen from a brain function. Organic complexity and the survival imperative existed from the outset whereas brains only appeared on the scene until about 550 million years ago with a rather simple bundle of nerves at one end of the flatworm body.
In discussing “internal communication” and “regulation” one typically thinks in terms of neural pathways. Yet while having no brain would have precluded inter-communication in electrochemical ways the cells would have been able to communicate in chemical ways.
Once the cell complexes became integrative so too did their chemical interactions. Since the cells were also composed of physical features, ie. protons, electrons etc which provided attractive/binding and repellant/energizing potentials (the roots of anabolism and catabolism) an a-cephalic recognition factor began to emerge. It was not an instinct per se, or an emotional trait. It was a simple behavioral reaction in which a self corrective mechanism derived from the memory of cellular integrity attempted to correct errors in cybernetic fashion to restore stasis. Thus the survival instinct might have begun as an error-correcting process that restored the organism to a state or to parameters to which it was accustomed. It might have represented a kind of biological inertia reflecting the tendency among all organisms with cyto-complexity to remain intact, resulting quite naturally from a monitoring and communication process within the cellular complex.
In that context, the apparent contradiction arising from the notion of a survival instinct and the fact that organisms without instincts or brains exhibited this characteristic is potentially resolved by simply stating that the “survival instinct” originated from the integrative momentum within the cells to remain in a steady state. All subsequent emotional, cognitive and philosophical manifestations of the drive to survive are presumed to derive from that basic process.
The Assimilation of Being and Doing
As organisms continued to evolve maintaining stasis involved a more complicated process, especially with the advent of movement capacities, which probably originated quite by accident with cellular protrusions extending from membrane scales and cilia. Beyond merely holding itself intact, mobile, complex organisms had to be concerned with energy conservation. Movement uses up more energy, thus the mobile organism requires more of it. They also had to factor in sensory perception – and one other thing. To move purposefully requires directionality. Directionality entails approach/avoidance behavior. Random movement is not helpful and in the long run potentially maladaptive, since it uses up energy without providing a high probability means by which to efficiently pursue or find new sources of food or avoid threat. Thus movement and directionality had to co-evolve for either capacity to pass the fitness test. The fact that eyes and appendages appeared during the Cambrian time period is indicative in that sense (Myers 2007), Waloscek, Chen et al 2005)
Immobile organisms weren’t necessarily maladaptive. The ocean is obviously turbulent and provides its own movement, carrying nutrients which stationary organisms could absorb. Also water is known in bio-chemical circles as the “universal solvent” because it breaks down molecular materials. That would have made ingestion and fuel conversion fairly convenient even for prokaryotic cells. Furthermore, mobility entailed a certain risk. Just as the nomadic proclivities of homo sapiens created environmental pressures favoring hominids with enhanced perceptual and cognitive abilities so did movement in the oceans require advanced decision making capacities. Consequently some mobile organisms developed an electrochemical transmission capability in the form of nerve nets which are now seen in various types of worms.
Before that could happen, primitive organisms had to undergo a physical re-alignment. All organisms – in fact all cells of any type – react to energy signatures as per Newton’s first law of motion. However it is the nature of the reaction that counts. As the body begins to move it must devote more body space and mass to the act of movement. That means its soma must become more specialized. As the middle portion becomes more devoted to controlling appendages, the front and hind sections will tend to become more functionally distinct.
That did occur and it created a trend toward body symmetry as well as a differentiation between the front/facial, and a rear/rectal ends. It was as though life itself discovered new dimensions in the course of evolution, requiring new faculties to perceive and act in terms of those dimensions.
With one end devoted to ingestion of nutrients and the other to eliminating unwanted nutrients the organisms so constructed became more energy efficient. The head/ anus design was a major success. The head could perceive sources of nutrition and was also the anatomical component responsible for absorbing nutrition – one stop shopping, as it were. It was also capable of picking up light sources and other energy signals and that made it a more aggressive seeker and problem solver, and ultimately more effective at restoring stasis.
The evolution of movement and body specialization appears to have been adaptive, but there was a catch to this. It also produced a byproduct known as competition. Such a beneficial adaptation proliferated among many organisms and eventually hordes of creatures were traveling around the ocean floor, occasionally conflicting with each other over access to nutrients, and as size differentials and teeth evolved even more occasionally dining on one another. That led to an evolutionary watershed.
The Eating Habits of Hunter-Travelers
The concept of “food” is so concrete, yet so mysterious in a broadly natural context. Why do animals seek certain prey? Why do some implicitly “know” that plants and animals provide nutrition? Is there something in the oldfactory system signaling that “this smells good” and “that doesn’t?” Is the Great White Shark contemplating the taste of a seal or simply recognizing its form, then attacking? The impetus involved in food intake is sort of like survival in that it has no definitive explanation. All organisms know what they should eat – small brain, large, brain or no brain for that matter. In order to explain eating habits one must assume that on some level all organisms know what makes up their bodies and therefore what ingredients are needed to replenish those bodies.
The animal body is a kind of smorgasbord, consisting of fats, sugars, protein and other components. Once that reserve of materials is depleted it becomes necessary to find more protein, fats and sugars to replace the loss. In other words, to survive, all creatures must have some sort of internal template directing them to “ingest something very much like yourself in order to replenish yourself.” It is virtually an isomorphic process.
This of course refers to the evolution of hunting and foraging capacities, but while such food finding behaviors favored survival the process might have been more complicated than that.
Organisms without a movement capability were forced to absorb what came to them, yet survived for a very long time. The way in which they did is a key to understanding the origins of eating behavior. Eating involves two general strategies, one of which is general, the other specific. An organism can ingest a lot of material, some of which nutritious, some not, and with adequate eliminatory capacities let go of the waste products. By employing that strategy almost anything can be ingested as long as it contains some degree of nutrition. Thus a human being lost in the woods could conceivably eat tree bark – as did some of the early hominids such as Homo erectus (Caldecott 2010) and extract some degree of nutrition from that. Yet while a generic eating strategy can be sufficient for a creature with a low energy turnover (ie. metabolism). a traveling organism needs something more specific and its food-attainment strategies would have to be more focal and efficient.
One way to do that would be to develop nerve signals registering a sense of taste, so that non-nutritive materials could be “taste-tested” the way some sharks mouth, then discard, non edible objects. The materials we need to survive all have a distinct taste. Sugar is sweet. Fat is salty. Protein is similarly attractive to the pallet, which is why so many animals fall prey to the lure of peanut butter in traps. It turns out that the taste buds of animals savor protein, sugars and fats – the same materials that make up and rebuild their own bodies. Such appetitive/anatomical isomorphy led to hunting as an adaptive behavior pattern in the oceans.
As organisms became mobile and efficient at seeking out nutrients, another element was added to the cell complex known as the animal body. A guidance mechanism responsive to external perceptual phenomena had to be added to the equation. At that point, integrity-maintenance included not just internal, cellular monitoring, but also movement, energy expenditures and perception. Consequently homeostasis expanded into a broader mechanism encompassing both the organisms and its environment. This might have set the stage for a new capability known as memory.
The More Things Change
That does not mean the basic dynamics of survival and motivation changed. In nature there are only so many ways to skin a cat and the process of restoration still involved information and error correction. The process might not have been very complicated. An organism came upon an object, mouthed it, rejected it, traveled further, found a digestible object and indulged. As it did so, activation of its neurons continued for a while, along with a concomitant re-apportioning of neuro-chemicals. Due to the duration of the activation the neural trace attained a high probability status and thus dominated the nerve net or brain. That created a preference or associative ‘probability spike” leading to a heightened attraction to the energy signatures, taste, and smell associated with that object. It was a process consistent with Premack’s definition of learning and memory as a function of skewed algorithmic probabilities in the brain. (1963).
In a small, sparsely wired brain that was significant because that dominant neuro-chemical trace could then be passed on to offspring. That doesn’t mean the subsequent generation inherited an instinct. It does mean it inherited a high probability, skewed and dominant pattern of neuronal receptivity.
The Evolution of Tension and Uncertainty
Yet having singular memories, no matter how adaptive, can become problematic after a while. It relegates the organism to narrow concerns and possibilities so that environmental change might eventually leave its brain “skewed” in the wrong direction. Furthermore, an organism might eventually encounter several sources of nutrition, several locations for the same source of nutrition or perhaps a look-alike object that was not only non-nutritious but downright dangerous. In that case it would need more than singular memories to survive and propagate. Under such conditions more than memory was needed. Consequently, a sensory discrimination capacity became necessary; in effect a yes/no binary program that led to differential responsiveness, featuring excitation/inhibition shifts in response to changing stimuli.
As soon as sensory discrimination capacities evolved (possibly as the result of simple brain growth and neuronal complexity) a secondary process, tied closely to pleasure and motivation might have emerged. It could be best described as a need and capacity for neuro-chemical resolution.
Despite the research of Olds and Milner on pleasure centers in the limbic ring (1954) a capacity to perceive pleasure appears to have originated prior to the evolution of the limbic system. While Olds and Milner’s classic study of the septal and hypothalamic areas did result in feelings of pleasure and sustained reinforcement-seeking behavior their research did not rule out the possibility that organisms without limbic circuits can feel pleasure. Olds himself warned about anthropomorphizing by insisting that organisms with very little brain can learn ro approach some stimuli and avoid others. He asked implicitly: If not from the existence of pleasurable and/or aversive states why would they engage in this sort of behavior?
To answer that question, first, consider that since the earliest “motivated” creatures had simple brains, the mechanism by which pleasure is regulated might have been simple as well. Conceivably all that is needed to create a pleasure response is some degree of competition among neurons for pre-eminence in the course of any given experience. When neurons are aroused, yet no single neuron or cluster is probabilistically dominant it tends to create activity. This will often include movement and behavior. When behavior occurs and when that behavior creates a new dominant pattern, irrelevant neurons are released from consideration. As a result the normal order of probabilities is restored. More important, an error manifest as neuronal uncertainty will have been corrected, information is attained, normal skewing is reinstated, stasis restored. Now the organism can engage in activity absent undue background noise and neuronal competition.
In that context the factor common to survival, motivation and pleasure might well be neuronal resolution. It is concisely defined as a shift from irresolution to resolution (Berlyne (1974). It has parameters. For example the greater the initial irresolution the greater the pleasure once it is resolved. The more rapid the shift from uncertainty to resolution (as in sexual release) the more heightened the pleasure response.
Contrary to the Freudian concept of tension reduction, neuronal resolution does not have to result in lowered arousal levels, merely a restoration of homeostasis in terms of the usual state of the organism. Thus a caged lion, well fed might be in a state of relaxation. However it has a typical activity-rest cycle that is programmed in its brain-body system and is supported by a specific metabolism. If it cannot adhere to that stasis it will become agitated and its capacity to sense pleasure will be diminished despite a low tension level.
Due to use of terms like resolution and uncertainty this is an information-based model. As such it is somewhat limited in describing complex biological and evolutionary processes. On the other hand it requires no psychological or experiential explanations (such as selfish genes or cognitive appraisals) to explain why all creatures insist on remaining alive, why they become motivated and why pleasure is such as important aspects of the lives of all organisms.
To help provide clarity regarding a fairly complicated, winding article the following synopsis might be helpful. It is in the form of a bio-logic.
In order to comprise what we refer to as “life” a structure has to have some degree of complexity. For it to remain extant and adaptive that complexity must be integrated and modulated. Any proto-biotic material without that capacity could not be defined as a life form or be viable enough to endure in any case (Berlyne (1974)
A complex biological entity needs to have biological inertia, i.e. a proclivity to remain intact. It must also have an error correcting mechanism arising naturally, automatically and in a sense, bio-mechanically. It must have regulatory/internal communicative abilities enabling it to recognize when deviations (errors) from stasis occur. When the correction occurs as a result of its biological inertia (or “memory” generically speaking) the precursors to pleasure, motivation and the survival instinct are activated. As brains and bodies become more complex in evolution this process was amplified as a result of greater neuronal competition/ neuronal resolution sequences. Each organism feels or interprets this basic process according to its own level of complexity. With exceptionally large, complex brains humans extend it to the existential/linguistic domains. Yet the paradigm remains the same for all organisms Survival, motivation and pleasure are reflective of error correcting processes of varying degrees of complexity such that organisms with and without brains, emotions, cognition and other mental faculties display these features in their behavior.
Allen, F (2010) Redox Homeostasis in the Emergence of Life; On the Constant Internal Environment of Nascent Living Cells. Journal of Cosmology. Vol. 10 3362-3373
Berlyne, D.E. (1974) Studies in the New Experimental Aesthetics: Steps Toward an Objective Psychology of Aesthetic Appreciation. Journal of Experimental Psychology 103, 240 – 244
Caldecott. T. (2010) Diet: A Short History. Health and Medicine, Physiology.
Dawkins, R. (1976) The Selfish Gene New York, Oxford University Press
Fetzer, J. (2005) The Evolution of intelligence: Are Humans the Only Animals with Mind? Open Court Publishing
Hamilton. G.R (2007) Game Theory; How the Mind Actually Works and Why We All Survive. Kindle Publishing, Game Theory.com
Minelli, A. (2003) The Origin and Evolution of Appendages. International Journal of Developmental Biology Vol. 47 7-8, pp 573-581
Olds. J & Milner, P. (1954) Positive Reinforcement produced by electrical stimulation of septal area and other regions of the brain. Journal of Comparative Physiological Psychology 47: 419-427
Premack, D (1963) Rate Differential Reinforcement in Monkey Manipulation. Journal of Experimental Analysis of Behavior. 6: 81-90
Waloscek, D. Chen, J. Mass, A & Wang, X. (2005) New Insights into the Arthropod Head and Structural Evolution,. Arthropod Structure and Development; 34, 189-205
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