The following article addresses human motivation from two perspectives. The first is based on genetic/evolutionary predispositions to behave in ways that enhance adaptation. The second is uncertainty reduction (neuropsychological resolution) as pertains to the role of immediate experience in prompting behavior beyond evolutionary influence. The argument is presented that behavioral heritability cannot singularly or even primarily account for human motivation and behavior.
In essence, the theory of natural selection appears to rest on solid ground. The notion that organisms undergo periodic mutations and that such mutations must be either consonant or at least not counterproductive vis a vis the demands of specific environments is virtually a tautology. Indeed given that mutations do occur and would invariably have some impact on structure and function, one could ask legitimately how it could be any other way.
Yet there are potential problems associated with the theory. As a result some have begun to question, not the barebones logic of natural selection, but its capacity to explain comprehensively how organisms change, adapt and most important of all, sustain the motivation that leads them to behave in an adaptive manner. (Bergman 1992), (Kutschera & Niklas 2004)
“EP”: NUTS AND BOLTS
The field of evolutionary psychology deals primarily with behavioral evolution. Its main thesis holds that like physical traits, certain human behaviors were either hard-wired or rendered highly probable in the course of evolution. In some sense the argument has merit. For example it would explain certain cross-cultural redundancies in human behavior that one might expect to be more variable if the environment were the prime source of influence (Joyce 2006).
However there is also a counter-argument. Unlike physiological traits, behavior is malleable and while not infinitely pliable, highly influenced by immediate environmental concerns. Arguably that is one reason it does not fit neatly into the natural selection template. One of the more confusing issues regarding behavioral evolution has to do with motivation. The confusion involves several factors. For example:
1. If evolution led to specific behavior patterns (presumably imbedded in the central nervous system) as a result of long term adaptive demands why would there be a need for motivational structures and dynamics in the brain and personality? Why the need for immediate feedback to sustain behaviors that nature has presumably selected and from which the organism can‘t deviate? Why would catecholamine production be so important in the various manifestations of mood and behavior, and as a corollary, why would autonomous instincts would require a momentary pleasure response to drive and reinforce behavior patterns?
2. Many of the so-called instincts of sub-mammalian species are only elicited through environmental stimuli (Lea & Herriot 1984). The behavior pattern eventually becomes stereotypical but only in the aftermath of a stimulus releaser. In that context, it seems fair to ask what terms like “inherited behavior” and “evolutionary psychology” really mean.
3. Another factor has to do with information transmission. Regardless of what behavioral engrams evolution has provided, some type of message has to be sent before the behavior can occur. Moreover, a second feedback signal is needed to indicate whether the behavior has been successful and also when it can be terminated. In other words, even the most ingrained behavior pattern must be elicited and sustained in the moment. While this point is similar to the one made above, it involves another element that could be described as an apex problem. More specifically, to assume that genes prescribe behaviors suggests (as per Dawkins’ notion of the “selfish gene” (1976) that increasingly complex behavior is being directed by rather simple (brainless) sources of communication. That would imply that molecules such as DNA and/or minute cell clusters could control massive cellular conglomerates – as for example in the cerebral cortex. It would also imply that DNA molecules, ribosomes, organelles and nuclei are capable of not only sending messages to the brain to prompt behavior but also confirming whether the cognitions and behaviors emanating from those sites coincide with evolutionary requirements. In order to accept that premise one must concede that non-neural cellular tissue can compute and provide moment to moment feedback support, and that neuro-chemical transmission is not, after all, at the root of experience.
Can DNA make decisions? Does it have memory -which is required with any type of feedback mechanism? If so, how is this accomplished, and if neurons are unnecessary in the communication process why is it necessary to have brains in the first place?
Not all brain scientists believe in a direct and perfect correlation between neural tissue and experience. For example renowned brain scientist James Olds (1974) issued a rather notable statement on this topic in which he pointed out that organisms with no brains seem to learn, make decisions, and utilize approach and avoidance behaviors when faced with positive and negative motivational circumstances. While he does not go so far as to say brains are unnecessary, the implication is that they might have evolved not to create behavior, mood and motivation but to enhance those faculties in a way similar to the gradual replacement of optical sensors with eyes in simple organisms.
Even if Olds contention is valid, that still does not explain the phenomenon of behavioral plasticity. Whether or not behavior and motivation are neurally-derived or not, they are in many instances extremely pliable processes.
4. Another factor has to do with behavioral variability, particularly in the case of humans. One look at how even the most ostensibly bio-adaptive human behaviors can change with time and circumstances raises questions about the influence evolution on behavioral dynamics. For example sex between males and females is a quintessentially adaptive behavior pattern. Yet a number of males and females develop a preference for the same sex.
On one hand this apparent contradiction to evolutionary psychology is perhaps not as contrary as one might think. It could theoretically be explained by saying that organisms that produce a certain proportion of homosexually-inclined offspring will be more able to control their population. At face value the fact that homosexual practices exists in many species would seem to support that argument.
The counter-argument would be that genetic evolution does not work that way. Mutations are not a species-wide phenomenon even if new versions of species emanate from them. Nor, as Darwin indicated, are mutations proportionate. They seem to occur by chance in individual organisms and families and typically over extended periods of time. Mutations can be enhanced in certain circumstances; for example in isolated environments or by deliberate horticultural practices. But the flow of evolution has no inherent proportion; as for example affecting 10 percent of the population in any given species. Thus such a mutation from a heterosexual to homosexual genetic template would seem to have no evolutionary basis. In support of this conclusion, several genetic studies have shown no significant genetic differences between heterosexual and homosexual subjects (Bailey 2000), (Schwarz, Kim et al 2010) (Schacter, Gilbert et al 2009).
Other ostensibly adaptive behaviors change even more frequently and readily. For example, one of the central assumptions in evolutionary psychology is that male dominance is a prevalent pattern among primates. The presumed advantage is that by imposing their will, alpha males will mate more often and consequently produce fitter, stronger offspring like themselves (Dixson 1999). The thinking goes that since strong males are needed to protect females and offspring that trend would ultimately enhance the group’s chances of survival.
In that context one might expect females to be genetically programmed to prefer dominant males. To some extent that is true, and not just with chimps. A typical mammalian mating ritual is often preceded and decided by combat among males; the loser walks away, the winner gets the girl. Yet even in chimp society, there is a lot of “genetic philandering” going on whereby opportunistic, lower ranking males will sneak off with females in estrus (who are quite accommodating). Absent the intrusion of the dominant male the two will mate and ostensibly produce offspring that are potentially “less fit.” Why would the female be inclined to violate the evolutionary best-practices standard of mate selection.? If her genes dictate that she mate only with “Mr. Right” why would she take pleasure in mating with “Mr. Wrong”?
When one considers human mating patterns the variety of sexual preferences is wide and varied. Some women prefer artists, others country-boys, some home-boys. Still others prefer athletes while others rely on image-familiarity and end up marrying someone like dad. Some even employ a practical, long term strategy in opting for a caring, kind, funny fellow with whom to live out their lives.
Even the presumably well-grounded studies on symmetry and sex in humans is confounded by actual human habits. Some research on this topic suggests that women prefer and are even more likely to have orgasms with men who have symmetrical physical features (Rhodes 2006) (Little 2001) (Radford 2005).
Yet few women describe their preferences in that way. Traits such as compassionate, intelligent, humorous, hard working, handsome, articulate, talented, reliable, gentle and wealthy occur frequently in conversation. So too does the word handsome, but even if that correlates with symmetry, it seems to comprise only one of a wide variety of preferences.
The problem with the evolutionary approach to human sexuality is that genetic makeup cannot explain such vicissitudes. Nor can it override the moment-to-moment decision making process that drives sexual selection. In one instance a woman might view a dominant male as being too rigid, non-empathic and perhaps too aggressive for the gentle rigors of fatherhood. The work of Snyder, Kirkpatrick et al (2008) implies as much. In another instance she might opt for a male with status, albeit one whose appearance is distinctly asymmetrical. In either case her behavior and decisions would be at odds with an evolutionary mandate and would instead be driven by momentary assessments.
For evolutionary psychology to be considered a singular explanation one would have to presume that there is a gene for behavioral variability; one that accounts for probabilities and changes in behavior: a gene or set of genes that weighs in on decisions, alters its configuration in light of changing circumstances and responds to external guidance. Once again evolution does not operate in that way. Neither does the DNA molecule. On the other hand neuro-chemical transmission does facilitate both decision making and figure-ground perception.
Obvously genes do have some influence over behavior and motivation. However while some genes are structural and responsible for creating proteins that make up fixed body parts, most genes (up to 95 %) are regulatory in nature (Donaldson 2005). Their main purpose is to create and inhibit the activity of other genes by facilitating enzyme production and other chemical reactions that trigger complex behavior patterns. This is often in response to environmental changes, which makes the argument for genetic behavioral permanence seem somewhat specious.
Regulatory genes are more pliable, and by virtue of their broad influence can set behavioral sequences in motion. (Kim, Zitnan et al 2006). Yet while genes can collectively string a series of behaviors together via chemical reactions and gene orchestration, that does not explain the counter-instinctive behaviors discussed above. In simple terms, regulatory genes could combine to create a female’s approach behavior toward dominant males, but if that behavior is A. patterned by natural selection and B. adaptive, why would she deviate from it? It is one thing to string a set of behaviors together, another to negate the entire behavioral sequence and override an ingrained evolutionary strategy.
The interactive effect of environment on genes and behavior is fairly well established (Caspi 2002) and would seem to support loosely the central thesis of evolutionary psychology. However the flexible nature of the interaction seems to require a modification in thinking: specifically the idea that genes do not affix either traits or behavior but merely create a structured but pliable template that can be altered by the intervention of regulatory genes via environmental triggers.
In a sense that ameliorates the relevance of evolutionary psychology because it brings the environment back into the equation – even in the most fundamental biological terms. It leads to the notion that there is no true and complete functional separation between instinct and environment. That’s where the role of immediate experience comes into play.
One of the keys to understanding how and why genes interact with the environment and why fixed behaviors are rare can be found in the idea of complexity…or uncertainty, which is an information theory concept. Whether it is 25 billion neurons in the brain or 3 billion base pairs of DNA (and 30,000 genes) in the human body, the expression of any single or group cluster will encounter competition and interference. The uncertainty inherent in that process must be reduced in the brain and genome to facilitate the expression of behaviors. Reduction of uncertainty – the shift from hyper-activation and irresolution to closure – must occur in the moment since the uncertainty arises in a specific time frame. No amount of evolutionary momentum can change that. Indeed as an organism’s genome and brain become more complex, the importance of uncertainty-reducing actions to cognitive, behavioral and motivational dynamics becomes paramount.
Uncertainty reduction equates with the perception of pleasure (Berlyne 1960) and consist of two main elements. One is the orchestration and alternation of inhibition and excitation patterns in brain and body that allows for fluid response-finding and cognitive, behavioral and psycho physiological resolution. The other (quite related) is the production of forceful pan-systemic chemicals that override uncertainty by forcing closure in behavior and mood. Among these are catecholamines such as norepinephrine, dopamine and epinephrine (Minzenberg 2008). Whether it be genes, neural or muscle tissue they cut through the morass of noise, providing a focused expression of behavior reinforced by pleasurable feedback.
A measured critique of evolutionary psychology would be that no behavior patterns are fixed. Thus the argument for amorality and/or against social probity implied in the work of some EP adherents (exemplified by Hutson’s notion that …men are genetically programmed to be promiscuous (2007) is easily refuted. Since evolution reflects genetic makeup, and since genes are flexible via their predominantly regulatory functions, there is little reason to assume any aspect of human behavior is either inevitable or unalterable.
When it comes to the apparent conflict between evolutionary psychology and the impact of momentary experience, there need not be any contradiction. Humans have genes. Some of those genes prompt certain behavior patterns, but most do not. Most respond to environmental triggers and those influence the actions of even the more rigid, structural genes. The reason immediacy of experience is a fact of life is that with so many genes, including those that build an extremely complex brain, there is an information component to deal with. It takes the form of neuropsycho-genetic uncertainty. Whenever a vast number of genes or neuronal combinations is activated, resolution, (I.e. information attainment) is required. Regardless of what evolution has bequeathed to us, those behaviors must be extracted from noise at some moment in time. They must be “found,” retrieved, separated from competing inputs to satisfy functional and hedonic purposes. Immediacy is nature’s way of providing us with information in the present that cuts through that genetic and neuronal noise. It is why, through the resolution-attaining functions of neural synchrony, catecholamines and mid brain pleasure centers, men and women can override evolutionary mandates on sexual selection. Immediacy prevails in any given moment because noise produces tension, pain, confusion and a cacophony of impulses that overwhelm the brain and body. Evolution has no such effect. It is a function of the past. Consequently In the battle for current concerns, it will invariably lose out to the momentary effects and enticements of pleasure and pain.
Bailey, J.M. Dunne, MP. & Martin, NG. (2000) Genetic and Environmental Influence on Sexual Orientation and its correlates in an Australian Twin Sample. Journal of Personality and Social Psychology.. 78 (3) 524-536
Bergman, J (1992) Some Biological Problems with the Natural Selection Theory. Creation Research Society Vol. 29 (3)
Berlyne, D.E. (1960) Conflict, Arousal and Curiosity. New York, McGraw Hill
Caspi, A. (2002) Role of Genotype in the Cycle of Violence in Maltreated Children. Science, (5582) 851-854
Dixson, A. Primate Sexuality: Comparative Studies of the Prosimians, Monkeys, Apes and Humans. Oxford University Press. USA
Donaldson, J. Dogs in Canada. Aug. 2005
Hutson, M. Promiscuity: Spread the Love. Article in Psychology Today Oct. 24, 2007
Joyce, R (2006) The Evolution of Morality (Life and Mind: Philosophical Issues In Biology and Psychology. Cambridge Mass. MIT Press.
Kim, YJ. Zitnar, D. Galizia, CG. Cho, KH. & Adams, ME. (2006) A Command Chemical Triggers an Innate Behavior by Sequential Activities of Multiple Pepidergic Ensembles: Current Biology 16: 1395-1407
Kutschera, U & Niklas, K.J. (2004) The Modern Theory of Biological Evolution: An Expanded Synthesis. Naturwissenschaften 91 (6) 255-276
Lea, P & Herriott, P (Ed) (1984) Instinct, Environment and Behavior. Routledge Pub.
Little, A.C. Burt, D.M. Penton-Yoak, I.S. & Perrett, D.J. (2001) Self-perceived Attractiveness Influences Human Female Preference for Sexual Dimorphism and Symmetry in Male Faces. Proceedings of Biological Science 268 (1462) 39-44
Mizenberg, MJ, Carter. C, (2008) Modafinil: A Review of Neurochemical Actions and Affects on Cognition Neuropsychopharmacology, (33) 1477-1502
Olds, J (1974) Phylogeny of Behavior. In: Brain Mechanisms and Behavior London Heineman Educational Books
Radford, T (2005) How Women Dream of Symmetrical Men. London, The Guardian. Retrieved 1/19/2010
Rhodes, G (2006) The Evolutionary Psychology of Facial Beauty. Annual Review of Psychology 57: 199-226
Schwartz, G. Kim, R Kolundzija, A Rieger, G & Sanders, A (2010) Biodemographic and Physical Correlates of Sexual Orientation in Men. Archives of Sexual Behavior 39 (11) 93-109.
Snyder, J. Kirkpatrick, L & Barrett, H. (2008) The Dominance Dilemma; Do Women Really Want Dominant Mates? Personal Relationships 15: (4) 425