Diagnosis and Evolutionary Theory

Reminders of Our Past

First, it was noticed recently that some of our female ancestors in Africa had smaller leg bones and a different ankle structure than the males, suggesting to modern scientists that women came to ground from the trees long after the males did. Observers next watched American children on playgrounds; surprisingly, the girls at age 6 climb higher on monkey bars than boys of the same age. Finally, giving young children in Israel or the United States a simulated escape game revealed that girls more often than boys choose to climb trees and climb further out on the branches in order to get away from predators. Israeli girls also climbed higher on the simulated Acacia tree after a coincidental but real terrorist attack.

This sequence of studies — reported by Richard Coss (rgcoss@ucdavis.edu) at the Human Behavior and Evolution Society in July 1998 — reveals not only one aspect of our mental architecture but also one of the tactics found in evolutionary research. It’s simple to make up stories of how we came to do one thing or another; confirmation requires a series of other steps that can be tedious, lengthy, and laced with possible errors. Despite the risks, evolutionists look for commonalities in response patterns that occur regardless of the human culture that is being studies. Behavior sequences are analyzed for their adaptive design — that is, what survival problems are solved and how do behavior sequences fit both with each other and with our physical structures. Finally, we try to make specific predictions about data that might be found in modern people, comparing them in different countries and of different races, and relating these new findings both to the environment of a particular era and to our other physical and psychological adaptations.

Another example — every human 6 year old has a naive biology, a naive physics, and a naive psychology. The last includes notions of how another person thinks and the capacity to interpret the feelings of a second person from facial and vocal displays. Each child tracks others’ conduct, monitors social exchanges, and has a sense of fairness and cheating. It seems very probable that chimpanzees, gorillas, and orangutans have the same capacities even if less Simonized.

Carl Sagan and Ann Druyan would perhaps have referred to these traits — whether tree climbing, the gymnastic talent of young girls, or the untaught capacity for empathy — as “shadows of forgotten ancestors.” Genetics, sociobiology, anthropology, evolutionary psychology, and paleontology offer structures and explanations for how those shadows came to be. These several disciplines also allow predictions about previously unnoticed details of our behavior. It seems plausible that understanding other shadows — those of emotional distress — could also be helped by consideration of our probable evolutionary history.

The DSM: An Insect Display Case

Naturalists put things — shells, insects or pieces of yellowed bone — in compartmented boxes. Arrays of specimens form on the basis of systematic differences in size, color, and shape, arrays that match the classifier’s mind as well as the relationships that he imagines.

Psychiatric diagnoses — roughly 400 of them — temporarily occupy a useful display case, the Diagnostic and Statistical Manual, 4th Edition. Intensity and duration are our classification standards for worry, fear, sadness, and grief. Empirical studies of the “natural occurrence” of various disorders show us relationships between some of them. However, because of the self-selected nature of the data and peculiarities of our own evolved mental apparatus, classification and explanation may sometimes be misleading.

Classification by Medicines

Some disorders are more recently classified according to the tools used for treatment — not such a bad refinement. For example, the ’50s and ’60s hosted the use of imipramine and lithium and diagnosis according to prescription was popularized. Practitioners commented about a “manic process” if lithium abated a patient’s distress; likewise for “schizophrenic process” if chlorpromazine settled them down.

Peter Kramer then gave us “cosmetic psychopharmacology” in the ’90s, an understanding that a continuum of discomfort exists for all of us and that many subclinical annoyances respond postively to changes in serotonin. He also suggested that we “listen to Prozac” in order to learn about serotonin and, indirectly, about normal functioning and about psychopathology. Thus, Peter taught us to study the hammer and nail — Prozac and serotonin — in order to understand the roof (psychopathology). We now have “serotonergic spectrum disorders” that link such events as self esteem, obsessive compulsive disorder, and panic attacks.

Kramer was right but there are further steps. Serotonin has been in living creatures for about a billion years and does a lot of things. Dopamine and norepinephrine may be equally ancient. Thus, modern information about serotonin reminds us to study not just what it does for us but also for our ancestral relatives and for other species. Prozac opened a door to our past.

A Diagnostic Foundation from Evolutionary Theory

There are several goals that might be achieved from keeping an eye on our ancestors’ life styles. Evolutionary understandings should help us to generate diagnostic arrays on the basis of the survival functions for both annoyances such as anxiety, depression, and paranoia but also the zest of elation, grandiosity, and silliness. We also should have a system for diagnoses that incorporates “traits” rather than “disorders” and describes the original functions of our assorted discomforts. An evolutionary system ought to meet the traditional obligations of diagnosis by giving an etiology (both phylo- and ontogenetic), a description of present complaints, suggestions for giving assistance, and a prediction of outcomes. An evolutionary diagnostic system should also:

  • Describe the interplay of psychological complaints
  • Suggest effective ways to reduce complaints through the modification not only of serotonin or GABA but also through environmental changes that tune the responses of the client’s genetic characteristics. Niches that allow greater personal satisfaction increase serotonin levels without requiring a weed. Instead of medicating the client to tolerate the intolerable, we draw on the client’s abilities to find new settings consistent with her talents or to change the one that she now occupies. (Evolution is not just environment’s hammering life into molds; we also make our own niches or move to ones that are less irritating.)
  • Allow a rational structure that ties our automated, finely honed adaptive systems to their corresponding overlays of thinking. Cognition has a deep structure; understanding that structure should allow us to teach ourselves and our children simpler techniques for reciprocal inhibition and for synergy between innate response systems.
  • Let us clearly see emotions and morals as tools that are uniform across cultures and that reflect survival mechanisms. A fist and the expression of anger are both tools; likewise for tears, anxiety, and guilt.
  • Provide a different appreciation of how we can each vary genetically but perform survival tasks — including those of social cooperation — in ways that are highly similar and complementary to one another.

Understanding Natural Selection

There are several points.

  • Natural selection shapes behavior as surely as does a Skinnerian. Random actions — whether exerted by genes or by muscle tissue — are pulled in a consistent direction by the consequences of those actions. Things that work, that aid survival and reproductive success, are repeated and become more frequent in each succeeding minute or generation. Learning merely allows a single creature to do in a few moments the tasks that formerly required many creatures and many generations.
  • It is not true that any structure is possible at any time. We build at each moment on the structure that we got from the past and it’s generally easier to modify or add pieces than to subtract them. We also follow mathematical, chemical, and physical laws in the structures that we develop.
  • Adaptations are the important output of natural selection. They also become a likely tree for our diagnostic schemes. Adaptations are the shaped behavior and structural organizations that efficiently solve survival tasks. Different components — eye, ear, mind, and muscle — perform as a single unit to escape a hunter or to raise a child. Adaptations can be physical as in the sculpted lines of a duck’s bill or behavioral as in a husband’s jealous guarding of his wife. Behavioral (psychological) adaptations include those for monitoring economic exchanges, social networks, mate selection, child rearing, hunting, gathering, and managing alliances and hierarchies. Even the phrase “common sense” has meaning within evolution — “common” because it reflects evolved understandings that are shared by the majority of humans and “sense” because the understandings help survival and reproduction.
  • Different adaptations appeared in different eras. Dan Sperber has commented, “We had better think of the mind as kludge, with sundry bits and components added at different times, and interconnected in ways that would make an engineer cringe.” Frogs have bug detectors, so do little hominids. Girls climb, birds soar perhaps because of the same neural foundations. The kids who wear rings in their tongue declare their fitness in the same manner as my mallards who flash their iridescent feathers. People universally seem to prefer blue; so do frogs and probably fish. Thus, the toad in a stream would also respond positively to the IBM logo and dress code. People who proclaim that they “ain’t related to no ape” might reconsider when they learn they are also related to lizards. Imagine being regressed under hypnosis back to your lizard stage!
  • An understanding of the things done by our adaptations and their survival value lets us understand and predict our behavior and in surprising ways. For example, many women are most likely to have extra marital sexual affairs just before ovulation, at times when they are most likely to get pregnant. Many women can sort men’s dirty shirts by odor and in a way that reflects the physical symmetry and attractiveness of the guy who wore it. Our commitment to romantic love possibly allows a fuller rein to imprinting and to familial and genetic similarity as a basis for marriage. We Americans often give presents but many cultures accurately view gifts as a means to get favors in return. A man often shows greater autonomic distress when fantasizing about his wife’s having sexual indiscretions than about her falling in love with someone else. Women often have the opposite pattern. We grieve more about the death of a 12 year old than we do for either an infant or for a 20 year old.
  • Emotions and morals are tools that amplify behavior sequences and extend their duration. For example, depression can be viewed as a means to conserve resources through a winter or to discontinue nonproductive relationships. The latter occurs in a subtle manner. Signs of depression elicit both sympathy and avoidance from other people. A skilled wife can be depressed to cause her aggressive husband to lose interest in her while at the same time she elicits closer allegiance from other women.

Aspects of Diagnosis and Treatment

  • Caring, emapthy, altruism, cooperation, alliance formation — all were crafted by natural selection. Thus, diagnostic and ameliorative functions are met not just by psychologists but also by barbers, neighbors, mates, bar maids, diner companions, and geishas. Lucky for chimpanzees and for most humans who do similar things, there has been no empirical demonstration that extensive training in psychology is sufficient or necessary to be an effective ally. Our clients assess competence probably as accurately as they assess being swindled and a competent ally is more vital than the language on a wall certificate. Friends often have more influence than a therapist and the sense of alliance probably accounts for the 45% placebo response commonly found in studies of depression. (Incidentally, the same analysis holds for teaching skills.)
  • We can expect variability in the intensity of every psychological adaptation, even those for breathing. Impaired or exaggerated adaptive foundations for child rearing, mating, and social exchanges may be found to be the most disruptive. Enablers and cheaters have always been in our group. We appear to have “cheater detectors” — untutored skills that recognize unfair exchanges and lies — that fire excessively or not at all, depending on who we are and our context. Cheater detector may eventually be as important a concept as rejection sensitivity.
  • Randy Nesse and George Williams have an excellent article on “mismatch” in the November 1998 issue of Scientific American. Their concept is that mismatch is due to incompatibilities between our treatment practices and our evolved needs. For example, we commonly treat fevers yet an elevated body temperature discourages bacterial infections. However, too often “mismatch” is described by many writers but in Rousseau’s terms, a whine that our nature is compatible with our culture and that our biology cannot maintain pace with our toys. Nonsense! Small children cannot build a Furbie but still know what to do with one. Indeed, a Furbie is attractive because it reflects our psychological adaptations. It may be more helpful to view mismatch, like our culture and our technology, as the product of our psychological adaptations. The shampoo counter in a market reflects technology, it also reflects our driving adaptations for sexual selection. Hunter-gatherer minds build hunter-gatherer cultures regardless of technology. Traffic jams, changing homes every few years, clothing styles — all reflect our nature and have their equivalents in other cultures and in other species.
  • Mismatch of another type seems common in psychological distress. I refer to the mismatch that can exist between a client and her setting. We are each slightly different in our adaptations. A certain amount of variability in us helps us to survive environmental variability. Psychology can be misdirected when it attempts to mold by lecture and training just any individual into any given slot. J. B. Watson’s boast was reactive; it was also wrong for any of us.
  • Genetic influences now appear to be more powerful than previously thought even though we are just learning how genes respond to changes in our settings and by our personal interpretations of those changes. Winning at tennis not only gives you more confidence at the next tennis game, it also raises your serotonin levels — you stand taller and attract more mates. Genes are different for each one of us; genes also can be tuned by the seasons, childbirth, or the relative youth of people around us. Winning, loss, age, and status — all may have unsuspected power to influence us. Thus, therapy and life can often be summarized in Brian Goodwin’s terms that life is about finding places to be yourself.
  • Anxiety has evolutionary significance and is not typically a random Pavlovian outcome. Primates not only fear easily, they tend to fear specific things. The details of anxiety, not just the global diagnoses, may run in families and reflect our evolutionary history.
  • PTSD. MacLean events — pain, death, illness, poisonings, abandonment — may easily bias the response of very primitive and very generalized emotional and cognitive systems. Conditioning occurs immediately and is often irreversible with present methods. Slight changes in posture, sounds, or appearance acquire power to elicit massive changes in mood or behavior sequences. Ulcers occur in restrained rats, likewise for mothers who don’t organize their children into hierarchies. The rodent and the human are both immobilized, one physically and the other by competing social demands. Reminders of these periods in our lives may never lose their power to elicit extreme discomfort. (Such events have their positive counterparts that are not customarily “diagnosed.” The mania that comes with infatuation, promotions, or unexpected acclaim might also be seen as MacLean events with their own distortions and costs.)
  • John Price and Russ Gardner have suggested that mania appears to be a disorder that involves hierarchy and dominance. Heightened activity level, sexual interest, word flow, and manipulative behavior accompany a diminished need for sleep. Mania is noticeable because of activity level; it’s damage however, may be in a limited sensitivity to social consequences. Self importance becomes so great and perceived consequences so small. Ambition outruns achievement; bipolar crashes follow. Ambition without success perhaps underlies dysthymia.
  • Mania and depression are often studied with charts drawn on a calendar. Goodwin and Jamison devote 900 pages to bipolar disorder — there is no mention of evolution and little consideration of event-driven mood changes. Yet, the late Dennis Cantwell once remarked that he could usually identify changes in external conditions that preceded bipolar episodes in children and adolescents. Nothing oscillates in nature as a function of time; rather time gives us a boundary for describing the results when stimuli are applied to particular structures. Whether capacitors and resistors or neurons and genes, the principle is the same.
  • There appear to be many different depressions, each with its positive functions and some of which may have more benefit to the client if they are not treated. Price suggests that depression is a survival tool for lowering your self importance when you are faced with a more able competitor. Self inhibition is a useful tool for maintaining alliances; women are usually superior to men with these skills. Girls at 14 quadruple their rate of depression, males double, perhaps an exaggeration of an internally imposed reduction of self-importance. The loss for a girl is her standing within a group of other girls; if successful, she gains male protection and resources for her self and her future children.
  • Moderate liveliness is ordinarily a blessing and is not a defining symptom for either Attention Deficit Hyperactivity Disorder (ADHD) or for mania. Liveliness is correlated with health, higher intelligence, better word flow, superior social skills, and high economic achievement. ADHD is more reasonably associated with impairments in executive functions — working memory, response inhibition, word and memory retrieval, affect regulation, and the capacity to analyze events and arrange new sequences of them. 200,000 years of evolutionary gains for the human mind are sabotaged in ADHD, making it a disorder of “Free Will” instead of hyperactivity.

Moving from Our Past to Our Future

Finally, Russ Barkley elaborated an earlier theory of Jacob Bronowski, that “executive functions” — working memory, development of language for memories and exchange of information, sharing of plans, using emotions strategically, and our ability to analyze situations and imagine novel sequences of events — are perhaps our finest gift from the past 200,000 years. Our executive functions allow us to compare ongoing situations with past experiences and to recall the outcome of our prior behavior. We can choose, on the basis of delayed outcomes, between repeating an earlier sequence of behavior or designing a new one in our minds and implementing it by ourselves or in cooperation with other people. Defects in executive functions commonly lead to the endless repetition of errors, to a failure to plan or to consider options and to depend on emotion and stereotyped responses despite the past ineffectiveness of those same strategies. (We might appraise executive functions more overtly when we see clients instead of making “global assessment of functioning.”)

Likewise for us as a species, ignorance of our past guarantees our repeating it. Failure to know about our evolutionary history and the genetic mechanisms that were evolved means that we will react blindly, impulsively, and perhaps disastrously. Certainly, we might have “flown blind” for the past 15 million years or more but have done well because of the survival strategies hammered into our biological executive functions that take the form of genes. However, we now enter times of rapid climate variability and significantly eroded resources. Evolution becomes relevant and not just for knowing our origins but also for using our origins to gain a sense of our possible futures. By knowing where we have been, we can appreciate where we might go. We might still make some choices with the newer parts of our minds instead of relying exclusively on more stubborn, primitive systems that have gotten us to this point.

1.) Dylan Evans, Ph.D. candidate at the London School of Economics and a student of Helena Cronin’s, presented a seminar on Evolutionary Psychology and the DSM at last summer’s Cape Cod Institute, Healing the Moral Animal: Lessons from Evolution. This year’s course is Clinical Sociobiology: Darwinian Feelings and Values and runs from July 19-23, 1999.

2) 1262 West Bridge St, Spring City, PA 19475. (610) 948-5344. Jbrody@compuserve.com. See related work at https:///cgi-bin/ls2.cgi?config=evolutionary/ or https://www.clinical-sociobiology.com. Also submitted to Across Species Comparisons and Psychopathology


Barkley, R. A. ADHD and the Nature of Self Control. Guilford, 1997

Buss, D. Evolutionary Psychology. Allyn & Bacon, 1999.

Duncan, R. Grooming, Gossip, and the Evolution of Language. Harvard, 1996

Ridley, Matt. Origins of Virtue. Penguin, 1996

Sagan, C. & Druyan, A. Shadows of Forgotten Ancestors. Random House 1992

Stewart, I. Life’s Other Secret: The New Mathematics of the Living World. Wiley, 1998

Wilson, E. O. Consilience. NY: Knopf, 1998

Wrangham, R. Demonic Males. 1996

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