A&O – DEEP – EVOLUTION – Ritualization




the evolution of traits exemplified in communications specialized for sexual selection

The INTEGRATIVE BIOLOGY of BEHAVIOR involves the coordinated activities of four broad areas (as biologists study them): DEVELOPMENT, ECOLOGY, EVOLUTION, and PHYSIOLOGY and how they are brought to bear on BEHAVIOR (“DEEP ETHOLOGY”





































EVOLUTIONARY BIOLOGY is concerned with changes in behavior across the generations by means of genes and/or memes.  The process of “ritualization” in particular is relatively rapid evolution, often under the intense form of natural selection the includes mate choice: “sexual selection.”     
























































COMMUNICATIONS between individuals involves “the transmission of a signal from one animal to another such that the sender benefits, on average, from the response of the recipient” (Slater (1983) in D&DVM4; chap. 12 p. 210).  Signals can be static (e.g., a continually visible change in body color) or dynamic (a controllable exposure of a signal such as body color)  more on the DEEP ethology of communications
























The EVOLUTIONARY TRANSFORMATION OF a trait to a function for which it was not initially selected is often most easily understood in the context of COMMUNICATION.  All traits, we can hypothesize, began as naturally selected to solve problems–cope with selection pressures–that might not even exist anymore (that is,they were selected in a different “evironment of evolutionary adaptedness” (EEA).”)   Traits, while solving one adaptive problem, almost always had other effects, often trivial.  They were, in the sense of having multiple effects (only one of which was particularly important), pleiotropic. Any of these collateral effects is then available to be adapted to solving new problems.   

The process of transformation though successive iterations (generations, in this case)–paricularly in the context of sexual selection is termed RITUALIZATION. (Sexual selection is natural selection wher the selection pressure–problem that needs to be solved–is communication of reproductive status and motivation to a potential reproductive partner. 

RITUALIZATION also serves ART & Organism as a metaphor for how very modest traits can become hugely important–small, even frivolusly adaptive traits, can be selected and changed to very elaborate expressionj.   It is exemplary also of the ingenuity of the organism in finding traits that can be employed in improving fitness or coping with new challenges — its expression of bricolage, familiar to anthropologists and handy-men: the adapting of a “tool” (trait) devised to serve one need to solve some other need, emphasizing the utilization of whatever traits might be available.  (used by Levi-Strauss in his anthropology; Understood sometimes by analogy to the television action character, MacGyver, who regularly solves complex problems by adapting ordinary objects to the task in ingenious ways; a bricoleur (a handyman good at using whatever materials are available).  “Bricolage” is also used in art (Wikipedia) –but still refers to the appropriation or adoption of an existing material to a new purpose

‘SELECTION PRESSURE’ is the term representing relative need in the environment that must be acommodated to provide an adaptive advantage to the individual expressing it.  “SEXUAL SELECTION” reflects the need to manifest a trait that provides an advantage in courtship or reproductive behavior that will reesult in increased biological fitness.   FOR EXAMPLE, there is an advantage in social signals becoming more precise, less ambiguous: HEAD-NODDING  in many reptiles, birds, and mammals may have begun as alternating dominant & subordinate signals (head up high, head down); over generations this may be the origin of head nodding signifying arousal only) but then dominant and subordinate males and females evolved more precise signals (e.g., in my favorite species, head up high + dewlap and nod pattern (challenge);  head nod then kept down (subordination); rapid nod (courtship) (question: might the “stress” of challenge and courtship accelerate testicular development imn males? or being courted accelerate ovarian development in females?)     

IN RITUALIZATION there is often sexual-selection pressure for behavior that indicates an individual’s internal state to be of adaptive value in social behavior.   Over the generations these behavioral patterns can become less ambiguous and more precise.







A communicative signal can be derived  from any attribute of an animal upon which natural selection can act—behavioral, physiological, developmental, or  morphological traits—and which can be detected by other individuals.  Traits often serve multiple functions, most of which may be incidental to the adaptive problem it evolved to solve.   In ritualization, one of those incidental behavioral patterns that also represents the state of the animal that may be detected manifests it in a way that it also  becomes a more effective or efficient in communicating.  For example, a motor pattern reflecting a homeostatic adjustment to changes in ambient temperature (e.g. feather fluffing to retain heat in a cold atmosphere) may also function as a signal that the actor is under mild stress. If it might be adaptive to communicate the underlying stress response, exaggeration of some specific aspect (size or shape of feathers) would improve its communicative function. 


The key attribute of the trait is that it conveys information, usually about one individual to another. (but possibly also informing an individual of their own state–as in EMBODIED COGNITION)  This information then makes the world of the recipient more predictable, less chaotic.     

Behavioral traits that have given rise to displays have been identified  by Hinde and Tinbergen (1958) and Morris (1956).


The primary somatic  responses are:

1.  Intention movements (such as adjustments in posture to facilitate subsequent motor pattern)

2.  Perseverance (animal attempts to continue behaving despite obstruction  or absence of releasing stimuli)

3.  “Snap decision” (animal responds quickly to only one element of a  stimulus situation)

4.  Ambivalent posture (animal experiences simultaneous arousal of  incompatible tendencies)

5.  Alternating ambivalent movements (successive expressions of  incompatible tendencies)


Secondary somatic responses are:

1.  Displacement activities (associated with conflicting motivations: animal expresses component of inappropriate  behavior pattern)

2.  Redirection activities (an appropriate motor pattern is expressed but  redirected to an inappropriate target) (“take it out on someone else”?)

3.  Regressive activities (frustrated animal “falls back” on earlier  behavioral patterns; espec. in laboratory) (“regresses?”)

4.  “Neurotic” inactivity (animal ceases to respond; Seligman’s “learned  helplessness” (?))





AUTONOMIC REFLEXES.  A rich source of displays are autonomic responses which have an external expression  (Morris 1956).  Many of these have an affect or stress-related proximate causation:       

1. Alimentary:  Increase or decrease in salivation.  Sphincter control,  urination, defecation.  (e.g., territorial marking)

2. Circulatory:  Pallor, flushing, vasodilation of sex organs.  Fainting.(e.g., skin patches)

3. Respiratory:  Changes in respiratory rate or amplitude.  Gasping,  sighing, panting.  (e.g., inflation displays, hissing, speech (?))

4. Thermoregulatory:  Sweating, pilomotor responses.  (e.g., hair or  feather erection, scent signals) Electrodermal response  (see FRISSON)

5. Lacrimatory:  weeping.

   6. Altered sensory system                             




Ways in which the displays can become elaborated  (Morris  1966):

1.  Development of conspicuous structures

2.  Schematization (“simplification”) by means of

a.   Lowering of threshold changes in absolute and relative thresholds of components)

b.   Rhythmic repetition

c.   Typical intensity

d.   Exaggeration of certain components of the movement

e.   Omission of components

f.   “Freezing” of movements

g.   Change in sequence of components

h.   Changes in coordination of the components.

i.    Change in speed of performance;

j.    Change in vigor.


When the movement comes to be governed by causal factors other than those that  governed the source of the display it is said to be emancipated. For example, feather fluffing that is evoked as a thermoregulatory reflex can come under the control of visual stimulus of a potential reproductive partner. (note that in this case, as in many others, a subclinical (relatively mild) physiological stress response is involved)



Reduction of signal ambiguity  Signals are most effective when they are unambiguous.  Three selective pressures to reduce ambiguity were identified by Cullen (1966)

  1.  Between species:  reproductive isolation and the prevention of   hybridization is fostered by unambiguous signals.
    1.  Character displacement is the emphasis of differences between otherwise similar species whose   interests are served by not mistaking each other — most striking in species that live on the same or neighboring area).
  2.  Within species:  Unambiguous signals are important to minimize confusion   (maximize predictability).  Darwin’s principle of antithesis (1873)   addressed this:  displays with opposite meaning should be as different as   possible.
  3.   Individual differences:  It is frequently important that the individual  emitting the display be accurately identified.




  • Language?  In humans, the hyoid apparatus is important in verbal communicating (see The Origin of Speech, below) … interestingly some of the neural connections controlling the cartilage and bone of this anatomical innovation are autonomic, and can be activated in anticipation of stressors that will call for increased respiration[i]to support increased metabolism in coping with an urgent challenge such as defense, aggression, courtship. The hyoid in fish: gill flaps of fish speed up to increase water flow and thus more oxygen exchange.  Can the hyoid affect the nervous movements of a man’s adam’s apple?  The “adam’s apple jump” is associated with anxiety[ii]
  • Frisson. An interesting example for Art & Organism is that of frisson –a “thrill” signal (often associated with elevated hair, or a chill) likely derived from stress-related responses such as coping with (or anticipating) the thermoregulatory challenges that attend fight-or-flight.   Many autonomic responses seem to play into specific ritualized behavioral patterns (alimentary, circulatory, respiratory, and thermoregulatory; see list from Morris 1956, in ritualization notes).  


“Looking for an evolutionary based rationale of emotional piloerection, one might also speculate that the ambivalent experience of being moved or touched in response to the sublime may involve feelings of vulnerability or even imminence (Keltner and Haidt, 2003 ;  Konečni, 2005). In animals, erection of body hair is known as a mechanism, which makes them appear larger and stronger, and which is applied in situations of imminence (Darwin, 1872, p. 87) as well as in the course of courtship (e.g., Nishida, 1997). According to this notion, emotional piloerection in humans could also be viewed as an evolutionary relic corresponding to a response to the threatening aspect of being moved or touched.” (EXCERPT from DISCUSSION of Benedek and Kaernbach (2011) article on piloerection and affect)

Brain enables evolution of language.    Dehaene (2013) published his theory of the evolution of literacy in the brain in the journal Cerebrum.  It focused on the visual word form area (VWFA) in the base of the left hemisphere–he calls it “the letterbox.”  The VWFA is now known to also contribute to attentional processes (Chen et al. 2019)  (read DeHaene and then Chen)


[i]  The U-shaped hyoid bone, located just under the chin, is an important contributor to both respiratory and digestive processes. The hyoid is attached to the tongue, and helps you to swallow at the start of digestion. In the respiratory system, structures that produce sound depend on the hyoid. The body and the greater horns of the bone serve as attachment points for neck muscles that raise and lower the larynx during speech (as well as during swallowing). ( https://www.visiblebody.com/learn/respiratory/upper-respiratory-system )

[ii] ADAM’S-APPLE-JUMP “is 1. A conspicuous up-and-down motion of the Adam’s apple. 2. A movement of the throat visible while gulping or swallowing, as in nervousness. … and an unconscious sign of emotional anxiety, embarrassment, or stress. … Unconscious and uncontrollable, it gives an exquisite look into the sympathetic (fight-or-flight) division of the autonomic nervous system.” (RESEARCH REPORTS1. Swallowing “associates well with flight and submission” (Grant 1969:528). 2. Stimulating the emotionally sensitive amygdala can cause involuntary body movements “associated with olfaction and eating, such as licking, chewing, and swallowing” (Guyton 1996:758-59). 3. The founder of kinesics, Ray Birdwhistell, included an entry for “Adams Apple Jump” (without defining or explaining the term) on p. 2 of his 1952 book Introduction to Kinesics. … Anatomy. Anxiety, social discomfort (e.g., embarrassment), and fear are often visible in unwitting, vertical movements of a projection at the front of the throat called the laryngeal prominence, where the largest (or thyroid) cartilage of the Adam’s apple shows, prominently in men, but less noticeably in women. Neuro-notes. Acting through the vagus nerve (cranial X), emotional tension from the brain’s limbic system causes unconscious muscular contractions of  the sternothyroidthyrohyoid, and associated inferior pharyngeal constrictormuscles of the Adam’s apple. Movement is evident as the muscles contract to swallow, to throat-clear, or to vocalize an objection which may be left unsaid. The Adam’s apple is emotionally responsive (i.e., reflects visceral or “gut” feelings) because its muscles are mediated by the vagus nerve, one of five cranial special visceral nerves.






Evolution & Physiology.  The few dozen categories of primate vocalizations (Passingham 1982 in Merlin. 1991) are all expressed in emotional or manipulative contexts: most control appears to be limbic or cingulate gyrus (so-called “limbic” speech, see Sutton and Jurgens 1988 in Donald  1991:183).  Donald (1991) believes that bringing vocalization under voluntary control is an adaptation for voluntary control of emotional responses (recalls ritualization).  And see pulvinar and its thalamic role: Pulvinar (posterior part of dorsal thalamus; afferents include lateral and medial geniculate and superior colliculus; efferents include cortex, parastriate, posterior parietal, posterior temporal, and frontal; projects to subarachnoid space; lots of synapses converge on a single  departing dendrite;.  Tectum projects (back to) the cerebral cortex through pulvinar;  typical ascribed function is visual-auditory association; it increases dramatically in size in primates along with ascending input from the superior colliculus  –consciousness may involve thalamus as much as cortex (p. 476)




Ritualization and Human Neurobiology


The term “ritualization” was employed after Huxley (1914) noted similarities between animal courtship displays and some human behavioral   patterns.  The possible fusion of genetic and cultural factors in giving rise to a display is accommodated in Smith’s (1979) definition:

 … ritual connotes, at least, behavior that is formally  organized into repeatable patterns the basic function of  which is to facilitate interactions between individuals,  between an individual and his deity, or between an individual  and himself across a span of time.


Famous scholars in the social sciences (e.g., Clyde Kluckhohn) have suggested that human ritual behavior reduces anxiety –that it can be (what a physician would call) “anxiolytic.”  This effect on health likely contributes in some way to fitness.  Ritual also synchronizes the activity of participants, a phenomenon that contributes to group cohesion –which can also contribute to fitness.


“Ritualization” leads to consistency in expression, also sometimes referred to as “stereotyped.”  This always refers to a pattern of behavior that is highly consistent in form whenever it is expressed –BUT, in the clinic, it also often refers to dysfunctional repetition–A “stereotypy.”  –That is, a compulsive repetition of behavior that can do more harm than good.  There may be an element of addiction involved that began with an innocent anxiolytic effect.







































The Origin of Speech by Constance Holden  — SCIENCE  Volume 303, Number 5662, Issue of 27 Feb 2004, pp. 1316-1319. [complete article]

How did the remarkable ability to communicate in words first evolve? Researchers probing the neurological basis of language are focusing on seemingly unrelated abilities such as mimicry and movement

“Archaeologists have identified various milestones in human behavior in the 5-million-year evolutionary void between animal communication and human speech, but there is no consensus on which achievements imply the capacity for language. For example, the first stone tools date to 2.4 million years ago; some researchers think this may indicate linguistic facility, but others argue that toolmaking is far removed from speech. Another possible starting point is 2 million years ago, when the hominid brain began a period of rapid expansion, including in the primary brain areas associated with producing or processing language–namely Broca’s area in the left frontal cortex and Wernicke’s in the left temporal lobe. (below)

As for actually producing the sounds of words, or phonemes, skeletal studies reveal that by about 300,000 years ago, our ancestors had become more or less “modern” anatomically, and they possessed a larynx located at the top of the trachea, lower than in other primates.

This position increases the range of sounds humans can make, although it also makes it easier for food going down the esophagus to be misdirected into the windpipe, leaving us more vulnerable than other mammals to choking. Such anatomy could have developed for no other purpose than speech, says Deacon.” (below)








Dangerous talk. Side view of human vocal tract shows that because of our lowered larynx, food and drink must pass over the trachea, risking a fall into the lungs if the epiglottis is open. ILLUSTRATION: C. SLAYDEN/SCIENCE




Wired for imitation? Classic language areas–Broca’s and Wernicke’s (yellow)–overlap (orange) with areas critical for imitation (red).








































ARCANE!  Fish farts may not just be hot air — Biologists discover that herring emit raspberry sounds by forcing out bubbles of air – it could be a way of communicating — noted in New Scientist


“Fish are known to call out to potential mates with low “grunts and buzzes”, produced by wobbling a balloon of air called the swim bladder located in the abdomen. The swim bladder inflates and deflates to adjust the fish’s buoyancy. The biologists initially assumed that the swim bladder was also producing the high-pitched sound they had detected. But then they noticed that a stream of bubbles expelled from the fish’s anus corresponded exactly with the timing of the noise. So a more likely cause was air escaping from the swim bladder through the anus.” – (from Biology Letters (DOI: 10.1098/rsbl.2003.0107)