The Emotional Foundations of Personality

by Kenneth L Davis

  However, clearly for Darwin, humans had evolved from earlier life forms and only differed from other animals by degree. He provided evidence that animals also had some capacity to “reason” and, conversely, that human behavior was subject to emotional instincts. This left open the possibility that instincts are a primal foundation for our ways of reasoning, making ethics dependent explicitly on affects, as the philosopher David Hume had already surmised, a view that has been refreshed by some modern philosophers (e.g., Greene, 2013). We must now conceive of human minds, at least their affective foundations, as residing on an evolutionary continuum with other animals. Thereby, insights into basic human mental characteristics could be gained from an understanding of other animals’ instinctual behaviors and affective experiences. This remains a radical perspective for academic psychology, as well as the field of personality research.

  Using comparative observation, Darwin came very close to the framework of emotional affects set out empirically by affective neuroscience over one hundred years later and, perhaps even more important, laid the foundation for later work on human emotion and personality (Davis & Panksepp, 2011), as well the better understanding and treatment of psychiatric disorders (Panksepp, 2005, 2015, 2016). Because of such achievements, a brief review of this beloved (and, in some quarters, reviled) thinker’s writings on the evolution of emotions is in order. Readers who are already familiar with Darwin’s writing may wish to skip the remainder of this chapter.

  CHARLES DARWIN’S EMOTIONAL INSIGHTS AND AN EMERGENT NEUROSCIENCE

  Darwin provided the foundation for the scientific study of modern human behavior and personality, even though he was not explicitly a personality theorist. All of his conclusions about behavior and the origins of behavior were not precisely accurate (to this day no one’s are). However, with his theory of human origins and his keen evolutionary observations, he pointed us in the right direction. In addition to describing the evolution of our physical bodies, he demonstrated the value of comparative research highlighting the similarities of behaviors and emotions across species and in so doing moved us conceptually closer to finding answers about the sources of human motivation and temperament. The neuroscience could not be done until the 1950s, when investigators first demonstrated the rewarding and punishing properties of DBS to brain systems from which emotional actions could be evoked (Delgado et al., 1954; Olds & Milner, 1954), a project that was extended by Panksepp (1974, 1982, 1998a, 2005, 2011b, 2011c, 2015) and many of his students.

  The theory of evolution had implications far beyond religion and philosophy. If, as the theory of evolution contended, there was biological-evolutionary continuity in the vast family of life on earth, it meant that humans were not altogether unique. Our bodily origins could be traced to other species. Importantly, one could infer that there would be many mental similarities between humans and other vertebrate species with which humans shared a common heritage. Because of our evolutionary descent, we would expect to discover not only many bodily but also mental homologies, that is, ancestral similarities, especially between humans and other mammals. However, the similarities would not only be physiological; they would also be behavioral and motivational. In fact, at every level of analysis, scientists could expect to find observations that would generalize from one species of animal to another. Work on the neuroanatomies, neurochemistries, and neurophysiologies of the brain has amply borne that out, especially during the past century. There are abundant detailed differences, for sure, but the underlying patterns and themes speak loudly for evolutionary continuities.

  For our purposes here, we note that in his most famous, second book, The Descent of Man (1871), subtitled and Selection in Relation to Sex, Darwin was quite clear on the topic of whether animals have subjective feelings: “The lower animals, like man, manifestly feel pleasure and pain, happiness and misery. Happiness is never better exhibited than by young animals, such as puppies, kittens, lambs, etc., when playing together, like our own children.” He proceeded promptly to note that “the fact that the lower animals are excited by the same emotions as ourselves is so well established that it will not be necessary to weary the reader by many details” (Darwin, 1874, p. 55). He fleshed out these arguments in his remarkably prescient, third most famous, and psychologically relevant book The Expression of Emotions in Man and Animals (1872). Although Darwin was no expert on the brain, he realized that emotions were ancient solutions for successful animal life on earth.

  He could not have known that the primary-process emotions were constructed by very ancient brain processes situated below the cortex. Indeed, only a few physiologists before the middle of the twentieth century recognized that primal emotional feelings emerged from subcortical brain regions that all mammals share, for example, most prominently Walter Cannon (1872–1945), of the famous Cannon-Bard theory, whose theory argued that emotional feelings arose from subcortical thalamic regions (Cannon, 1927, 1931), supplemented by the work of his most famous graduate student, Phillip Bard (1898–1977), whose dissertation focused more on hypothalamic contributions (Bard, 1928). These empirical breakthroughs, which challenged William James’s speculations about higher brain (cortical) read-outs of bodily autonomic commotions causing emotional feelings, inspired the postulation that subcortically situated circuits formed coherent networks for emotionality, as proposed by James Papez (1937), and dramatically extended by Paul MacLean (1950, 1990) and Panksepp’s Affective Neuroscience (1998a), which is resonant with these historical antecedents. (For a summary of William James’s theory of how bodily physiological “read-outs” to upper brain regions may engender emotional feelings, see the January 2014 issue of Emotion Review.)

  SPECIFIC EMOTIONS IN ANIMALS

  In Expression, Darwin began with chapters on bodily emotional displays in animals. On the negative affect side, what we would recognize as the RAGE/Anger and FEAR systems are discussed for dogs cats, horses, and monkeys. The PANIC/Sadness system is discussed with reference to monkeys, which is included in paragraphs on “painful emotions.”

  On the positive affect side, he discussed how ticklish orangutans and chimpanzees were, along with discussions of their “laughter,” which has only recently been empirically studied by others (Davila Ross, Owren, & Zimmermann, 2009), and extended to even lowly laboratory rats (Burgdorf & Panksepp, 2006; Panksepp & Burgdorf, 2003). Darwin’s remarks certainly qualify as the first empirical discussion of a potential PLAY system in the brain. Obviously Darwin was well versed in LUST and CARE systems, although he, as well as practically all neuroscientists to the present day, had not conceptualized evidence indicating that the so-called brain reward system is better conceptualized as a SEEKING/Enthusiasm system (Panksepp, 1981b, 1982, 1998a; for more recent discussions, see Panksepp & Biven, 2012; Panksepp & Wright, 2009; Wright & Panksepp, 2009).

  SPECIFIC EMOTIONS IN HUMANS

  Darwin became more definitive as he presented the expression of emotions from a human perspective, but he continued to integrate examples from animals in the discussion of human emotions. To avoid duplication, the summary that follows here of the various emotions presented by Darwin blends his animal and human discussions. Darwin’s descriptions are not just insightful and useful; with only a few exceptions they are consistent with modern affective neuroscience. We provide enough flavor and detail from Expression to allow comparisons with the primary emotions in the Affective Neuroscience Personality Scales (Davis & Panksepp, 2011).

  Hatred, Rage, and Anger: RAGE

  In Expression, Darwin offered an operational definition of rage: “Unless an animal does thus act, or has the intention, or at least the desire, to attack its enemy, it cannot properly be said to be enraged” (Darwin 1872/1998, p. 78). He observed that when even moderately angry one’s heart will beat more rapidly, one’s face is likely to redden, and a specific facial expression is displayed, which features a strongly marked frown, that is, the drawing in of the “corrugators” or furrowing of the brow. Darwin noted that the reddening of
the face can also be seen in monkeys and human infants and also pointed out that because of the strong affect of anger on the heart “not a few men with heart disease have dropped down dead under this powerful emotion” (p. 235).

  He observed that angry humans often exposed their clenched teeth, which he argued revealed the evolutionary descent of this anger display, because, unlike animals, men seldom used their teeth in fighting (Darwin 1872/1998, p. 238). In a similar vein, when discussing human displays of anger and rage, Darwin also touched on the “sneer” in which canine teeth were uncovered by drawing up the outer upper lip, which we have all seen in snarling dogs. Again, Darwin thought such facial displays illuminated our animal heritage, because if a human did try to bite his or her enemy during a fight, the bite would not be made with the canine teeth the individual was displaying.

  Darwin also noted in humans an “angry tone of voice” (Darwin 1872/1998, p. 242). Indeed, all over the world, angered individuals hurled verbal abuse upon their adversaries with bodies and heads leaning toward their opponents. At the level of infantile rage, he observed that enraged children screamed, kicked, and often tried to bite. In adults, the teeth and fists are often clenched. Also, the desire “to strike often becomes so intolerably strong, that inanimate objects are struck or dashed to the ground” (p. 236). Similarly, in enraged primates, emotional expressions included showing teeth, striking the ground with the hands, rolling on the ground, biting things, and sometimes “uttering terrific yells” in the case of gorillas. Highlighting another link between humans and the great apes, Darwin noted that orangutans and chimpanzees, like humans, could not move their ears, which kept them from drawing back their ears when angry as did some monkeys and all cats and dogs.

  Surprise, Astonishment, Fear, Terror: FEAR

  Darwin’s comparative observations likewise supported a fear emotion. While affective neuroscience focuses on a more discrete primal FEAR system, Darwin believed that gradations of this emotion advanced from astonishment to fear to terror. Darwin described fear as resulting from sudden but dangerous events and used terror as the term for extreme fear. He stated that a frightened person “first stands like a statue motionless and breathless” and “the skin instantly becomes pale” (Darwin 1872/1998, pp. 290–291). This description perfectly fit a bank teller the first author saw immediately after she had been robbed back in 1998 as the “base-ball-capped” bank robber walked past him on his way out of the bank. The teller was standing frozen but trying to draw attention to herself by holding her left hand in the air. Her face was totally white as she stood like a statue unable even to speak for several seconds. She was finally able to blurt out “I’ve been robbed” as the man was walking out the bank door.

  Darwin’s comprehensive description of the fear response also included the skin often breaking out in a “cold sweat” and “the hairs on the skin standing erect” (Darwin 1872/1998, p. 291). Muscles may shiver or tremble, and the mouth become dry. If more extreme, fear sends the subject into flight, and there may be screams of terror. Sphincter muscles may fail as well. The forehead is wrinkled, and the eyebrows are furrowed. The mouth is open, and the eyes are wide open. When experiencing terror, monkeys’ lips were also drawn back, teeth were exposed, and their hair became erect, all similar to fear responses in humans.

  Suffering, Weeping, Grief: PANIC/Sadness

  Darwin clearly reported the elements of the PANIC/Sadness system, although he treats “suffering and weeping” separately from “low spirits, anxiety, grief, dejection, despair.” In his treatment of weeping he notes that human infants do not shed tears until two or three months of age, prior to which, like other animals, distress and cries are not accompanied by tears. He also observed that human tears do not only come with suffering, because tears often accompany bouts of laughter.

  Darwin specifically discussed weeping in adult elephants and reported a case of a female elephant that shed tears when her baby was taken away from her. He also mentioned several species of monkeys that cry. Darwin seems to be relying on reports from other observers here, and current evidence suggests that while other mammals emit social separation cries or whines, only humans shed tears of sorrow from their tear ducts.

  When discussing painful emotions in animals, Darwin focused on loss and “grief,” which encompassed many features of the PANIC/Sadness system. He also claimed that dejection is plainly observable in young chimpanzees and orangutans, and he described them as listless with fallen countenances and dull eyes, not unlike humans suffering from depression.

  Love, Tender Feelings: CARE

  In the chapter on joy, Darwin also discussed love, which referred to the kind of love a mother has for her infant or, as he referred to it, “the tender feeling.” Even though it is one of the strongest emotions, Darwin pointed out that it has no particular expression. It may be associated with “a gentle smile and some brightening of the eyes,” but it does not have a facial expression that would be easily recognized out of context. Darwin observed that this tender feeling is most typically expressed by “a strong desire to touch the beloved” (Darwin 1872/1998, p. 212). As a sign of affection, he also noted that animals from dogs to chimpanzees like to rub against and touch those to whom they are attached.

  Darwin’s investigations also led him to conclude that human kissing was not innate, because kissing was not known among the natives of Tierra del Fuego, whom he encountered during his five-year circumnavigation of the earth on the HMS Beagle. Also, his observers informed him that kissing was not known among Eskimos or the natives of New Zealand, Australia, and West Africa. He concluded, however, that many different expressions of affection, such as rubbing noses, do always include “close contact with the beloved person” (Darwin 1872/1998, p. 214).

  Darwin remarked about the complexity of all the feelings that can be associated with what we might call CAREing love. He reminded us of the tears of joy shown by a father and son when reunited after a long separation—which in affective neuroscience terms would be a PANIC/Sadness response. Still, he was perplexed and wondered whether those tears might be due to thoughts going through their heads of the potential grief they would probably have felt had they not been able to reunite. He likewise noted that the tears from thinking about “long-past happy days” probably have to do with the thought “that these days will never return” (Darwin 1872/1998, p. 215) and that we may be sympathizing with ourselves. Again, these tears may come more from the sense of social loss associated with the PANIC/Sadness system responses in humans. No other species weeps so clearly as human beings, and the tears of joy may arise from higher thoughtful reflections on the agony of PANIC/Sadness.

  Joy, High Spirits: PLAY

  For Darwin, joy was synonymous with laughter and children playing: “Laughter seems to be the expression of mere joy or happiness. We clearly see this in children at play, who are almost incessantly laughing” (Darwin 1872/1998, p. 195). Darwin also reported that the blind and deaf are also seen to laugh and clap their hands even though they could not have learned this through imitation.

  Darwin saw tickling as one way to evoke this joyous state. He noted that the tickler must not be a stranger, and the tickler’s touch must be light. He noted that the parts of the body that are easily tickled are among those that are not often touched, such as armpits and the soles of the feet. He reasoned that because a child cannot tickle him or herself, the “precise point to be touched must not be known [by the child]” (Darwin 1872/1998, p. 198). From this Darwin reasoned the unexpected is a strong element in general humor.

  Similar to modern affective neuroscience work on the “tickling” of rats (Panksepp & Burgdorf, 2000), Darwin pointed out that young chimpanzees and orangutans have ticklish armpits, like children, and when tickled utter “chuckling or laughing” sounds with their mouths drawn backward like in a smile. Darwin described the sound that apes make when tickled as a “reiterated sound” (Darwin 1872/1998, p. 198), which corresponds to human laughter and its “short, interrupted,
spasmodic contractions of the chest” (Darwin 1872/1998, p. 199)—a description that would also fit the ultrasonic “chirps” juvenile rats emit when playing with another rat pup or being “tickled” by a human hand (Panksepp, 2007c).

  Darwin went on to describe the human facial expression associated with laughter and smiling. In a full smile, the orbicularis muscles surrounding the eye socket make the eye squint. Hence, with a full natural smile “crow’s feet” are formed in the corners of the eye, in contrast to a partial smile, which is probably more forced and less natural.

  Darwin also suggested the principle that opposite emotions would produce opposite actions. An example would be a smile with the corners of the mouth turned up and a sad expression with the corners of the mouth turned down. Darwin argued that this idea applied to the sounds made with laughter as well. Laughter sounds are “short and broken,” whereas the cries of distress are “prolonged and continuous” (Darwin 1872/1998, p. 206). These observations are consistent with Panksepp’s (2007c) play chirps in rats and John Paul Scott’s (1974) distress vocalizations in dogs (for the first neuroscience study, see Panksepp, Herman, Conner, Bishop, & Scott, 1978). These insightful observations across mammalian species illustrate the kind of learning and generalization that can be achieved by Darwin’s comparative approach to the study of emotions, which consistently supported his important principle of continuity among species.