Nothing in our subjective self-experience gives us so much the impression of individuality and uniqueness as our feelings. Not only poetry but art in general has elevated the realm of emotions to a world of its own, which seems to exist of itself without purpose.

Victor Johnston makes us abandon this view with his biopsychological theory of emotions. He points out that the fact that we have feelings and the way we feel are relentlessly determined by the evolutionary selection process. Evolution has refined our system of appraisal of our perceptions, ultimately according to reproduction advantages. Johnston’s rigorous theorizing by means of Darwinian learning principles dismantles human narcissistic illusions of the uniqueness and grandeur of our moods, emotions, affects, and their reflection. Feelings appear as mere by-products of an ever self-refining system for maximum gene survival. This painfully plausible book makes it difficult to hold anything against it; therefore, those who by all means want to stick to man’s uniqueness in creation due to our emotional life should be warned against reading it.

The informed reader may consider the entry to the book somewhat tedious up to the chapter about the basics of learning mechanisms in adaptive biological systems that have survived the evolutionary selection process. Johnston starts off with Socrates’ cave metaphor: what we see as "green" has no such quality equivalent in nature but is entirely made up of perceptual appraisals generated in our brain. The seemingly arbitrary selection, for example, of a tiny band of electromagnetic wave frequencies for our perception of green has been determined by the survival benefit of those biological systems which could sense the green plant for food. Very small differences between frequency bands have to be exaggerated by the "proximal valuing system," whereas a vast amount of information about other wave frequencies remains unnoticed because it is irrelevant for the reproduction advantage. This means that there is greenness neither in nature nor in our brain. Greenness exists only as "emergent property," which is a tool for the evolutionary selection process. It just happens to emerge from the development of the organism according to its survival benefit. This emergent property can be submitted to further evolutionary molding.

The basic learning principles extracted by the author, mainly from well-known working mechanisms of the immune system and from other paradigms of evolutionary learning, include the following:

1. The system has to offer to the outside world a random variation of selectable or moldable tools—"emergent properties" like antibody proteins, organ sensations, or feelings—for selection by the evolution process. Randomness of the variations is the most essential principle. Adaptiveness and creativity, the ability to transcend the learning system itself, depend on it.

2. The repetition of this process by "entangled learning processes" of different degrees of freedom entails phylogenetic learning for long-term stability (adaptation to the day-night cycle, for example), ontogenetic learning (as in the morphological and neural network organization of the brain) to adapt to medium-range stable environmental cues like food, and functional adaptability to very volatile short-living cues for adaptation (like mimic changes in the face of a mate).

3. Steering the degree of variation at its optimum between preservation of ascertained adaptive functions and instigation of the evolutionary process by increasing the number of variations presented to the outside world for selection is another important principle, recently exemplified with the heat proteins (see, for example, the disputation between Gould and Dawkins provided by Groß [1]).

Johnston applies his generalized Darwinian learning theory to the development of a novel method to gain the most adequate facial composite to track a criminal. Instead of asking a witness to describe the face of the criminal, Johnston offered a random sample of faces of which the witness had to select the one that best resembles the suspect. Of this, another sample of random variations was generated, and so forth. The result turned out to be far more accurate than those faces which emerged from the usual description procedure.

Transferring the principles of the evolutionary learning theory to the world of feelings means, first, that feelings—i.e., appraisals—are considered nothing else than "emergent properties" that the evolutionary selection acts upon. Johnston considers feelings to be "proximate values" whose task has become to steer the "two-loop" (phylogenetic and ontogenetic) learning model by selecting the best-fitting hypothesis from several hypotheses generated by the sensory input. From the establishment of lasting behavior patterns up to more volatile memory storage, feelings decide what is kept and what is let go according to the reproduction advantage. The tuning spectrum of hedonic versus unhedonic does it. Johnston exemplifies this with many amusing observations and, in the end, with an artificial intelligence creature, a dog-like sniffer whose sensory and feeling systems decide whether it can sniff successfully to get hold of its prey or runs into starvation.

One most disenchanting for human narcissism but most plausible example of Darwinian learning theory applied to emotions is Johnston’s work on beauty and erotic partner selection, for which he won a scientific award. To prove that our feelings for beauty and sex appeal do not follow arbitrary individual patterns but the stern rules of the "net reproduction gain," Johnston invited the world to choose the most attractive female and male faces of those he posted on the World Wide Web. Statistical evaluation demonstrated that from full lips (due to little fat cushions after estrogen rise in puberty) to the hip-waist ratio for the pelvis most likely to deliver without complications, every sign of sexual attraction is in fact related to the "net reproduction gain," i.e., the likelihood to win the most fertile and successfully delivering woman. The attractiveness of male faces seemed to rest mainly with signs of health and physical strength. Furthermore, according to the selection experiment, our feelings are tuned to the age of highest fertility. Again, these cues cause exaggerated feelings, in the sense of a "discriminant amplifier," to waste not even a minimal reproduction advantage.

The same learning principles underlie memory. Johnston claims that memory stores only experience related to events that matter for biological survival. Memories work by indexing episodes according to their hedonic tone—the basis for man’s reasoning on future events. The ability of "mind reading" is based on the comparison of currently perceived and formerly experienced social situations and their past and presumptive future social sequelae. It is obvious that this ability has an enormous impact on the competence to adjust to and influence other individuals’ feelings and hence to improve the reproduction rate.

Social feelings have played an increasing role in evolution for man’s reproduction advantage. Experimental games like "the prisoner’s dilemma" suggest that modesty and cooperation may do better than directly acting on the individual’s instant advantage. Johnston describes a set of feelings particularly adjusted to this somewhat paradoxical condition: an elaborate emotional monitoring system for the mutuality of affection, protection, and concern. If the reciprocity is broken by recklessness, a "pop out feeling" indicates the loss of the "investment"—hopefully not too late. In addition to anger, "pop out emotions" are fear and love—Johnston comments at length on their serendipity and their potential reproduction advantages. Emotional framing for decisions by a hedonic tone is also seen in the context of gene survival. The group size, for example, plays a crucial role in the amount of reciprocal interactions of social altruism offered by the group members to each other. Johnston quotes studies that relate the maximum group size allowing for altruism to the size of hunting bands in prehistoric times—the root of an adjustment that may no longer fit, like many others: the "naturalist’s fallacy." The nepotistic, oligarchic regimes in some countries may resemble these mechanisms, however.

Johnston’s book is both amusing and plausible, but its basic theories are not novel. For the clinician, the harvest of the great factual knowledge in this book is not as rich as it is for the theoretician and biologist. The mechanisms of learning, the language of emotions in primary relationships, and the consequences of its failure or distortion (2) do not play major roles in the book, although it starts with a clinical case vignette of schizophrenia. The neurophysiology of brain systems that generate and process emotions is touched upon only very briefly. There is a vast body of research that strives to disentangle the universally stable basic patterns of emotions from their individually changeable parts (3–5). The microsocial and individual developments of distorted patterns of emotional language dealt with in trauma research could also build a bridge to clinical aspects, which obviously was not an intention of the author.

What lasts as a stimulating and original message of the book for the clinician is the generalization of principles of the Darwinian transgenerational "learning theory" concerning DNA under the selection process to other biological systems in general. Although DNA does not "learn" but just happens to change under the pressure of selection, the task of balancing the preservation of functions and their modification is the same in truly learning biological systems. Johnston’s application of the "Russian doll" learning processes to neuropsychology seems promising.

The strength of this book, namely its rigorous Darwinism and the relentless uncovering of what is seen as the ultimate purpose of feeling, nevertheless causes disillusionment and even disenchantment. Historical comparisons come to mind. After the overstretched adoration of rationality in the late enlightenment toward the end of the eighteenth century, when reason was put on the altar, the Sturm and Drang period swept away logic and returned to the realm of feelings as a colorful but less calculable world in its own right. Johnston has not indulged in those worlds which are best represented by art and religion. Certainly he would find "net-reproductive gains" in societies with superior ethical and religious systems; and fine arts may be considered tentative appraisals that at some time will lead to "emergent properties," but a little bit of illusion may also be necessary to survive.