Natural selection is based on reproductive success. Genetic traits are naturally selected when they increase in a population because of reproductive success leading to more offspring than would occur without the traits. According to life history theory natural selection can result from any mechanism that increases reproductive success. There are a number of life history characteristics that can change reproductive success. Chief among these is that of increasing the probability of living long enough to reproduce after attaining the age of sexual maturity. If our hominid ancestors lived long enough to reproduce throughout the span of their reproductive years, with everything else being equal, their opportunity for reproductive success would on average be greater than if they had died young and had no or limited opportunity to reproduce. This scenario made it likely that the traits that contribute to prolonging the lives of our hominid ancestors and of their progeny to and beyond the age of sexual maturity would be naturally selected.
Evolutionary psychologists have uniformly supported the notion that reproductive success is increased by prolonging survival. This has been shown by their considerations of kin selection and group selection theories, wherein it is posited that an altruist risks his life and reproductive success to ensure the survival and reproductive success of his kin or of members of his group. Also, adaptations are thought to work by increasing survivability. Natural selection can result from increased survivability and also can result in increased survivability. Therefore, natural selection in hominids has generally been viewed from the perspective of a survivalist paradigm.
But a survivalist paradigm does not explain the mechanism by which genetic traits enhance survivability. In order for a genetic trait to be naturally selected, the trait must program for a mechanism, or for a structure that enables a mechanism, to increase survivability. The mechanism that is proposed here is that of security-seeking behavior, because threats to survival can be counteracted by security-seeking (safety-producing) behaviors that provide protection against the threats. Security is freedom from danger, harm, or loss of life. Examples of security-seeking behaviors that protect against loss of life are: safe driving, which decreases fatal accidents; learning to swim, which helps to prevent drowning; not smoking, which helps to avoid lung cancer; and treating hypertension, which helps to prevent heart attacks, strokes, and the resulting loss of life.
Eyes and ears, and the components from which eyes and ears are assembled, have been naturally selected because eyes and ears are structures that produce behaviors of seeing and hearing, which are mechanisms that increase an organism's security by protecting it from threats to its survival, such as from predators. The behavior of all organs and organ systems and human behavior itself, increase our security by protecting us from threats to our survival. Although, because of natural selection, increased survivability is the ultimate goal of behavior, behavior, nevertheless, acts at the level of its proximate goal, that of increasing security, in order to achieve its ultimate goal. For this reason security is the goal of behavior. That security is the goal of behavior is crucial to the understanding of much that follows in this paper.
That security is the goal of our physical and mental behavior was confirmed in The Primal Instinct: How Biological Security Motivates Behavior, Promotes Morality, Determines Authority, and Explains Our Search for a God (Jaffe 2010, pp.15-22) by serially considering numerous human actions, and by showing that they all had security as their goal. We have been programmed by natural selection so that everything we do has the same goal: to increase our security. Our actions, therefore, always favor that which gives us the most security. Our desire for security is the motivator for all of our behavior, including attaching, moral, altruistic, learned, volitional, and valuing behaviors. It is the preeminent principle in psychology and is the reason theists believe in God.
The more physically and mentally competent we are in protecting against threats to our survival the more secure we are and the more secure we feel. Playing games is a technique for practicing and demonstrating competent behavior. When children play hide-and-go-seek, or adults play any physical or intellectual game, such as playing at sports or at cards, they have fun. We feel good when we have fun. We feel good and have fun when we are able to demonstrate competent behavior. Our self-esteem rises when we win a contest, solve a puzzle, satisfactorily complete a task, master a subject, or perform well: when we demonstrate competent behavior. Levels of self-esteem correspond to levels of security feelings because self-esteem monitors and reflects how secure we feel as a consequence of our demonstrating physical or, especially, intellectual competence. That which is associated with increased feelings of security, such as having fun, demonstrating competent behavior, or increasing self-esteem, is associated with feeling good. We are motivated to seek security by our desire to experience good, pleasant feelings which emanate from our mental reward system. This will be discussed next.