Pain = Bad

Pain = bad

Many organisms have inherited responses that help protect them from harm. In humans, these include rapid reflexes and more complex responses to perceived danger.

People differ in what they experience as threatening and how they respond. A protective response may help in immediate danger yet become disruptive when it persists in a situation that does not require it.

Think of reflexes. These are involuntary, automatic actions that our bodies perform in response to a stimulus. For example, if you put your hand on a hot stove, a withdrawal reflex can start moving your hand before you consciously register a “hot!” message. This rapid reaction can limit injury. Blinking is another example. When dust or bugs approach the eye, the eyelid automatically closes without having to voluntarily contract any muscle to close the eye. These simple examples demonstrate that self-preservation is hardwired in. The better your survival reflexes, the greater chances of survival, and so these systems are easily selected for in the evolutionary process.

A more complex self-preservation instinct is the fight, flight, or freeze response in humans and other mammals. When human beings are faced with imminent danger, this mechanism kicks in with the mobilization of the sympathetic nervous system. The results in the body are a sharp increase in blood sugar levels, constriction of blood vessels, increase in heart rate, and the diversion of blood from nonessential organs to heart and skeletal muscles. These changes can prepare an animal to respond quickly to danger.

Some behaviors impose costs on an individual while helping relatives survive and reproduce. Kin selection explains how such behavior can spread when the benefit to relatives, weighted by relatedness, outweighs the cost to the actor. A benefit to a population alone does not establish that a trait will be selected for.

Parental care offers many examples of costly behavior that benefits offspring. Some will literally sacrifice their own lives, like the black lace weave spider, which will allow its babies to eat it. Some animals, like African elephants, zebras, and sea lions will work together in large groups to protect the offspring of others. Orcas and dolphins remain awake for a full month after the birth of their young to care for and protect them. Other animals, including polar bears and penguins, may go months without eating for the sake of their offspring. Marmots will delay their own reproduction if others in their group need help with childcare.

Worker honeybees usually care for the queen’s offspring rather than reproduce themselves. Workers can also destroy eggs laid by other workers.1 The account also describes male drones dying during mating and being removed from the hive when resources are conserved. These examples involve costs to individuals within the colony.2

Helping relatives can increase the transmission of genes shared with them. But relatedness, costs, and reproductive benefits must be established for a particular case; membership in the same herd does not by itself demonstrate kin selection.

Some defensive behaviors kill the animal performing them while protecting others. One species of ant, Colobopsis explodens, will explode when threatened by a predator, killing the individual but helping the group survive by releasing a poisonous substance. Bees and some types of termites behave similarly, attacking predators by destroying themselves.3 Belding’s ground squirrels announce the presence of a predator through alarm calls that make themselves more conspicuous and therefore vulnerable.

Protective responses do not require an animal to reason about survival. Natural selection can favor inherited traits that increase reproductive success, whether through the individual’s offspring or, under the right conditions, through relatives.

Humans are also, however, capable of overriding our own biological survival instincts. Sometimes it is innocuous, like when we go on a roller coaster. We tell ourselves it’s perfectly safe, so the biological reaction of terror gets processed as a thrill. Sometimes, though, we override them because our situation seems to demand it, and we put ourselves in situations of chronic stress and pressure. Self-preservation and costly care for others can therefore coexist. Neither requires organisms to consciously calculate the survival of their genes.