Unnecessary Risk Taking

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True   Likely   Speculative
Human Uniqueness Compared to "Great Apes": 
Relative Difference
Human Universality: 
Population Universal (Some Individuals Everywhere)
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While other species take risks for food or mating success, unnecessary risk taking is a human specific personality trait. Many humans are fond of taking unnecessary risk, for example, recreational activities like sky diving, cliff jumping and rock climbing or negative antisocial activities like crime, drug use, and gambling. While a few studies have shown examples of the other non-human species exhibiting unnecessary risk, the extent is much more limited than that of humans, and is usually in a domain of activity the animal can already carry out instinctively. Hypothesized reasons range from the need for haste, financial crises, complacency, peer pressure and others. There is as yet no commonly accepted theory for why humans evolved to take risk. Additionally, recent studies show genetic influence and environment also plays an important role in this trait. 


Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

Possible Appearance: 
5,000 thousand years ago
Probable Appearance: 
1,400 thousand years ago
Definite Appearance: 
100 thousand years ago
Background Information: 

Currently, few studies of risk taking behavior have been conducted in non-humans; those studies show risk seeking in other species is very rare. One study investigating unnecessary risk taking behavior in the Great apes found chimpanzees and orangutans exhibit riskier behavior than gorillas or bonobos. A similar study showed competition to be a driving force for greater risk taking in apes.

The Human Difference: 

It is probable that early humans took unnecessary risks both for survival and due to humans’ generally inquisitive nature. Examples of early risk taking behavior include invention of traps and weapons for wild animals and consumption of novel plants. These activities likely encouraged more risk both for themselves and for the group.

In modern humans, unnecessary risk has increased across the human population primarily due to social context, competition, and financial crises. Greed is also a motivator for irrational risk. 

Universality in Human Populations: 

The human population is divided into two groups: risk seekers and avoiders. While not all humans are risk seekers some individual in all populations tend to take unnecessary risk. Risk seekers themselves can also be grouped: positive or rewarding risk seeking (cliff jumping, paragliding, rock climbers, etc) and negative or antisocial risk seeking (crime, drug use, gambling, etc). However, depending upon the situation, individuals may exhibit both risk seeking and avoidance behaviors.

In addition to population wide differences in risk seeking behavior, males are more likely to engage in riskier behavior than females. This difference may be adaptive for early human male group protection, hunting, and exploring. Although risk-taking behavior is exhibited in modern human females, comparatively, males still tend to participate in more financial and recreational risks than females do. Increased risk taking during human adolescence is also well documented. 

Mechanisms Responsible for the Difference: 

As the brain is the central governing organ, it regulates and controls all behavioral activities performed by the body. Brain areas known to activate during risk taking behavior are the hippocampus, known to play a role in spatial learning and novelty detection, the amygdala, which is the controlling region for fear and emotional learning, and the frontal cortex, shown to have a major role in decision-making and executive function.

Steroids such as testosterone and cortisol play a significant role in regulating risk-taking behavior. Testosterone and cortisol levels are regulated by the Hypothalamic-pituitary-gonadal (HPG) and Hypothalamic-pituitary-adrenal (HPA) axes, respectively, which maintain normal physiological homeostasis. Studies show the release of dopamine (neurotransmitter) from the nucleus accumbens increases desire for a particular outcome or reward. Both testosterone and cortisol are responsible for dopamine transmission in this region, and as such, may regulate dopamine in response to risk-taking behavior. Elevated testosterone may induce dopamine levels during athletic, adventurous, and aggressive events, whereas cortisol, a stress activated hormone, likely affects dopamine during negative risk taking activities.

Risky behavior also induces the release of endorphins (natural opiates), to help maintain homeostasis during an adrenaline rush. Endorphin sensitive early humans, who took risks and survived, may have passed this trait to offspring. Genetic variation in three genes have been associated with endorphin sensitivity, all of which have a role in the processing of neurotransmitters:

  1. Dopamine Receptor D4 (DRD4)
  2. Serotonin-transporter-linked polymorphic region (5-HTTLPR)
Monoamine Oxidase A (MAOA)
Possible Selection Processes Responsible for the Difference: 

One possibility is individuals willing to take unnecessary risk who survived were selected for within the population.
 Moreover, modern society may reinforce and maintain this personality trait within the population through encouragement of individuals willing to engage in risk-taking activities. 

Implications for Understanding Modern Humans: 

Increased levels of risk taking in the modern humans is observed in both positive activities, such as risky recreational sports, as well as in negative behaviors, such as gambling, drug abuse, and crime. Especially in the case of negative risk-seeking behavior, there are detrimental implications for society as a whole. 

Occurrence in Other Animals: 

Unnecessary risk taking behaviors observed in other species include the following:

  • Adolescent rodents show risk during performance on plus maze, as well as impulsivity and restless behavior.
  • Pumpkinseed fish (Lepomis gibbosus), an inquisitive fish species, enjoys exploring novel objects and environments suggesting they are risk seeking.
  • Guppies (Poecilia reticulate) shows predator inspection behavior, a risky behavior where predators are approached and monitored. Male guppies exhibiting this behavior tend to be more attractive to females; therefore, riskier male guppies are sexually rewarded and more likely to pass on their risk taking genes.
  • The great tit bird (Parus major) is divided into fast and slow birds. Fast birds are generally more curious, explorative, and aggressive than their slower counterparts. 
Related MOCA Topics
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