What to expect this week:

Surely there are plenty of things that separate us from the rest of the animal kingdom. Each species has its unique evolutionary history, and we’ve developed our own divergent forms and behaviors.

However, evolution is still constrained by the laws of biology. No species is exempt from being influenced by its genetic predispositions, including us. Evolutionary mismatches and traps are prime examples of this. We have altered our environments dramatically in the past 10,000 years and our genes have not yet caught up. As a consequence, we often fall victim to poor behavioral choices rooted in things like our opportunistic instincts.

This week’s article provides some examples of these types of mismatches in the animal world, and four traps that modern humans experience.

Housekeeping:

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Evolutionary Mismatches and Modern Traps

We are all susceptible to the modern traps of physical inactivity, unhealthy dietary choices, and screen time. Like a mouse following its natural instinct to snag the small block of cheese, but getting caught by mouse guillotine, we too are fooled by our instincts. They often mislead us not by their own fault, but also by the fault of the environments we’ve created.

Traps like these are actually quite common in nature. So common, that biologists have studied them and termed them evolutionary traps (or ecological traps). An intuitive way to define traps like these was presented by Martin A. Schlaepfer and colleagues [1]. It reads:

Typically, this happens “when a novel element in the environment mimics a traditional cue for habitat choice, thereby misleading the organism.” For example, nocturnal insects use light cues to help them navigate. This was the case for most of their evolution and they are adapted to those light cues. However, the artificial light that humans have created is so novel, often disorienting and attracting these bugs.

This attraction to artificial light can lead insects to spend excessive energy flying around light sources, which can result in decreased foraging time, increased predation risk, and reduced reproductive success. In extreme cases, insects may be drawn towards artificial lights to the point of exhaustion or death.

A large portion of these evolutionary traps are the product of human intervention. But, nonhuman species are not the only victims. We are too. We are both the beneficiaries and the victims of the modern world we’ve constructed. Have we constructed our own evolutionary traps, tempting us towards suboptimal behavioral choices? Are we not that much more intelligent than the insects getting falsely wooed by artificial light? What are the negative consequences of this?

Evolutionary Mismatches

To understand an evolutionary trap and its negative consequences, we need to understand the mismatch at play. An evolutionary mismatch occurs when an organism's environment is misaligned with the ancestral environments to which it is adapted. That mismatch is what triggers the mistake made by the organism falling into the trap.

Here is another example. There is a species of beetle in Australia called the jewel beetle. Male jewel beetles have been observed copulating with beer bottles [2]. Why? Wouldn’t it be maladaptive for the beetle to do so, wasting its time and reproductive resources on an inanimate object that can’t even deliver its offspring?

It’s because the glossy brown finish on the beer bottles resembles a female beetle. Since beer bottles were never a feature of the beetles’ environment until very recently, they never evolved to delineate between them and the females the bottles imitate. There is a mismatch between their ancestral environments (which lacked beer bottles) and their current environments (which contain novel and attractive bottles).

As a result, they waste their energy and resources on a fruitless mating pursuit.

“But humans would never fall for something like that. We are too conscious and smart.” I beg to differ. There is content on the internet that is drawing people in (predominately men) with false signals of real-life mating opportunities - to the point of addiction. This may be the topic of a future episode, but for now, I hope you can infer what I’m referencing here.

Novelty can be a dangerous thing and the modern cultures we live in are hyper-novel. When comparing ancestral human environments to contemporary towns and cities, they are so conceptually dissimilar, that it's like they’re settings on different planets. The rate of change occurring in the past 10,000 years has led to the greatest evolutionary mismatch our species has seen, with traps around every corner. 

Here are 4 traps that you and I are susceptible to but, will hopefully become more aware of, giving us the advantage when fighting off ourr beetle-like instincts. 

1. Processed Foods: Food is and always has been a necessary component of survival. However, it has always been a finite resource. There is limited evidence that our hunter-gatherer ancestors experienced frequent bouts of famine or starvation [3], but this does not mean that they had an infinite supply of food. Our ancestors would have evolved to be opportunistic eaters. They would have capitalized on food when it presented itself, especially calorically dense foods that could supply them with a lot of energy.

   Our modern food environments look very different, but we still have that opportunistic instinct to chow down some high-calorie food when we catch sight of it. Today, food is more accessible than before. Also, we make our food hyper-palatable. This means that it’s tastier and easier to eat large quantities of it. About 60% of the American diet comes from ultra-processed foods [4]. The preference for these foods, once advantageous for survival, has become a trap that can lead to overconsumption and health problems like obesity, cardiovascular disease, and type 2 diabetes. These are often considered mismatch diseases.

2. Sedentary Lifestyles: Just as opportunistic eating would have been advantageous for humans who were unsure of their next meal, so too were they opportunistic loungers. Physical activity was inevitable. Moving was another key component to survival, and hunter-gatherers did (and still do) a lot of it. Modern hunter-gatherers are estimated to travel 5-9 miles per day on average [5]. While those miles are mostly spent walking, a good portion can be spent running as well - like during a persistence hunt.

   Because life in the wild requires high energy outputs, it would have been foolish for ancestral humans to waste energy on unnecessary activities. So, they likely would have evolved a tendency to conserve their energy when the chance arose. Life in the modern world provides more of a chance to do so than ever before. Because we no longer have to earn our food physically, the opportunity to remain inactive is pervasive. Especially in combination with our easy access to calories, physical inactivity has contributed to our population’s obesity epidemic, by decreasing our energy output relative to input. 

3. Artificial Light at Night: Artificial light is a circadian disruptor. It dissociates your physiological clock from the natural day/night cycle. “Circadian disruption leads to metabolic disturbances associated with several abnormal physiological conditions such as cancer, obesity, coronary heart disease, oxidative stress, and immunological variation,” says Kumar et al [6].

   The natural environments we evolved in did not permit us to view bright lights late into the night. The bright sun marked the day, and the dim moon marked the night. Returning back to such an environment can actually help realign our circadian rhythms with these natural fluctuations. One study compared participants’ circadian rhythms during regular daily life to when they spent one week camping with no artificial light but a campfire. They found that after just one week, the natural light/dark cycle of camping can advance the circadian clocks of night owls, inducing sleep patterns more in line with natural fluctuations in daylight [7].

   It’s also very interesting that this effect occurred despite exposure to fire light. This could be because humans have been using fire long enough to adapt to its presence, unlike electrical light.

4. Politics: We may even be experiencing an evolutionary mismatch in politics. Another aspect of our modern cultural environments is the size and scale of our political organizations. We live in cities with millions of people, which are nested in large nations coordinating and competing at the geopolitical scale. This is in stark contrast to the few-hundred-person tribes (at most) our ancestors lived in for millions of years.

   Glen Geher and colleagues sought to test whether or not we are cognitively adapted to understanding our modern political climate. Participants of their study were asked to describe various political situations, ranging from large-scale impersonal scenarios to small-scale scenarios involving oneself. They found that “participants had an easier time processing information related to small-scale political situations than large-scale political situations,” [8]. 

   So, even our political arena is a trap. Maybe one reason why people are so frustrated with the current state of politics and why politicians seem so out of touch with the general public, is that we are not psychologically adapted to thinking at such large organizational scales. 

Conclusion

Like a fish biting the bait, we are also deceived by our senses. Our perceptions, being adapted to the environments of a pre-modern state of nature, often fail to assign the proper value to modern environmental cues. In ancestral environments, high-calorie foods meant survival - high calorie = high value. In the obesigenic state of today, high-calorie foods pose a health risk. 

These traps can be so powerful, that they often pull us in despite our conscious efforts to maintain discipline and avoid them. 

I’ve now shown how food is just one example of an evolutionary mismatch people may struggle with today. Sedentary lifestyles, artificial light, and even politics are all features of the human environment that have changed dramatically in the past few centuries millennia. 

Yet, understanding these traps offers hope. By recognizing the evolutionary roots of our mismatches and the behaviors they create, we can strive to make conscious choices that align with our long-term well-being. Through education, awareness, and deliberate efforts to rewire our instincts and environments, we can mitigate the effects of these traps and forge a path towards healthier, more sustainable lifestyles.

References:

[1] Schlaepfer, M., et al. 2002. “Ecological and evolutionary traps.” Trends in Ecology & Evolution 17(10):474-480.

[2] Gwynne, D. and  Rentz, D. 1983. “BEETLES ON THE BOTTLE: MALE BUPRESTIDS MISTAKE STUBBIES FOR FEMALES (COLEOPTERA).” Australian Journal of Entomology 22(1):79-80

[3] Cordain, Loren, et al. 1999. “Scant evidence of periodic starvation among hunter-gatherers.” Diabetologia 42(3):383-4.

[4] Poti, J., et al. 2015. “Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households?” American Journal of Clinical Nutrition 101(6):1251-62.

[5] Pontzer, Herman, et al. 2018. “Hunter-gatherers as models in public health.” Obesity Reviews 19(1):24-35.

[6] Pravin, K., et al. 2019. “Artificial Light Pollution at Night: A Risk for Normal Circadian Rhythm and Physiological Functions in Humans.” Current Environmental Engineering 6(2):111-125.

[7] Wright, K., et al. 2013. “Entrainment of the human circadian clock to the natural light-dark cycle.” Current Biology 23(16):1554-8.

[8] Geher, G., et al. 2016. “The evolutionary psychology of small‐scale versus large‐scale politics: Ancestral conditions did not include large‐scale politics.” European Journal of Social Psychology 46(3):369–376.

Fit Fuel Song Suggestion

The Fit Fuel song suggestions are hand-picked by yours truly to elicit the motivation (and possibly aggression) needed to initiate or persist through a grueling workout. They consist of heavy, brutal guitar riffs and gruesomely guttural vocals. Additionally, I timestamp what I believe to be the best riff of the song - one that will kick your nervous system into overdrive when approaching a personal record (PR).