Common wildebeests Connochaetes taurinus , which make up a third of the lion diet, were the most attuned to the lunar cycle. But as nights got darker, the buffalo were more likely to form herds. Grazing in groups might offer safety in numbers. But unlike the other prey, these animals reacted more directly to changing light levels across the evening, Palmer says. Gazelles were more active after the moon had come up. That may seem like risky behavior, but being unpredictable could be a zebra defense strategy to keep lions guessing, she says.
These scenarios playing out in the Serengeti really demonstrate the wide-reaching effects of moonlight, Dominoni says. For nocturnal dung beetles, moonlight is a compass. How well the insects navigate depends on the phases of the moon. In South African grasslands, a dung pat is like an oasis, providing scarce nutrients and water that draw a crowd of dung beetles. The beetle then buries the ball and itself in the ground. The most efficient getaway is a straight line to a suitable burial spot, often many meters away, says James Foster, a vision scientist at Lund University in Sweden.
Some lunar light scatters off gas molecules in the atmosphere and becomes polarized — meaning the light waves tend to vibrate in the same plane. But beetles may use this sky pattern to orient themselves, inferring where the moon is without even having to see the orb directly. In recent field tests, Foster and colleagues evaluated the strength of the polarization signal in the night sky over dung beetle territory. As the moon gets darker across the lunar cycle, the signal weakens.
By the crescent moon, beetles have trouble staying on course , the researchers reported in January in the Journal of Experimental Biology. Polarized light during this lunar phase may be at the limit of what the dung harvesters can detect. At this threshold, light pollution could become a problem, as artificial light interferes with patterns of polarized moonlight, Foster says.
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He is conducting experiments in Johannesburg to see if city lights affect dung beetle navigation. Although rural African grasslands may not yet be bathed in an artificial glow, dung beetles are probably not the only nocturnal invertebrates that use polarized moonlight to find their way, Foster says. Many reef fish spend their infancy at sea — maybe because the deeper waters make for a safer nursery than the predator-packed reef.
Researchers determined that moonlight enhances the growth of young common triplefin fish an adult shown, bottom by studying the tree ring—like growth of an inner ear structure called an otolith a roughly 0. Fortunately for Shima, adults carry an archive of their youth within the inner ear.
Calcium carbonate structures called otoliths, or ear stones, grow a new layer every day. By matching otoliths from more than triplefins with a calendar and weather data, Shima and marine biologist Stephen Swearer of the University of Melbourne in Australia found that larvae grow faster during bright, moonlit nights than on dark nights.
Shima suspects that bright nights enable larvae to better see and hunt plankton. Likely predators, such as lantern fish, shy away from moonlight to avoid the bigger fish that hunt them by light. With nothing chasing them, larvae may be able to focus on foraging. But when young fish are ready to return to the reef, moonlight may become a hindrance.
In a different study, more than half of over 1, young sixbar wrasses Thalassoma hardwicke observed arriving at coral reefs in French Polynesia over 11 months did so during the darkness of a new moon.
Behavior and Environment
Only 15 percent came during a full moon , Shima and colleagues reported in Ecology in Because many predators in coral reefs hunt by sight, a cover of darkness may give young sixbar wrasses the best chance of settling into a reef undetected. In fact, Shima has shown that some of these fish appear to stay at sea several days longer than normal to avoid a homecoming during the full moon. Moonlight might similarly influence larvae of many kinds of reef fish and affect many aspects of the life cycle, Shima says.
In the seasons when the sun rises and sets in the Arctic, zooplankton plunge into the depths each morning to avoid predators that hunt by sight. But many scientists had assumed that, in the heart of winter when the sun is absent, zooplankton take a break from the up and down. But the light of the moon appears to take over and direct the migrations , Last and colleagues suggested in in Current Biology.
The instruments record the echoes of sound waves bouncing off swarms of zooplankton as the critters move up and down in the ocean. Normally, migrations follow a hour rhythm, with zooplankton, including krill and copepods, descending many centimeters to tens of meters into the ocean around dawn and moving back toward the surface at night to graze on phytoplankton. But winter trips follow a slightly longer That timing coincides exactly with the length of a lunar day, the time it takes for the moon to rise, set and rise again. And for about six days around a full moon, the zooplankton hide especially deep, down to 50 meters or so.
Zooplankton seem to have an internal circadian clock that sets their sun-based, hour migrations. Whether the swimmers also have a lunar-based biological clock that sets their winter journeys is unknown, Last says. But laboratory tests show that krill and copepods have sensitive visual systems that can detect very low levels of light, he says. The light of the moon also influences animals that are active in daytime.
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Their findings about universal patterns suggest which impulses and reactions are hardwired into the human psyche. Even with the convergence of findings in these disciplines, the field of evolutionary psychology is controversial. Some scientists, for instance, believe that evolutionary psychology overstates the biogenetic origin of cultural mores and norms and understates the capacity of learning and language to shape human nature. Further, evolutionary psychology clearly challenges what some religions, including Christianity, believe about the creation and free will.
And finally, the tenets of evolutionary psychology also directly dispute a great deal of popular management theory, which contends that people can change their personalities if correctly trained or motivated. Thus, evolutionary psychology may not be the only lens through which managers choose to view their work and their world, but it is a challenging perspective that calls for a closer look. But evolutionary psychology is by now well established enough to merit examination. Understanding evolutionary psychology is useful to managers because it provides a new and provocative way to think about human nature; it also offers a framework for understanding why people tend to act as they do in organizational settings.
Put another way, evolutionary psychology, in identifying the aspects of human behavior that are inborn and universal, can explain some familiar patterns. Evolutionary psychology goes so far as to raise the questions: How might organizations be designed to work in harmony with our biogenetic identity?
One hundred and thirty-nine years ago, the British naturalist Charles Darwin rattled the world with his theory of natural selection. Instead, they were an evolved species, the biological descendants of a line that stretched back through apes and back to ancient simians. In fact, Darwin said, human beings shared a common heritage with all other species. Genes that produce faulty design features, such as soft bones or weak hearts, are largely eliminated from the population in two ways. This is called environmental selection. Second, these same creatures are unattractive to other members of their group because they appear weak and less likely to reproduce.
This is called sexual selection. The genes that survive environmental and sexual selection are passed on to succeeding generations. At the same time, genetic mutations occasionally crop up. They produce new variations—say, improved hearing or sharp teeth. The characteristics that help a species thrive and propagate will survive the process of natural selection and be passed on. By these means, species evolve with stable genetic profiles that optimally fit the environmental niches they occupy.
Thus, fish that live at the bottom of the sea can see in the darkness, and dogs that prey on burrowing rodents have keen senses of smell. Species become extinct and new species emerge when radical shifts in environmental conditions render obsolete one set of design features and offer opportunities for a new set to prosper.
Darwin and his proponents over the decades have used the theory of natural selection to explain how and why human beings share biological and physical traits, such as the opposable thumb and keen eyesight, with other species. Evolutionary psychologists go further. They use the theory of natural selection to explain the workings of the human brain and the dynamics of the human group. If evolution shaped the human body, they say, it also shaped the human mind. A range of variations in their biogenetic design briefly flourished and then became extinct, leaving Homo sapiens as the all-conquering survivor.
The success of Homo sapiens was no fluke. For most of our history, this is how people lived, until their world radically changed with the invention of agriculture approximately 10, years ago. This suddenly allowed people to accumulate wealth and live in larger numbers and in greater concentrations, and freed many from hand-to-mouth subsistence.
From this agricultural period, fast and short steps have brought us to modern civilization, with its enormous social changes wrought by advanced technology and communications. But evolutionary psychologists assert there are three reasons that these changes have not stimulated further human evolution.
First, as far back as 50, years ago, humans had become so scattered across the planet that beneficial new genetic mental mutations could not possibly spread. Second, there has been no consistent new environmental pressure on people that requires further evolution. Third, 10, years is insufficient time for significant genetic modifications to become established across the population. Thus, evolutionary psychologists argue that although the world has changed, human beings have not. Evolutionary psychology offers a theory of how the human mind came to be constructed.
And that mind, according to evolutionary psychologists, is hardwired in ways that govern most human behavior to this day. Several key hypotheses among evolutionary psychologists speak directly to executives, however, because they shed light on how human beings think and feel and how they relate to one another. Life on the Savannah Plain was short and very fragile. The food supply and other resources, such as clothing and shelter, were unreliable and varied in quality.
Natural life-threatening hazards abounded. The thoughts and emotions that best served them were programmed into their psyches and continue to drive many aspects of human behavior today. Chief among them are:. Emotions Before Reason. In an uncertain world, those who survived always had their emotional radar—call it instinct, if you will—turned on. And Stone Age people, at the mercy of wild predators or impending natural disasters, came to trust their instincts above all else. That reliance on instinct undoubtedly saved human lives, allowing those who possessed keen instincts to reproduce.
So for human beings, no less than for any other animal, emotions are the first screen to all information received. Today businesspeople are often trained to dispense with emotions in favor of rational analysis and urged to make choices using logical devices such as decision trees and spreadsheets. But evolutionary psychology suggests that emotions can never fully be suppressed.
That is why, for instance, even the most sensible employees cannot seem to receive feedback in the constructive vein in which it is often given. Because of the primacy of emotions, people hear bad news first and loudest. Managers should not assume they can balance positive and negative messages. The negatives have by far the greater power and can wipe out in one stroke all the built-up credit of positive messages.
In fact, because of the primacy of emotions, perhaps the most discouraging and potentially dangerous thing you can do is to tell someone he or she failed. Be careful, then, of who you put in charge of appraisal systems in your organization. These managers must be sensitive to the emotional minefields that all negative messages must navigate. Loss Aversion Except When Threatened. Human beings who survived the harsh elements of the Stone Age undoubtedly tried to avoid loss. After all, when you are living on the edge, to lose even a little would mean that your very existence was in jeopardy.
Indeed, when the circumstances felt safe enough, that is very likely just what they did. We can see this same kind of behavior in children; when they are securely attached—confident that an adult will prevent any harm from coming to them—they can be quite adventurous.
But when harm looms, such behavior evaporates. Their descendants, with this genetic inheritance, would therefore also be more likely to avoid loss.
Sometimes our ancestors lived below the margin, with barely enough food to get by and no secure shelter. Or they experienced a direct threat to their lives from a predator, a natural disaster, or another human being. There are no historical records of what Stone Age people did in such circumstances, but it stands to reason that they fought furiously. And certainly those human beings willing to do anything to save themselves would be those that lived to pass on the genes that encoded such determination.
Thus, we are hardwired to avoid loss when comfortable but to scramble madly when threatened. Such behavior can be seen in business all the time. Their instinct is to take risks as soon as losses start to mount. A stock starts to fall and they double up their positions, for instance. That said, experienced traders know how damaging these instincts are; and rules and procedures that force them to cut their and let their lossess and let their profits run.
But without such rules and procedures, human nature would most likely take its course. Consider what happens when a company announces impending layoffs but does not specify which people will lose their jobs. In these situations, people will do almost anything to save their jobs and avoid the pain of such loss.
How else can you expain the kinds of leaps in productivity we see after a company makes usch an announcement? By another dynamic emerges when a company announces that entire divisions will close. The people affected—those who cannot escape the loss—do the unthinkable. They scream at their bosses or perform other acts of aggression. Instead of acting rationally, they flame out in a panic to survive. On the Savannah Plain, these desperate efforts apparently paid off.
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But a flaming out when feeling desperate is hardly a blueprint for survival in the modern organization. Besides being aware that people are hardwired to act desperately when directly threatened, managers must heed another message. Both are risky behaviors. Indeed, any kind of change is risky when you are comfortable with the status quo. And evolutionary psychologists are not surprised at all by the fact that, despite the excellent press that change is given, almost everyone resists it—except when they are dissatisfied.
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But what of those Silicon Valley entrepreneurs who have made a high art form of bet-the-company behaviors? Evolutionary psychology would tell us that these individuals are the type of men and women who over the millennia have sought thrills and lived to tell about them.
Human behavior exists along a continuum. On average, people avoid risk except when threatened. But imagine a bell curve. At one end, a small minority of people avidly seek risk. The vast majority fall in between, avoiding loss when comfortable with life and fighting furiously when survival requires them to do so. Managers would do well to assume that the people with whom they work fall under the bell of the continuum. Perhaps the most concrete take-away from this contention is that if want people to be risk takers, frame the situation as threatening.
The competition is goinig to destroy us with a new product. Or, our brand has lost its cache and market share is slipping fast. On the other hand, if you want people to eschew risk-taking behaviors, make sure they feel secure by telling them how successful the business is. That advice does raise a question, however.
What if you want people in your organization to be creative, to explore new ideas, and to experiment with different approaches to business? After all, most executives want their people to be neither outlandish fantasists nor mindless robots. The happy medium is somewhere between the extremes. What is a manager to do? They will see this as empty rhetoric; in fact, instinct will tell them that making mistakes involves loss possibly of their jobs.
Sadly, evolutionary psychology brings this managerial quandary to the surface but cannot solve it. Effective managers need to be adept at the very difficult task of framing challenges in a way that neither threatens nor tranquilizes employees. Confidence Before Realism. In the unpredictable and often terrifying conditions of the Stone Age, those who survived surely were those who believed they would survive. Their confidence strengthened and emboldened them, attracted allies, and brought them resources. In addition, people who appeared self-confident were more attractive as mates—they looked as if they were hardy enough to survive and prosper.
Thus, people who radiated confidence were those who ended up with the best chances of passing on their genes. The legacy of this dynamic is that human beings put confidence before realism and work hard to shield themselves from any evidence that would undermine their mind games.
Countless management books have been written extolling the virtues of confidence; they cleverly feed right into human nature. Given their biogenetic destiny, people are driven to feel good about themselves. But if you operate on a high-octane confidence elixir, you run into several dangers.
11.1 Homeostasis and Osmoregulation
You neglect, for instance, to see important clues about impending disasters. You may forge into hopeless business situations, assuming you have the right stuff to fix them. The truth is, even with self-confidence we cannot control the world. Some events are random. Or ask any young M. Perhaps that it makes sense sometimes to challenge human nature and ask questions such as, Am I being overly optimistic?
Yes, you can train people, teach them about different ideas, and exhort them to change their attitudes. But evolutionary psychology asserts that there is a limit to how much the human mind can be remolded. The theory of evolutionar y psychology is complex, and its implications equally so. But below is a summary of some points that evolutionary psychologists would make to managers tr ying to understand human behavior. Classification Before Calculus. The world of hunter-gatherers was complex and constantly presented new predicaments for humans.
Which berries can be eaten without risk of death? Where is good hunting to be found? What kind of body language indicates that a person cannot be trusted? In order to make sense of a complicated universe, human beings developed prodigious capabilities for sorting and classifying information. In fact, researchers have found that some nonliterate tribes still in existence today have complete taxonomic knowledge of their environment in terms of animal habits and plant life. They have systematized their vast and complex world. In the Stone Age, such capabilities were not limited to the natural environment.
To prosper in the clan, human beings had to become expert at making judicious alliances. They had to know whom to share food with, for instance—someone who would return the favor when the time came. They had to know what untrustworthy individuals generally looked like, too, because it would be foolish to deal with them. Thus, human beings became hardwired to stereotype people based on very small pieces of evidence, mainly their looks and a few readily apparent behaviors.
Whether it was sorting berries or people, both worked to the same end. Classification made life simpler and saved time and energy. Your classification system told you instantly. Every time a new group came into view, you could pick out the high-status members not to alienate.
And the faster you made decisions like these, the more likely you were to survive. Sitting around doing calculus—that is, analyzing options and next steps—was not a recipe for a long and fertile life. And so classification before calculus remains with us today. People naturally sort others into in-groups and out-groups—just by their looks and actions. In fact, research has shown that managers sort their employees into winners and losers as early as three weeks after starting to work with them. People are complex and many sided. But it is illuminating to know that we are actually programmed not to see them that way.
This perhaps helps to explain why, despite the best efforts of managers, some groups within organizations find it hard to mix. The battle between marketing and manufacturing is as old as—well, as old as marketing and manufacturing. The techies of IT departments often seem to have difficulty getting along with the groups they are supposed to support, and vice versa.
Everyone is too busy labeling others as outsiders and dismissing them in the process. A final point must be made on the matter of classification before calculus, and it comes in the area of skill development. Lists are attractive and often memorable. But advanced math and science education largely relies on sophisticated models of processes—complex explanations of cause and effect in different circumstances. It also advocates probabilistic ways of thinking, in which people are taught to weigh the combined likelihoods of different events together as they make decisions.
Many people may come to understand and use these methods—weather forecasters and investment analysts are examples—but even lengthy training cannot fully eliminate our irrational and simplifying biases. Along with a scarcity of food, clothing, and shelter, and the constant threat of natural disaster, the Stone Age was also characterized by an ever-shifting social scene. From one season to the next, it was not easy to predict who would have food to eat, let alone who would be healthy enough to endure the elements.
In other words, the individuals who ruled the clan and controlled the resources were always changing. Survivors were those who were savvy enough to anticipate power shifts and swiftly adjust for them, as well as those who could manipulate them. They were savvy because they engaged in, and likely showed a skill for, gossip. That has always been true in human society. The people who chat with just the right people at just the right time often put themselves in just the right position.
In fact, it is fair to assume that human beings have stayed alive and increased their chances of reproducing because of such artful politicking. What are the implications for managers? And since the interest in rumors is ingrained into human nature, it makes little sense to try to eliminate such interest by increasing the flood of official communications. Rather, managers would be smart to keep tabs on the rumor mill. They might even use their own networks to plug into the grapevine. But when it comes to gossip, it may be that managing by wandering about is the most effective way to communicate, as long as it is performed in a climate of trust and openness.
Empathy and Mind Reading. Simply stated, these two skills are the building blocks of gossip. People are much more likely to hear secrets and other information if they appear trustworthy and sympathetic. Likewise, people with a knack for guessing what others are thinking tend to ask better—that is, more probing and leading—questions. Thus, because empathy and mind reading abet the survival skill of gossip, they too became hardwired into the human brain. At the same time, people are also programmed for friendliness.