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Dogs Love to Play, but They Don’t Do so for Pleasure
Could it simply be pleasure for its own sake?
A Jack Russell terrier tears in and out of its doggie door, skidding and sliding on a hardwood floor, only to repeat the performance over and over again. A Border collie in the park leaps to catch a ball, runs and drops it back at the owner’s feet with a look of anxious anticipation. There’s no food treat in store for these animals, no pats on the head – they seem to do it out of sheer playful exuberance. But what are they really up to? What does it mean for a dog to ‘play’?
Konrad Lorenz, Nikolaas Tinbergen and Karl von Frisch, founders of the field of ethology (the study of animal behaviour) shared a 1973 Nobel Prize for their demonstration that, just like physical shape and structure, the patterned movements of animals in time and space are evolutionary adaptations. These ‘motor patterns’ are products of natural selection that enable animals to meet the fundamental challenges of life: to acquire energy by feeding, to avoid hazards to life and health, and to successfully reproduce.
However, when we look at puppies enthusiastically chasing and nipping at each other, or chewing on a favourite rubber toy and tossing it in the air, it’s hard to find any biologically adaptive value in the activity. If anything, it often looks just like fun to us, a joyful waste of time and energy.
Could the goal simply be pleasure for its own sake? The problem is that this doesn’t fit into the classical model of Darwinian natural selection, which we assume is the main force that drives adaptive change. Dogs chasing each other in the park probably aren’t going to get more food than their less lively peers; chewing a rubber ball yields no calories at all. Indeed, playing is energetically wasteful. It doesn’t help young animals to avoid dangers such as predation, and it doesn’t produce more offspring. So what’s the (biological) reason for play?
Hypotheses abound. Could it be, for example, that play behaviour is a way for young animals to practise skills they’ll need in adulthood? It does seem to contain parts of adult behaviour – ‘playing’ animals often chase and capture things as if they were engaged in mock hunting, for example. Perhaps play helps young animals learn how to deal with aggression more effectively, or to interact more successfully with potential sexual partners. There isn’t any immediate fitness benefit, no calories to be gained, but maybe the adaptive pay-off is that you’ll eventually be a more effective adult, ultimately with a greater chance of reproductive success.
In our recent book How Dogs Work, we come to a different conclusion: ‘play’ is not, at its heart, an adaptive form of behaviour at all. Instead, it simply emerges as an artefact of the way that animals develop over the course of their lifetimes. Mammals, for instance, must make a profound and far-reaching change from being a dependent newborn, through a juvenile stage, into an independent adult in its own right. The adult has a new form and a new behavioural repertoire: it has changed from a nursing, care-soliciting neonate into a foraging, courting adult with the ability to escape from predators without help.
As a newborn grows over time, its behaviour, like its physical form, needs to be ‘re-modelled’. In effect, it has to undergo a physical and behavioural metamorphosis into an adult. Not unlike the transformation of a caterpillar into a butterfly, the structures of the newborn mammal are partly disassembled and then ultimately reconstructed into the adult. This transitional metamorphic form is often called a juvenile. As development unfolds, the animal’s whole physical system, along with its behavioural repertoire, must constantly be re-integrated so that the organism can continue to work as a functioning whole.
In the course of this metamorphosis, a juvenile animal still exhibits some of its newborn behaviours at the same time that it is developing a set of adult motor patterns. Until it is fully adult, it has only partial sequences of these patterns. Many of these are still non-functional. Juvenile canids for example (say a dog or a wolf) might eye, stalk and chase things but they have not yet developed the grabbing and killing-bite motor patterns that will make them effective adult predators. Some of the necessary pieces of behaviour are present in the juvenile, but they are not yet fully in place, and often they aren’t assembled together in the proper order. (That’s one reason why we’re skeptical of the ‘play as practise for adulthood’ theory.)
Juvenile mammals – the archetypal playing animal – are organisms in the midst of this radical transformation. As they grow, they tend to randomly combine bits and pieces of waning newborn behaviour and emerging adult behaviour. These combinations are often repetitive, and sometimes quite novel, but rarely adaptive in the standard Darwinian sense. They are the accidental product of interacting behavioural systems that are re-modelling as the animal develops over time.
Dogs have longer periods of juvenile development than rats or cats; mammals in general have a much longer and more varied ‘metamorphosis’ than birds or reptiles. So dogs appear to play more than many other animals, not because there is an advantage in dogs playing more frequently, or because they enjoy it more, or because they want to please us more, but simply because they grow at different rates and in different ways.
Development has another effect on apparently playful activity. Many motor patterns require a ‘releaser’, something in the world that triggers the animal to behave in a characteristic way. In many cases, the response to these stimuli is instinctive, built-in and automatic. But sometimes an animal needs a little experience in the course of development to get it just right. A colleague of ours once watched a big wolf pup on a frozen lake doing a ‘fore-foot stab’, a classic carnivore motor pattern where the animal jumps at prey with an outstretched front paw. But the object of this pup’s attention wasn’t a mouse or vole: it was pouncing over and over again on little bubbles under the ice.
Normally, detecting a small running rodent should trigger the movement since it’s an adaptive, evolutionary and ancient behavioural response that leads to food. As we observe a wolf pup jumping at bubbles, or a dog leaping to catch a Frisbee, it looks for all the world as if these are simply animals happily at play. But they are instead simply expressing a developing motor pattern that is directed to an inappropriate stimulus. Think of dogs chasing cars instead of sheep, or kittens eyeing and stalking a ball of string.
Lots of so-called play, we think, might simply be the playing-out of developmentally incomplete, cobbled-together behaviours that are sometimes mistakenly triggered by inappropriate or misidentified stimuli. Perhaps these behavioural mistakes feel pleasurable to animals. Maybe they ultimately will contribute to adult fitness. But, in our view, playlike behaviour doesn’t need to be explained by an evolutionary history of adaptation, and it doesn’t have a special biological purpose. ‘Play’ is simply a byproduct of the way that young animals grow and develop.
Raymond Coppinger & Mark Feinstein
This article was originally published at Aeon and has been republished under Creative Commons.
Innovation in manufacturing has crawled since the 1950s. That's about to speed up.
Health officials in China reported that a man was infected with bubonic plague, the infectious disease that caused the Black Death.
- The case was reported in the city of Bayannur, which has issued a level-three plague prevention warning.
- Modern antibiotics can effectively treat bubonic plague, which spreads mainly by fleas.
- Chinese health officials are also monitoring a newly discovered type of swine flu that has the potential to develop into a pandemic virus.
Bacteria under microscope
needpix.com<p>Today, bubonic plague can be treated effectively with antibiotics.</p><p style="margin-left: 20px;">"Unlike in the 14th century, we now have an understanding of how this disease is transmitted," Dr. Shanthi Kappagoda, an infectious disease physician at Stanford Health Care, told <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">Healthline</a>. "We know how to prevent it — avoid handling sick or dead animals in areas where there is transmission. We are also able to treat patients who are infected with effective antibiotics, and can give antibiotics to people who may have been exposed to the bacteria [and] prevent them [from] getting sick."</p>
This plague patient is displaying a swollen, ruptured inguinal lymph node, or buboe.
Centers for Disease Control and Prevention<p>Still, hundreds of people develop bubonic plague every year. In the U.S., a handful of cases occur annually, particularly in New Mexico, Arizona and Colorado, <a href="https://www.cdc.gov/plague/faq/index.html" target="_blank">where habitats allow the bacteria to spread more easily among wild rodent populations</a>. But these cases are very rare, mainly because you need to be in close contact with rodents in order to get infected. And though plague can spread from human to human, this <a href="https://www.healthline.com/health-news/seriously-dont-worry-about-the-plague#Heres-how-the-plague-spreads" target="_blank">only occurs with pneumonic plague</a>, and transmission is also rare.</p>
A new swine flu in China<p>Last week, researchers in China also reported another public health concern: a new virus that has "all the essential hallmarks" of a pandemic virus.<br></p><p>In a paper published in the <a href="https://www.pnas.org/content/early/2020/06/23/1921186117" target="_blank">Proceedings of the National Academy of Sciences</a>, researchers say the virus was discovered in pigs in China, and it descended from the H1N1 virus, commonly called "swine flu." That virus was able to transmit from human to human, and it killed an estimated 151,700 to 575,400 people worldwide from 2009 to 2010, according to the Centers for Disease Control and Prevention.</p>There's no evidence showing that the new virus can spread from person to person. But the researchers did find that 10 percent of swine workers had been infected by the virus, called G4 reassortant EA H1N1. This level of infectivity raises concerns, because it "greatly enhances the opportunity for virus adaptation in humans and raises concerns for the possible generation of pandemic viruses," the researchers wrote.
So far, 30 student teams have entered the Indy Autonomous Challenge, scheduled for October 2021.
- The Indy Autonomous Challenge will task student teams with developing self-driving software for race cars.
- The competition requires cars to complete 20 laps within 25 minutes, meaning cars would need to average about 110 mph.
- The organizers say they hope to advance the field of driverless cars and "inspire the next generation of STEM talent."
Indy Autonomous Challenge<p>Completing the race in 25 minutes means the cars will need to average about 110 miles per hour. So, while the race may end up being a bit slower than a typical Indy 500 competition, in which winners average speeds of over 160 mph, it's still set to be the fastest autonomous race featuring full-size cars.</p><p style="margin-left: 20px;">"There is no human redundancy there," Matt Peak, managing director for Energy Systems Network, a nonprofit that develops technology for the automation and energy sectors, told the <a href="https://www.post-gazette.com/business/tech-news/2020/06/01/Indy-Autonomous-Challenge-Indy-500-Indianapolis-Motor-Speedway-Ansys-Aptiv-self-driving-cars/stories/202005280137" target="_blank">Pittsburgh Post-Gazette</a>. "Either your car makes this happen or smash into the wall you go."</p>
Illustration of the Indy Autonomous Challenge
Indy Autonomous Challenge<p>The Indy Autonomous Challenge <a href="https://www.indyautonomouschallenge.com/rules" target="_blank">describes</a> itself as a "past-the-post" competition, which "refers to a binary, objective, measurable performance rather than a subjective evaluation, judgement, or recognition."</p><p>This competition design was inspired by the 2004 DARPA Grand Challenge, which tasked teams with developing driverless cars and sending them along a 150-mile route in Southern California for a chance to win $1 million. But that prize went unclaimed, because within a few hours after starting, all the vehicles had suffered some kind of critical failure.</p>
Indianapolis Motor Speedway
Indy Autonomous Challenge<p>One factor that could prevent a similar outcome in the upcoming race is the ability to test-run cars on a virtual racetrack. The simulation software company Ansys Inc. has already developed a model of the Indianapolis Motor Speedway on which teams will test their algorithms as part of a series of qualifying rounds.</p><p style="margin-left: 20px;">"We can create, with physics, multiple real-life scenarios that are reflective of the real world," Ansys President Ajei Gopal told <a href="https://www.wsj.com/articles/autonomous-vehicles-to-race-at-indianapolis-motor-speedway-11595237401?mod=e2tw" target="_blank">The Wall Street Journal</a>. "We can use that to train the AI, so it starts to come up to speed."</p><p>Still, the race could reveal that self-driving cars aren't quite ready to race at speeds of over 110 mph. After all, regular self-driving cars already face enough logistical and technical roadblocks, including <a href="https://www.bbc.com/news/technology-53349313#:~:text=Tesla%20will%20be%20able%20to,no%20driver%20input%2C%20he%20said." target="_blank">crumbling infrastructure, communication issues</a> and the <a href="https://bigthink.com/paul-ratner/would-you-ride-in-a-car-thats-programmed-to-kill-you" target="_self">fateful moral decisions driverless cars will have to make in split seconds</a>.</p>But the Indy Autonomous Challenge <a href="https://static1.squarespace.com/static/5da73021d0636f4ec706fa0a/t/5dc0680c41954d4ef41ec2b2/1572890638793/Indy+Autonomous+Challenge+Ruleset+-+v5NOV2019+%282%29.pdf" target="_blank">says</a> its main goal is to advance the industry, by challenging "students around the world to imagine, invent, and prove a new generation of automated vehicle (AV) software and inspire the next generation of STEM talent."
A new Harvard study finds that the language you use affects patient outcome.
- A study at Harvard's McLean Hospital claims that using the language of chemical imbalances worsens patient outcomes.
- Though psychiatry has largely abandoned DSM categories, professor Joseph E Davis writes that the field continues to strive for a "brain-based diagnostic system."
- Chemical explanations of mental health appear to benefit pharmaceutical companies far more than patients.
Challenging the Chemical Imbalance Theory of Mental Disorders: Robert Whitaker, Journalist<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="41699c8c2cb2aee9271a36646e0bee7d"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/-8BDC7i8Yyw?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>This is a far cry from Howard Rusk's 1947 NY Times editorial calling for mental healt</p><p>h disorders to be treated similarly to physical disease (such as diabetes and cancer). This mindset—not attributable to Rusk alone; he was merely relaying the psychiatric currency of the time—has dominated the field for decades: mental anguish is a genetic and/or chemical-deficiency disorder that must be treated pharmacologically.</p><p>Even as psychiatry untethered from DSM categories, the field still used chemistry to validate its existence. Psychotherapy, arguably the most efficient means for managing much of our anxiety and depression, is time- and labor-intensive. Counseling requires an empathetic and wizened ear to guide the patient to do the work. Ingesting a pill to do that work for you is more seductive, and easier. As Davis writes, even though the industry abandoned the DSM, it continues to strive for a "brain-based diagnostic system." </p><p>That language has infiltrated public consciousness. The team at McLean surveyed 279 patients seeking acute treatment for depression. As they note, the causes of psychological distress have constantly shifted over the millennia: humoral imbalance in the ancient world; spiritual possession in medieval times; early childhood experiences around the time of Freud; maladaptive thought patterns dominant in the latter half of last century. While the team found that psychosocial explanations remain popular, biogenetic explanations (such as the chemical imbalance theory) are becoming more prominent. </p><p>Interestingly, the 80 people Davis interviewed for his book predominantly relied on biogenetic explanations. Instead of doctors diagnosing patients, as you might expect, they increasingly serve to confirm what patients come in suspecting. Patients arrive at medical offices confident in their self-diagnoses. They believe a pill is the best course of treatment, largely because they saw an advertisement or listened to a friend. Doctors too often oblige without further curiosity as to the reasons for their distress. </p>
Image: Illustration Forest / Shutterstock<p>While medicalizing mental health softens the stigma of depression—if a disorder is inheritable, it was never really your fault—it also disempowers the patient. The team at McLean writes,</p><p style="margin-left: 20px;">"More recent studies indicate that participants who are told that their depression is caused by a chemical imbalance or genetic abnormality expect to have depression for a longer period, report more depressive symptoms, and feel they have less control over their negative emotions."</p><p>Davis points out the language used by direct-to-consumer advertising prevalent in America. Doctors, media, and advertising agencies converge around common messages, such as everyday blues is a "real medical condition," everyone is susceptible to clinical depression, and drugs correct underlying somatic conditions that you never consciously control. He continues,</p><p style="margin-left: 20px;">"Your inner life and evaluative stance are of marginal, if any, relevance; counseling or psychotherapy aimed at self-insight would serve little purpose." </p><p>The McLean team discovered a similar phenomenon: patients expect little from psychotherapy and a lot from pills. When depression is treated as the result of an internal and immutable essence instead of environmental conditions, behavioral changes are not expected to make much difference. Chemistry rules the popular imagination.</p>