Eli Elster, University of California, Davis

Of the 8.7 million species on Earth, why are human beings the only one that paints self-portraits, walks on the Moon and worships gods?

For decades, many scholars have argued that the difference stems from our ability to learn from each other. Through techniques such as teaching and imitation, we can create and transmit complicated information over many generations.

So if a human finds, for instance, a better but more complex way to make a knife, they can pass along the new instructions. One of those learners might stumble upon their own improvement and pass it along in turn.

If this loop continues, you get a ratchet effect, in which small changes can accumulate over time to produce increasingly intricate behaviors and technologies. This process produces our uniquely complex cultures: Scientists call it cumulative cultural evolution.

But extensive data has emerged suggesting that other animals, including bees, chimpanzees and crows, can also generate cultural complexity through social learning. Consequently, the debate over human uniqueness is shifting in a new direction.

As an anthropologist, I study a different feature of human culture that researchers are beginning to think about: the diversity of our traditions. Whereas animal cultures affect just a few crucial behaviors, such as courtship and feeding, human cultures cover a massive and constantly expanding set of activities, from clothing to table manners to storytelling.

This new view suggests that human culture is not uniquely cumulative. It is uniquely open-ended.

What is cumulative culture?

In the early 2000s, a research team led by psychologist Michael Tomasello tested 105 human children, 106 adult chimpanzees and 32 adult orangutans on a battery of cognitive assessments. Their goal was to see whether humans held any innate cognitive advantage over their primate cousins.

Surprisingly, the human children performed better in only one capacity: social learning. Tomasello thus concluded that humans are not “generally smarter.” Rather, “we have a special kind of smarts.” Our advanced social abilities allow us to transmit information by accurately teaching and learning from each other.

Humans’ apparent social learning abilities suggested a clear explanation for our unique cultural traits. Knowledgeable humans – say, someone who discovers a better way to make a spear – can successfully transfer that skill to their peers. But an inventive chimp – one who discovers a better way to smash nuts, for example – can’t successfully share their innovation. Nobody listens to Chimp Einstein. So our inventions persist and build upon each other, while theirs vanish into the jungle floor.

Or so the theory went.

Now, though, scientists have hard evidence showing that, just like us, animals can learn from each other and thus maintain their cultures for long periods of time. Groups of swamp sparrows appear to use the same song syllables for centuries. Meerkat troops settle on different wake-up times and maintain them for a decade or more.

Of course, long-term social learning is not the same as cumulative culture. Yet scientists also now know that humpback whale songs can oscillate in complexity over many generations of learners, that homing pigeons create efficient flight paths by learning from each other and making small improvements, and that hooved mammals cumulatively alter their migration routes to exploit plant growth.

Once again, the animals have shot down our claim to uniqueness, as they have innumerable times throughout scientific history. You might wonder, at this point, if we should just settle the uniqueness question by answering: “We’re not.”

If not cumulative culture, what makes us unique?

But it remains the case that humans and their cultures are quite different from animals and their equivalents. Most scholars agree about that, even if they disagree about the reasons why. Since cumulative complexity appears not to be the most important difference, several researchers are sketching out a new perspective: Human culture is uniquely open-ended.

Currently, anthropologists are discussing open-endedness in two related ways. To get a sense of the first, try counting the number of things you’re engaged with, right now, that came to you through culture. For example, I picked my clothes today based on fashion trends I did not develop; I am writing in a language I did not invent; I tied my shoes using a method my father taught me; there are paintings and postcards and photographs on my walls.

Give me 10 minutes, and I could probably add 100 more items to that list. In fact, other than biological acts such as breathing, it is difficult for me to think of any aspect of what I’m doing right now that is not partially or completely cultural. This breadth is incredibly strange. Why should any organism spend time pursuing such a wide range of goals, particularly if most of them have nothing to do with survival?

Other animals are much more judicious. Their cultural variation and complexity pertains almost entirely to matters of subsistence and reproduction, such as acquiring food and mating. Humans, on the other hand, lip-synch, build space stations and, less grandiosely, have been known to do things such as spend six years trying to park in all 211 spots of a grocery store lot. Our cultural diversity is unparalleled.

Open-endedness, as a unique human quality, is not just about variety; it reflects the quantum leaps by which our cultures can evolve. To illustrate this peculiarity, consider a hypothetical example regarding the rocks that chimpanzees use to smash nuts.

Let’s say these chimps would benefit from using rocks that they can swing as hard and accurately as possible, but that they don’t immediately know what kind of rocks those would be. By trying different options and observing each other, they might accumulate knowledge of the best qualities in a nut-smashing rock. Eventually, though, they’d hit a limit in the power and precision available by swinging a rock with your fist.

How could they get past this upper limit? Well, they could tie a stick to their favorite rock; the extra leverage would help them smash the nuts even harder. As far as we know, though, chimpanzees aren’t capable of realizing the benefits of harnessing this additional quality. But we are – people invented hammers.

Crucially, discovering the power of leverage allows for more than just better nut-smashing. It opens up innovations in other domains. If adding handles to wielded objects allows for better nut-smashing, then why not better throwing, or cutting, or painting? The space of cultural possibilities, suddenly, has expanded.

Through open-ended cultural evolution, human beings produce open-endedness in culture. In this respect, our species is unparalleled.

What’s next?

Researchers have not yet answered most of the major questions about open-endedness: how to quantify it, how we create it, whether it has any true limitations.

But this new framework must shift the tides of a related debate: whether there is something obviously different about the way human minds work, other than social learning capacities. After all, every cultural trait emerges through interactions between minds – so how do our minds interact to produce such a degree of cultural breadth?

No one knows yet. Interestingly, this shifting debate over how cognition influences culture coincides with a spate of research bridging psychology and anthropology, which explores why certain behaviors – such as singing lullabies, curative bloodletting and storytelling – recur across human cultures.

Human minds produce unparalleled diversity in their cultures; yet it is also true that those cultures tend to express variations on a strict set of themes, such as music and marriage and religion. Ironically, the source of our open-endedness may illuminate not only what makes us so diverse, but also what makes us so often the same.

Eli Elster, Doctoral Candidate in Evolutionary Anthropology, University of California, Davis

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Lori Frasier, Penn State

In the early 1990s when I was a young pediatrician, I was responsible for evaluating children with developmental and learning problems. Two unrelated boys, ages 7 and 9, were found to have IQs in the range of 60-70, which indicates a severe cognitive disability.

During my medical review, the mothers revealed that their children were shaken violently as infants and that afterward behaved as if “the wind had been knocked out of them.” Both mothers reported shaking by a boyfriend or a father. No child was seen for medical care at the time.

At the same period of my career I was working with a renowned pediatrician who was studying shaken baby syndrome. The link between shaking and later cognitive impairment was not lost on me.

This scenario of shaken babies having neurological and developmental disabilities has played out over the past 30 years of my career as a child abuse pediatrician.

The high rates of death and disability

Shaken baby syndrome is a condition that can injure babies and young children, and in some cases lead to death.

A 2024 study on babies with shaken baby syndrome found that 20% to 25% of infants die, another 20% to 25% look normal on discharge from the hospital, and fully half are left with long-term disabilities. These include learning and behavioral problems that appear later in life.

The dangers of shaking babies have been recognized for over 50 years.

In the early 1970s, John Caffey, a pediatric radiologist, coined the term “Whiplash Shaken Infant Syndrome.” Caffey linked permanent brain damage and bleeding in the backs of the retina to violent shaking of infants. Caffey suggested a multipronged approach to prevention of this severe form of abuse that included educating and supporting young families, especially mothers. As primary caregivers, mothers are often most easily reached by the message, but the message of prevention can involve fathers, babysitters and any other caregivers.

Since Caffey’s original description, there have been tremendous advancements in the research behind shaking babies and infant head trauma. In 2009, the American Academy of Pediatrics recommended that medical providers use the term “abusive head trauma” to include many actions other than shaking that can injure the brains of infants and children. The use of shaken baby syndrome is still recommended for public education and prevention, and health care providers and other experts also recommend the use of the term because it’s commonly recognized by the lay public and understood by parents.

How the brain is affected

What happens to the brain of an infant when they are shaken?

Infants – the most common population to be shaken – are small and have undeveloped neck muscles.

In these incidents, the infant is typically grabbed around the chest and shaken back and forth several times. Small blood vessels around the brain break and bleed, causing blood to flow around the brain. This condition is called a subdural hematoma. In some cases, similar forces occur in the back of the eye, and hemorrhages in the retina can occur.

In the most severe forms of shaking, the tissue of the brain itself is injured, and the child may experience unconsciousness or even stop breathing. Neck injuries occur when shaking causes injuries to ligaments and muscles that support the neck. Sometimes children have other injuries after being thrown down or impacted against something. Skull fractures or fractures of other bones, bruising and other injuries are often found.

A complex diagnosis

An infant or child must be diagnosed as having abusive head trauma by a team of pediatric specialists. Usually, a concerned parent or caregiver who may or may not know an infant has been injured becomes concerned that the child is not behaving normally. The child may have symptoms ranging from persistent vomiting to seizures or even seem unconscious.

The medical team begins addressing the child’s condition through blood testing and X-rays. Often a CT scan is performed in order to determine if there is a brain injury or some other abnormality. Bleeding around the brain is an indicator of trauma. However, other conditions can also cause this type of bleeding, including bleeding disorders, vitamin deficiency or genetic problems.

Carefully assessing a child for all of these possibilities may lead to discovery of other areas of trauma, such as broken bones and bruises. A child abuse physician is often called in to assist with the evaluation when trauma becomes a leading diagnosis. That trauma could be accidental, or it could be a sign that someone has abused or hurt an infant.

There are other medical conditions and even accidental injuries to a child that may resemble abusive head trauma. Experienced clinicians will evaluate a child carefully for these well-described conditions. Controversy about many of these conditions may exist in the courtroom, but in the medical setting it is often clear which conditions are present and when injuries are caused by trauma versus other medical conditions.

All 50 states and territories of the U.S. require that a report is made to child protective services agencies, with law enforcement often being involved when someone suspects or knows that a baby has been shaken.

Investigators and doctors work together along with parents and caregivers to try to determine what led to the infant or child’s condition. Bruising, fractures and retinal hemorrhages may support a diagnosis of child abuse, specifically shaken baby syndrome.

During an investigation, a rare accidental cause may be determined. The purpose is to make sure infants and children are not being harmed or that a medical condition is uncovered that can be treated.

As a pediatrician working in a children’s hospital and trauma center, it will never get easier for me to see infants and children with abusive injuries as well as other head traumas. The U.S. has come a long way in ensuring the safety of children through the use of car seats and many safety devices.

Education can help

Crying in infancy is a common trigger in cases where shaking occurs. Other risk factors include isolation, poverty, domestic violence and substance use. During severe economic downturns, the rate of shaken baby incidents rises, since research shows that social stressors often contribute.

Although anyone can injure a baby in a moment of frustration, most prevention research has focused specifically on helping parents understand why infants cry or become fussy. Recognizing your infant’s needs and addressing those needs is an important piece of learning how to parent. Studies have shown that focused education for new parents in maternity wards by nurses is effective.

If you or someone you know is concerned that a child or infant is being harmed in any way, each state has a process for reporting these concerns to appropriate authorities. Reporting can help prevent further harm to an infant and provide assistance to families.

The National Center on Shaken Baby Syndrome, the American Academy of Pediatrics and the Centers for Disease Control and Prevention offer some helpful resources.

Lori Frasier, Professor of Pediatrics, Penn State

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Abdulmalik Alluhidan, Vanderbilt University

Social media is a complex environment that presents both opportunities and threats for adolescents, with self-expression and emotional support on the one hand and body-shaming, cyberbullying and addictive behaviors on the other. This complexity underscores the challenge to regulating teen social media use, but it also points to another avenue for protecting young people online: how social media platforms are designed.

The growing debate around teen social media use has intensified, with recent bipartisan policy efforts in the U.S., such as the Kids Online Safety Act, seeking to protect young people from digital harms. These efforts reflect legitimate concerns. However, broad restrictions on social media could also limit benefits for teens, throwing the baby out with the bath water.

I am a researcher who studies online safety and digital well-being. My recent work with colleagues in computer scientist Pamela Wisniewski’s Socio-Technical Interaction Research Lab underscores a critical point: social media is neither inherently harmful nor entirely beneficial. It is a tool shaped by its design, how teens use it, and the context of their experiences.

In other words, social media’s impact is shaped by its affordances – how platforms are designed and what they enable users to do or constrain them from doing. Some features foster connection while others amplify harms.

As society moves toward practical solutions for online safety, it is important to use evidence-based research on how these features shape teens’ social media experiences and how they could be redesigned to be age appropriate for young people. It’s also important to incorporate teens’ perspectives to pinpoint what policies and design choices should be made to protect young people using social media.

My colleagues and I analyzed over 2,000 posts from teens ages 15-17 on an online peer-support platform. Teens openly discussed their experiences with popular social media platforms such as Instagram, YouTube, Snapchat and TikTok. Their voices highlight a potential path forward: focusing on safety by design – an approach that improves platform features to amplify benefits and mitigate harms. This approach respects young people’s agency while prioritizing their digital well-being.

What teens say about social media

While social media’s worst outcomes such as cyberbullying or mental health crises are often in the spotlight, our research shows that teens’ experiences are far more nuanced. Instead, platforms enable diverse outcomes depending on their features and design.

Teens commonly described negative experiences involving social drama, cyberbullying and privacy violations. For example, Instagram was a focal point for body-shaming and self-esteem issues, driven by its emphasis on curated visual content. Facebook triggered complaints about privacy violations, such as parents sharing private information without teens’ consent. Snapchat, meanwhile, exposed teens to risky interactions due to its ephemeral messaging, which fosters intimate but potentially unsafe connections.

At the same time, teens expressed that social media provides a space for support, inspiration and self-expression, particularly when offline spaces feel isolating. Teens used social media to cope with stress or seek out uplifting content.

Platforms such as Snapchat and WhatsApp were key spaces for seeking connection, enabling teens to build relationships and find emotional support. Snapchat, in particular, was the go-to platform for fostering close personal connections, while YouTube empowered teens to promote their creativity and identity by sharing videos.

Many praised Instagram and Snapchat for providing inspiration, distraction or emotional relief during stressful times. Teens also used social media to seek information, turning to YouTube and Twitter to learn new things, verify information or troubleshoot technical problems.

These findings underscore a critical insight: Platform design matters. Features such as algorithms, privacy controls and content-sharing mechanisms directly shape how teens experience social media. These findings further question the perception of social media as a purely negative force. Instead, teens’ experiences highlight its dual nature: a space for both risk and opportunity.

Key to safer social media

The concept of affordances – design and features – helps explain why teens’ experiences differ across platforms and provides a path toward safer design. For example, Instagram’s affordances such as image sharing and algorithmic content promotion amplify social comparison, leading to body-shaming and self-esteem issues. Snapchat’s affordances, such as ephemeral messaging and visibility of “best friends,” encourage personal connections but can foster risky interactions. Meanwhile, YouTube’s affordances, such as easy content creation and discovery, promote self-expression but can contribute to time-management struggles due to its endless scroll design.

By understanding these platform-specific designs and features, it is possible to mitigate risks without losing the benefits. For example, Facebook could allow for appropriate levels of parental oversight of teen accounts while preserving privacy. Instagram could reduce algorithmic promotion of harmful content. And Snapchat could improve safety features.

This safety by design approach moves beyond restricting access to focus on improving the platforms themselves. By thoughtfully redesigning social media features, tech companies can empower teens to use these tools safely and meaningfully. Policymakers can focus on holding social media companies responsible for their platforms’ impact, while simultaneously promoting the digital rights of teens to benefit from social media use.

Call for safety by design

It’s important for policymakers to recognize that social media’s risks and rewards coexist. Instead of viewing social media as a monolith, however, policymakers can target the features of social media platforms most likely to cause harm. For example, they could require platform companies to conduct safety audits or disclose algorithmic risks. These steps could encourage safer design without limiting access.

By addressing platform affordances and adopting safety by design, it is possible to create digital spaces that protect teens from harm while preserving the connection, creativity and support that social media enables. The tools to build a future where teens can thrive are already available; they just need to be designed better.

Pamela Wisniewski contributed to the writing of this article.

Abdulmalik Alluhidan, Ph.D. student in Computer Science, Vanderbilt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.