The article reveals that early human ancestors began consuming carbohydrate-rich foods such as grains and underground plant organs before they had the ideal teeth to do so. This behavior drove evolution, leading to longer molars in modern humans that allow for efficient chewing of tough plant fibers.

A Dartmouth-led study analyzed fossilized hominin teeth for carbon and oxygen isotopes left behind from eating plants known as graminoids, which includes grasses and sedges. The researchers found that ancient humans gravitated toward consuming these plants far earlier than their teeth evolved to chew them efficiently. This shift in diet was a significant factor in the success of early humans.

The study’s findings suggest that the ability to adapt to new environments despite physical limitations was a key advantage for hominins. As anthropologists, they often assume behaviors on the basis of morphological traits, but these traits can take a long time to appear in the fossil record.

However, the researchers used isotope analysis to overcome this challenge and show that behavior can be a force of evolution in its own right. They analyzed the teeth of various hominin species, including Australopithecus afarensis, and found that they began consuming graminoids before their teeth evolved to chew them efficiently.

The study also explored how the consumption of different parts of graminoids progressed over millennia. The researchers found that all three species (hominins and two primates) veered away from fruits, flowers, and insects toward grasses and sedges between 3.4 million to 4.8 million years ago.

The team’s analysis revealed a significant lag between the emergence of novel feeding behaviors and the physical adaptations necessary to support them. This suggests that behavior can drive evolution, leading to changes in morphology and diet.

One possible explanation for this spike is that later hominins gained regular access to underground plant organs like tubers, bulbs, and corms, which provided a reliable source of carbohydrates. This shift would have made sense for a species growing in population and physical size.

The transition from grasses to these high-energy plant tissues may have created a glut of carbs that were perennial, allowing early humans to access them at any time of year to feed themselves and other people.

Measurements of hominin teeth showed that while they became consistently smaller, molars grew longer. The study found that the ratio flipped about 2 million years ago with Homo habilis and Homo ergaster, whose teeth exhibited a spurt of change in shape and size more suited to eating cooked tissues, such as roasted tubers.

Overall, this groundbreaking study sheds light on how early humans adapted to their environments and developed behaviors that drove evolution. By analyzing fossilized hominin teeth for carbon and oxygen isotopes, researchers were able to identify the key role that carbohydrates played in shaping human history.

In south-east Asia, a 4,000-year-old practice has been hidden in plain sight – the use of psychoactive plants to enhance alertness, energy, euphoria, and relaxation. The people of ancient Thailand and other parts of the region have long chewed betel nuts, which contain compounds that produce pronounced physiological effects on humans. However, this practice was thought to be lost to time, until a team of international researchers discovered evidence of its use in dental plaque from Bronze Age Thailand.

The study, published in Frontiers in Environmental Archaeology, analyzed 36 dental calculus samples from six individuals at the Nong Ratchawat archaeological site in central Thailand. The researchers found that three of these samples contained traces of arecoline and arecaidine – organic compounds found in betel nuts and other psychoactive plants like coffee, tea, and tobacco.

“This is the earliest direct biomolecular evidence of betel nut use in south-east Asia,” said Dr Piyawit Moonkham, an anthropological archaeologist at Chiang Mai University in Thailand. “We demonstrate that dental calculus can preserve chemical signatures of psychoactive plant use for millennia, even when conventional archaeological evidence is completely absent.”

The researchers used a new method to analyze the dental plaque samples, which involved removing tiny amounts of plaque and analyzing the chemical residues found therein. They also produced betel liquid samples themselves to ensure that they could reliably detect psychoactive compounds through their analysis.

The results suggest that betel nuts were chewed as early as 4,000 years ago in Thailand. However, the absence of tooth-staining raises questions about different consumption methods or post-consumption teeth cleaning practices. While traces of betel nut chewing were found in samples from only one individual, there is currently no proof that this individual received special treatment or was of elevated social status compared to the other burials at Nong Ratchawat.

The methods used by the researchers can be applied to examine the remaining burials at Nong Ratchawat and at other sites. “Dental calculus analysis can reveal behaviors that leave no traditional archaeological traces, potentially revolutionizing our understanding of ancient lifeways and human-plant relationships,” said Dr Shannon Tushingham, the senior author of the study.

The study highlights the importance of understanding the cultural context of traditional plant use. Psychoactive, medicinal, and ceremonial plants are often dismissed as drugs, but they represent millennia of cultural knowledge, spiritual practice, and community identity. Archaeological evidence can inform contemporary discussions by honoring the deep cultural heritage behind these practices.

As we navigate the complexities of global politics, it’s essential to consider the health and decision-making abilities of our leaders. A recent study from the University of Otago, New Zealand, has raised concerns about cognitive collapse among former leaders of nuclear-armed nations. The research analyzed the health information of 51 deceased leaders and found that many had multiple serious health issues while in office.

The study’s lead researcher, Professor Nick Wilson, noted that 15 of these leaders likely had their performance impaired by health conditions, including dementia, personality disorders, depression, and drug and alcohol abuse. This is a stark reminder that even the most powerful leaders can be vulnerable to cognitive decline.

One notable example is Ariel Sharon, who became comatose after suffering a stroke in office, and Menachem Begin, whose severe depression kept him isolated for his final year as leader. Even Richard Nixon’s heavy drinking raised concerns during a nuclear crisis involving the Middle East.

The study also highlighted instances where health information about leaders was kept secret at the time, including the cases of US presidents Dwight D Eisenhower, John F Kennedy, and Ronald Reagan. In some cases, this secrecy led to impaired decision-making, as seen in Kennedy’s poor performance during his first two years in office.

This latest research follows previous studies on the health of former New Zealand Prime Ministers, which found that at least four leaders’ performances were impaired by poor health or heavy drinking. Professor Wilson emphasizes the importance of strong leadership and governance, particularly for nuclear-armed nations like the United States.

To mitigate global security risks from leaders whose judgment is in question, Professor Wilson proposes various measures, such as removing nuclear weapons from high alert status, adopting no-first-use policies, ensuring multi-person authorization for weapon launches, and progressing nuclear disarmament treaties. He also suggests introducing term limits, recall systems, medical and psychological assessments before taking office, and maintaining a strong media with investigative journalists to expose impairment in leaders.

Ultimately, finding ways to reduce stress on politicians and better address their mental health needs can be crucial in reducing global security risks. As we move forward, it’s essential to prioritize the well-being of our leaders to ensure they make informed decisions that protect us all.