Chimpanzees rationally revise their beliefs

 

Chimpanzees rationally revise their beliefs

The selective revision of beliefs in light of new evidence has been considered one of the hallmarks of human-level rationality.

In a new Science study, researchers report that chimpanzees can also update their beliefs on the basis of the quantity and quality of new evidence. 

New evidence? No problem. Chimps can weigh conflicting clues, just like humans

Study is first to suggest our closest relatives think about their own thoughts

30 Oct 20252:00 PM ET By Cathleen O’Grady

Editor’s summary

The ability of humans to think rationally and weigh the evidence when making a choice is well known. Such decision making requires a metacognitive process in which an individual can evaluate an overall set of evidence and make the best supported choice. Whether other animals can also do this has been unknown. Schleihauf et al. tested whether our closest relatives, chimpanzees, were able to evaluate weak and strong evidence regarding the location of a food reward (see the Perspective by Hare). They found that the chimps correctly inferred the most rational location based on the strength of the evidence that they received about the reward’s location. —Sacha Vignieri

Abstract

The selective revision of beliefs in light of new evidence has been considered one of the hallmarks of human-level rationality. However, tests of this ability in other species are lacking. We examined whether and how chimpanzees (Pan troglodytes) update their initial belief about the location of a reward in response to conflicting evidence. Chimpanzees responded to counterevidence in ways predicted by a formal model of rational belief revision: They remained committed to their initial belief when the evidence supporting the alternative belief was weaker, but they revised their initial belief when the supporting evidence was stronger. Results suggest that this pattern of belief revision was guided by the explicit representation and weighing of evidence. Taken together, these findings indicate that chimpanzees metacognitively evaluate conflicting pieces of evidence within a reflective process.

https://www.science.org/content/article/new-evidence-no-problem-chimps-can-weigh-conflicting-clues-just-humans

Miss Goodall and the Wild Chimpanzees (1965) (1988 Edited Version)

 

Miss Goodall and the Wild Chimpanzees (1965) (1988 Edited Version)

Documents the experiences of British zoologist Jane Goodall, who spent five years studying chimpanzees in Tanzania's Gombe Stream Preserve. Discusses her belief that thorough understanding of chimpanzee behavior will lead man toward clearer understanding of himself.

https://youtu.be/s2U6d_2ghIc

Jane Goodall R.I.P.

Reflections from Jane Goodall on her 55 years of research with the Chimpanzees of Gombe

Dr. Jane Goodall & the Jane Goodall Institute

https://youtu.be/O3oVyRalfck

 

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Jane Goodall, with her mascot Mr. H. on March 4, 2004.

© H. Darr Beiser, H. Darr Beiser / USA TODAY NETWORK

Legendary chimpanzee researcher Jane Goodall has died, the conservation organization she founded announced on Oct. 1.

Goodall, 91, died due to natural causes while she was in California on a cross-country speaking tour, according to The Jane Goodall Institute.

"Dr. Goodall’s discoveries as an ethologist revolutionized science, and she was a tireless advocate for the protection and restoration of our natural world," the institute said in statement on social media.

The British ethologist – a scientist who studies animal behavior within their habitat – had no formal training when she embarked on a study of chimpanzees in what would become Gombe Stream National Park in Tanzania, Africa, in the early 1960s. She skyrocketed to fame thanks in part to a National Geographic documentary about her fieldwork and used her science celebrity status to advance conservation efforts for chimpanzees and other endangered species through her eponymous foundation.

"I passionately care about the natural world of which we are a part and which we depend. I love it," Goodall told USA TODAY in 2021. "I passionately care about animals. I want to fight the fact that many are becoming extinct and I want to fight the cruelty."

Who was Jane Goodall?

Born in London, England, in 1934, Goodall had a fascination with animals from a young age. In 1957, she traveled to Kenya where she met Louis Leakey, a Kenyan and British paleontologist and archaeologist whose fossil digs ultimately helped establish that humans evolved in Africa.
Goodall became his secretary and eventually joined him on a field expedition studying chimpanzees on the shores of Lake Tanganyika in what is now Gombe National Park in Tanzania, East Africa.

There she observed chimpanzees using grass stems to pull termites out of their mounds for food, which shattered the mainstream scientific belief that only humans made and used tools and is "considered one of the greatest achievements of twentieth-century scholarship," according to the Jane Goodall Institute.

The National Geographic Society funded more of Goodall's chimpanzee research and sent along cameraman, Hugo van Lawick, to document her efforts. Goodall and van Lawick later married in March 1964, and the documentary, "Miss Goodall and the Wild Chimpanzees," released in 1965, attracted an estimated 25 million viewers in North America upon its first broadcast on CBS.

The couple had one son, Hugo Eric Louis van Lawick, known as "Grub," and divorced in 1974. In 1975, she married Derek Bryceson, who died in 1980.

Goodall, a United Nations Messenger of Peace, was appointed a Dame of the British Empire in 2003 and awarded the U.S. Presidential Medal of Freedom in 2025.

Goodall "worked tirelessly for our planet and all its inhabitants, leaving an extraordinary legacy for humanity and nature," the United Nations said in a post on social media mourning her death.

Jane Goodall spent life, career focused on chimpanzee research
Goodall would go on to publish more than 30 books, star in more documentaries and continue the expansion of research into chimpanzees.

After winning the prestigious Templeton Prize in 2021, which has been awarded since 1972 to luminaries such as Mother Teresa, the Dalai Lama and South African Archbishop Desmond Tutu, Goodall told USA TODAY from the home where she grew up and still lived that she "never planned" to become such an iconic figure.

"There’s basically two Janes – this one talking to you now, sitting here and looking out on my childhood and the other one that’s out there. ... I have to reconcile the two," she said.

"I try to live up to the one out there and realize I was given gifts and I have to go on using them to the best of my ability," Goodall added.

As a pioneer in her field, Goodall forged a path for many other women to follow in her footsteps including the late Dian Fossey and Biruté Mary Galdikas. The trio, who all studied primates and counted Leakey as a mentor, came to be known as The Trimates or Leakey's Angels.

Galdikas told USA TODAY she was in "absolute shock" over news of Goodall's death. She recalled first meeting Goodall more than 50 years ago in London, and staying in touch over the years, often speaking together and supporting one another's work.

"What she did for chimpanzee conservation is extraordinary. So she truly was an extraordinary person," Galdikas said. "She was an inspiration, I would say, not just to thousands of people, but probably to millions. And her legacy will never die, her legacy will last forever."

In 1977, she founded the Jane Goodall Institute, helping continue the long-running study of chimpanzees in the Gombe and boost conservation efforts for other species around the globe. Its Roots & Shoots program, established in 1991, also engages young people in local efforts to protect animals and the environment.

"Every single day we live, we make some sort of impact on the world. Most of us can choose what sort of impact we make," Goodall told the Detroit Free Press, part of the USA TODAY Network, during a stop on her speaking tour in September. "Hope isn't wishful thinking. I tell people, 'Find something you can do in your community. Do it. Get your friends to support you. See that you can make a difference. Know that all around the world, other people like you are making a difference.'"

Contributing: Karen Weintraub and Reuters

(This story has been updated to add new information.)

This article originally appeared on USA TODAY: Jane Goodall, iconic wildlife conservationist, has died at age 91

Barack Obama

@BarackObama

·

Jane Goodall had a remarkable ability to inspire us to connect with the natural wonders of our world, and her groundbreaking work on primates and the importance of conservation opened doors for generations of women in science. Michelle and I are thinking of all those who loved and admired her.

Uakari: Secrets of the English Monkey

 

Uakari: Secrets ofthe English Monkey

This program is a fascinating journey into the pristine flooded Rainforests of the Peruvian Amazon to investigate the mysterious Red-Faced Uakari monkey, rarely seen by the outside world and never filmed until now.

https://youtu.be/K9eOeyc-iMw

The tallest and smallest dogs in the world meet up for adorable doggy playdate in America

 

  Reggie and Pearl sitting on a couch 

Guinness World Records

 

The tallest and smallest dogs in the world meet up for adorable doggy playdate in America

By Katherine Gross Published 30 April 2025

A pair of pooches from America – tallest dog, Reginald, and smallest dog, Pearl – met earlier this month for a unique doggy playdate that truly demonstrates how new friends can come in all shapes and sizes.

Reginald (Reggie), a seven-year-old Great Dane from Idaho, towers over most other dogs –  the Guinness World Records title holder for tallest dog living (male) stands at a shocking 3 ft 3 in (1.007 m) from the floor to the withers.

But his new pal, Pearl, a four-year-old Chihuahua from Florida, holds the title for shortest dog living at just 3.59 in (9.14 cm).

 

Pearl, a pocket-sized pup from Florida, is a true diva.

 

 

https://www.guinnessworldrecords.com/news/2025/4/the-tallest-and-smallest-dogs-in-the-world-meetup-for-adorable-doggy-playdate-in-america

Tallest Dog Meets Smallest Dog - Guinness World Records

 

https://youtu.be/Z_NrWgG7sWA

How button boards are changing human-canine communication

 

A viral, online phenomenon claims to have further opened the door to human-canine communication. Buttons allow dogs to seemingly talk with their humans, but are all these button enthusiasts barking up the wrong tree? William Brangham and his pup Macy doggedly pursue the truth. 

https://youtu.be/czLwLol6eHY

Baby monkey Obi helps dad take care of ducklings and eat tomato salad

 

https://youtu.be/hZckJDObVJI?si=VppgHEGZNkWAlxNa

The Champions

 

 

 The inspiring story of the rescue and redemption of the pit bulls rescued from the notorious dog-fighting ring of Michael Vick.

https://www.humanedecisions.com/the-champions-a-documentary-about-the-pit-bulls-rescued-from-the-notorious-michael-vick-dog-fighting-case/#Watch%20The%20Film

https://www.championsdocumentary.com/the-dogs

For Dogs, a Passive, Unresponsive Human Face Is a "Bad" Face

 

For Dogs, a Passive, Unresponsive Human Face Is a "Bad" Face

Active facial expressions are most likely to keep dogs focused on a person.

A lot of research shows that dogs look at our faces and read our emotions from our expressions. Some new research suggests that a passive, unchanging human face (think "poker face") is interpreted by dogs as a negative expression, and dogs respond accordingly.

KEY POINTS

An active stream of facial expressions is part of the normal communication process between humans.

A still and unresponsive face causes a negative reaction for young human children.

Dogs don't like to continue interacting with a person whose facial response is unchanging and unresponsive.

Stanley Coren PhD., DSc, FRSC

Canine Corner

https://www.psychologytoday.com/intl/blog/canine-corner/202307/for-dogs-a-passive-unresponsive-human-face-is-a-bad-face

NPR Visits Skid Row with Dr. Kwane

https://youtu.be/YE3RHZttT5U

SMOKING CHIMPANZEE

 

SMOKING CHIMPANZEE