Visual Perception Taking Emerged in Dinosaurs Long Before Evolution in Mammals

Wednesday - May 24 2023, 03:32 UTC - 1 year ago

Researchers from Lund University found that visual perspective taking, the ability to follow an obstructed gaze, originated in the dinosaur lineage around 60 million years prior to its emergence in mammals. This highlights the cognitive abilities of birds and their dinosaur ancestors, challenging the notion that complex cognition evolved only within the mammal lineage.

Researchers at Lund University found that visual perspective taking, the cognitive ability to follow an obstructed gaze, originated in the dinosaur lineage about 60 million years before appearing in mammals. This finding challenges the notion that complex cognition evolved primarily in mammals and highlights the cognitive abilities of birds and their dinosaur ancestors.

When someone near you turns their head towards something in the environment, you likely can’t help to follow their gaze direction. This reaction is observed in mammals, birds, and even reptiles alike. It’s an effective way to gather information about what caught the attention of your fellow, which you might otherwise have missed. However, a far more advanced behavior is to follow someone’s gaze to a location that is initially obstructed from your view. By repositioning yourself to see what the other person is looking at, you demonstrate an understanding that the other has a different perspective. This ability, known as visual perspective taking develops in children between the ages of one-and-a-half to two years and serves as the foundation for later comprehending referential communication and that others have minds that differ from your own.

Visual perspective taking has, to date, only been found in very few species. Mainly in apes and some monkeys, but also in dogs and crow birds. However, there is limited knowledge regarding the evolutionary origins of this crucial social skill. A team of researchers from Lund University aimed to investigate a potential early emergence of visual perspective taking in dinosaurs. Through a comparison of alligators with the most primitive existing birds, known as palaeognaths, they discovered that visual perspective taking originated in the dinosaur lineage likely 60 million years, or more, prior to its appearance in mammals.

Crocodilians are the closest living relatives to birds. Their neuroanatomy has remained largely unchanged for hundreds of millions of years, and is similar to that of the common ancestor of dinosaurs and crocodilians. Palaeognath birds comprise the ostrich birds, such as emus and rheas, but also the flighted tinamous. Their brains are in large parts comparable to their forebearers, the non- avian paravian dinosaurs, which feature such celebrities as the velociraptors. Comparing these two groups of animals creates a bracket around the extinct lineage of dinosaurs leading up to modern birds.

The study revealed that alligators do not demonstrate visual perspective taking, although they do follow gaze to a visible location. In contrast, all tested bird species exhibited visual perspective taking. Additionally, the birds engaged in a behavior called "checking back," where the observer looks back into the eyes of the gazer, and re-tracks the gaze, when unable to find anything in the direction of their gaze the first time. This behavior indicates an expectation that the gaze is referring to a target in the environment. Previously, this has only been observed in humans, apes and monkeys, and ravens.

Palaeognath birds emerged 110 million years ago, predating the two mammal groups endowed with perspective taking by 60 million years. This finding challenges the notion that complex cognition, as enabled by visual perspective taking, could have evolved solely through the mammal lineage as previously assumed.