Do New Caledonian crows solve physical problems through causal reasoning?
My friends working on the New Caledonian Crow have a new paper out in today's Proceedings of the Royal society. The paper "Do New Caledonian crows solve physical problems through causal reasoning?" by Alex Taylor et al provides evidence of how crows can reason about physical problems:
The extent to which animals other than humans can reason about physical problems is contentious. The benchmark test for this ability has been the trap-tube task. We presented New Caledonian crows with a series of two-trap versions of this problem. Three out of six crows solved the initial trap-tube. These crows continued to avoid the trap when the arbitrary features that had previously been associated with successful performances were removed. However, they did not avoid the trap when a hole and a functional trap were in the tube. In contrast to a recent primate study, the three crows then solved a causally equivalent but visually distinct problem—the trap-table task. The performance of the three crows across the four transfers made explanations based on chance, associative learning, visual and tactile generalization, and previous dispositions unlikely. Our findings suggest that New Caledonian crows can solve complex physical problems by reasoning both causally and analogically about causal relations. Causal and analogical reasoning may form the basis of the New Caledonian crow's exceptional tool skills.
We're trying out a new way of presenting results - crowtube! Another friend of ours, Marc Tadaki, has made a (wonderful) video of Alex explaining the experiment:
Mirror self-recognition in Magpies
Frans de Waal in PLoS Biology:
The Eurasian magpie (Pica pica) has a poor reputation. As a child, I learned never to leave small shiny objects, such as teaspoons, unattended outdoors as these raucous birds will steal anything they can put their beaks on. This folklore even inspired a Rossini opera, “La gazza ladra” (“The Thieving Magpie”). Nowadays, this view has been replaced with one that is more sensitive to ecological balance, in which magpies are depicted as murderous plunderers of the nests of innocent songbirds. Either way, they are black-and-white gangsters.
But no one has ever accused a magpie of being stupid. The bird belongs to the Corvidae, a worldwide family (also including crows, ravens, jackdaws, jays, and nutcrackers) marked by an exceptionally large forebrain, which permits innovative foraging. In recent years, this family has begun to pose a challenge to the idea that primates constitute the pinnacle of cognitive evolution by showing creative tool-use, visual perspective-taking, foresight, and so on.
I have tried hard to substitute deer and mosquitoes for sharks and rats in my house of horrors, but it’s just not working.
Joe Queenan in the LA Times tries to justify his hatred of sharks, hyenas and anacondas:
Like most people in this country, I have long hated sharks, largely because of what they did to Robert Shaw in "Jaws." For years, I thought of sharks as mindless, demonic eating machines, an attitude reinforced by the harrowing story Shaw told Richard Dreyfuss and Roy Scheider about the 1945 Japanese torpedo attack on the U.S. cruiser Indianapolis. Although many of the 880 casualties died because of exposure or drinking saltwater, many were eaten by the tigers of the deep. So, all in all, it seemed almost unpatriotic not to hate them.
Dinosaurs, Supertrees, and the Cretaceous Terrestrial Revolution
Today's PRS.B sees the publication of a supertree of 600 Dinosaur species. Awesome. ScienceDaily has more information here. Here's a picture of it (note: a full version is available here):
The abstract says:
The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125–80Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion.
Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history.
Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR
Could Nim do this?
Back in the 1970s, a chimpanzee named Nim Chimpsky took part in a Columbia University research study called "Project Nim."
Project Nim was led by Herbert Terrace, a psychologist at Columbia who was attempting to find out if a chimpanzee could learn to communicate using American Sign Language.
"Everyone knows that words are learned one at a time," but something happens when children begin to combine words and create true language, Terrace says.
Mayan Blue, the color of Chaak
Kenneth Chang in the NY Times talks about The Grim Story of Maya Blue:
The vibrant sky color can be seen on pottery, murals and other artifacts produced by the Maya people of Central America centuries ago and the unusual, durable pigment remains vibrant today long after other colors have faded away.
It was also the color of Chaak, the rain god, and of human sacrifice.