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.
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
A Phylogenomic Study of Birds Reveals Their Evolutionary History
Today's Science sees the publication of a phylogenomic study of 196 bird species, which has some rather marked differences to the traditional phylogenies of bird species. Abstract says -
Deep avian evolutionary relationships have been difficult to resolve as a result of a putative explosive radiation. Our study examined ~32 kilobases of aligned nuclear DNA sequences from 19 independent loci for 169 species, representing all major extant groups, and recovered a robust phylogeny from a genome-wide signal supported by multiple analytical methods. We documented well-supported, previously unrecognized interordinal relationships (such as a sister relationship between passerines and parrots) and corroborated previously contentious groupings (such as flamingos and grebes). Our conclusions challenge current classifications and alter our understanding of trait evolution; for example, some diurnal birds evolved from nocturnal ancestors.
Abstract is here. Much news coverage will be forthcoming, I suspect, and I'll link to some of these as they come through.
Update: GrrlScientist has covers the paper excellently (although, not enough phylogenetic details for my liking :)
Reflections of Alex the Parrot
Margaret Talbot in The New Yorker talks about "the woman behind the world's chattiest Parrots", Irene Pepperberg:
As the crowd at the Midwest Bird Expo waited for the cognitive scientist Irene Pepperberg to take the podium, the hum of human chatter was punctuated by the sound of parrots whooping it up—twittering and letting loose with wolf whistles, along with the occasional full-out jungle squawk. The birds, many of them for sale, were displayed in cages just beyond the curtained-off stage, which was inside the main hall of the DuPage County Fairgrounds, in Wheaton, Illinois. Nobody seemed particularly distracted by the commotion. ...
Here were admirers who had sent in ten-dollar bills to help support her research with Alex, the African gray parrot that she worked with for thirty years; and here were people who, after Alex died, unexpectedly, of heart arrhythmia, on September 6, 2007, helped form an online community that comes together on the sixth day of every month to reflect about him.
Chicken testicles and the role of humor in language change
William Thurston on the role of humor in language change in his 1987 book "Processes of Change in the languages of North-Western New Britain":
Many linguistic innovations arise in the context of humor, a common mechanism for mediating interpersonal relationships. For example, in 1978, during my second trip to work with the Anêm, but Goulden's first, we had passed weeks without eating an egg. One morning, an Anêm woman proudly presented Goulden with one, and carefully enunciated the phrase nilŋêm texik 'chicken-egg' (nil-ŋ2 'egg/testicle', texik 'chicken') for Goulden to repeat. (The Anêm apply Pavlovian principles to language teaching.) At this stage, Goulden's knowledge of Anêm was at the wordlist level. He graciously accepted the gift, but in his fluster to be polite and repeat what he thought he had heard, he uttered biŋêm texik 'chicken vulva' instead. Both bi-ŋ2 and nil-ŋ2 belong to the genital class of nouns.
No sooner had the slip left his tongue than he knew his mistake, but it was too late. Goulden's obvious discomfiture only accentuated the hilarity of the event. Acutely embarrassed, he returned to the house with the egg in hand. In subsequent weeks, Goulden was the recipient of all available eggs in Karaiai and Pudeling villages; each one was presented as biŋêm texik, a lexeme temporarily reassigned a new meaning for the duration of the gag. (pp. 66-67)
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.