An Investigation into the Cognition Behind Spontaneous String Pulling in New Caledonian Crows

The ability of some bird species to pull up meat hung on a string is a famous example of spontaneous animal problem solving. The “insight” hypothesis claims that this complex behaviour is based on cognitive abilities such as mental scenario building and imagination. An operant conditioning account, in contrast, would claim that this spontaneity is due to each action in string pulling being reinforced by the meat moving closer and remaining closer to the bird on the perch. We presented experienced and naïve New Caledonian crows with a novel, visually restricted string-pulling problem that reduced the quality of visual feedback during string pulling. Experienced crows solved this problem with reduced efficiency and increased errors compared to their performance in standard string pulling. Naïve crows either failed or solved the problem by trial and error learning. However, when visual feedback was available via a mirror mounted next to the apparatus, two naïve crows were able to perform at the same level as the experienced group. Our results raise the possibility that spontaneous string pulling in New Caledonian crows may not be based on insight but on operant conditioning mediated by a perceptual-motor feedback cycle

Prolonged Parental Feeding in Tool-Using New Caledonian Crows

According to life-history theory, the duration of extended parental feeding is determined by the costs and benefits of maximising reproductive success. Therefore, the length of regular parental provisioning should be correlated with the time required for juveniles to acquire the skills that they need to be independent. The relatively few cases of extremely prolonged parental feeding in both land and sea birds appear to be consistent with this prediction because they are associated with learning-intensive foraging techniques. New Caledonian crows have the most intricate tool manufacture techniques amongst non-human animals and juveniles take over 1 yr to reach adult-like proficiency in their tool skills. We investigated the prediction that this species also should have prolonged parental provisioning. We found that these crows have one of the longest known periods of regular extended parental provisioning in birds. Some parents regularly fed juveniles for up to 10 mo post-fledging. Humans also stand out amongst primates because of their learning-intensive foraging strategies and an extended period of juvenile dependence. The independently evolved association between a relatively high level of technological skill in foraging and prolonged juvenile provisioning in both humans and New Caledonian crows raises the possibility that these two characteristics might be causally related.This work was supported by a grant fromthe New Zealand Marsden Fund (R.D.G. andG.R.H.)

Spontaneous Metatool Use by New Caledonian Crows

SummaryA crucial stage in hominin evolution was the development of metatool use—the ability to use one tool on another [1, 2]. Although the great apes can solve metatool tasks [3, 4], monkeys have been less successful [5–7]. Here we provide experimental evidence that New Caledonian crows can spontaneously solve a demanding metatool task in which a short tool is used to extract a longer tool that can then be used to obtain meat. Six out of the seven crows initially attempted to extract the long tool with the short tool. Four successfully obtained meat on the first trial. The experiments revealed that the crows did not solve the metatool task by trial-and-error learning during the task or through a previously learned rule. The sophisticated physical cognition shown appears to have been based on analogical reasoning. The ability to reason analogically may explain the exceptional tool-manufacturing skills of New Caledonian crows

Cultura e inteligência: reflexões antropológicas sobre aspectos não físicos da evolução em chimpanzés e humanos Culture and intelligence: anthropological reflections on non-physical aspects of evolution in chimpanzees and humans

Trata da história recente dos estudos sobre o comportamento de chimpanzés, enfatizando os resultados das pesquisas, as proposições acerca da existência de 'culturas de chimpanzés' e sua validade. O trabalho problematiza a ideia a partir dos mecanismos de transmissão e aprendizado social bem como de concepções antropológicas e paleoantropológicas de cultura que associam tal fenômeno, entre humanos modernos, às suas capacidades simbólicas e cognitivas.<br>The scope of this work is the recent history of studies on the behavior of chimpanzees, emphasizing research results, propositions about the existence of 'chimpanzee cultures' and their validity. The work discusses the idea based on transmission mechanisms and social learning as well as anthropological and paleoanthropological concepts of culture that associate such phenomena, among modern humans, to their symbolic and cognitive abilities