Environmental harshness does not affect the propensity for social learning in great tits, Parus major.

According to the harsh environment hypothesis, natural selection should favour cognitive mechanisms to overcome environmental challenges. Tests of this hypothesis to date have largely focused on asocial learning and memory, thus failing to account for the spread of information via social means. Tests in specialized food-hoarding birds have shown strong support for the effects of environmental harshness on both asocial and social learning. Whether the hypothesis applies to non-specialist foraging species remains largely unexplored. We evaluated the relative importance of social learning across a known harshness gradient by testing generalist great tits, Parus major, from high (harsh)- and low (mild)-elevation populations in two social learning tasks. We showed that individuals use social learning to find food in both colour-associative and spatial foraging tasks and that individuals differed consistently in their use of social learning. However, we did not detect a difference in the use or speed of implementing socially observed information across the elevational gradient. Our results do not support predictions of the harsh environment hypothesis suggesting that context-dependent costs and benefits as well as plasticity in the use of social information may play an important role in the use of social learning across environments. Finally, this study adds to the accumulating evidence that the harsh environment hypothesis appears to have more pronounced effects on specialists compared to generalist species.

Blue tits are outperformed by great tits in a test of motor inhibition, and experience does not improve their performance.

Motor inhibition refers to the ability to inhibit immediate responses in favour of adaptive actions that are mediated by executive functions. This ability may be an indication of general cognitive ability in animals and is important for advanced cognitive functions. In this study, our aim was to compare motor inhibition ability of two closely related passerines that share the same habitat. To do this, we tested motor inhibition ability using a transparent cylinder task in blue tits in the same way as we previously tested great tits. To test whether the experience of transparent objects would affect the performance of these species differently, both in the present experiment using blue tits and our previous one on great tits, we divided 33 wild-caught individuals into three different treatment groups with 11 birds each. Before the test we allowed one group to experience a transparent cylindrical object, one group to experience a transparent wall and a third group was kept naive. In general, blue tits performed worse than great tits, and unlike the great tits, they did not improve their performance after experience with a transparent cylinder-like object. The performance difference may stem from difference in foraging behaviour between these species.

A prospective observational cohort study of traumatic brain injury in the northern region of Sweden.

OBJECTIVE: Generally, to map epidemiological and demographic features of patients with traumatic brain injury (TBI) in Umeå county, Sweden. Specifically, to evaluate the subjects needing a computed tomography (CT) of the head after suffering from TBI and frequencies of 1) intracranial lesions detected with CT, 2) need for neurosurgical intervention and 3) admission to hospital. METHODS: Patients with a suspected TBI, undergoing CT within 24 hours of arrival to hospital, were included in a database for evaluation. RESULTS: Out of 302 patients (63% male), 83% were GCS 13-15, 7% were GCS 9-12 and 10% were GCS <9. The frequency of abnormal CT findings was 23% in GCS 13-15, 67% in GCS 9-12 and 97% in GCS <9. Neurosurgical intervention was needed by 4% of those with GCS 13-15, 52% of those with GCS 9-12 and by 76% of those with GCS <9. CONCLUSIONS: Subjects with GCS 13-15  had higher frequencies of abnormal CT findings, need for neurosurgical intervention and hospital admission than previously reported. A similar trend was observed for patients with GCS 9-12, which can be of serious nature, with a higher frequency of need for neurosurgical intervention than previously described.

High level of self-control ability in a small passerine bird.

ABSTRACT: Cognitively advanced animals are usually assumed to possess better self-control, or ability to decline immediate rewards in favour of delayed ones, than less cognitively advanced animals. It has been claimed that the best predictor of high such ability is absolute brain volume meaning that large-brained animals should perform better than small-brained ones. We tested self-control ability in the great tit, a small passerine. In the common test of this ability, the animal is presented with a transparent cylinder that contains a piece of food. If the animal tries to take the reward through the transparent wall of the cylinder, this is considered an impulsive act and it fails the test. If it moves to an opening and takes the reward this way, it passes the test. The average performance of our great tits was 80%, higher than most animals that have been tested and almost in level with the performance in corvids and apes. This is remarkable considering that the brain volume of a great tit is 3% of that of a raven and 0.1% of that of a chimpanzee. SIGNIFICANCE STATEMENT: The transparent cylinder test is the most common way to test the ability of self-control in animals. If an animal understands that it only can take food in the cylinder from the cylinder's opening and controls its impulsivity, it passes the test. A high level of self-control has been demonstrated only in cognitively advanced animals such as apes and corvids. Here, we demonstrate that the great tit, a small song bird that is very good at learning, performs almost in level with chimpanzees and ravens in this test.