Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition

Comparative studies suggest that at least some bird species have evolved mental skills similar to those found in humans and apes. This is indicated by feats such as tool use, episodic-like memory, and the ability to use one's own experience in predicting the behavior of conspecifics. It is, however, not yet clear whether these skills are accompanied by an understanding of the self. In apes, self-directed behavior in response to a mirror has been taken as evidence of self-recognition. We investigated mirror-induced behavior in the magpie, a songbird species from the crow family. As in apes, some individuals behaved in front of the mirror as if they were testing behavioral contingencies. When provided with a mark, magpies showed spontaneous mark-directed behavior. Our findings provide the first evidence of mirror self-recognition in a non-mammalian species. They suggest that essential components of human self-recognition have evolved independently in different vertebrate classes with a separate evolutionary history

Through the looking glass: how do marked dolphins use mirrors and what does it mean?

Funding: Studienstiftung des Deutschen Volkes; Deutsche Forschungsgemeinschaft (Gu227/16-1).Mirror-guided self-inspection is seen as a cognitive hallmark purportedly indicating the existence of self-recognition. Only a few species of great apes have been reported to pass a standard mark test for mirror self-recognition in which animals attempt to touch a mark. In addition, evidence for passing the mark test was also reported for Asian elephants, two species of corvids, and a species of cleaner fish. Mirror self-recognition has also been claimed for bottlenose dolphins, using exposure of marked areas to a mirror as evidence. However, what counts as self-directed behaviour to see the mark and what does not has been debated. To avoid this problem, we marked the areas around both eyes of the animals at the same time, one with visible and the other with transparent dye to control for haptic cues. This allowed the animal to see the mark easily and us to investigate what side was exposed to the mirror as an indicator for mark observation. We found that the animals actively chose to inspect their visibly marked side while they did not show an increased interest in a marked conspecific in the pool. These results demonstrate that dolphins use the mirror to inspect their marks and, therefore, likely recognise a distinction between self and others.Publisher PDFPeer reviewe

Interaction of magnetite-based receptors in the beak with the visual system underlying 'fixed direction' responses in birds

Background: European robins, Erithacus rubecula, show two types of directional responses to the magnetic field: (1) compass orientation that is based on radical pair processes and lateralized in favor of the right eye and (2) so-called 'fixed direction' responses that originate in the magnetite-based receptors in the upper beak. Both responses are light-dependent. Lateralization of the 'fixed direction' responses would suggest an interaction between the two magnetoreception systems. Results: Robins were tested with either the right or the left eye covered or with both eyes uncovered for their orientation under different light conditions. With 502 nm turquoise light, the birds showed normal compass orientation, whereas they displayed an easterly 'fixed direction' response under a combination of 502 nm turquoise with 590 nm yellow light. Monocularly right-eyed birds with their left eye covered were oriented just as they were binocularly as controls: under turquoise in their northerly migratory direction, under turquoise-and-yellow towards east. The response of monocularly left-eyed birds differed: under turquoise light, they were disoriented, reflecting a lateralization of the magnetic compass system in favor of the right eye, whereas they continued to head eastward under turquoise-and-yellow light. Conclusion: 'Fixed direction' responses are not lateralized. Hence the interactions between the magnetite-receptors in the beak and the visual system do not seem to involve the magnetoreception system based on radical pair processes, but rather other, non-lateralized components of the visual system

Building an Asymmetrical Brain: The Molecular Perspective

The brain is one of the most prominent examples for structural and functional differences between the left and right half of the body. For handedness and language lateralization, the most widely investigated behavioral phenotypes, only a small fraction of phenotypic variance has been explained by molecular genetic studies. Due to environmental factors presumably also playing a role in their ontogenesis and based on first molecular evidence, it has been suggested that functional hemispheric asymmetries are partly under epigenetic control. This review article aims to elucidate the molecular factors underlying hemispheric asymmetries and their association with inner organ asymmetries. While we previously suggested that epigenetic mechanisms might partly account for the missing heritability of handedness, this article extends this idea by suggesting possible alternatives for transgenerational transmission of epigenetic states that do not require germ line epigenetic transmission. This is in line with a multifactorial model of hemispheric asymmetries, integrating genetic, environmental, and epigenetic influencing factors in their ontogenesis

Asymmetry pays: visual lateralization improves discrimination success in pigeons

AbstractFunctional cerebral asymmetries, once thought to be exclusively human, are now accepted to be a widespread principle of brain organization in vertebrates [1]. The prevalence of lateralization makes it likely that it has some major advantage. Until now, however, conclusive evidence has been lacking. To analyze the relation between the extent of cerebral asymmetry and the degree of performance in visual foraging, we studied grain–grit discrimination success in pigeons, a species with a left hemisphere dominance for visual object processing [2,3]. The birds performed the task under left-eye, right-eye or binocular seeing conditions. In most animals, right-eye seeing was superior to left-eye seeing performance, and binocular performance was higher than each monocular level. The absolute difference between left- and right-eye levels was defined as a measure for the degree of visual asymmetry. Animals with higher asymmetries were more successful in discriminating grain from grit under binocular conditions. This shows that an increase in visual asymmetry enhances success in visually guided foraging. Possibly, asymmetries of the pigeon’s visual system increase the computational speed of object recognition processes by concentrating them into one hemisphere while preventing the other side of the brain from initiating conflicting search sequences of its own

Adjusting foraging strategies : a comparison of rural and urban common mynas (Acridotheres tristis)

The research was funded by a FP7-PEOPLE-2013-IRSES research staff exchange grant to TB, SH, OG and ASG. OG was additionally supported by Gu227/16-1 and IF by an FWF grant (Y366-B17) to TB.Establishment in urbanized environments is associated with changes in physiology, behaviour, and problem-solving. We compared the speed of learning in urban and rural female common mynas, Acridotheres tristis, using a standard visual discrimination task followed by a reversal learning phase. We also examined how quickly each bird progressed through different stages of learning, including sampling and acquisition within both initial and reversal learning, and persistence following reversal. Based on their reliance on very different food resources, we expected urban mynas to learn and reversal learn more quickly but to sample new contingencies for proportionately longer before learning them. When quantified from first presentation to criterion achievement, urban mynas took more 20-trial blocks to learn the initial discrimination, as well as the reversed contingency, than rural mynas. More detailed analyses at the level of stage revealed that this was because urban mynas explored the novel cue-outcome contingencies for longer, and despite transitioning faster through subsequent acquisition, remained overall slower than rural females. Our findings draw attention to fine adjustments in learning strategies in response to urbanization and caution against interpreting the speed to learn a task as a reflection of cognitive ability.PostprintPeer reviewe