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The role of the face and the body size in predators' recognition by untrained birds
Fišer, Ondřej ; Fuchs, Roman (advisor) ; Petrusková, Tereza (referee)
The face plays an extremely important role in human communication. It enables individual recognition and provides other information about the person, such as social or emotional information. Human psychology has shown that face recognition uses a specific cognitive process called holistic processing. In recent decades, it has been shown to play an important role in animal communication as well. In the first part of my thesis, I tested whether changing the uniform configuration of a bird's face would affect the ability of the red-backed shrike (Lanius collurio) to recognize a potential predator. Due to unfavourable conditions in both breeding seasons when the experiments were conducted, no firm conclusions can be drawn from the results. They only suggest that the shrike perceives the configuration changes. An essential characteristic of all predators is their size, which affects the ability of prey to defend themselves. Several studies have already found that birds discriminate between different predators of different sizes. In the second part of my thesis, I evaluated experiments in which shrikes were exposed to dummies of two predator species with modified size. The shrikes responded with less aggression to the enlarged jays, whereas aggression increased only slightly to the shrunken crows. Thus,...
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Faces recognition as a distinctive cognitive process
Fišer, Ondřej ; Fuchs, Roman (advisor) ; Pokorný, Šimon (referee)
Facial recognition has been a major scientific topic. What particular cognitive process is responsible for recognition was a great unknown. Now, scientists are most inclined to the theory of holistic facial perception that we perceive the face as a whole. For successful face recognition it is necessary to pay attention to individual components and their configuration. Thanks to this approach, a person is an expert on faces and can obtain many types of information from them in a short time. Behavioral and neurological evidence supported the theory of holistic facial perception. The main behavioral tasks that support holistic facial perception are three: part-whole task, face inversion task, and composite task. The first two showed that face recognition negatively affects both the manipulation of individual components and their configuration. The composite task then shows that we are not able to perceive individual parts of the face independently. Holistic perception in animals has not been unequivocally confirmed, but for animals the face is as important as for humans. Moreover, the possibility of applying holistic perception to objects other than faces is currently being pointed out. Holistic perception today appears to be a robust type of perception applicable to various stimuli that meet the...
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