. The biology of birds. Birds. SENSES, INSTINCTS, AND INTELLIGENCE 335 flame. When carrier-pigeons make from a distance for their home, they may be utihsing some tropism as well as the results of geographical education. When a migrant bird flies in a constant direction across the pathless sea it may be automatically obeying an engrained Fig. 49.—Diagram illustrating the inclined plane of animal behaviour. I., ver/ simple actions; i, reactions; li., simple tentatives ; 2, fixed reactions ; 111., trial and error experiments ; 3, simple reflexes ; iv. v. VI., experiments, experiential l
. The biology of birds. Birds. SENSES, INSTINCTS, AND INTELLIGENCE 335 flame. When carrier-pigeons make from a distance for their home, they may be utihsing some tropism as well as the results of geographical education. When a migrant bird flies in a constant direction across the pathless sea it may be automatically obeying an engrained Fig. 49.—Diagram illustrating the inclined plane of animal behaviour. I., ver/ simple actions; i, reactions; li., simple tentatives ; 2, fixed reactions ; 111., trial and error experiments ; 3, simple reflexes ; iv. v. VI., experiments, experiential learning and associative learning; 4, 5, 6, more complex reflex actions, tropisms, and enregistered rhythms ; vii., intelli- gent behaviour ; 7, 8, simple instincts and chain instincts ; vni., rational conduct (confined to man) ; 9, habituated intelligent behaviour ; 10, un- conscious cerebration. Each line is drawn double, the convex side indicating biosis or physiological processes, the concave side indicating psychosis or mental processes. As we ascend the series the psychical aspect becomes more and more obvious. The well-known Planarian worm called Convoluta ascends to the surface of the sand whenever the tide goes out, and disappears below the surface whenever the tide comes in. This is more than reaction to stimuli, for the worms will manifest the same periodicity in a tideless aquarium, and will continue doing so for some time. There are many of these enregistered rhythms in the internal economy of animals. It is probable that they account in part for the restlessness of migrant birds when the time comes for their Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933. New York : Macmillan
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectbirds, bookyear1923
