A key by which the toad's visual system gets access to the domain of prey

• Published in: Physiology & behavior 1996-09, Vol.60 (3), p.877-887
• Main Authors: Wachowitz, S., Ewert, J.-P.
• Format: Article
• Language: English
• Subjects: Anatomical correlates of behavior; Animals; Behavior, Animal - physiology; Behavioral psychophysiology; Biological and medical sciences; Bufo bufo; Bufonidae; Configurational cues; Discrimination (Psychology) - physiology; Feature analysis; Female; Fundamental and applied biological sciences. Psychology; Key stimulus concept; Male; Photic Stimulation; Prey catching; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Space life sciences; Toad; Vision; Visual Perception - physiology
• ISSN: 0031-9384; 1873-507X
• DOI: 10.1016/0031-9384(96)00070-4

Searching for principles that allow toads to distinguish between prey and nonprey, we wondered how the toad's prey-catching activity measured as R differs in response to changes in significant configurational stimulus features. Elongated shapes moving worm-like in the direction of their longer axes are preferred prey dummies; but a toad is not a worm detector, and a worm is not the unique prey-catching releaser. Considering the frequency distributions of R values, we show that the release of prey catching is in a specific manner sensitive to the relation between the extensions of an object parallel ( xl 1) and perpendicular ( xl 2) to its direction of movement. It is the xl 1, and xl 2 features-relating algorithm that provides the key (instruction) by which the toad's visual system gets access to the domain of potential prey in terms of configurational cues. This, within behaviorally relevant limits, largely invariant algorithm also holds for segmented stimuli. Further investigations show that this principle of object discrimination is not due to experimental procedures but emerges as a species-common property, of which different toad species take advantage in a species-specific manner. Neurobiological correlates are discussed.