Perception of illusory surfaces and contours in goldfish.

@article{Wyzisk2007PerceptionOI,
  title={Perception of illusory surfaces and contours in goldfish.},
  author={Katja Wyzisk and Christa Neumeyer},
  journal={Visual neuroscience},
  year={2007},
  volume={24 3},
  pages={291-8}
}
Goldfish (Carassius auratus) were trained to discriminate triangles and squares using a two choice procedure. In the first experiment, three goldfish were trained with food reward on a black outline triangle on a white background, while a black outline square was shown for comparison. In transfer tests, a Kanizsa triangle and a Kanizsa square were presented, perceived by humans as an illusory triangle- or square-shaped surface of slightly higher brightness than the background. The choice… CONTINUE READING