Can you find all the animals in the drawing below?
In all likelihood, you saw the horse right away. With a little change of perspective, you can find a frog as well!
Carrying along with the same theme, what animals do you see in the drawing below?
In this scenario, most people do see a rabbit first, and with a little prompting, they see a duck too.
As your brain can only perceive one or the other image at any given moment, chances are you will likely have a hard time if you try to perceive both animals at the same time. This concept is associated with the Gestalt effect – the notion that the brain perceives objects in their whole forms rather than simpler, unrelated elements or parts.
Defined more precisely, this illusion exemplifies a multi-stable perception effect. Abstract objects or illustrations such as these invariably switch between one interpretation and another. In contrast to the behaviourist approach, Gestalt theory unfortunately only records the phenomenon without providing neurological explanations as to why this happens.