Which optical illusions can animals see?

Male bowerbirds in Australia use a technique called forced perspective to make themselves look bigger to potential mates who visit their carefully constructed bowers. Visual illusions remind us that we are not passive decoders of reality but active interpreters. Our eyes capture information from the environment, but our brain can play tricks on us. Perception doesn't always match reality. Scientists have used illusions for decades to explore the psychological and cognitive processes that underlie human visual perception.