You've probably seen the "duck or bunny" optical illusion before, but did you realize that how you perceive it depends on the time of year?

It's no surprise that perception of certain optical illusions (or just objects in general) depends on biases and associations. For instance, the optical illusion below changes depending on your age. 

An Australian study found that younger people tend to see a young woman first, while older participants were much more likely to see an older woman first. The researchers concluded that "own-age biases affect the initial interpretation of an image at a subconscious level." 

Similarly, the way you see the "duck or rabbit" image is affected by associations brought about by the time of year.

"To study the influence of motivational expectancy on perception, the ambiguous drawing of a duck/rabbit was shown to 265 subjects on Easter and to 276 subjects in October," researchers explained in a study published in the journal Perceptual and Motor Skills.

Subjects were interviewed as they entered Zurich Zoo, with only those on their way in surveyed to avoid bias from any critters they came across on their visit. Going the extra mile, the researchers state that "To exclude further bias due to clouds resembling animal shapes, the sky on both test days was cloudless."

"The ambiguous drawing, though perceived as a bird by a majority of subjects in October, was most frequently named a bunny on Easter. This biasing effect of expectancy upon perception was observed for young children (2 to 10 years) as well as for older subjects (11 to 93 years)."

What you see here doesn't just tell you what time of year it is (although viewing the rabbit should not be used to replace a calendar) but could also tell you about your creativity.

A study in 2012 found that people who find it easy to flip the image in their mind between rabbit and duck performed better on a creativity task, in which they were asked to think of five novel uses for an everyday item they had been presented with.