  Vision-Language Models (VLMs) are trained on vast amounts of data captured by
humans emulating our understanding of the world. However, known as visual
illusions, human's perception of reality isn't always faithful to the physical
world. This raises a key question: do VLMs have the similar kind of illusions
as humans do, or do they faithfully learn to represent reality? To investigate
this question, we build a dataset containing five types of visual illusions and
formulate four tasks to examine visual illusions in state-of-the-art VLMs. Our
findings have shown that although the overall alignment is low, larger models
are closer to human perception and more susceptible to visual illusions. Our
dataset and initial findings will promote a better understanding of visual
illusions in humans and machines and provide a stepping stone for future
computational models that can better align humans and machines in perceiving
and communicating about the shared visual world. The code and data are
available at https://github.com/vl-illusion/dataset.
