Upon approaching a work of art, there is an expectation that an experience will be had. Most likely, we anticipate an emotion: sadness, awe, delight, comedy, repulsion, even disappointment if our expectation is not met. Less expected is an uncontrolled physiologic response, an effect that makes the viewer disoriented. This was a key feature of artists working under the Op-Art moniker in the 1960s. They used a simple vocabulary of basic forms and colors, but created visually complicated works that engendered a novel and involuntary frequency between art and viewer. Consequently, their works defined the experience of art as something more empirical than emotional.