Using abstract images instead of real photographs, UGA researchers are one step closer to understanding visual misperceptions and discovering why people experience a phenomenon known as boundary extension.
Boundary extension happens when someone takes a look at a scene, glances away and remembers seeing a more wide-angle view than was actually present. In just a few short seconds, the human brain helps most people extend the scene beyond what actually is seen.
Scientists at the University of Delaware discovered this concept in 1989 when they showed study participants real photographs of 20 scenes for 15 seconds and then had participants draw a picture of what they’d viewed. Ninety-five percent of the drawings included information that wasn’t physically present but would have been just outside the camera’s field of view. This phenomenon consistently has been demonstrated since that time, but researchers have not been able to explain why it occurs.
James Brown, an associate professor in the Franklin College of Arts and Sciences psychology department, and graduate students Benjamin McDunn and Aisha Siddiqui decided to study whether the use of an abstract image-instead of a photograph-would produce different results.
They found that showing subjects geometrical images on random-dot or white backgrounds had similar results. The study was published recently in Psychonomic Bulletin & Review.
Familiarity with an environment or an object may have much less of an effect than previously was thought on whether or not people remember viewing things through a wide-angle lens.
McDunn and Brown now are examining spatial perception by constructing a study in which participants view scenes depicting the real world-with similar object features such as size and spatial attributes-to see if the phenomenon exhibits with the same pattern.
“Spatial vision in general is somewhat enigmatic and difficult to study in isolation,” McDunn said. “Boundary extension may provide a means of determining what characteristics of a stimulus cause us to perceive it as depicting space.”
While researching spatial vision is difficult, Brown said, it’s important to understand more about how people see the world.
“Boundary extension,” he said, “seems to be strongly tied to our perception of a continuous spatial expanse around us, knowing a given view depicts a truncated portion of the world, a characteristic that is common to all scenes in the real world.”
