When we see airplanes and toothbrushes and other visible things, we see them in relation to other objects — on top of a runway or inside of a mug on the bathroom counter.
Many psychologists believe that location plays a special role in feature binding, the process through which the brain turns visual information about distinct features (e.g., location, color, and shape) into a cohesive image that represents an object. But a 2011 study published in the Journal of Cognitive Psychology by Snehlata Jaswal of the Indian Institute of Technology in Ropar, India, and Robert H. Logie of the University of Edinburgh shows that even though location may be important in early stages of feature binding, it seems to become less important to our ability to remember what we’ve seen as time passes.
For their study, Jaswal and Ropar used change detection experiments that function like memory games: Participants were shown six shapes, each of which was randomly assigned a different color. Then, they were shown a new display that included the same six shapes and the same six colors. Their task was to determine whether or not the color-shape combinations in the two sets of images were identical.
In half of the trials, the shapes in the first and second set occupied the same locations; in the other half of the trials, the shapes were in different locations in the two sets. The researchers also manipulated the amount of time that elapsed between exposure to the two sets.
In general, when the locations of the shapes remained constant, participants’ performance declined as the interval between the first and second shape display got longer. On the other hand, when location was not constant, participants’ performance actually improved as the interval between the first and second sets increased.
Jaswal and Logie propose that when location remains unchanged, people perform best when little time elapses between the two displays because “spatial attention can operate only in the presence of spatial information.” However, when location is not constant, people tend to disregard spatial information, because it is not directly relevant to the color-shape task at hand. Consolidating and inhibiting this information takes time and mental resources, which could explain why participants performed better in the randomized location condition when the time between displays was longer.
While participants showed pronounced differences in performance between the constant and random location trials when the interval were brief (0 or 200 ms), performance on the two conditions converged at longer intervals (1500 ms or longer). According to the researchers, their experiments confirm the importance of location in the early stages of perception or visual attention. Even when information about location is irrelevant to the task at hand, people cannot disregard it until an initial visual binding process has allowed them to recognize the object at hand.
Jaswal and Logie hope that future experiments will help to elucidate just how much our cognitive resources are strained when visual working memory tasks require us to disregard irrelevant visual information.
Jaswal, S., & Logie, R. (2011). Configural encoding in visual feature binding Journal of Cognitive Psychology, 23 (5), 586-603 DOI: 10.1080/20445911.2011.570256