By James Devitt
April 11, 2013
We rely on our visual system more heavily than previously thought in determining the causality of events. A team of researchers has shown that, in making judgments about causality, we don’t always need to use cognitive reasoning. In some cases, our visual brain—the brain areas that process what the eyes sense—can make these judgments rapidly and automatically.
The study appeared in the journal Current Biology.
“Our study reveals that causality can be computed at an early level in the visual system,” says Martin Rolfs, who conducted much of the research as a postdoctoral fellow in NYU’s Department of Psychology. “This finding ends a long-standing debate over how some visual events are processed: We show that our eyes can quickly make assessments about cause-and-effect—without the help of our cognitive systems.”
Rolfs is currently a research group leader at the Bernstein Center for Computational Neuroscience and the Department of Psychology of Berlin’s Humboldt University.
We frequently make rapid judgments of causality (“The ball knocked the glass off the table”), animacy (“Look out, that thing is alive!”), or intention (“He meant to help her”). These judgments are complex enough that many believe that substantial cognitive reasoning is required—we need our brains to tell us what our eyes have seen. However, some judgments are so rapid and effortless that they “feel” perceptual—we can make them using only our visual systems, with no thinking required.
It is not yet clear which judgments require significant cognitive processing and which may be mediated solely by our visual system. In the Current Biology study, the researchers investigated one of these—causality judgments—in an effort to better understand the division of labor between visual and cognitive processes.
In a series of experiments, the researchers found that certain causal judgments show the classic properties of visual processing (i.e., adaptation) and appear to be determined in the visual system without input from cognition. The finding, the researchers concluded, provides strong evidence that in some cases, the understanding of action—causality, animacy, and intention—is encoded on a perceptual level rather than on a cognitive one.