Sunday, August 14, 2005
It's the pictures themselves that make you go blind:
The new study by US psychologists found that people shown erotic or gory images frequently fail to process images they see immediately afterwards. And the researchers say some personality types appear to be affected more than others by the phenomenon, known as “emotion-induced blindness” . . . .
The closer these emotionally charged images occurred prior to the target image, the more frequently people failed to spot the target image, the researchers found.
“We observed that people failed to detect visual images that appeared one-fifth of a second after emotional images, whereas they can detect those images with little problem after neutral images,” Zald says.
“We think there is essentially a bottleneck for information processing and if a certain type of stimulus captures attention, it can jam up the bottleneck so subsequent information can’t get through,” Zald explains. “It appears to happen involuntarily. The stimulus captures attention and once allocated to that particular stimulus, no other stimuli can get through” for several tenths of a second . . . .
“It is possible that emotionally-charged stimuli produce preferential rapid routing of the impulse that bypasses the slower cortical route via the amygdala," Zald told New Scientist. "Patients with amygdala lesions pick out the target image without reacting to violent images, although they show normal blindness reactions when sexual images are introduced, which suggests another mechanism may also be involved.”