Purpose: For normally sighted people, there is a general consensus that objects that appear in a congruent context (e.g., a hair dryer in a bathroom) are processed more accurately and/or more quickly than objects in an incongruent context (e.g., a hair dryer in a corn field). We investigated whether people with AMD, who have impairments in recognizing objects embedded in complex scenes, can nevertheless take advantage of contextual information for object detection.
Methods: TWENTY-TWO PEOPLE WITH AMD AND 18 AGE-MATCHED, NORMALLY SIGHTED CONTROLS TOOK PART IN THE STUDY. THEY WERE TESTED IN TWO TASKS: (1) an object detection task in which a foreground target object was set within a congruent background or an incongruent background, with no information being given to the participants as to the relationship between the target and its background, and (2) a task in which the participant had to explicitly state whether or not the foreground object was congruent with its background. A go/no-go paradigm was used in both tasks (i.e., a key press when the target is present and no key press when it is absent). The same participants, stimuli, and presentation conditions were used in both tasks.
Results: In the context task, the people with AMD exhibited higher sensitivity when the target object was consistent with its background; however, they performed no better than chance in the explicit task. Normally sighted controls benefited from the congruent context in both tasks.
Conclusions: Our results suggest that when central vision is impaired (as in AMD), the contextual information captured by peripheral vision provides cues for object categorization.