Final answer:
Kanwisher's (incorrect reference, should be Simons and Chabris) research examined inattentional blindness through experiments where participants focused on specific tasks, such as counting passes, and thus often failed to notice other visible stimuli. This demonstrated how visual attention is selective and our perception is significantly influenced by what we choose to focus on.
Step-by-step explanation:
Kanwisher and her colleagues conducted experiments to explore the concept of inattentional blindness, which is a phenomenon where an individual fails to notice something fully visible because their attention is engaged elsewhere. Although the question incorrectly states 'Kanwisher' rather than Simon and Chabris, their well-known study involved participants watching a video of people passing basketballs and counting the passes made by individuals in white shirts. A person in a gorilla suit walked amongst the players, and despite being clearly visible, about half the participants didn't notice the gorilla because they were focused on counting the passes - a clear illustration of inattentional blindness.
These studies demonstrate how visual attention is selective and limited - we often miss visual information when our attention is directed towards a particular task or aspect of the environment. As part of exploring alternatives to this hypothesis, other experiments involved tasks where individuals had to identify objects or details while their attention was directed at something specific, like the one where participants were told to focus on a black dot and identify faces shown on a screen away from the center. The experiments provided evidence suggesting that blood flow increases in active nervous tissue when performing visual tasks, supporting the connection between attention and perception.