Blindness

The ability to spot changes in scenes provides an evolutionary advantage. It allows predators to be spotted ad prevent being eaten for example. There is evidence that we overestimate our ability to do this however. There are two main types of blindness:

• Change blindness and Inattentional blindness

Change Blindness

• This is the inability to detect changes in attended scenes
• Simons and Levin (1998) They carried out an experiment whereby there was an attentional disruption during a conversation where a board was carried between people. When this happened the conversational partner was changed. Generally this went unnoticed. This experiment suggests the key role in distraction, for example an eye blink, a flashed blank screen or a cut in motion picture.
• Flicker Teschnique (1997) - Rensink, O'Regan & Clark. In this experiment, 2 pictures were presented in rapid succession. The second had an object missing from it. The missing object is very difficult to detect.

Inattentional Blindness

• This type of blindness allows illusionists and 'hustlers' to direct attention towards a distractor.
• We are very overoptimistic about our ability to perceive important events when we are focussing on current goals
• Attention has an important role in the link between perception and the visual field