Inattentional blindness

Unaufmerksamkeitsblindheit (even blindness due to inattention, . Engl inattentional blindness ) is the non-perception of objects, due to the limited processing capacity of the human brain.

Overview

The non-perception of major changes to objects in the environment is called change blindness (change blindness ). Taken together, these findings lead to the conclusion that only objects and details are perceived or noticed, to which attention was directed. The brain has to select what information is relevant and which are less. Only when attention turns to a stimulus, it is aware of. The direction of attention affects the activity of certain brain structures.

Experiments by Mack and rock

Mack and rock (1998) presented their subjects initially confronted with the task to decide whether the horizontal or the vertical line of a cross shown for 200 milliseconds was longer. In the third round of the experiment, another stimulus was unexpected ( eg a small square ) appears. Then the subjects were asked if they had seen it, which is about 25 percent said no. This "sight- blindness" therefore seems to stir, that the subjects have the stimulus did not expect and focus on something else, namely concentrated the cross. Mack and rock call this phenomenon inattentional blindness or on German Unaufmerksamkeitsblindheit.

Since they assume that there is no conscious perception without attention, they come to the conclusion that the other stimuli have aroused the attention of 75 percent of the subjects and thus pulled up.

"Gorillas in our midst " (Simons and Chabris )

The study "Gorillas in our midst " (English: Gorillas in our midst ) of the University of Illinois shows that urban people can see a passing man in gorilla costume itself. Based on classic studies of divided visual attention, and referring to Unaufmerksamkeitsblindheit of Mack and rock examined Simons and Chabris in their gorilla experiment, the phenomenon of Unaufmerksamkeitsblindheit for complex objects and events in motion scenes. The results of the study suggest that the probability of noticing an unexpected object depends on both the similarity of this object with the other objects presented as well as the difficulty of the original observation task. Simons and Chabris refer to various studies ( Ulrich Neisser et al 1979, Grimes 1996, Mack & Rock 1998), have shown that conscious perception seems to demand attention.

The material for Simons and Chabris ' experiment to Unaufmerksamkeitsblindheits phenomenon are four videos of 75 seconds' duration. Each film shows two teams of three players, one wearing white, the other black T -shirts. The members of each team to play a normal orange basketball by throwing or dribbling. After 44 to 48 seconds, something unexpected happened: In the umbrella woman version ( Umbrella Woman) is a large woman with an open umbrella from left to right through the scene. In the gorilla version of a smaller woman who is completely wrapped in a gorilla suit running in the same way through the picture. During this unexpected events the basketball players place their actions continued undeterred.

Furthermore, there are the videos in two styles: in a transparent version (transparent condition) and an opaque ( opaque condition). For the former white and black team and the " incident" was first filmed separately, then made ​​partially transparent, and set using digital post about each other. For the opaque version, all seven actors were filmed simultaneously. The result are four films: Transparent / Umbrella Woman, Transparent / Gorilla, Opaque / Umbrella Woman, Opaque / gorilla.

Attempts

The first experimental setup (Transparent / Umbrella Woman) corresponds to that of Neisser (1979 ), describe the Simons and Chabris in their products too. Before they watch a video, get the subjects which task to focus either on the team in white or in black and all rallies of the observed teams in the head counted (easy condition) or the cast and the gedribbelten rally separated to count ( hard condition). After the subjects had seen the video and fulfilled their observation task, they were asked to write down their numbers. Then we asked them if they had noticed during the counting something unusual ( a), ( b ) whether they had noticed something else than the six players, (c) whether a person had appeared differently in the video, finally, ( d ) Have you see a gorilla (a woman with umbrella ) Go through the picture?

Ultimately remained for evaluation 192 subjects left ( some had to drop out because they already knew a similar experiment, forgot counted, etc. ), of which, across all of the above versions of the film, 54 percent of the "incident " noticed and 46 percent did not. (Simons and Chabris break the results according to transparent and opaque condition, easy and hard condition. ) It is interesting that the woman with the umbrella was detected more frequently than in the gorilla suit (65 % versus 44%). And again, the subjects who watched the black team, noticed the gorilla more often than those who focus their attention the white team had (black 58%, white 27%). However, it made for discovering the woman with the umbrella is very little difference whether white or black rally were counted (black 62%, white 69%). The gorilla was black, while the woman was dressed light with the umbrella and stood out equally from the black as the white team.

Results

• Approximately half of the subjects take a longer lasting, actually very striking, but unexpected event is not it, when they are busy with an elementary observation task.
• The amount of Unaufmerksamkeitsblindheit depends on the difficulty of the observation task.
• The subjects take more notice of an unexpected event, when this essential visual features ( such as color ) with the observed situation shares - a contradiction to the traditional pop-out phenomenon in visual search tasks ( and unlike Neisser, 1979).
• Objects can move directly through the center of attention ( foveal vision) and are still not "seen" when we have placed in them no special attention.