Inattentional blindness

Inattentional blindness, also known as perceptual blindness, is a psychological lack of attention that is not associated with any vision defects or deficits. It may be further defined as the event in which an individual fails to perceive an unexpected stimulus that is in plain sight. When it simply becomes impossible for one to attend to all the stimuli in a given situation, a temporary blindness effect can take place as a result; that is, individuals fail to see objects or stimuli that are unexpected and quite often salient. The term was coined by Arien Mack and Irvin Rock in 1992 and was used as the title of their book of the same name, published by MIT press in 1998, in which they describe the discovery of the phenomenon and include a collection of procedures used in describing it. A famous study that demonstrated inattentional blindness asked participants whether or not they noticed a gorilla walking through the scene of a visual task they had been given.

Research on inattentional blindness suggests that the phenomenon can occur in any individual, independent of cognitive deficits. However, recent evidence shows that patients with ADHD performed better attentionally when engaging in inattentional blindness tasks than control patients did, suggesting that some mental deficits may decrease the effects of this phenomenon. Recent studies have also looked at age differences and inattentional blindness scores, and results show that the effect increases as humans age. There is mixed evidence that consequential unexpected objects are noticed more: Some studies suggest that we can detect threatening unexpected stimuli more easily than nonthreatening ones, but other studies suggest that this is not the case. There is some evidence that objects associated with reward are noticed more.

Numerous experiments have demonstrated that inattentional blindness also has an effect on people's perception.

The following criteria are required to classify an event as an inattentional blindness episode: 1) the observer must fail to notice a visual object or event, 2) the object or event must be fully visible, 3) observers must be able to readily identify the object if they are consciously perceiving it, and 4) the event must be unexpected and the failure to see the object or event must be due to the engagement of attention on other aspects of the visual scene and not due to aspects of the visual stimulus itself. Individuals who experience inattentional blindness are usually unaware of this effect, which can play a subsequent role on behavior.

Inattentional blindness is related to but distinct from other failures of visual awareness such as change blindness, repetition blindness, visual masking, and attentional blink. The key aspect of inattentional blindess which makes it distinct from other failures in awareness rests on the fact that the undetected stimulus is unexpected. It is the unexpected nature of said stimulus that differentiates inattentional blindness from failures of awareness such as attentional failures like the aforementioned attentional blink. It is critical to acknowledge that occurrences of inattentional blindness are attributed to the failure to consciously attend to an item in the visual field as opposed the absence of cognitive processing.

...
Wikipedia