Design Course
Visual Perception for Communication Designers
Human Factors and Sociotechnical Systems Studios
by
9.4 Why does inattentional blindness and change blindness take place?
One apparent reason is the mental workload. According to the mental workload theory, when we devote a lot of mental energy to one stimulus, we exhaust our cognitive resources and are unable to comprehend additional stimuli at the same time. Similarly, some psychologists describe how we pay attention to various stimuli with differing degrees of attentional capacity, which may impact our capacity to process several stimuli simultaneously. For instance, when someone concentrates intensely on one stimulus (such as a text on a phone while driving), they pay less attention to other stimuli (e.g., the position of other cars on the road).
Another reason is known as conspicuity. According to the principle of conspicuity, sensory and cognitive stimuli are two categories that are more likely to be processed. Sensory stimuli could be colour, brightness, and cognitive stimuli could be something familiar. As a result, stimuli that do not fall into one of these two groups may be overlooked. Seeing a gorilla in a basketball game is unusual in the actual world and is one of the reasons why people so frequently "miss the gorilla." Also, due to the busy focus on white T-shirts, the brain "zones out" the people in the black T-shirts. As a result, the brain misses the black-coloured gorilla, which is completely focused on tracking white T-shirts passing the balls. Consequently, one could not notice such peculiar visual cues while preoccupied with cognitively taxing tasks such as observing the game's specifics.
While a visual stimulus's salience is determined by its physical characteristics, its cognitive salience is determined by the observer's previous knowledge. Inattentional blindness will likely result when a stimuli's sensory or cognitive conspicuity significantly decreases. For instance, an object that is visible but not visually striking may pass unnoticed. On the other hand, if an object is unrelated to the observer's interests, even a visually intriguing object may fail to hold the observer's attention.
As mentioned previously, change blindness is when an observer fails to detect a change made to the visual stimulus. The interstimulus interval is the brief period between the two subsequent visual scenes, with the latter slightly modified.
The visual sensory memory register, known as iconic memory, is where visual images are stored after a physical stimulus has ceased to exist. Although it has a large capacity, iconic memory deteriorates quickly. Typically, information recorded in iconic memory vanishes in less than a second.
The iconic memory store is hypothesized to be diminished by the interstimulus interval duration. In other words, recognizing changes in a visual scene depends on iconic memory. But when the interstimulus gap gets longer, the likelihood of failures in iconic memory increases, causing change blindness.
Here is another example of inattentional blindness
Here are a few more examples of change blindness videos and what has been changed.
Main Video: https://www.youtube.com/watch?v=qnczjwSXz7I
Source: Susana Gomez
Source: Vedang Pathre
Source: Vedang Pathre
Source: Dishant Mehlawat, Hemant & Yash Vardhan
Source: Dishant Mehlawat, Hemant & Yash Vardhan
Source: Shreyas Vernekar, Sanskruti Landage & Akshata Khare
Source: Shreyas Vernekar, Sanskruti Landage & Akshata Khare