In the Monkey Illusion video most people who have seen it be

In the Monkey Illusion video, most people who have seen it before look for the gorilla but miss other changes such as a play in black leaving and the curtain changing color. https://youtu.be/IGQmdoK_ZfY

What is this phenomena called and explain why it occurs?

List a design implication of this (i.e., what do we have to keep in mind when designing products as a result of this propensity)?

Solution

Phenomenon:

The phenomenon in Monkey illusion video is called as Inattentional blindness or Perceptual blindness, \"the failure to notice unusual and salient events in their visual world when attention is otherwise engaged and the events are unexpected\". It  is a psychological lack of attention that is not associated with any vision defects or deficits.

Reason for occurence:

It occurs due to high perceptual load and therefore more significant use of attentional resources appears to increase the likelihood of the inattentional blindness episodes. It occurs in any individual, independant of cognitive deficits.

Design Implications:

1) environmental cues aid in the detection of stimuli by providing orienting cues but is not enough to produce awareness,

2) perception requires effortful sustained attention, interpretation, and reinterpretation,

3) implicit memory may precede conscious perception, and

4) visual stimuli that is not expected, explored, or interpreted may not be perceived.