Generally, people looking at an example of a Rubin Vase see either the vase, or the faces. The brain seems to make a decision on which one is being viewed, but both cannot be focused-on at the same time.

Is the Rubin vase a form of inattentional blindness, caused by the same brain function that only allows us to focus on certain objects in our field-of-view, but not others? The Gorilla-in-the-Room is another example.

  • $\begingroup$ Did you mean, inattentional blindness: "a psychological lack of attention that is not associated with any vision defects or deficits"? The gorilla example is listed explicitly on this wiki. What did you mean it to be 'another' example of? $\endgroup$
    – Steven Jeuris
    Sep 7 '16 at 15:38
  • $\begingroup$ Which is the brain function which "allows us to focus on certain objects in our field-of-view but not others"? $\endgroup$
    – Steven Jeuris
    Sep 7 '16 at 15:40
  • $\begingroup$ What does it mean when you're able to view both possibilities of an ambiguity at once? $\endgroup$
    – Don Joe
    Nov 14 '17 at 1:01
  • $\begingroup$ @DonJoe you can consider asking this as a new question. The answer pane is reserved for answers $\endgroup$
    – AliceD
    Nov 14 '17 at 8:29

Short answer
The Rubin Vase is a visual illusion, which can be traced down to the way the visual system analyzes visual scenes in terms of objects and background. Inattentional blindness is not an illusion, it is the failure to detect stimuli when the mind is focused on something else. It has to do with the limitations in the capacity of the visual system to extract relevant information from a visual scene.


  • The Rubin Vase illusion (Fig. 1) is an example of an ambiguous figure/ground illusion. The visual system interprets patterns in terms of external objects. To do this, the visual system distinguishes objects (figure) from background (ground). In the Rubin Vase illusion, when the faces are considered background, you will see the vase as figure, and vice versa.

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Fig. 1. Rubin vase illusion. source: TU Dresden

The visual system represents objects primarily in terms of their contours. Also, elements that are close together, or share certain features, or are homogeneous in certain respects tend to be grouped together (grouping). The sudden reversal one may perceive is thought to be due to a shift of attention on the shape of the contour. The observer's "perceptual set" and individual interests can also bias the situation. Biasing the shapes or contours can make one interpretation stronger than the other one. This particular illusion involves higher cortical processing, because previously stored information about vases and faces are resourced (source: TU Dresden).

  • The Invisible Gorilla (see a video clip here) (Fig. 2) is the effect where people instructed to focus on a particular target are prone to miss other salient, sometimes striking stimuli. The classic, familiar example being subjects shown a basketball game and they are instructed to keep count of how many times the ball is passed between players in the black team. When the subjects watch the video clip and attentively count the number of passes, about half of the subjects totally miss the scene in the video where a man in a giant gorilla suit walks slowly into the middle of the screen, beats his chest and then wanders off, because they were so focused on counting the passes (that’s not to mention the other deliberate mistakes in the video) (source: Life in the Fast Lane). A newer version hits home even harder; 24 experienced radiologists were asked to perform a familiar lung-nodule detection task. A gorilla, 48 times the size of the average nodule, was inserted in the last case that was presented. Eighty-three percent of the radiologists did not see the gorilla. Eye tracking revealed that the majority of those who missed the gorilla looked directly at its location. Thus, even expert searchers, operating in their domain of expertise, are vulnerable to inattentional blindness (Drew et al.,, 2013).

invisible gorilla
Fig. 2. Invisible Gorilla. source: Persuasion Blog

The Invisible Gorilla is an example of inattentional blindness. Inattentional blindness can be defined as:

The failure to notice unexpected objects or events when attention is focused elsewhere [...] (source: Simons).

- Drew et al., Psychological Science (2013); 24(9): 1848–53

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    $\begingroup$ Just a thought. If you would rephrase a Rubin Vase exp to "how many faces do you see?" thereby drawing attention away from the vase, then the two (Rubin and the gorilla) appear to be very similar. Isn't it for the Rubins vase also a matter of attention (what you attend to is what you see)? Probably if you were instructed to look for a gorilla, no nodule/passes would be seen. $\endgroup$ Sep 8 '16 at 6:15
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    $\begingroup$ @RobinKramer, the Rubin Vase is also a matter of attention, but it's ambiguous, even when you focus on the faces it may flip flop. It's not purely a matter of conscious effort. Inattentional blindness surely is purely a matter of attention as you say. $\endgroup$
    – AliceD
    Sep 8 '16 at 7:28
  • $\begingroup$ In the early 1900's research, primarily in Germany, was done to quantify the parameters of the brain function that led to such items as the Rubin Vase. This group of studies and research has become known as gestalt. Because of the nature of the brain to (not) remember certain items in the field of vision it becomes very difficult to quantify. How would, or could, one answer definitively what is it I didn't see? I would like to (see) more research done in this area. $\endgroup$
    – D. Wade
    Sep 8 '16 at 12:04
  • $\begingroup$ @D.Wade - yes,it is related to the gestalt principle. I deliberately left that term out of my answer, as the answer stands well without referring to it. $\endgroup$
    – AliceD
    Sep 8 '16 at 12:24
  • $\begingroup$ The brain also does the opposite. Sometimes the brain will (add) information to a memory to produce a different image than what is in the field of vision. In other words, it is difficult to be certain what information is actually contained in the field of vision. As a part of what is envisioned we can't be certain as to what is being left-out, or what has been added-in - even if the scene is photographed. It is difficult to convince people of this. Generally, people believe (seeing is believing). $\endgroup$
    – D. Wade
    Sep 8 '16 at 13:48

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