New Zealand Chalk Advertisement

Perception is making sense of the sensory information around us and interpreting experience. Human beings tend to use their eyesight more than any other sense which is called visual capture. The brain likes to organize sight stimuli in many different ways, one of which is the figure-ground relationship. The figure-ground relationship is determining objects, or figures, standing out from the background. In the case of this lava ad, part of what makes the illusion work is the figure-ground relationship being tricked. In the first second or two of looking at this ad, it really does look like a lava hole is right there on the sidewalk. After a few seconds is when the realization of it being just a life-like picture dawns.

It is after that realization that one reads the words that are sending the real message, "Over 900 pedestrians were injured on Auckland City roads in the past five years: Don't step into danger." This is trying to relate to the pedestrians walking around by telling them to pay attention. The message sort of sends to the viewer that if you weren't watching where you were going you could have stepped into a lava pit and not even known until it was too late, the same with crossing the street.

But, why can one perceive this 3D image to be on the flat sidewalk? Humans have the ability of depth perception by retinal disparity, perceiving objects as three dimensional even though the retinas in our eyes see things as two dimensional. Humans have two eyes, so the brain must combine two seen images into one. The greater the difference between the two eyes, the closer the object is. Depth perception is typically used to judge distance, like how far away a car is. But, it isn't just horizontal, depth perception allows us to see things that go vertically as well, like the lava hole illustration. Also, in the picture, the person who took the picture must have been standing very close to it, because I perceive the illustration to be right in front of me, so there is a lot of difference from one eye to the other. It can be tested by closing one eye at a time and the picture will appear to greatly shift positions.

So, while we see the image in 3D, what makes us see the image as a hole in the ground? That has to do with being able to see light and shadow. Our brain almost always makes one assumption when it comes to light; we assume the light source is always from above, probably because of the importance of the sun through time. If an object appears lighter, it is either closer to you, because objects that are closer reflect more light, or it is facing in the direction of the light source. What is not lit by the light source is shaded. For this ad, it is placed outside, so its light source is the sun. So, seeing those darker, shaded areas cues our brain into perceiving depth, not a flat one color sidewalk, and to step around the hole.

One other principle helps make this a relative campaign to those standing around it. It is the use of placement. Placing the ad on the sidewalks by the busy streets not only ensures that more people will see the advertisement, but, it provides more relevance to those viewing it. The ad matches the setting it is placed in. If this drawing was placed in a quiet, suburban neighborhood it probably would not have much effect. Not only because of less people seeing it, but, due to people discounting it as not relevant to their situation. People in quiet neighborhoods usually do not have to worry about a whole lot of vehicles coming at them while crossing the street, so, this group will not see the ad as really all that important.

Furthermore, the use of brighter, more vivid colors for the advertisement campaign like orange, yellow, blue, and white are much more eye catching to those passing by these creations on the sidewalk. If more dull colors were used I do not think the campaign would have the same effect, because many people would ignore them and probably associate them to being silly drawings on the ground done by bored kids instead of an important message. If one looks closely at the picture, the colors give the illusion that the lava depicted there is very hot and churning because of the difference in the lava color, the appearance of swirling, and the perception of steam rising. The colors give more of a sense of meaning and more life-like illustrations. They grab someone's attention quickly and the colors bring their eyes to the campaign's message of assuming there is danger even on the sidewalk.

One of the compelling parts of this ad campaign is the use of danger. The word danger implies something threatening and to stay away from it. Lava holes, snake pits, and water full of sharks are definitely situations that a normal person would stay out of. Walking across a sidewalk has become a more careless activity, something this city in New Zealand thought that pedestrians weren't taking seriously enough. Many people do not even bother to look while crossing the street in major metropolitan areas, assuming that everyone in vehicles see them and will stop just because they are pedestrians, leading to many pedestrian hits. This is where the word danger comes in. The creators of the campaign want to associate crossing the street with the threatening situations of snake pits, etc. As said before, the situations created in the ads are things that most people would take care to avoid or take precautions and go around. If the campaign is successful, it will provoke more thought in pedestrians in the metro area to take more precautions where many vehicles are present, reducing the number of fatalities, which is the whole purpose of the advertisement.

http://www.moillusions.com/2008/12/dont-step-into-danger-3d-chalk-drawings.html