So far there is no evidence that many car designers know much of the theories of Richard L. Gregory. I have been working a bit lately on the psychology of visual perception and by chance I might have found a case where an understanding of his ideas may have changed a design outcome.
The case is the Peugeot 308 tail lamp. Like other current Peugeots it features a small tab of body colour which projects into the main body of the lamp. It seems to me to be wrong. Maybe a bit of Gregory’s theory could explain why.
Gregory developed ideas on “perception as hypothesis”. According to Gregory vision is not merely the passive reception of shapes from outside the mind. It involves memory and the interplay of various cognitive processes. In particular, his theory casts some light on how one can misinterpret visual stimuli or, in other words, experience an optical illusion.
According to Gregory there are four classes of optical illusion. You can read this for an overview of the four. They are: ambiguities, distortions, paradoxes and fictions. Today we deal with an ambiguity.
A classical example of an ambiguity is the Necker Cube:
Much of the information points in the direction of this being a three-dimensional cube. It has four exterior edges meeting at angles. The front and back squares meet at right angles. The diagonals are parallel.
According to Gregory we build up quickly the hypothesis that it is a cube. However, the hypothesis can’t be fully resolved as to which face of the cube is nearer. It might be the lower one or the upper one. The fact we can see either as the front or back tells us the mind can actively decide how it is seen. Other theories of perception (such as Gibson’s) can’t account for this.
The ambiguity is caused by the way the verticals and the horizontals are not clearly in front of or behind each other. The Gestalt Law of continuity leads us to assume a line crossed by another line is one line and not two. This applies to the horizontals interrupted by verticals and vice versa.
In the case of the Peugeot we have another ambiguity where the shapes can be read two ways and it is not clear which is “correct”. First, we can read the outline as belonging to the lamp:
Or we can read it as if part of the outline belongs to the body. The effect is clearer in the metal. This is caused by the way the crease runs from the door handle rearward, joins the lamp tab and then runs down the bumper-to-body panel gap:
For a tail lamp with a tab that is unambiguous consider the 2008-2016 Renault Megane:
The Megane’s tail lamp has full ownership of its outline as per the Gestalt Law stating the outline belongs to the figure where a figure-ground relationship is perceived.
At some point the Mégane’s name was written with an accent. At Renault’s French website they shout it as MEGANE.
You could say that the ambiguity of the 308 is a form of design richness, where one has the opportunity to gaze and switch between interpretations. I rather think it simply disturbs my eye as the alternative interpretation where the outline is joined with the panel gap and feature line has no structural meaning.
It’s curious though how few examples there are of this kind of ambiguity in car design.
Here is my solution to the “problem”: