impossible!

Explanation

Once again, it is a matter of lateral inhibition between the center and surround of the receptive field. Note the lower right part of the diagram. The receptive field that lies at the intersection of the white cross has more light falling on its inhibitory surround than does the receptive field that lies between the two black squares. Consequently, the excitatory center of this receptive field between the squares yields a stronger response than that which lies at the intersection of the white cross. This explanation is appropriate for those circumstances where the receptive fields are larger than the spaces between the squares.

< back >