ABSTRACT
This chapter presents an existence proof. Its subject is a factor of perceptual grouping to be added to the list produced by Wertheimer in his seminal article of 1923. The factor must be identified with that feature that satisfies the conditions: if the factor is changed, then the amount of unitariness present in the situation changes; and it should, in some instances, be able to conflict with the known factor, albeit weakly. Under the rules just stated, because the proximity factor is acting neither in favour nor in disfavour of either of the articulations, the minimum principle applied to the edges should be the deciding factor, just as is the case with continuous and chromatically uniform figures. Thus, the perceived structure cannot be explained by referring to the minimum principle of edges, but, once more, to the greater robustness of the rows determined by the directionality factor.
