The Aubert-Foerster phenomenon and its relation to manifest anxiety

Abstract

The Aubert-Foerster Although Foerster collaborated with Aubert in the original demonstration of the phenomenon, his name does not appear as co-author of the published work. phenomenon is the easier recognition of small objects when near, as compared with larger, more distant objects subtending the same visual angle. Thus, if the subject is fixating a point on a white ground 20 cm from the eye, and two black squares of side-length 4 mm, separated on a white ground at a distance of 8 mm centre to centre, are introduced into the visual field from the periphery along the horizontal meridian, they will be clearly recognised as two squares at an angle of 42°. However, if the distances between the eye and fixation point and between the two squares are doubled, and the area of the stimulus squared, clear identification will be achieved at angle 30°; if distances are increased five-fold, and square-size raised to the fifth power, the visual angle narrows to 22° (Figure I) although the size of retinal image is the same in all cases (Aubert, 1865).