Vision Res.(09) Helson

Research into Visual Perception conducted by Helson and Fehrer

One of the most frequently cited (pre-1950) works is that of Helson and Fehrer:
H.Helson & E.V.Fehrer, "The role of form in perception", Am.J.Psychol., Vol.44, pp.79-102 (1932).
This work includes a comprehensive summary of the investigations undertaken prior to 1932. The purpose of their own experiments was to determine the effect of the shape of an object on the human perception of it. They also investigated whether some shapes, notably a circle, were more likely to be correctly perceived than others.

Experiments were conducted to determine the
* __ ‘lower limens of light’ (detection thresholds),
* __ ‘ just noticeable form’ (lowest/most optimistic recognition thresholds), and
* __ ‘ certain form’ (highest/most pessimistic recognition thresholds)
for six different figures, all of the same area.

The figures used were an isosceles triangle (standing on its base); a rectangle (on its longer side); a circle; a semicircle (resting on its straight side); an irregular shape (formed by removing a square from the corner of a larger square and displaying the resulting shape in an inverted V orientation); and finally, a square.
The stimuli were presented in a randomly selected order.

The experimental findings were that:
“ The perception of light at the absolute threshold for vision is formless, and only at higher levels of brilliance are forms just perceived; at still higher illuminations the certain form of the stimulus emerges”.

The quantitative results of Helson and Fehrer’s experiments suggest that the form which is most easily seen/recognised varies according to the precise definition used to compare the detection/recognition data for the different shapes. For example, possible definitions of the most easily recognised shape include, ‘that shape requiring the least amount of light’, ‘that reported the largest number of times on the barely perceived level’, and ‘that confused with other shapes the least number of times’.
Helson and Fehrer concluded that the assertion that forms are "first and primary in perception" could not be upheld by their studies.

The possibility of identifying a shape which is most easily detected and recognised, based on all of their criteria taken together, is discussed. No single such form emerged.

Helson and Fehrer’s work is frequently cited in modern research, over sixty years after it was published. (It also received attention at the time of publication - not all of which was supportive of their results. For example, in 1933 Wilcox described Helson and Fehrer’s evidence as ‘inadequate and misleading’.)

This Section consists of short summaries of historial research and theories into human visual perception of simple two-dimensional objects (these are extracted and summarised from a Ph.D. Thesis [67] dated 1996).
For more general information about the human visual system see the sections about:
The Eye; Parts of Eye; Visual Disorders; Ophthalmological Procedures.