Vision Res.(09) Helson
Research into Visual Perception conducted by Helson and Fehrer
One of the most frequently cited (pre-1950) studies of human visual perception is that of Helson and Fehrer (see ref. below), in which they describe 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’ (i.e. detection thresholds)
- ‘just noticeable form’ (lowest/most optimistic recognition thresholds)
- ‘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
- 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/recognized 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 recognized 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 recognized, 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. 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’.
Ref. to Paper:
H.Helson & E.V.Fehrer, "The role of form in perception",
Am.J.Psychol., Vol.44, pp.79-102 (1932).
This section includes summaries of historial research and theories of human visual perception of simple two-dimensional objects. For more about the human visual system see The Eye, Parts
of Eye, Eye & Vision Disorders, Ophthalmological Procedures.
