Each card showed one of the two alternative arrangements of its facsimile and enantiomorph silhouettes.
In the circumstances of facsimile and enantiomorph responses being equally frequent, the ratio has the value of 0.5.
(2000) point out that the difficulties in discriminating between mutually enantiomorphic patterns show that the perceptual encodement of a pattern must necessarily involve encodement of its enantiomorph; a discrimination error occurs whenever an observer responds to the enantiomorph as if it were the facsimile of the original pattern.
In the present task embedding is achieved, in spite of the clear delineation of the figure, by means of the fact that the figure together with its enantiomorph forms a symmetrical pattern.
(2) The derivative element of the encodement is the enantiomorph of the facsimile element.
Three experiments investigated a hypothesis, suggested by studies of the difficulties of discriminating between shapes forming symmetrical pairs, that spatial orientations of thin flat plates (lamellae) may be encoded in a plane, the encodement consisting of two enantiomorphs. The results indicated that participants encoded the spatial orientation of lamellar stimuli in terms of the difference in cogency between their two enantiomorphic elements (Expt 1).
That is to say they enshrine differences in the balance of power between competing enantiomorphs. The perceptual mechanism involved in enantiomorphic confusions is thus involved in the encodement of orientation.
Furthermore, as the sloping stimuli are more readily confused, the two postulated enantiomorphs by means of which each stimulus is encoded must differ much more markedly in the case of stimuli in the fronto-parallel plane than in the case of the stimuli in inclined planes.