ABSTRACT Two observers performed simple reaction‐time responses to peripheral stimuli of varying intensity (–2.5 to +1.0 log td) and angular subtense (10 to 210 min). The area‐intensity combinations that produced each of three scotopic reaction‐time criteria were calculated. Analysis of these combinations showed that the area‐intensity reciprocity could not be predicted by traditional theories of spatial summation. Like earlier findings for peripheral photopic reaction‐time criteria, the results indicated that for small stimulus sizes, area has a greater effect than intensity in determining the scotopic reaction‐time responses.
Edmonds et al. (Tue,) studied this question.