November 1967
Situations Requiring Different Types of Exploratory Ocular Behavior
J. J. Gibson, Cornell University
The World Wide Web distribution of James Gibson’s “Purple Perils” is for scholarly use with the understanding that Gibson did not intend them for publication. References to these essays must cite them explicitly as unpublished manuscripts. Copies may be circulated if this statement is included on each copy.
(Some of the different types of scanning an optic array. A preliminary draft.)
I. The ambient array from the environment
— ordinary “looking around” (e.g. after entering an unfamiliar room)
— the looking around of a mountain climber after reaching the summit
— the observation of the night sky for “celestial objects” and their groupings
II. The ambient array with respect to its occlusion information
— searching for a hidden object, or a mislaid (“lost”) object in a familiar environment (child’s game).
— searching for a hiding place in an environment (place where a thing would be occluded from view). This could be adapted for an experiment with children of different ages.
III. The polarized regions of the array at the side of a highway
— looking “both ways” before a pedestrian crosses a street with automobile traffic (skill in which children must be trained).
IV. The expanding array with respect to goal and obstacles
— the type of looking required for the guidance of locomotion (keeping the focus of expansion of the optic array away from the patches that specify obstacles).
— for walking
— for tricycle riding
— for automobile driving
— for airplane piloting
V. The array with respect to negative affordances
— more generally, the looking activity necessary for detecting dangers in the environment (holes in the ground, cliff edges, sharp proturbances, fires, snakes, missiles).
VI. The pictorial array
— getting the information from a picture (either consisting of projected surfaces as in painting or photography, or projected edges as in line-drawings (Cf. Buswell, How people look at pictures).
— getting the information (whatever that may be) from a geometrical form.
VII. The array from a face
— getting information from the physiognomic forms and the kinetic transformations of a human face (begins in infancy).
VIII. The array from a graphic surface
— reading a map
— reading a list
— reading a text. Only in this last type of array does the scanning sequence have to follow the adjacent order of a matrix, such as left to right and top to bottom. This conventional rule for scanning is to be contrasted with the rules (or strategies) for optimal scanning of the other types of array listed below.
Note than the hypothesis of different rules for scanning different types of information-bearing arrays alleviates some of the difficulties in the hypothesis that all scanning is governed simply by peripheral detection of the information loci in an array (“peripheral search-guidance”). The latter hypothesis is susceptible to the dangers of “subception” theory if one isn’t careful.