{"id":141,"date":"2016-02-04T16:22:24","date_gmt":"2016-02-04T21:22:24","guid":{"rendered":"http:\/\/commons.trincoll.edu\/purpleperils\/?page_id=141"},"modified":"2016-02-04T16:40:05","modified_gmt":"2016-02-04T21:40:05","slug":"psychophysical-hypothesis-for-stationary-edge-perception","status":"publish","type":"page","link":"http:\/\/commons.trincoll.edu\/purpleperils\/1968-1969\/psychophysical-hypothesis-for-stationary-edge-perception\/","title":{"rendered":"Psychophysical Hypothesis for Stationary Edge Perception"},"content":{"rendered":"<p align=\"RIGHT\">1968<\/p>\n<p align=\"CENTER\"><strong>Psychophysical Hypothesis for Stationary Edge Perception<\/strong><\/p>\n<p align=\"CENTER\">J. J. Gibson, Cornell University<\/p>\n<p align=\"CENTER\">\n<h5>The World Wide Web distribution of James Gibson&#8217;s &#8220;Purple Perils&#8221; 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 References to these essays must cite them explicitly as unpublished manuscripts.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.<\/h5>\n<p>&nbsp;<\/p>\n<p>1. An occluding edge will tend to appear on the <u>inside<\/u> of a closed contour but not on the <u>outside<\/u> (Rubin&#8217;s principle of figure on ground. It can be extended to state that the <u>more<\/u> a contour tends to be <u>closed<\/u>(con<u>cave<\/u>, or an <u>acute<\/u> angle) the more it will tend to appear as an occluding edge).<\/p>\n<p>Exception: when the interior of a closed contour is textureless and the exterior is textured, an occluding edge tends to appear on the <u>outside<\/u> of the contour if the form is large enough. This follows from the general principle that any large enough sample of textureless light appears <u>insubstantial<\/u>. (Results of experiments on apertures, holes or windows, and with Metzger&#8217;s homogeneous field.)<\/p>\n<p>2. When there is optical texture on one side of a contour but not on the other an occluding edge will tend to appear on the side with the texture.<\/p>\n<p>Exception: when the contour is <u>closed<\/u> and the area enclosed is <u>small<\/u> the texture may be outside but the superposed edge will be on the <u>inside<\/u> (Katz). Likewise when the contour is shrunken to a <u>spot<\/u> it will appear <u>in front<\/u>.<\/p>\n<p>Question: How are these principles interrelated?<\/p>\n<p>Note that from this psychophysical point of view, Wertheimer&#8217;s &#8220;laws of grouping&#8221; do <u>not<\/u> refer to organization of sensory elements in the brain but to conditions for the perception of surfaces, to optical texture; and that the figure-ground phenomenon of Rubin is <u>not<\/u> an expression of a general tendency to experience <u>objects<\/u> (&#8220;forms&#8221;) but only of the optical information for the perception of an occluding edge.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>1968 Psychophysical Hypothesis for Stationary Edge Perception J. J. Gibson, Cornell University The World Wide Web distribution of James Gibson&#8217;s &#8220;Purple Perils&#8221; 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 &hellip; <a href=\"http:\/\/commons.trincoll.edu\/purpleperils\/1968-1969\/psychophysical-hypothesis-for-stationary-edge-perception\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Psychophysical Hypothesis for Stationary Edge Perception&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1001,"featured_media":0,"parent":18,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/pages\/141"}],"collection":[{"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/users\/1001"}],"replies":[{"embeddable":true,"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/comments?post=141"}],"version-history":[{"count":1,"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/pages\/141\/revisions"}],"predecessor-version":[{"id":154,"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/pages\/141\/revisions\/154"}],"up":[{"embeddable":true,"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/pages\/18"}],"wp:attachment":[{"href":"http:\/\/commons.trincoll.edu\/purpleperils\/wp-json\/wp\/v2\/media?parent=141"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}