Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!caip!sri-spam!nike!ucbcad!ucbvax!brahms!m128abo From: m128abo@brahms.BERKELEY.EDU (Michael Ellis) Newsgroups: net.ai,net.philosophy,net.cog-eng Subject: Re: Gibson's theory of perception Message-ID: <14987@ucbvax.BERKELEY.EDU> Date: Thu, 24-Jul-86 07:16:24 EDT Article-I.D.: ucbvax.14987 Posted: Thu Jul 24 07:16:24 1986 Date-Received: Thu, 24-Jul-86 21:21:29 EDT References: <1782@mtuxo.UUCP> <3483@sdcc3.ucsd.EDU> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: m128abo@brahms.UUCP (Michael Ellis) Organization: University of California, Berkeley Lines: 112 Xref: mnetor net.ai:1063 net.philosophy:2195 net.cog-eng:239 > Rick Frey >> A Reed >> In this view, the >> natural light sources present in the environment, the reflective >> properties of the surfaces of objects, and the optical characteristics >> of the atmosphere are as much a part of the human perceptual system as >> the eyes and the brain. Thus, the retinal stimulation pattern is not the >> input to perception, but rather an internal stage in the process. The >> input to the perceptual process is the object itself; > >Gibson's major mistake. This simply isn't true. Obviously it has to be >the light that makes it to the organism. If no light reaches the >organism, then there's no perception. Period. Unless the organism >*perceives* the object, it doesn't exist to the perceiver. Perception >starts once there is something to perceive, and that only can begin when >perceptual information about the object makes its way to the perceiver. Major mistake? Simply isn't true? Does anyone understand the relevance of this to Adam's original statement? As far as I can tell, you have simply refused to acknowledge a difference between your word "perceive" and Gibson's. >> the output is >> organism's awareness of the object. The information contained in this >> awareness is the original, and not a re- (or transformed), presentation >> of the object to consciousness. > >Information contained in awareness? This is somewhat Gibsonian in that >he uses words that have no clear definitions, but I don't think even he >would quite say this. What is awareness? What stage of processing are >you referring to? Aside from the actual collection of excited and >inhibited receptors at the retinal level, *all* perception is transfor- >mation. Sorry, no homunculae. (sp??) My, we're being doctinaire! No awareness, no homunculae? All perception is transformation? Are you really sure?? Are you telling us that there is nothing in the real world that corresponds to "awareness"? How quaintly Cartesian! Homunculism is by no means dead. Dennett in "Brainstorms" speaks of mental processes in terms of progressively stupider homunculae. As to awareness itself, are you sure you really wish to overlook the concept? Is all we wish to know about perception simply how a mess of brain cells work? Or is it not at the same time to understand how it is that we become AWARE of our environment? >> According to Gibson, the experimental psychologist's laboratory use of >> two-dimensional representations, tachistoscopic stimuli, illusions, and >> other materials that were not part of the ecological environment in >> which the human perceptual system evolved, amounts to studying the human >> perceptual system with some of its key parts removed. > >In some cases, this is a valid claim of Gibson's, but his whole theory >rests on it and it isn't 100% true. He'd love to have us believe that >the external world is rich in information and that perception is an easy >task of picking out of the multitude of cues available. That's simply >not true. Must the Gibsonians be 100% right lest their entire case come crashing to the ground? Who says so? The anti-Gibsonians? Why? And if Gibson would "love to have us believe the external world is rich in information", whatever do you find hard to believe about that? Do you mean to imply that the world is poor in its information content? As far a I can tell, there IS an enormous wealth of unused information in the natural world. I did not know Gibson's "theory" was either true or false; rather, I thought that it was more unified approach, a redefinition of just what it is our perceptions are, generally in keeping with the wider view of evolution, not of just species, but of interdependent systems ranging from genes to ecologies. If so, there doesn't seem very much to be "wrong" about it, at least none of the criticisms you've offered. >Experimental psychologists aren't blind to this criticism, and far too >many experiments have been done that don't fall under Gibson's >criticisms of artificiality. Perception developed under situations >where the available information was far from over-abundant. Without >this over-abundance of information, Gibson's ideas start falling apart. Totally absurd. Life evolved in the presence of light, which contained vast amounts of environmental information that was almost completely unused until creatures evolved that were complex enough to exploit vision. Or are you denying that light carries information? >Perception developed in a piecemeal fashion such >that there wasn't an overabundance of information at various stages in >the development. So where did this 'perceptual laziness' come into >play? You try finding a small tree frog in a huge tree. The whole idea >of an overabundance of perceptual information might apply to recognizing >people's faces, but it has no basis in the reality of where and how >perception developed. No basis in reality? How different is recognizing people's faces (for beings who need to do so, like other people) from recognizing the kinds of places where frogs hang out (for beings who need to eat frogs)? Now my perceptions did not evolve so that I could locate frogs more readily than many other kinds of things, but if humans had evolved into tree climbers with a diet consisting largely of frogs, I have little doubt that we'd have no trouble locating that frog, even blindfolded. -michael