The concept of affordance and GIS: a note on Llobera (1996).

The concept of affordance and GIS: a note on Llobera (1996). Llobera's project Marcos Llobera (1996: 612) attempts to use Geographical InformationSystems (GIS) in a more `humanistic way', to explore `places andspaces' and to `close the gap between theory and method'. Thetheory in question is that of human practices and relates toGidens' concept of structuration The theory of structuration, proposed by Anthony Giddens (1984) in The Constitution of Society, (mentioned also in Central Problems of Social Theory, 1979) is an attempt to reconcile theoretical dichotomies of social systems such as agency/structure, and Bourdieu's concept ofhabitus habitus/hab��i��tus/ (hab��i-tus) [L.]1. attitude (2).2. physique.hab��i��tusn. pl. . As a methodological tool, GIS offers, as Kvamme (1993: 91)notes, `excellent display capabilities together with embedded systems ofquantitative analysis Quantitative AnalysisA security analysis that uses financial information derived from company annual reports and income statements to evaluate an investment decision.Notes: [that] can provide an ideal environment forspatial investigation'. Gidens and Bourdieu are now regular sources for archaeologicaltheorizing, but the American psychologist, James J. Gibson is not.Gibson studied perception and developed an `ecological psychology'based on a theory of direct perception. The concept of affordance iscentral to the theory of direct perception. For Llobera, the concepts of structuration, habitus and affordancemake up a trinity of key concepts that, it is hoped, will make humanpractices within the landscape explicable ex��plic��a��ble?adj.Possible to explain: explicable phenomena; explicable behavior.ex��plic (but note; the utility of theconcept of practices for social science has been severely questioned byStephen Turner (1994)). Finally, Llobera's approach to understanding `places andspaces' in the Wessex landscape is also influenced by theanthropology of Tim Ingold, who in turn, draws on Gibson's theoryof direct perception. Llobera is therefore doubly influence by Gibson;directly by his attempt to use the concept of affordance and indirectlythrough the anthropology of Ingold. What, then, does Gibson'stheory of direct perception amount to? Gibson's theory of `direct perception' Although Gibson's theory of direct perception is generallyapplicable to the senses, most of the experimental work he undertookexplored the processes of visual perception, so I will confine mydiscussion to vision. Orthodoxy (Descartes onwards) holds that light falls onto theretina producing a `retinal image' from which the mind/brainconstructs representations of things in the world. Visual cognition thusamounts to manipulating these representations. Gibson, however, contested the relevance of the `retinalimage' for vision. Gibson pointed out that light entering theenvironment -- as rays of radiation -- is reflected back and forth offsurfaces and is scattered by particulate matter particulate mattern. Abbr. PMMaterial suspended in the air in the form of minute solid particles or liquid droplets, especially when considered as an atmospheric pollutant.Noun 1. in the atmosphere. Inthis way radiant light becomes illumination and an ambient array atevery point. Thus, light comes to every point and thereby environs everypoint. In this way, light at the point of observation is different inintensity in different directions. As we move through this ambient array, invariant (programming) invariant - A rule, such as the ordering of an ordered list or heap, that applies throughout the life of a data structure or procedure. Each change to the data structure must maintain the correctness of the invariant. ratios ofillumination intensity presented in temporal sequence constitute astructure or texture in the form of deeply nested sets of invariantrelations of illumination; these nested sets of invariant ratios ofillumination are what are registered or picked up by the perceptualsystem. By perceptual system, Gibson means the reflexive organization ofthe animal -- the mobile eye on a mobile head on a mobile body.Perception for Gibson is active and exploratory. Gibson rejected theidea that the world is reassembled from a projected image on the retina,rather, the world is specified in a lawful and reflexive way by ourdirect interaction with it.(1) Affordances of the environment The lawful specification of the environment's layout given byinvariant relations of illumination in ambient light carries aqualitative value for a given animal. It is this qualitative value thatGibson termed an affordance. Gibson (1986: 127) states that The affordances of the environmentare what it offers the animal, what it provides or furnishes either forgood or ill. The invariants in the optical flow consist of`lower-order' and `higher-order' invariants. These two classesof invariants are interrelated, analogously, with the way ratio orinterval scales (e.g. numbers) are related to nominal or ordinal (mathematics) ordinal - An isomorphism class of well-ordered sets. scales(e.g. categories). The lower-order invariants specify the facts ofenvironmental lay-out and thus specify the joint relations between thesurfaces of the environment including those of oneself and others. Thehigher-order invariants are compounded from lower-order invariants andspecify the affordance properties of the environment for the animal. Putotherwise, higher-order invariants specify to an animal which of itsaction systems might realize an affordance offered by its environment. The following example adapted from Reed et al. (1986) should helphere. A hotel lift contains an adult and two children, one aged nine,the other aged four. The lift starts perfectly level with the groundfloor, but at each subsequent level the lift stops above the floor, suchthat with each new level reached the gap between the lift and the floorgets bigger. If the adult and the children were to get out of the liftat the first level up, there would be no problem stepping out. But ifthey get out on second level, the four-year-old has to have her handheld while stepping out, lest she over-balance. However, thenine-year-old and the adult can still step out without losing theirbalance. Now, if they get out on the third level, the adult can stillstep out but has to take care not to over-balance, the nine-year-old hasto jump and the four-year-old has to be lifted out by the adult. The lower-order invariances specify the joint relations between thesurfaces of the lift, the building it is giving access to, and thebodies of the people concerned. The higher-order invariances arise outof the combined lower-order invariance in��var��i��ant?adj.1. Not varying; constant.2. Mathematics Unaffected by a designated operation, as a transformation of coordinates.n.An invariant quantity, function, configuration, or system. of the environment. On the groundand first level, all three are afforded stepping out of the lift. By thethird level only the adult can step out. The height between the floorand the lift can vary continuously (lower-order invariance) but theaffordance of stepping out is bounded to different ranges of heightabove the floor (higher-order invariances) depending on the height --thus leg length -- of the individual in question. It may be said thatthe lift sometimes affords stepping out, but sometimes not, depending onwho wishes to step out. For the nine-year-old, the affordance ofstepping out become the affordance of jumping off. Social affordance Social affordance is a specialization of the term affordance, and refers to the properties of an object or environment that permit social actions. Social affordance is most often used in the context of a social technology such as wiki and chat applications. In the case of social affordance there are two or more loci loci[L.] plural of locus.lociPlural of locus, see there ofaction, but only one with nonsocial affordance. For instance, when aperson approaches a narrow opening, the opening does not respond (getnarrower or expand) to the fact that the person is turning sideways onin order to pass through it. With social affordance, however, eachindividual can see that they are being experienced in some way and, inconsequence, each will guide at least some of their conduct inaccordance with the perceived identity and on-going responses of theother. The metaphor of a dance comes to mind here. The problem with explicating or unfolding the structure of actionbeing afforded is that actions can be described in either narrow orbroad terms and in many intermediate ways. The trajectory of action canbe carved up in a multitude of ways depending on what seems appropriatefor the analysis being undertaken. Still & Good (1992) faced thisproblem with their study of the social affordances present when feedingan infant. In the transcripts of a recorded feeding session, they triedto give as complete a description as possible at the level of meaningfulaction. But it became clear that even the simplest actions can have arich and unique meaning within the flow of activity. This meaning getslost if they are treated as invariant and repeatable units of action forthe purposes of description. In other words Adv. 1. in other words - otherwise stated; "in other words, we are broke"put differently , the necessity ofthird-person description results in a necessary loss of information. Inlived experience we do not act in accordance with a priori a prioriIn epistemology, knowledge that is independent of all particular experiences, as opposed to a posteriori (or empirical) knowledge, which derives from experience. descriptiveanalysis, we do our experiential analysis `on-line' underconditions of constant feedback and adjustments. As Still & Good(1992: 117) remark, `there is no single action "eating with aspoon" because different instances are embedded within differentcontexts'. The affordances of Wessex ditches Llobera (1996: 622) wishes to use `GIS to explore affordances inthe landscape derived from an individual's perspective withinit.' But it should be clear (it is hoped) from the foregoingdiscussion that the presentations of affordances to an individual areintimately dependent on the specifics of the individual, e.g. theirheight, physical strength, manipulative skills and modes of interactionwith others (and the relations of social power operating). And although`affordance' is a noun, there is no thing that is an affordancethat can be seen, felt or heard, rather, affordance is the apprehensionof possible actions with what we see, hear and feel. Places and spaces, as Ingold rightly contends, are marked by thequality of our `dwelling' within them. Ingold (1993:156) statesthat `the landscape is the world as it is known to those who dwelltherein, who inhabit its places and journey along its paths connectingthem'. But knowing here is a `knowing how' not a `knowingthat' that is, knowing as skilled performance. Our dwelling withina place is marked by what the individual can bring to the animal side ofthe affordances offered by its immediate environment. Perceptionpresents to us the possible transformations of the places within whichwe dwell. But again, the concept of affordance is internal to an accountof the processes of perception, and while we may gloss matters withlocutions such as `a pencil affords grasping' we must be preparedto specify in detail the who and the when (and whatever else) to makegood on our analytical accounts. It may be the case that GIS can be used in constructing the ratherdetailed and dynamic description required to tease out one flow ofaffordance as opposed to some other. Certainly, Llobera (or whoever)needs to go beyond the mere adopting of a standard height for theirviewing individual (i.e. 1.6 m), but I suppose that is, at least, astart. (1) Current theories of vision are somewhat more `Gibsonian'than when Gibson was alive, in that the importance of invariance isaccepted. Nevertheless, the central role of representations maintainsits grip, but that too is beginning to slip. References GIBSON, J.J. 1986. The ecological approach to visual percep-tion.Hillsdale (NJ): Lawrence Erlbaum Associates INGOLD, T. 1993. The temporality tem��po��ral��i��ty?n. pl. tem��po��ral��i��ties1. The condition of being temporal or bounded in time.2. temporalities Temporal possessions, especially of the Church or clergy.Noun 1. of the landscape, WorldArchaeology 25: 152-74. KVAMME, K.L. 1993. Spatial statistics and GIS: an integratedapproach. Aarhus: Aarhus University Press. CAA CaaSee CCC. 92. LLOBERA, M. 1996. Exploring the topography of mind: GIS, socialspace and archaeology, Antiquity 70: 612-22. REED, E., P.N. KUGLER & R.E. SHAW. 1986. Work group on biologyand physics, in W.H. Warren & R.E. Shaw (ed.), Persistence andchange. Proceedings of the first international conference on eventperception. Hillsdale (NJ): Lawrence Erlbaum Associates. STILL, A. & J.M.M. GOOD. 1992. Mutualism MutualismAn interaction between two species that benefits both. Individualsthat interact with mutualists experience higher sucess than those that do not. in the human sciences:towards the implementation of a theory, Journal for the Theory of SocialBehaviour 22: 105-28. TURNER, S. 1994. Social theory of practices: tradition, tacitknowledge The concept of tacit knowing comes from scientist and philosopher Michael Polanyi. It is important to understand that he wrote about a process (hence tacit knowing) and not a form of . , and presuppositions. Oxford: Polity Press. DAVID David, in the BibleDavid,d. c.970 B.C., king of ancient Israel (c.1010–970 B.C.), successor of Saul. The Book of First Samuel introduces him as the youngest of eight sons who is anointed king by Samuel to replace Saul, who had been deemed a failure. S. WEBSTER, Department of Psychology, University of Durham (body, education) University of Durham - A busy research and teaching community in the historic cathedral city of Durham, UK (population 61000). Its work covers key branches of science and technology and traditional areas of scholarship. ,Science Laboratories, South Road, Durham DH1 3LE, England.d.s.webster@durham.ac.uk & d.s.webster@btinternet.com