Spatial Visualtzation-A Gateway to Computer-Based

Spatial Visualtzation-A Gateway to Computer-Based Technologpr KENT L. NORMAN, Universipof Maryland Abrfract The positive impact of computer-basedtechnology in educadon varies in part as a function of the individual abilities of users. A model is proposed for how individual differencesare expected to affect performance when technolog5lis intoduced. The p,rimary cognitive factor driving differences in performance using computer-based technology is spatid vl$alizadon ability. Four techniques for mitigating the negative impact of knl spatial visuafi-ation are discussed. The use of gotiol mdaphors and gmphiul u*r interfocesare promising, but intatoe apryrtlnqt, revealing hidden relationships and shorring condngencies, and interface manipulatob,lify, allou/ing users to direcdy manipulate objects and see intermediate steps, are the mct fikely to beneftt individuals with low spatid visualiza6enability.

Computer technology has great potential in education. Unfortunately, that potential may not be distibuted equally across populations. In fact, some technologiesmay serveto further handicap some populations while benefiting others. What is facilitatingfor one individual may have little impact or even a negativeeffect for another.What is promoted as an "enabling technology" may actually b€ a disabling technology for another population. For this reason, it is naive to think that the mere application of technology in education will benefit everyone equally. The use of computers in education has been fraught with problems (Holden, 1989). Some of theseproblemsmay be due not only to the inequity in the distibution of computer This r,vorkwas supported in pad from a gnnt from AT & T Information Sptems to the Hurnan/Computer lnteraction laboratory in the Center for Autornation Researchand to the Computer Science Center at the University of Maryland. The author wishes to thank Amy Sfuerman who conducted the str.rdyon graphical user lnterfacesand Scott Buder, Al Cavalier, and Karen Norrnan who provided helpful commenb and suggestions. Corapondence and rques{s tor rq'ints should be oddr*sed a Kent L. Norman, Deporbnentof Psr,lchology, Uniuersityof Morylond, bllege Po*, MD 20742411. Journal of Special EducationTechnology

resources, but also to an imbalance in outcomesarnongstudenb and teachers.Computer literacalamong teacherss€rves to determine the successfulimpact of the technology in the classroom(e.9., Kearsley& Seidel, 1985). Similarly, the varying abilities of the studens may serve b atenuate the advantages of computer technolog/. Rather than folloudng a path of exbeme polarity which might either blindly condemn or extol technobgl, this paper takes the route of a causal andlrsis of the problem and propos€s a redesign of technology to accommodate individual differences.SpeAficaUy,it addresses the questions:"What is the major source of individual differences in performance using computer interfaces?" and "Hour can the interface be redesignedto facilitate dre performance of all users without handicapping a minority?" To this end the paper first hyn the background br the adverse interaclion between technolog/ and the magrritude of individual differences.lt then erplores a major cognlfiw conelate to human/computer performanoe; namely, spatal visualizationabillty. fu a cognitive factor, spatial visualization is Vdume Xll Number3 Sp.ing1994

196

SpatialMsualization

defined as the "ability to manipulate or t-ansform the image of spatial pattems into other arrangemenb" (Ekstom, et al., 1976, p. 173). Serrenl experiments involving spatial visualizationand the ability of usersto perform tasks are reviewed. hnally, the design of the human/computerinterfaceis consideredfrom a cognitive point of viarr to ftnd ways to minimizethe detiment of low spatialvisualization ability. The factorsof interfaceapparency and manipulatability are proposd as spatial visualization gatewa!,s to computer-based technologl. The idea of a "gateuray" is to prwide an enEy point through the design of technologr to either cut through or bridge over a cognitiw deficit that urould otherwise have hmited an individual's ability to use the technologr to his or her bene0l Technology May Ampltfo Indlvldual Dlfierencer A number of models have been proposed to predict hov,rtechnologl combines with human perfonnance to yield an overall outcome (Dehning, Esdg, & Maass, 1981; Nelson, 197Q Norman & Singh, 1989). In general, aeecta$ors are that r.rser proffciency and syst€rnpors€r combine multiplicatively. Figure I showsthe expectedrelationship.The [nt on the top shows the e{fect of an increase in the

power of the technolog5rfor individuals with high proffciency.The line at the bottom shows the effectfor individualswith low proftciency.If the user's proftciencyis high, performancl is amptfted as indicated by the steep line. However, if the user's proficiencyis low, the impact of computer-basedtechnologylis severely attenuatedas indicated by the nearly flat line. Thus, technology is expectedto amplifu the performance of those initially having ability; but it does little for those who have little. . lf this is the case, then it is also expected that performanceusing computer-basedtechnologgr will be a multiplicative function of performance prior to the intoduction of that technolog5l.If P, is performancewith technologl and Po is perforrnance prior to the inhoduction of the technolog5r,then P r= A P p,6> 7.0,

Eq. 1

where 6 is the impact of technology. While this idea is probably not very contoversial, ib effect on individual differences is. lt oo2 is the population standard deviation prior to the intoduction of technoloW and of is the population shndard deviationwith technologr then,

High

Overall Performance

Human Proficiency

SystemPower -> HGUNE I lfuldplfcadve eifiect of urcr proficlency and ryatem powcr on overalt h'man/ cooputaf pcrformancc.

tn

Norman of

= 6t oo'.

F4.2

Thus, there will be a 62-foldincreasein the population variance due to the intoduction of technology. In addition to the multiplicative effect that leads to an increasein the variance, there may be an addidve effect that will lead to an overall change in the mean across all populations. A review of the effectivenessof computer-based instuction by Kulik and Kulik (1991), for example, suggesb positive effecb across all age groups.

Figure 2 shours three cases drat could result. ln the ftrst case (top panel of FBure 2), most individuals improve, but those at tfie lov.,erend of the distibuton achrally do r,'rorse than before. In the second case (middle panel of Figure 2), most individuals imprwe, but those at the loper md of the distibufion only imprwe slighdy or stay the same. Finally in the third case (bottom panel of Figure U, an individuals impro.re, but still the distibufron becomes more disperse. Evm with an additive benefit acrcs the board, the inboduction of computer-based

Prior

Prior

Prior

of Students OutcomePerforrnance FIGURE 2 Effects of the appllcation of technology on the dlstrlbutlon of outcomec of ctudents. (Top panel shows a decrease ln performance for ctudents at tfre bottom of the dlstributton and an Increase for students at tfie top. Mlddle panel chows llttle or no change for studentc at the bottom of the dlstrlbudon. Bottom panet chowe an overall lncrease for all students, but more for etudents at the top of the dlstrlbudon.)

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technology is e: