The Acquisition of Symbolic Skills || Mental Imagery and Mental Maps

MENTAL IMAGERY AND MENTAL MAPS

Annabel J. Cohen and Joan E. Foley

Scarborough College, University of TorontoCanada

We have been investigating the acquisition and use of themental representation of a large, complex, environment in a varietyof studies. The environment is Scarborough College, a selfcontained arts and science campus serving 4 to 5,000 users. Oftenreferred to as an example of a megastructure (Drexler, 1979), itencompasses distances spanning up to one-quarter mile. Themulti-level building comprises three irregular wings connected atthe level of the main pedestrian concourse. Figure 1 indicates thelocation of some places on this level which are familiar tostudents and among those used in the experiments, e.g., thebookstore, a cafeteria, and main central stairway.

The major task for our subjects is to estimate the straightthrough distances between pairs of locations specified by theexperimenter. After completing this task, the subject is asked torate on a 5-point scale the extent to which different kinds ofimagery were used while estimating distances, e.g., images ofwalking through the building, of the exterior appearance of thebuilding, or a map-like image, and in one case, of a threedimensional model.

Our focus is not on the image as such but rather on anyconsistencies in the reports of imagery and on any relationshipsbetween imagery and other aspects of performance.

Typically a subject reports using several types of imagery.Generally we have found that images of the external appearance ofthe building are reported least. For example, immediately aftertheir first tour of the building, subjects who take part in themagnitude estimation task report a mean rating of 4.1 for imageryof walking through the building, 3.2 for map-like image, .and 1.8for imagery of the external appearance of the building. However,the emphasis on different forms of imagery does depend on a numberof independent variables.

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D. Rogers et al. (eds.), The Acquisition of Symbolic Skills© Plenum Press, New York 1983

382 A. J. COHEN AND J. E. FOLEY

Figure 1: Layout of Scarborough College and locations used incertain studies. A - Main Stairway; B,C,F - Classrooms;D - Bookstore; E - Cafeteria; G - Gymnasium; H - PinballRoom; I - Student Information Desk; J - Student RadioStation. Scale is 1:1600 (D-G = approximately 1/4 mile)

Context Locations

In one experiment involving more experienced subjects, fourcentral locations were used in testing together with three otherswhich were:

(I) central but on higher or lower floors of the building

(II) on the same levels as the cornmon set but not quite ascentral

(III) on the same levels as the cornmon set but at the extremeouter ends of the three wings of the building.

Condition I evoked most frequent reports of three-dimensionalimagery while condition III evoked the most frequent reports ofimages of the exterior of the building (see Figure 2).

In this study subjects were also asked to indicate on a 5point scale their extent of use of visual and logical thought


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Appearance dimensional

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IMAGE TYPE

Figure 2: Mean report of imagery as a function of 10cationa1context. In Set I locations are differentiatedvertically and in Set III horizontally.

processes. While application of visual imagery was constant overall context conditions, condition I which emphasized the verticaldimension evoked the greatest report of logical thought. Estimateswere generally exaggerated in this condition, an observation alsonoted by Pick and Lockman (1981) for judgments of verticaldistances in a two-storey building. That subjects may have tocombine information from essentially independent mappings of eachlevel in making vertical distance judgments is consistent with theview of Chase and Chi (1980) and others who argue that representations of large-scale space may depend on organizations of smallerlocal representations.

Experience

The degree of experience which the subject has in theenvironment also influences the type of imagery used. In the studyjust described, subjects with several years of experience in thebuilding reported greater use of the more abstract map-like andthree-dimensional imagery than those with a few months ofexperience. Slopes of the functions relating log judged distanceto log actual distance reflected greater sensitivity of seniorsubjects (.94 vs••85). This suggests that the abstractrepresentation supports the spatial task more effectively.However, experience generally leads to greater sensitivity indistance estimation tasks (Foley & Cohen, 1982; Thorndyke &Hayes-Roth, 1980; Go11edge, Rivizzigno, & Spector, 1976).Therefore, these data do not rule out the possibility that senior


subjects could do just as well even if they chose to use morescenographic imagery (i.e., images of walking through the buildingor of its external appearance).

Structural Organization: Central Reference

Other data do more strongly suggest that abstract imagery issuperior to scenographic in a distance estimation task. For manyof the distances to be judged it was possible to specify whichend-point was closer to the center of the building. Half of thesubjects received distances directed away from the centre (i.e.,the more central location was named first) and the other halfreceived the distances directed toward the centre. As shown in theleft-hand panel of Figure 3, trials directed toward the centre wereassociated with slightly higher reports of scenographic imagery butwhen trials were directed away from the centre there was a declinein the report of scenographic imagery and an increase in map-likeimagery. For distances within the wings of the building directionwith respect to the centre of the building is quite clear. Forthis class of distances, distance sensitivity was much higher inthe away-from-centre condition, as shown in the right-hand panel.

The tendency for away-frorn-centre trials to elicit map-likeimages suggests that the abstract representation of thisenvironment is organized around the centre of the building and thatthis encoding is most readily accessed if the retrieval cues areconsistent with its organization.

Figure 3: Mean report of scenographic and abstract imagery as afunction of direction of trial distance (Left Panel).Mean sensitivity in judgment as a function of trialdirection (Right Panel).


Recency

385

A similar observation was made for male subjects who hadrecently had their first exposure to the building in the form of aguided tour. In this case, subjects were highly sensitive in theirdistance judgments for the most recently exposed part of thebuilding if the trials were directed away from the subject'spresent location. This condition also elicited high reports ofmap-like imagery. This suggests to us that a subject maintainsorientation in a new environment by constructing and continuallyupdating a "working map" with his current location serving as areference point. Retrieval cues for this representation are thosethat are directed opposite to that of travel. They prompt greaterreport of map-like imagery and higher sensitivity in response. Onthe other hand, trials in which locations are presented in the sameorder as that encountered in most recent travel prompt scenographicrepresentations and are associated with poorer distance judgments.The distinction between scenographic and map-like representationsis similar to the dichotomy of route and survey maps (e.g., Siegel& White, 1975). The directional component has not been enunciatedpreviously.

Normalization

Although we have reported a correlation between sensitivity todistance variation, the use of abstract imagery, and experience inthe environment, nevertheless, the mental representation does notnecessarily become increasingly veridical in all respects asexperience increases. We have found that judgments of the endsegments of the longest and the shortest wings were increasingly inerror; i.e., the longer wing is increasingly under-estimated bymore-experienced subjects, who also over-estimate the shorter one.A plausible interpretation is the in~sing role of principles oforganization, such as symmetry, as experience increases. Suchdistortions would not adversely affect wayfinding in thisparticular environment but they might reduce the cognitive load ofthe representation. Similarly, Hardwick, McIntyre and Pick (1976)noted errors in the direction of symmetry in a sighting task andoffered the same account. On the other hand, architects resistedthis type of distortion in drawing a map of a familiar environment(Chase & Chi, 1980). It is not known whether their success relatesto better cognitive maps or awareness of a tendency to makenormalization errors. Thorndyke & Stasz (1980) noted that superiorspatial knowledge acquisition could in part be attributed toreliable self-evaluation and appropriate focus of attention onunlearned as opposed to already learned information.


Figure 4: Mean report of scenographic and abstract imagery (lowerpanels) and sensitivity (upper panels) as a function ofavailability of a map and level of exposure to theenvironment.

Availability of a Map

We have compared the performance of subjects who are workingfrom their memory of the building (NO MAP) with that of groups whoare viewing a map while making the distance judgments (MAP) or havestudied a map which is then removed prior to the estimation task(PREVIEW). Subjects who have no knowledge of the campus have alsoparticipated in the MAP and PREVIEW conditions.

Examination of the mean total report of all kinds of imageryin all conditions reveals that senior subjects report more imagerythan freshmen in the NO MAP condition but less in the MAP andPREVIEW conditions. The lower panel of Figure 4 shows that this isdue to higher reports by freshmen of scenographic imagery in boththe l~P and PREVIEW conditions, although they were instructed toestimate the distance on the map, either perceived or remembered:i.e. seniors more successfully suppress inappropriate scenographicimages.

Nevertheless, in the PREVIEW condition, the most experiencedsubjects fare worst in their distance judgments as seen in the toppanel. We suspect that this difficulty may arise from some aspectof the relationshi~ between the map presented by the experimenterand the well-organized cognitive map which these subjects have

MENTAL IMAGERY AND MENTAL MAPS 387

developed. The availability of the cognitive map might interferewith the encoding of the map during the study period or elseprovide a source of confusion during the test phase if the abstractrepresentation is less successfully suppressed than thescenographic ones. We note that the confidence which experiencedsubjects express in their distance judgments is also lowest in thePREVIEW condition.

Conclusion

The reported mental imagery used for solving problems ofdistance estimation has been shown to depend on many variables,e.g. the experience of the subject with the environment inquestion, the structure accentuated by the set of loci in thestudy, the direction of the distance with respect to both thestructure of the environment and the direction of travel, and theavailability of a map. Performance level is related to the type ofimagery reported. We have distinguished two classes of imagery,literal scenographic and more abstract map-like. They are notmeant to represent an exhaustive list.

We choose the term "working map" for the representation whichthe subject generates in order to solve a spatial problem. Kolersand Smythe (1979) liken imagery to symbols on a mental sketch-pad,an aide-memoire for solving problems and carrying out skilledbehaviour. A similar metaphor, scratch-pad, has been employed byBaddeley and Lieberman (1980) in the framework of a working memorysystem. The term "working map" accommodates both the specificproperties of different types of imagery suggested by the notion ofKolers and Smythe (1979) and moment to moment dynamics emphasizedby Baddeley & Lieberman (1980).

Our results suggest that the abstract working map facilitatesdistance estimation more than does the scenographic representation.The advantage could arise from better memory associated withabstract as opposed to detailed representations similar to thatdemonstrated by Ritchey (1982) for pictorial information. Otheraccounts are possible. First, the task of distance estimationcontains a number of sub-tasks, e.g. to represent a standardreference distance, to locate a test pair of items, compute theirdistance, and bring this result into relation with the standarddistance. Literal representations of sub-tasks may mutuallyinterfere more than corresponding abstract representations ofsub-tasks. Confusion may arise with scenographic imagery becauseof the need to "look through" opaque objects such as walls or toreconstruct a route travelled as the best approximation to thestraight-through distance; there is some doubt as to whether theroute can be constructed from memory in its entirety (Garling,Book, & Ergezen, 1981). A somewhat related source of difficulty


with scenographic imagery is information separate from that havingto do with location, e.g. that the stairway is crowded, possiblydetracting from the task at hand. Finally, independent entities inthe scene may not as easily admit to holistic processing as symbolsin more abstract representations (Thompson & Klatsky, 1978;Presson, 1982).

While the abstract working map better serves the task ofestimation of distance than the scenographic representation,nevertheless, the evidence of greater selectivity by seniorsubjects is consistent with the notion that skilled navigators inthe real-world integrate information of both types. As Nickerson(1978) argued with respect to information processing tasks,practice leads to flexibility. Experienced navigators can moreintelligently select useful vantage points as informed by theirmap-like representations. Integration does not necessitate directlinkage in simple hierarchical fashion as implied by Hardwick etale (1976), Stevens & Coupe (1978), and others. Kinsbourne andHicks (1979), and Neisser (1982) have commented on the facilitationby dissimilarity for concurrent mental processing.

The present study emphasizes the potential variety ofrepresentations underlying a given cognitive skill. The mostreadily generated representation may not be the most effective.

REFERENCES

Baddeley, A. D. and Lieberman, K., 1980, Spatial working memory,in: "Attention and Performance VIII", R.S. Nickerson, ed.,Erlbaum, Hillsdale, N.J.

Chase, W.G., and Chi, M.T., 1980, Cognitive skill: Implicationsfor spatial skill in large-scale environments, in:"Cognition, Social Behaviour, and the Environment", J.Harvey, ed., Erlbaum, Potomac, Maryland.

Drexler, A., 1979, "Transformations in Modern Architecture", Museumof Modern Art, New York.

Foley, J., and Cohen, A.J., 1982, Mental mapping of a megastructure, unpublished manuscript, Scarborough College,University of Toronto, west Hill, Ontario.

Garling, T., BOok, A., and Ergezen, N., 1981, Memory for thespatial layout of the everyday physical environment. I.Accuracy and precision, Scandinavian Journal of PsychologY,22.

MENTAL IMAGERY AND MENTAL MAPS 389

Golledge, R.G., Rivizzigno, V.L. and Spector, A., 1976, Learningabout a city: Analysis by multidimensional scaling, in:"Spatial Choice and Spatial Behaviour",.R.G. Golledge and G.Rushton, eds., Ohio State University Press, Columbus.

Hardwick, D.A., McIntyre, C.W. and Pick, H.L., 1976, The contentand manipulation of cognitive maps in children and adults,Monographs of the Society for Research in Child Development,41: Serial No. 166.

Kinsbourne, M., and Hicks, R.E., 1978, Functional cerebral space:A model for overflow, transfer, and interference effects inhuman performance, in: "Attention and Performance VII", J.Requin, ed., Erlbaum, Hillsdale, N.J.

Kolers, P., and Smythe, W.E., 1979, Images, symbols and skills,Canadian Journal of Psychology, 33:158.

Neisser, U., 1982, Skills, affordances and divided attention.Invited address presented to the 43rd Annual Convention ofthe Canadian Psychological Association, Montreal, Que.

Nickerson, R.S., 1978, Comment on W.R. Garner's "Selectiveattention to attributes and to stimuli", Journal ofExperimental Psychology: General, 107:452.

Pick, H.L. and Lockman, J.J., 1981, From frames of reference tospatial representations, in: "Spatial Representation andBehaviour Across the Life Span", L. Liben, A.H. Patterson,and N. Newcombe, eds., Academic, Toronto.

Pressen, C.C., 1982, Strategies in spatial reasoning, Journal ofExperimental Psychology: Learning, Memory and Cognition,8:243.

Ritchey, G., 1982, Pictorial detail and recall in adults andchildren, Journal of Experimental Psychology: Learning,Memory and Cognition, 8:139.

Siegal, A.W., and White, S.H., 1975, The development of spatialrepresentations of large-scale environments, in: "Advancesin Child Development and Behaviour (10)", H. W-.-Reese, ed.,Academic, New York.

Stevens, A., and Coupe, P., 1978, Distortions in judged spatialrelations, Cognitive Psychology, 10:422.


Thompson, A.L., and Klatsky, R.L., 1978, Studies in visualsynthesis: Integration of Fragments into forms, Journal ofExperimental Psychology: Human Perception and Performance,4:244.

Thorndyke, P.W., and Hayes-Roth, B., 1980, Differences in knowledgeacquired from maps and navigation, The RAND Corporation,Santa Monica, Calif.

Thorndyke, P.W., and Stasz, C., 1980, Individual differences inprocedures for knowledge acquisition from maps. CognitivePsychology, 12:137.

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The Acquisition of Symbolic Skills || Mental Imagery and Mental Maps