Spatial memory encodes information about location, orientation, distance and direction. Every time we remember where we left our keys, find our way by locating a prominent building, successfully return home from the grocery store, and remember where our car is parked after coming out a different door, we are using spatial memory.
Functions and Characteristics of Spatial Memory
Spatial memory refers to memories for locations of events and the events occurring at these locations. It consists in the formation of environment-specific place maps. The information orients a subject in space and thus is critical for the contextualization of memories and actions that rely on it (Mose and Moser, 2008; Hasselmo, 2009).
Spatial memory has numerous functions critical in our everyday life.
- It enables us to remember places and to remember how to find our way around.
- With spatial memory, we can recognize places as familiar and recall routes from one location to another.
- We can devise novel routes or short cuts for reaching a goal.
Spatial memory is also used for locating objects, and for remembering Opens in new window how to find things, which may range from landmarks along routes such as a service station on the motorway, to objects lying around the house such as a pair of spectacles.
Memory Opens in new window for scenes and for the layout of objects within scenes mediates our interaction with the immediate environment.
All these functions involve knowledge of the spatial layout of the environment.
- Spatial representations Opens in new window in memory allow us to mentally revisit known places;
- to work out and evaluate routes without actually travelling;
- to search for objects and scan possible locations mentally without actually going and looking.
Spatial memory also has the characteristic that, although it may be partitioned into small local segments, these segments are linked together into larger configurations. Space is not inherently hierarchical, but Neisser (1988) suggested that we tend to represent it mentally as nested hierarchical structures with local representations nested inside global ones.
This structure enables us to locate, for example, a particular restaurant in a particular street, but also within a district, city, and country. Cognitive space is relational. Every element is related to every other.
Spatial Memory for Routes: Navigating in the Environment
In everyday life people have to find their way about within buildings, within cities, or across country. They may be pedestrians or they may be using various forms of transport. They may be equipped with maps, or instructions, or be relying on memories of previous experience.
The most important variables in navigation tasks are
- complexity, and
In finding your way around your own home, or following a daily route to shops in the next street, the environment is familiar, small-scale, and relatively simple. These are very different problems from finding your way when driving through a strange city or walking through mountainous country, where the environment is large-scale, unfamiliar, and complex.
In a simple, small-scale, familiar environment, navigation is a matter of following routes that are remembered as a set of paths, with specific directions and specific distances, linking known landmarks. It is unlikely that you will get lost.
Problems only arise if you emerge from a building or a shopping center by an unfamiliar exit and have difficulty reorienting yourself with respect to the known routes.
Or, if you have learned a route in one direction only, it will be unfamiliar if you need to traverse it in the reverse direction. In this case, landmarks must be recognized from different viewpoints and changes of direction transposed.
In a less familiar, larger-scale urban environment, navigation becomes more complex. It may involve finding short cuts or new routes.
In this case, the kind of spatial ability required includes orientation and making spatial inferences.
To work out a quick way to the station, or to orient yourself after your known route is blocked by a newly imposed one-way restriction, you have to be able to orient yourself in respect to your destination: To remember the spatial relationships that hold between alternative routes and to infer.
For example, that if the station is at two o’clock from your present position, a sequence of turns, such as right-left-right, will bring you approximately to its location.
In this situation, you can get lost if your spatial inferences are based on inaccurate estimates of distances and directions.
Following directions in an unfamiliar environment presents different problems. You may be given route instructions such as “Go past the post office, take the first right and then turn left at the town centre”.
To map this description on to the scene in front of you requires that you be recognize the landmarks that are described. You have to match the buildings you encounter against your mental representation of a post office.
You can get into difficulties deciding whether a particular configuration of roads and buildings answers the description “town centre”, or whether a narrow entry should be counted as a turning or not. Navigating in a strange environment may involve following a map instead of following route instructions.
To match the actual environment to the mapped representation you have to abstract and simplify in order to extract the essential skeleton of the road layout from the cluttered scene in front of you.
Of course, if the map you are following is in memory, you may get lost because your memory is inaccurate. If the map is available in front of you, you may still make navigation errors if you cannot match it to the area you are traveling through, as, for example, when the map omits minor roads.
Observations of naturally occurring navigation behavior are too haphazard to yield much insight into the mental representations and mental processes that underlie memory for places.
To gain greater understanding, psychologists have used a variety of methods including experiments that range from naturalistic, ecologically valid situations to more artificial tasks and self-assessment questionnaires.
Individual Differences in Memory for Routes
Most people would agree intuitively that individuals vary very considerably in navigational ability. Some have a poor sense of direction. Put them in a maze or an unfamiliar town and they have little idea which direction they have come from, or which direction they should be heading for.
Some are notoriously poor map readers and car drivers are tempted to risk trying to study the A–Z while driving, rather than rely on their guidance. Other people have a good sense of direction and a good track record as successful navigators.
One study that attempted to analyze these differences was carried out by Kozlowski and Bryant (1977). They examined the relationship between self-assessed “sense of direction” and a variety of performance measures. They asked students to rate their own sense of direction on a 7-point scale ranging from very poor to very good.
The performance measures included:
- pointing to the location of buildings on the campus when these buildings could not be seen from the room where testing took place;
- estimating distances;
- pointing to the location of nearby cities; and
- filling in the location of six buildings on an incomplete map of the campus.
Self-assessed sense of direction correlated significantly (r = 0.49) with the accuracy of pointing to campus buildings, and with the accuracy of pointing to cities.
Kozlowski and Bryant considered the possibility that the subjects with a good sense of direction might be performing better because they were more familiar with the campus environment, rather than because they had superior spatial ability.
To test this, they walked subjects through a maze of underground service tunnels beneath the campus from a start point to an end point and back again.
Subjects were divided on the basis of their self-assessed sense of direction into good and poor groups. On return to the start, they had to point to the location of the end-point.
In this unfamiliar environment, there was no difference between good and poor groups on the first trial, but on later trials those with a good sense of direction improved more than the poor group.
Kozlowski and Bryant concluded that this kind of directional orientation is not automatic but requires effort, attention, and repeated exposures. Those with a “good sense of direction” are those who are able to benefit from experience and acquire an accurate cognitive map.
Besides performing better on these tasks, those with a good sense of direction also rated themselves as better at giving and following directions; at remembering routes experienced as a passenger in a car; at remembering written directions and as liking to read maps and to find new routes to places.
It is not clear, however, whether a sense of direction can be regarded as a unitary ability that mediates performance in a variety of spatial tasks, or a constellation of different abilities (such as visuospatial memory, ability to estimate angular relations and distances, ability to visualize, and spatial reasoning) that reinforce each other.