How Do We Find Our Way?

A large amount of modern navigation, including the Global Positioning System (GPS), relies heavily on positions determined electronically by receivers gathering information from satellites. However, we tend to be lost if the satellite service’s digital maps become even slightly outmoded. Then much reliance will be laid on the ancient human expertise of navigating in three-dimensional space. Fortunately, our biological detector has a significant advantage over GPS: we can ask the pedestrians on the pavement for assistance, or follow a street which seems familiar, or observe the navigational rubrics. The human positioning system is flexible and capable of learning. Anyone who knows the way from point A to point B – and from A to C – can possibly figure out how to leave B for C as well.

Yet how does this complex cognitive system actually function? Scientists are looking into several approaches people conduct to orient themselves in their life: guidance, path inte-gration and route following. All three or combinations may be used by us thereof, and as experts learn more about these navigational skills, the case that our abilities may underlie our powers of logical thinking and memory is being made. For instance, you may visit New York City for the first time, and you get off the train at Grand Central Terminal in Midtown Manhattan. You have a few hours to look around several notable spots recommended: Rockefeller Centre, Central Park and the Metropolitan Museum of Art. You meander in and out of shops along the way. It suddenly is the time to return to the station. But how?

If you approach a passer-by for help, it is most likely for you to get access to information in many various forms. A person orienting himself or herself by a compelling landmark would gesture southward: ‘Look down there. See the tall, broad MetLife Building? Head for that – the station is right below it.’ Neurologists call this navigational means ‘guidance’, meaning that a landmark visible from a distance serves as the marker for one’s destination.

Another dweller might say: ‘Do you remember the places you have gone through? … Okay. Go toward the end of Central Park, and then walk down to St. Patrick’s Cathedral. A few more blocks, and Grand Central will be off to your left.’ Under this circumstance, you are pointed toward the most recent place you can recall, and you aim for it. Once there you head for the next popular spot and so forth, retracing your path. Your brain is putting together the individual leg of your trek into a cumulative progress report. This strategy is known as the ‘path integration’. Many animals employ primarily path integration to get around, including insects, spiders, crabs and rodents. The desert ants of the genus Cataglyphis perform this method to get back from foraging as far as 100 yards away. They note the general direction they came from and retrace their steps, using the polarisation of sunlight to direct themselves even under overcast skies. On their way back they are faithful to this inner homing vector. Even when a scientist picks up an ant and puts it at a totally different site, the insect stubbornly proceeds in the originally determined direction until it has gone ‘back’ all of the distance it wandered from its nest. Only then does the ant realise it has not fulfilled, and it starts to walk in successively larger loops to find the way home.

While trying to return to the anthill or the railway station, any animal adopting path inte-gration has to keep track of its own movements so that it knows, while returning, which segments it has already completed. As you move, your brain collects data from your envi-ronment – sight, sounds, smells, lighting, muscle contractions, a sense of time passing – to confirm which way your body has gone. The church spire, the sizzling sausages on that vendor’s grill, the open courtyard and the train station – all represent the snapshots of memorable junctures during your journey.

Apart from guidance and path integration, a third strategy for finding our way may be suggested. An officer you turn to for a hand on a Manhattan street might say: ‘Walk straight down Fifth, turn left on 47th, turn right at the park, go through the walkway under the Helmsley Building, then go across the street to the MetLife Building into Grand Central.’ This method, called ‘route following’, takes advantage of landmarks such as buildings and street names, plus directions – straight, turn, go through – for reaching the ultimate points. Route following is more accurate than guidance or path integration. However, if the details cannot be memorised and you take a wrong bending, the only recovering channel is to backtrack till you reach a familiar spot, since you have no idea of the general orientation or a reference landmark for your goal. The brain is truly challenged by the route-following navigation strategy: all the landmarks and related directions must be learned in our mind. It is the most precise and hence most dependable method, but it can be undone by routine memory lapses. With path integration, our cognitive memory is less burdened; it has to deal with only a few simple instructions and the homing vector. Path integration becomes effective because it relies most fundamentally on our knowledge of our body’s general orientation of movement, and we always have access to these inputs. Nevertheless, people often opt to give route-following guidance, in part because saying ‘Go straight that way!’ just does not work in our complex, man-made surroundings.

During your second trip to Manhattan, your memory will assist you in walking around. It is a good chance for you to use guidance, path integration and route following in diverse com-binations. But how exactly do these constructs deliver concrete directions? Do we humans have, as an image of the real world, a sort of road map in our heads? Neurobiologists and cognitive psychologists do call the portion of our memory that regulates navigation a ‘cognitive map’. The metaphor as a map seems apparently seductive: map is the most practical tool to display geographic information for convenient visual inspection. Yet the notion of a literal map in our heads may be misleading; more and more extensive research implies that the cognitive map is mostly a metaphor. It may be more like a hierarchical structure of relationships.

Questions 14 – 18

Look at the following statements (Questions 14–18) and the list of navigation methods below.

Match each statement with the correct navigation method, A, B or C.

Write the correct letter, A, B or C, in boxes 14–18 on your answer sheet.

NB You may use any letter more than once.

List of Navigation Methods 

A guidance

B path integration

C route following

• 14.Divide your route into some smaller sections.
• 15.Pay attention to a range of places and references directing you to your destination.
• 16.Find an iconic building that can be noticed from far away.
• 17.Retrace your steps when mistakes are made.
• 18.Regard a spot that you have passed by as a signpost.

Questions 19 – 21

Choose the correct letter, A, B, C or D.

Write the correct letter in boxes 19–21 on your answer sheet.

• 19.How does a Cataglyphis ant react when placed in a new location?
• 20.According to the writer, the route following method
• 21.Which of the following is true of the ‘cognitive map’ in the passage?

Questions 22 – 26

Do the following statements agree with the information given in Reading Passage 2?

In boxes 22–26 on your answer sheet, write

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this

• 22.Biological navigation is characterised by flexibility.
• 23.There are many ways for insects to navigate that are in common with other animals.
• 24.When someone follows a route, he or she collects comprehensive perceptual information in mind on the way.
• 25.Path integration has a higher requirement of memory compared with route following.
• 26.The route following method is inapplicable to the complicated situation in real life.

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