Practice Test 27: Farming in the Shadow of Volcanoes and the Problem of Too Much Choice

A Volcanoes are usually seen as destroyers, yet many of the most densely farmed regions of the world lie in their shadow. The reason is the soil. Volcanic ash and rock break down into soils rich in minerals that plants need, and in warm, wet climates this happens relatively quickly. Farmers have cultivated the slopes of active volcanoes for thousands of years.

B Not all volcanic soils are equally fertile. Young ash can be loose and dry, and soils formed from certain types of rock lack important nutrients. Fertility also depends on rainfall and temperature, which control how fast rock weathers and how quickly nutrients are washed away. In some places, centuries of eruptions have built up deep layers of fertile soil; in others, a single eruption buried farmland under thick, sterile deposits.

C Living near a volcano therefore involves a trade off between a valuable resource and a serious hazard. Many farmers know the risks but stay because their livelihoods depend on the land, and because eruptions may be decades apart. Monitoring has improved greatly: instruments now measure small earthquakes, ground swelling and gas emissions that can give warning of an eruption.

D Warnings help only if people can act on them. Evacuation plans, clear communication and support for families who must leave their farms are as important as scientific instruments. Some authorities also limit building in the most dangerous zones, though such rules are difficult to enforce where land is scarce and families have lived for generations.

A It seems obvious that more choice is better. If a shop offers twenty kinds of jam rather than five, every shopper should be able to find one they like. Yet psychologists have long been interested in cases where a large choice appears to discourage people from choosing at all.

B A well known study set up a tasting stall in a supermarket that sometimes offered a large selection of jams and sometimes a small one. More shoppers stopped at the large display, but a higher proportion of those who saw the small display went on to buy. The researchers suggested that too many options can make a decision feel difficult, so people postpone it.

C Later research has shown that the picture is more complicated. Some attempts to repeat the effect found it, while others did not, and reviews of many studies suggest that the effect depends on circumstances. Large choices seem most likely to discourage people when the options are hard to compare, when people do not know what they want, and when they are under time pressure.

D This has practical lessons. Organisations that offer many options can help by grouping them, providing a sensible default or describing each option clearly. Rather than simply reducing choice, the aim is to make choosing easier, so that people benefit from variety without being overwhelmed by it.