One of the delights of working with human intelligence is how applicable it is to everyday life. As we will see in this chapter, ability tests show surprisingly large correlations with real-life behaviours (such as job performance, or even whoever we select as a partner). Some of these relationships are fairly unsurprising. For example it probably comes as no great shock to learn that scores on ability tests correlate quite substantially with academic achievement and work performance. But there are some areas where the relationships are far less obvious. For example, who would have predicted that intelligence (measured in middle childhood) could predict how long people would live?