Geraldine Wright, a professor of entomology at the University of Oxford, gives the example of hunger, which is a state of mind that helps you to alter your decision-making in a way that"s appropriate, such as prioritising food-seeking behaviours. Other emotions can be equally motivating – rumblings of anger can focus our efforts on rectifying injustices, and constantly chasing happiness and contentment nudges us towards achievements that keep us alive.