It is often said that dogs and their owners come to resemble each other. In terms of how their personalities evolve, research suggests they may indeed follow similar paths.

A study has revealed how dog personalities change over time, with traits appearing to follow distinct trajectories. Similar patterns have previously been observed in people.

A dog’s interest in solving problems, for instance, appears to rise until they reach middle age — about six years old for a border collie, the breed that was studied. It then hits a plateau.

Their curiosity about novel objects and situations peaks at the age of three then starts to decline. How sociable they are — measured by their reaction to a friendly stranger — remains constant throughout their lives.