This work belongs to a series of paintings sparked by the 1952 unsolved murder of Betty Shanks, a university friend of the artist’s wife. One of the first and largest works in this series, The exchange explores the emotional and psychological tensions of innocence and danger, combining a playful scene of bright colours and bold outlines with an underlying sense of aggression and voyeurism. The seeming innocence of the schoolgirls’ embrace is tainted by their sharply pleated skirts and short, pointed ties, as well as the shadows cast over their furtive sideways glances.