In her book, Henley discusses how many non-verbal behaviours used in our everyday lives express power, with power defined as the ability to get what you want by controlling the resources around you. Women, she found, are often sensitive to this exhibition of power, and often respond with submissive behaviours. For example, men may frown or use a strong stare when interacting with women, and women may react by smiling or lowering their gaze. These gestures, like many others discussed in the book, are subtle and under the radar, and we are therefore unaware of the impact they have on us. Henley points out that what some characterize as sex differences in non-verbal behaviour are actually more accurately characterized as power differences.