Researcher Michael Slepian at Tufts University said: "What you are experiencing every day can influence your thoughts, like if you are sitting on a hard chair or a soft chair." In their study, Slepian and his colleagues had subjects clench either a hard ball or a squishy ball in their hands while looking at pictures of faces that had been altered to appear gender-neutral. They then were asked to categorize the faces as either male or female. When touching the hard ball, volunteers were about 10 percent more likely to categorize a face as male; for those clutching the soft ball, the results were slanted toward females.