In a recent study, Quantified Communications analyzed speech samples from Fortune’s 50 greatest leaders of 2016, focusing on the type of appeals they used. What they found was that these top leaders used three times as many appeals to emotion and intuition as they did appeals to logic.
For the purpose of the analysis, appeals to logic include “studies, statistics, data, and proof.” Appeals to emotion include “stories, imagery, metaphors, and visual aids.” Appeals to intuition include “achievements, testimonials, citing sources, and case studies.” In the language of The Science of Speaking, these are essentially equivalent to head, heart, and expertise.
While the analysis doesn’t explicitly examine the effects that this trend toward emotion and expertise has on the audience (though other research suggests it will be positive), if you want to speak like the greatest leaders of today, it clearly tells you what you need to do.