Miller's 2003 book The Mating Mind: How Sexual Choice Shaped the Evolution of Human Nature proposes that human mate choices, courtship behavior, behavior genetics, psychometrics, and life cycle patterns support the survival value of traits related to sexual selection, such as art, morality, language, and creativity. According to Miller, the adaptive design features of these traits suggest that they evolved through mutual mate-choice by both sexes to advertise intelligence, creativity, moral character, and heritablefitness. He also cites the Fisherian runaway, a model created by Ronald Fisher to explain phenomena such as the peacock'splumage as forming through a positive feedback loop through sexual selection, as well as the handicap principle. In an article entitled What should we be worried about? he talked about eugenics in China and how Deng Xiaoping instigated the one-child policy, "partly to curtail China's population explosion, but also to reduce dysgenic fertility". He argued that if China is successful, and given what he calls the lottery of Mendelian genetics it may increase the IQ of its population, perhaps by 5–15 IQ points per generation, concluding that within a couple of generations it "would be game over for Western global competitiveness" and hopes the West will join China in this experiment rather than citing "bioethical panic" in order to attack these policies.
Consumerism
In Miller's 2009 book Spent: Sex, Evolution and the Secrets of Consumerism he has used Darwinism to gain an understanding of consumerism and how marketing has exploited our inherited instincts to display social status for reproductive advantage. Miller argues that in the modern marketing-dominated culture, "coolness" at the conscious level, and the consumption choices it drives, is an aberration of the genetic legacy of two million years of living in small groups, where social status has been a critical force in reproduction. Miller's thesis is that marketing persuades people — particularly the young — that the most effective way to display that status is through consumption choices, rather than conveying such traits as intelligence and personality through more natural means of communication, such as simple conversation. Miller argues that marketing limits its own success by using simplistic models of human nature, lacking the insights of evolutionary psychology and behavioural ecology, with a belief "that premium products are bought to display wealth, status, and taste, and they miss the deeper mental traits that people are actually wired to display, traits such as kindness, intelligence, and creativity" which limits the success of marketing.
Abnormal psychology
Miller's clinical interests are the application of fitness indicator theory to understand the symptoms, demographics, and behavior genetics of schizophrenia and mood disorders. His other interests include the origins of human preferences, aesthetics, utility functions, human strategic behavior, game theory, experiment-based economics, the ovulatory effects on female mate preferences, and the intellectual legacies of Darwin, Friedrich Nietzsche, and Thorstein Veblen. In 2007, Miller published an article in Evolution and Human Behavior, concluding that lap dancers make more money during ovulation. For this paper, Miller won the 2008Ig Nobel Award in Economics.
Virtue signaling
Miller has written extensively about virtue signalling describing it to be an innate human act, used as a psychological and political tool. He applies the concept of virtue signaling to his own life living as a libertarian in a politically divided climate with a politically fertile upbringing, and criticizes the use of the term as it pertains to the expression of free speech.