human motivation Humans 162 Motivation 132 female 124 male 119 adult 114 Female 78 article 71 Male 70 Adult 62 Article 59 controlled study 58 psychology 51 young adult 51 human experiment 47 Young Adult 42 adolescent 42 major clinical study 42 Adolescent 40 physiology 35 middle aged 31 questionnaire 29 reward 29 Middle Aged 28 Reward 26 Goals 24 clinical article 23 decision making 22 aged 21