Emotion in a century: A review of emotion recognition

Emotion plays an important role in our daily lives. Ever since the 19th century, experimental psychologists have attempted to understand and explain human emotion. Despite an extensive amount of research conducted by psychologists, anthropologists, and sociologists over the past 150 years, researchers still cannot agree on the definition of emotion itself and have continued to try and devise ways to measure emotional states. In this paper, we provide an overview of the most prominent theories in emotional psychology (dating from the late 19th century to the present day), as well as a summary of a number of studies which attempt to measure certain aspects of emotion. This paper is organized chronologically; first with an analysis of various uni-modal studies, followed by a review of multi-modal research. Our findings suggest that there is insufficient evidence to neither prove nor disprove the existence of coherent emotional expression, both within subjects and between subjects. Furthermore, the results seem to be heavily influenced by both experimental conditions as well as by the theoretical assumptions that underpin them.