The most notable research into the topic came from psychologist Paul Ekman, who pioneered research into emotion recognition in the s. His team of researchers provided their test subjects with photos of faces showing different emotional expressions. The test subjects then had to define the emotional states they saw in each photo, based on a predetermined list of possible emotions they had seen prior. Through these studies, Ekman found a high agreement across members of Western and Eastern cultures when it came to selecting emotional labels that corresponded with facial expressions. Expressions he found to be universal included those indicating happiness, disgust, anger, sadness , surprise and fear. Working with his long-time friend Wallace V.