Is happy better than sad even if they are both non-adaptive? Effects of emotional expressions of talking-head interface agents

Hedonic preference and contextual appropriateness are two general principles governing humans’ emotional expressions. People in general prefer perceiving and expressing positive emotions to negative ones, but also modulate their emotional expressions to be appropriate to social contexts. Although computer-based characters such as interface agents are able to express basic human emotions, they cannot yet automatically and effectively adapt their emotional expressions to the changing context. Would hedonic preference hold up without contextual appropriateness? A 2×2 mixed-design experiment (happy vs. sad expression by happy vs. sad context) (N=24)(N=24) was conducted with a talking-head agent presenting happy and sad novels to users. Supporting the hedonic preference principle, results showed that although both happy and sad agents were non-adaptive to the varying emotional tone of the context, the happy agent elicited greater intent to consume the books, more positive evaluation of the book reviews, more positive attitudes towards the agent and the interface, and more positive user experience than the sad agent.