To address this problem, we probe an alternative modality: expressive light. Thus, it is important to investigate new methods that can improve a user's interaction experience while being simple and adequate to apply. It can be complex or even impractical to apply human-like design methods to such PCs. Unfortunately, these methods are not applicable to many currently-in-use devices such as personal computers as most PCs at present use a keyboard, a mouse, and/or a touchpad as input modalities and a display (monitor) and/or a speaker as output modalities. For this reason, various studies tried to reach a more natural interaction design by using anthropomorphism methods such as adding human-like eyes and body parts to a device ( Osawa and Imai, 2013) or providing human-like body movements ( Hoffman et al., 2015). (2008) well-demonstrated the intrinsic mechanism of humans to anthropomorphize objects. Moreover, Tremoulet and Feldman (2000) and Fussell et al. According to Reeves and Nass (1996), people interact with new media in much the same way as they interact with other people. Among them, anthropomorphism has been considered as one key factor for interaction design as it can influence a user's perception of a device substantially. Such an objective has become an important research topic in human-computer interaction (HCI) and human-machine interaction (HMI) in general. In all cases, it is important for such devices to guarantee their users a pleasant and natural interaction experience. They are used in various applications such as education, entertainment, and information services. The findings can open up possibilities for the design of ambient light systems for various applications where human-machine interaction is needed.Įlectronic devices such as computers are widely used in our daily lives, either personally or publicly. They consequently behaved with more tolerance and cooperation to the computer when it was positive compared with when it was negative. Particularly, they perceived the computer as positive and friendlier when it displayed green and low intensity light animation, while red and high intensity light animation was perceived as negative and more hostile. Participants liked and anthropomorphized the computer more when it displayed light animations.

Our evaluation of the results suggested that expressive lights do affect human perception and decision-making. To explore this, we performed three experiments using a ping-pong game, Ultimatum game, and Give-Some game, in which we attached an LED strip to the front-bottom of a computer monitor and had it display a set of light expressions. It is still unclear whether and how the lights can influence people's perception and decision-making.

However, they mainly focused on using ambient lights to convey certain information. Previous studies explored the design of ambient light displays and suggested that such systems can convey information to people in the periphery of their attention without distracting them from their primary work. In other words, computers are often required to not only inform users of information but also communicate with them socially.

They are used in various applications, such as for education, entertainment, and information services. Today's computers are becoming ever more versatile.

2Digital Content and Media Sciences Research Division, National Institute of Informatics, Tokyo, Japan.

1Department of Informatics, The Graduate University for Advanced Studies (SOKENDAI), Tokyo, Japan.

Lighting ambiance