Keywords: Sociology , Affective interaction, SMS, gestures

ABSTRACT - We discuss a user-centered approach to incorporating affective expressions in interactive applications, and argue for a design that addresses both body and mind. In particular, we have studied the problem of finding a set of affective gestures. Based on previous work in movement analysis and emotion theory [Davies, Laban and Lawrence, Russell], and a study of an actor expressing emotional states in body movements, we have identified three underlying dimensions of movements and emotions: shape, effort and valence. From these dimensions we have created a new affective interaction model, which we name the affective gestural plane model. We applied this model to the design of gestural affective input to a mobile service for affective messages.

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1. Introduction

Affective computing, as discussed in the literature, is computing that relates to, arises from, or deliberately influences emotions.

To get the users involved in a more active manner we would, instead, like to propose the user-centered approach to affective computing. Our aim is to have users consciously expressing their emotions rather than having their emotions interpreted or influenced by the system, while still maintaining the mystery and open interpretation of emotional interaction and expression.

Our specific focus in this paper is to describe the process of finding affective gestures for interacting with a mobile service. Our idea is that gestures will address the body-part of emotions people.

An important part of telephone communication is its usage to maintain intimate and close relationships between people [Castelfranchi]. In mobile phones this is done both through phone conversations but also through text messaging (e g SMS1 and MMS2) [e g Grinter and Eldridge]. In the messaging interaction, the affective bandwidth is narrow, and most of the richness of the emotional content is lost.


2. Designing for affect.

Depending on the social setting we may also express our emotions differently.

?.and emotions cannot be seen solely as a mental state but also a physical, bodily, state [Ekman, Picard]. Emotions can be generated through someone?s imagination without physical interaction, but they can also be generated from body movements [Ekman]?.

In order to design for subjective affective experiences with a usercentered perspective that addresses both body and mind, we extracted four, interrelated design principles that we adjusted to the particular motives and needs of our design situation.

Designing for embodied affective interaction thus entails both looking for the physical artifact embodiment of abstract emotion concepts, as well as allowing for social practice and interpretation of meaning of the emotional expressions. The physical embodiment concurs nicely with the strong connection between body and emotion, as discussed above.

*** !!! An application is a designed artifact and can therefore not build solely upon (whatever is meant by) ?natural? emotional expressions. On the other hand, using mainly designed expressions bearing no relation whatsoever to the emotional experiences people have physically and cognitively in their everyday lives, would make it hard for the user to recognize and get affected by the expressions. Therefore we argue that emotional expressions should be aiming to be natural but designed expressions. !!! ***

The aim of the affective loop idea, is to couple the affective channels of users closely to those of interactive applications, so that the user?s emotions are influenced by those emotions expressed by or through the application, and vice versa. [?.] By having users express their emotions in interacting with the system, they can be engaged in an affective loop, where their emotions are either affected or increased in intensity, either by the modality by which the emotions are submitted or as a response to output.


3. A Model of affective gestures

*** !!! We asked the actor to express nine different emotional processes in body language, while we videotaped him. In a questionnaire distributed to 80 SMS-users in Sweden we found the emotions they mostly wanted to communicate in mobile messages: excitement, anger, surprise-afraid, sulkiness, surprise-interested, pride, satisfaction, sadness and being in love. !!! ***


SHAPE AND EFFORT:

Using Laban?s theories of shape the actor?s interpretation can be described as follow:

*) Excitement ? extremely spreading, rising and advancing movements.
*) Anger ? somewhat spreading, rising and advancing movements.
*) Surprise-afraid ? enclosing, somewhat descending and retiring movements.
*) Sulkiness ? enclosing, somewhat rising and retiring movements.
*) Surprise-interested ? somewhat spreading, neutral in the vertical plane and advancing movements.
*) Pride ? somewhat spreading, rising and somewhat advancing movements.
*) Satisfaction ? neutral in all planes of movements.
*) Sadness ? enclosing, descending and retiring movements.
*) Being in love ? somewhat spreading, somewhat rising and somewhat advancing movements.

Figure 4 presents the corresponding effort graphs using Laban?s notation. From looking at our analysis of emotional body language the nine emotions, presented in figure 4, can be divided into three groups with different effort levels, starting with the one with highest effort:

1) Excitement, anger, surprised-afraid
2) Sulkiness, surprised-interested, pride, satisfaction
3) Sadness, being in love

Effort comprises four motions factors: space, weight, time and flow. Each motion factor is a continuum between two extremes (Table 1).


Figure 5: RUSSEL'S CIRCUMPLEX MODEL OF AFFECT

*** !!! In the questionnaire (mentioned briefly above) the answers indicated that most users feel limited or alien to expressions such as smilies as a means to express emotions in text messages. Not only is the emotional content restricted but also the emotional interaction with the other party. In a phone conversation, the voice itself can be a bearer of emotional content that complements what is being said. Thus, both parties in the conversation receive too little emotional feedback and are provided with too little emotional expressive power when composing or receiving textmessages. The users in our questionnaire expressed a need for a richer medium. !!! ***