UX evaluation methods — 2DES
Two-dimensional emotion space
Abstract
Based on a previous computational music-emotion rule engine measurement of the emotion expressed by a stimulus.
The Affect Grid (Russell et al., 1989) is a two-dimensional labeled visual scale to assess effect along the principal dimensions valence and arousal, based on Russell (1980)’s circumplex model of effect.
Currently, you can find out 2DES (two-dimensional emotion space) as a computer program used to collect continuous ratings provided by study participants.
How does it work?
Participants use the Emoji Grid (five emoji on each side of the grid) to report their emotion by moving the mouse in a space defined by the two bipolar dimensions valence and arousal.
Both dimensions are labeled by little pictograms representing a human face (smiling or frowning for valence, with eyes and mouth wide open or closed for arousal).
A central neutral expression serves as a baseline or anchor point. The facial expressions vary from disliking (unpleasant) via neutral to liking (pleasant) along with the horizontal (valence) axis, and gradually increase in intensity along with the vertical (arousal) axis
Usually, each quadrant has a meaning as below described:
- Q1 Happy (high valence and arousal)
- Q2 Angry (low valence and High arousal)
- Q3 Depressed (low valence and arousal)
- Q4 Dreamy (high valence and low arousal)
The facial expressions are defined by the eyebrows, eyes, and mouth configuration of the face.
The arousal dimension is represented by the opening of the mouth and the shape of the eyes, while the valence dimension is represented by the concavity of the mouth, the orientation, and curvature of the eyebrows, and the vertical position of these features in the face area (representing a slightly downward-looking face for lower arousal values and a slightly upward looking face for higher valence values).
These facial features represent a minimal set needed to express the range of emotions over the Affect Grid.
To avoid potential biases in ratings due to the emotional connotation of colors usually is a good practice to adopt a monochromatic (yellow) color scheme in the design of the Emoji Grid. Users place a checkmark at the location in the grid that corresponds to the emoji (facial expression) that best represents their affective state (feelings) after perceiving a certain product or service.
Areas of impact
- 2DES is particularly useful to study affective evaluation of food and product sounds
- Used in children and younger populations could be effective enough because of the easy adaptation to emojis.
- The 2DES may also be a useful tool for evaluating other affective stimuli such as photographs, paintings, music, smells, tactile signals, etc.
- In consumer research, the 2DES can also be used to assess the emotional response to for instance oral care products, fragrances, fabrics, affective ambiances or servicescapes, etc.
Weaknesses detected
- A high-fidelity prototype must be available
References
Russell, J. A. (1980). A circumplex model of affect. J. Pers. Soc. Psychol. 39, 1161–1178. doi: 10.1037/h0077714
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Russell, J. A., Weiss, A., and Mendelson, G. A. (1989). Affect grid: a single-item scale of pleasure and arousal. J. Pers. Soc. Psychol. 57, 493–502. doi: 10.1037/0022–3514.57.3.493
