Affective Sleeve

(MIT) Affective Computing 2017

CONTRIBUTORS: ATHINA PAPADOPOULOU & JACLYN BERRY

PUBLICATION
Affective Sleeve: Wearable Materials with Haptic Action for Promoting Calmness in the proceedings of HCII 2019

The Project

What if our clothing could respond to our emotional needs and positively impact our health? This project explored the effect of programmable materials as emotion regulation systems. We created a prototype Affective Sleeve that applied rhythmic haptic action (pressure and warmth) along the wearer’s forearm. We designed a controlled study to test how different paces of haptic action from the Affective Sleeve could affect the wearer’s level of stress.

How We Made It

The Affective Sleeve prototype consists of six autonomous cuffs of adjustable circumference to cover an adult’s forearm. The rhythmic haptic action in each cuff was created by sandwiching 0.5mm Nitinol wire (a shape memory alloy) between two layers of felt.

The wires took on an arc shape when sewn into the fabric and were “programmed” to return to flat when heated to temperatures above 45C. We passed electrical current through the wires to transform the geometry of each cuff, thus creating pressure and warmth on the wearer’s arm. When the current was disconnected, the wires cooled and the stiffness of the fabric forced them back into the original arc shape.

sleeve_haptic.png

For our study, we programmed each cuff to activate in sequence from the palm towards the elbow. The time of activation for each cuff was determined by the wearer’s baseline breathing rate. We hypothesized that the pace of haptic action would modulate the wearer’s breathing rate and electrodermal activity (EDA), two psychophysiological symptoms of stress.

User Studies

We recruited 18 participants for the study. Participants wore the Affective Sleeve on their non-dominant arm, a sensor on their dominant wrist to measure EDA, and a chest sensor to measure breathing rate.

sleeve_sensors.png

The experiment consisted of four phases:

  1. Establish baseline measurements for EDA and breathing rate (Relaxed state)
    Participants watched a nature documentary for 15 minutes while wearing the E4 and BioPatch sensors.

  2. Habituation Task
    Participants put on the sleeve and completed a practice quiz to get used to wearing the prototype.

  3. Performance Task (Stressed state)
    We activated the haptic action in the Affective Sleeve and induced stress on participants by having them complete an impossibly long spatial reasoning test in 15 minutes.

  4. Qualitative Surveys
    Participants completed multiple choice questionnaires about their experience wearing the Affective Sleeve.

The participants were randomized into three test groups:

  • Control Group — inactive sleeve, but we told participants it was active

  • Fast Group — haptic action 25% faster than baseline breathing rate

  • Slow Group — haptic action equal to baseline breathing rate

Based on our hypothesis, we expected the Slow Group would exhibit lower EDA and lower breathing rate than those in the Control and Fast Groups. Conversely, we expected higher EDA and breathing rate for those in the Fast Group than the other groups.

FINDINGS

Our small test groups made it difficult to draw statistically significant results from our physiological data. However, results from breathing rate data showed promising trends. Participants in the Slow Group exhibited a lower increase in breathing rates between the relaxed and stressed states than those in the Fast Group (p=0.095). Participants in the Fast Group also exhibited a greater increase in breathing rates than those in the Control Group (p=0.027). These initial results suggest that the faster haptic action is associated with higher breathing rates. Further studies are necessary to determine if a significant relationship exists between the rate of haptic action and physiological responses.

sleeve_breathing.png

Qualitative results from the surveys showed that the rate of haptic action was negatively correlated with the perceived comfort of the Affective Sleeve: the faster the action, the less comfortable. Results also indicated that warmth from slow haptic action was more calming than fast or no action. And finally, the slow haptic action of the sleeve produced the most positive experience for participants.