# Emotional Response to Vibrothermal Stimuli
## 3 Results  
We studied the effect of three factors: spatiotemporal vibrotactile patterns (12 patterns), duration (long and short), and dynamic temperature (hot and cold) on the emotional response. A three-way repeated measures ANOVA was conducted with the aforementioned factors on the valence (V) and arousal (A) scores obtained from subjects. The thermal sensation data were collected to check for inconsistencies in thermal feedback device performance. Data collected for one male subject were excluded from the analysis, as the thermal sensations were deemed ineffective as the scores indicated that changes in temperatures were not perceived adequately. A total of 1488 trials were analyzed for a set of 48 stimuli. The data were not normalized so that individual emotional responses were represented more accurately in the analysis. To understand the general central tendencies, the mean VA scores of emotional responses averaged across each independent factor were plotted, as shown in Figure 6. The following are the observations: (1) on average, most patterns were associated with the upper right quadrant (excited/happy) except \"shoulder tap\" (pattern 12); (2) on average, across all patterns and thermal conditions, longer durations (1000 ms) increased both V and A compared to shorter durations (100 ms); (3) on average, a warm dynamic temperature decreased V and had no significant effect on A compared to a cool dynamic temperature. Table 1 displays a summary of the findings from the three-way repeated measures ANOVA. No significant interaction effects were found, meaning that each factor may have a more independent effect on the emotional response. The type of spatiotemporal pattern,  
Figure 6: Mean VA scores of emotional responses averaged across each independent factor. The numbers adjoining the Pattern (purple square) datapoints refer to the spatiotemporal pattern type as depicted in Figure 4.  
duration or temperature had a significant effect on V, whereas only pattern and duration had a significant effect on A. To understand the effect of pattern and duration on emotional response, Figures 7 and 8 plot stimuli at hot and cold dynamic temperatures, respectively. In Figure 7, the extent of the effect of duration is unique for each pattern; nevertheless, increasing duration leads to an increase in both V and A. Pattern 1 (_alternate_--_top to bottom_) was highly affected by the change in duration (V, A) = (\(-\)0.06, 0.1) \(\rightarrow\) (0.87, 1). At a shorter duration, this pattern was more neutral, whereas at a longer duration, this pattern created a more excitable and pleasant experience. Pattern 10 (_snake horizontal_) was least effected by a change in duration (V, A) = (0.45, 0.9) \(\rightarrow\) (0.71, 0.97). A notable exception is pattern 12 (_shoulder tap_), which transformed from (V, A) = (0.06, \(-\)0.32) \(\rightarrow\) (\(-\)0.03, 0.19), that is, A increased (keeping in trend with the rest of the data points), but V slightly reduced. Another observation is the clustering effect of increasing duration. Patterns subjected to longer duration tend to cluster together, which may have significant design implications. The effect of duration on patterns at a cold dynamic temperature seem to be similar. As seen in Figure 8, increasing duration increases V and A of the patterns. Interestingly, even pattern 12 was consistent with the rest of the datapoints (V, A) = (\(-\)0.03, \(-\)0.39) \(\rightarrow\) (0.52, 0.29). Pattern 1 is still highly affected by duration, but there is significant separation between the short and longer duration clusters. Keeping in line with the central tendencies, the bulk of the patterns occupy the excited/happy quadrant. Shoulder tap seems to be a pattern that is highly susceptible to changes in duration and temperature affecting its emotional quality. As expected from the means, increasing the duration has a consistent effect of increasing the V and A of the emotional response to patterns at both dynamic temperatures.