*3.3. Automated Facial Expression Response Measurements*

The mean and standard deviation for the facial expression parameters (joy, sadness, disgust, contempt, anger, fear, surprise, valence, engagement and smile) are shown in Table 5. No significant differences in the facial expressions were reported for both products. Some marginal differences were observed in a few emotion categories, such as "smile", "engagement", "joy", "disgust", and "surprise". The intensity of "engagement" was highest for both sample types (2.79 and 1.25 for sample A and B, respectively), followed by "contempt" (2.36 and 0.15 for sample A and B, respectively) and "joy" (0.56 for sample A and 0.97 for sample B). For energy drink B, the participants elicited slightly more "joy" and "smile" compared to that of energy drink A. The intensities of "joy" and "smile" were almost double in energy drink B than that of in energy drink A. The negative emotions such as "sadness", "anger", and "fear" were marginally elicited in both sample types.


**Table 5.** Facial expressions and facial features during the tasting of energy drinks A and B.

Means values of the different facial expressions with different superscripts in each row indicate a significant difference (*p* < 0.05). \* F value = Mean square or mean square error. Effects were considered significant if Pr (probability) > F was <0.05 (bold probability and F value). <sup>a</sup> Means with different superscripts in each row indicate significant differences (*p* < 0.05).
