Heart rate, skin conductance, and explicit responses to juice samples with varying levels of expectation (dis)confirmation

Eighty-six participants tasted fruit and vegetable juices in two separate sessions. They were divided in two conditions. In Condition A, expectations were manipulated by showing participants the image of an ingredient and then providing them with a juice whose flavour was as expected, differed slightly, or differed greatly from that of the image. In Condition B, each juice was first tasted without explicit information shown beforehand and the image of the ingredient was shown afterwards. The images were the same as in Condition A. Heart rate and skin conductance were measured. To confirm that participants perceived confirmations and large and small disconfirmations when tasting the juices, they rated the samples in different sensory properties before and after tasting them. Results from most of the sensory ratings, except sourness and taste intensity, showed that participants perceived the designed confirmation and disconfirmation of expectations accordingly. Regarding ANS responses, heart rate had a larger increase during the second session than during the first. Skin conductance responses increased in Condition A but decreased in Condition B. In conclusion, our design managed to create confirmations and varying levels of disconfirmations. ANS responses did not capture them but seemed to capture factors like attention and the orientation response.