Biometric Analysis Of Emotional Responses And Cognitive Effort To Stimuli In Euhydrated Versus Hypohydrated States

Abstract

Improper body water regulation contributes to physiological changes, affects mood states, and impacts regulation of behavioral responses. With the emergence of biometric analysis (facial emotions) and eye tracking technology (fixation, frequency, and duration), the ability to measure emotional responses and their focal points is now possible. PURPOSE: To examine the effects that hydration status, (euhydrated vs. hypohydrated), has on emotional responses and the intensity of these responses to two separate stimuli of a carbohydrate-electrolyte drink. METHODS: Six college aged males underwent a singular trial of active dehydration in an environmental chamber at 35 °C until 2% body water loss was achieved. Participants viewed two stimuli, pre and post dehydration in a randomized order, consisting of a video commercial (3 areas of interest (AOI)) and three still images of a carbohydrate-electrolyte drink. Biometric software and eye tracking were used to obtain mental effort (ME) scores while viewing a video commercial and still image stimuli. The order of the stimulus viewing was constant pre and post exercise but randomized amongst participants. Prior to trials, participants underwent familiarization of both stimuli. RESULTS: ME measurements, using fixations within the AOI over time (sec), increased across the video commercial (AOI 1: 10.15 ± 7.51 to 19.54 ± 16.75), (AOI 2: 6.60 ± 6.46 to 12.18 ± 12.20), and (AOI 3: 6.73 ± 4.58 to 14.68 ± 10.99) from euhydrated to hypohydrated. The three beverage still images revealed increases in ME (fixation time (sec)) from 9.04 ± 4.89 to 14.88 ± 14.76 (p = 0.002), 9.51 ± 6.90 to 13.47 ± 9.85, and 9.06 ± 4.58 to 15.31 ± 10.18 (p = 0.017), respectively. Engagement scores, measured through biometrical analysis failed to detect changes between trials across all stimuli. CONCLUSION: Increases in ME in hypohydrated states were seen across all stimuli. Data also revealed much variability among subjects. It is plausible that changes in ME within hypohydrated states impact behavioral choices. Future research should investigate the effects of greater ME and fluid consumption tendencies in regards to self-regulation of body water. Additionally, greater ME in regards to hydration stimuli could impact given task or skills performance when hypohdrated.