You can’t measure a gut feeling. Or at least, that’s what marketers used to believe. But in 2025, emotional response data isn’t just measurable, it’s quietly becoming one of the most powerful tools in performance marketing. Today’s tools can read a lot more than clicks. Facial recognition software tracks micro-expressions to detect flashes of joy or surprise. Voice analytics picks up shifts in tone during customer calls. Even wearable devices are capturing heart rate and skin