01 — What people say
Explicit measures capture an experience put into words.
An explicit measure asks users to consciously evaluate a quality, emotion or overall impression. AttrakDiff distinguishes pragmatic and hedonic qualities and attractiveness. The Self-Assessment Manikin (SAM) places affective state on valence — pleasantness — and arousal — felt intensity.
These instruments are standardized and interpretable, but they rely on introspection, memory and the available categories. Answers may be influenced by timing, social desirability or the difficulty of verbalizing a continuous experience.
02 — What the body does
Implicit measures observe a reaction before it is verbalized.
Response time, errors, trajectories, gaze, facial expression, electrodermal activity or heart rate can be recorded during use. They reveal dynamics and reduce some reconstruction biases.
In Mahlke and Thüring’s experiment, manipulating pragmatic and hedonic qualities affected emotion, judgment and some signals. Each relationship requires contextual interpretation: increased arousal may reflect interest, effort, surprise or frustration.
03 — Signal interpretation
One signal can correspond to several experiences.
The term ‘implicit’ describes how a measure is obtained. Its relationship with emotion or user-experience evaluation must then be demonstrated in the protocol. De Wijk and Noldus emphasize the complementarity of reported and observed measures, which document different dimensions of experience.
A long fixation may indicate interest or difficulty; a mouse pause, reflection or distraction. Emotional inference therefore requires validation in the task at hand.
04 — Triangulation
Formulate the hypothesis before choosing the sensor.
The protocol starts from a precise product hypothesis: does the user understand the offer, hesitate before acting or feel in control? We then combine an explicit outcome, observable behavior and possibly a physiological signal.
A fast journey paired with low perceived control provides different information from effortless success. Triangulation connects these signals with the journey outcome while preserving uncertainty.
05 — From concept to decision
A useful protocol connects what someone does with what they experience.
For checkout, I would measure success, errors and time, then perceived control immediately after the task. Traces would support discussion of a specific step. A fast but opaque payment calls for a different improvement from a slow payment whose steps are understood.
The protocol can remain lightweight: the research question determines whether an additional sensor contributes enough information to justify its complexity.