This is an electrophysiological monitoring method that records electrical activity in the brain. It is typically non-invasive, with the electrodes placed along the scalp. Most of the electrical activity collected in the EEG is generated by groups of pyramidal neurons. These neurons have cell bodies primarily in layers three and five of the cerebral cortex. When they are activated, local current flows are produced. The electrical activity recorded on the scalp is generated by the summation of the excitatory and inhibitory postsynaptic potentials. This activity can be represented by dipoles parallel to the orientation of the pyramidal cells. Only large populations of active neurons can generate recordable electrical activity at the surface of the head. Electrical signal must propagate from the brain, through the skull, skin, and hair before reaching the electrode. The weak electrical signals detected by the scalp electrodes are massively amplified and then recorded in the computer. Because of its ability to assess normal and abnormal electrical activity in the brain in real-time, EEG has proven to be a very powerful tool in the field of neuroscience and clinical neurophysiology [11]. Its temporal resolution is below the millisecond, which makes it a good candidate for the real-time study of emotions. The use of EEG in the measurement of emotions has a long history, although not in the area of cosmetics. Dimensional models have been employed extensively to measure emotions with EEG. They have suggested that emotion is best understood as occurring within a dimensional space, most commonly a two-dimensional space, spanning valence and arousal [12]. Emotional valence describes the extent to which an emotion is positive or negative, whereas arousal refers to its intensity, i.e., the strength of the associated emotional state [13, 14, 15]. The activity of the prefrontal cortex, which acts as a modulator of primary emotional responses through its connections with deep brain structures [16], is fundamental in the evaluation of emotional valence. Dominant activity in right versus left prefrontal areas is associated with withdrawal behavior and negative emotions, while the opposite representation (i.e., left versus right) accompanies approach behaviors and positive emotions [17; 18; 19]. Reduced alpha activity in the right prefrontal cortex is associated with negative emotions, for example after viewing unpleasant films [19; 20]. On the other hand, reduced alpha activity in the left hemisphere is related to positive emotions, for example after viewing happy movies or listening to pleasant music [20; 21]. Frontal asymmetries associated with emotions and motivation have also been observed at the theta band level [22; 23] and the upper beta band level [24; 25]. In addition to the measurement of emotional valence, [PERSON] and [PERSON] added an additional parameter in determining arousal by calculating the ratio of beta and alpha oscillations, to conform to the dimensional models of emotion studies [26; 27]. The purpose of this pilot study was to use EEG to compare the emotions induced by the application of two cosmetic products. We hypothesized that the preferred application would generate emotions of more positive valence, as detected with EEG. Our second objective was to offer to the experimenter a real-time representation of participants' emotional states while they were applying the products. To that end, we developed a visual representation of emotions based on a collaboration between scientists and digital artists [28]. With this system, we expected to visualize the particles moving to the right in real-time when participants were applying the products.