Insight represents a special element of knowledge building. From the beginning of their lives, humans experience moments of insight in which a certain idea or solution becomes as clear to them as never before. Especially in the field of visual representations, insight has the potential to be at the core of comprehension and pattern recognition. Still, one problem is that this moment of clarity is highly unpredictable and complex in nature, and many scientists have investigated different aspects of its generation process in the hope of capturing the essence of this eureka (Greek, for "I have found") moment.

In this paper, we look at insight from the spectrum of information visualization. In particular, we inspect the possible correlation between epiphanies and emotional responses subjects experience when having an insight. In order to check the existence of such a connection, we employ a set of initial tests involving the EPOC mobile electroencephalographic (EEG) headset for detecting emotional responses generated by insights. The insights are generated by open-ended tasks that take the form of visual riddles and visualization applications. Our results suggest that there is a strong connection between insight and emotions like frustration and excitement. Moreover, measuring emotional responses via EEG during an insight-related problem solving results in non-intrusive, nearly automatic detection of the major Aha! moments the user experiences. We argue that this indirect detection of insights opens the door for the objective evaluation and comparison of various visualizations techniques.