Successfully Defended Dissertation: Dr. Tjark Müller

Tjark Müller's successful defence of his doctoral thesis provides scientific confirmation of an observation that many of us may have made in our personal lives: The optimal seat for a game night is the one that offers a direct view of the board. Things get difficult if you find yourself peering around corners or, worse, staring at an upside-down board.

In his doctoral thesis, Tjark Müller focused on the mental rotation of data visualisations. Specifically, he examined the presentation of diagrams on multi-touch tables, a setting in which multiple people often view an illustration from different angles at the same time. Confirming expectations, a series of studies showed that mentally rotating an inverted image – known as mental normalisation – placed an additional cognitive burden on participants.

A key finding was that when diagram labels and content were rotated separately, the labels emerged as a critical factor contributing to this cognitive load. Highlighting the practical implications, Tjark Müller said: "This is an important point to keep in mind when designing data visualisations and applications for multi-touch tables." In his current role as a software engineer in the Media Development division at the IWM, he is able to apply these findings to improve his daily work.