MPI's Paul Hömke will defend his thesis

Unlike most other animals, humans tend to face each other in everyday communication. This allows us to rely on facial expressions in communication. Hömke investigated the face of the listener in face-to-face communication, specifically blinking and brow movements. He found that long blinks are used as a communicative signal of understanding, conveying ‘I’ve received enough information for current purposes, please go on’. Listeners’ furrowed brow, on the other hand, was shown to signal a lack of understanding, conveying ‘I’ve not received enough information for current purposes, please clarify’. Closing the eyelids by blinking (as if having seen enough) and furrowing the eyebrows (as if not seeing clearly) point to a metaphorical use of the muscles surrounding the eyes, signalling sufficient or insufficient understanding. Thus, in everyday social interaction, it is not only the eyes themselves, but crucially, the regions surrounding the eyes, that serve as windows to the mind.