In a "matching" task the experimental animal is presented with a stimulus ("sample") and two comparison stimuli. Only one comparison stimulus - the so called positive stimulus - is identical to the "sample". The task of the animal is to choose the positive stimulus. In previous experiments our seals had large difficulties learning visual matching tasks which led us to decide to test how fast they can acquire a matching task if they are allowed to explore the objects haptically with their vibrissae.
The video shows a seal in the haptic matching experiment. First the seal is masked; it is carrying a stocking mask in order to prevent a visual solution of the task, it is equipped with headphones in order to prevent it from perceiving acoustical cues during the installation of the stimuli that could provide secondary cues. The animal is then first touching the "sample" in the middle, explores the comparison stimuli and pushes the comparison stimulus that matches the sample backwards. In this example the stimuli consisted of cylinders differing in diameter.