Multisensory perception in harbor seals (Phoca vitulina)

• Applicant: Professorin Dr. Frederike Diana Hanke
• Subject Area: Sensory and Behavioural Biology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 544171290

Complex behaviors such as foraging or orientation/navigation are usually multimodal, i.e. they are (mostly) based on information obtained from different sensory systems. This information converges in the brain where they are being integrated (or segregated). However, previous experimental approaches to explain complex behavior of marine mammals have mostly taken only a unimodal rather than a multimodal perspective, and multisensory phenomena have not been explicitly investigated. Therefore, multisensory integration is a very attractive field of research with respect to a marine mammal. It is conceivable that weak sensory stimuli, which are quite common under water, can be integrated leading to improved/enhanced perception. Multisensory integration also allows flexibility in dealing with sensory information. This flexibility seems essential for an organism that is confronted with constantly changing sensory input of varying reliability. As first, basal approaches to the study of multisensory phenomena in a marine mammal, the harbor seal, we propose three behavioral experiments: First, in a matching-to-sample experiment (experiment 1), we will test whether a seal can associate an object that it has haptically perceived with its visual appearance, which would require that the information of the sensory modalities be brought together at the perceptual level. This cross-modal approach allows a smooth transition from unimodal to multimodal research approaches. Furthermore, we will investigate whether a multimodal compared to a unimodal stimulus presentation leads to quantitative (differences in speed of learning, precision of response behavior and reaction time; experiment 2) or qualitative differences (visual illusion induced by an acoustic cue; experiment 3). We are convinced that with the studies outlined in this project proposal, we will take first fundamental steps towards a holistic understanding of sensory perception of seals in the context of complex behaviors on behavioral level. These investigations will reveal whether the performance of harbor seals can be described by the fundamental principles of multisensory integration as previously published for other organisms or whether the adaptation to a (semi-)aquatic lifestyle has altered sensory perception in general and thus subsequently multisensory processing. The results will extend our general understanding of multisensory perception – beyond marine mammal research.

• DFG Programme: Research Grants