Three questions to this year’s winners of the Otto Hahn Medal...

... Sofie Valk and Emiliano Zaccarella

Each year, within the framework of its annual meeting, the Max-Planck-Gesellschaft honours a few truly outstanding performances of its PhD students and postdocs. This year marks the 40th anniversary of the Otto Hahn Medal, bestowed by the Max-Planck-Gesellschaft to honour its best junior scientists. Like very few others, Otto Hahn epitomised scientific excellence in his own life, alongside the struggle for progress on both a personal and a societal level. It was in his late twenties that Otto Hahn began his exceptionally fruitful cooperation with Lise Meitner, which led to the discovery of nuclear fission for which he received the Nobel Prize in Chemistry in 1944. As president he oversaw the successful transformation of the Kaiser-Wilhelm-Gesellschaft into the Max-Planck-Gesellschaft starting in 1946.

This year, two excellent scientists from the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) won the award: Sofie Valk and Emiliano Zaccarella. Valk wanted to address environmental factors that shape inter-individual differences in social behaviour and brain topology. Zaccarella, in turn, dealt with the idea that humans are endowed with a simple yet flexible combinatorial mechanism called Merge which allows for the generation of infinite word combinations by using our finite amount of words.

In addition to the Otto Hahn Medal, Sofie Valk also received the Otto Hahn Award, which is presented by the Max-Planck-Gesellschaft each year to particularly worthy recipients of the Otto Hahn Medal. The award provides for a research residency abroad, followed by an independent research group, led by the scientist, at one of the Max Planck Institutes. The award is intended to pave the way for a scientific career in Germany.

After the ceremony in Heidelberg on June 13^th, 2018 we asked the two winners about their outstanding research, their motivation and their future plans.

Sofie Valk, Department of Social Neuroscience

Could you explain what is special about your work?

The focus of my PhD was to understand whether socio-affective skills, meaning emotional knowledge about our social environment, such as empathy and compassion are related to brain structures different from those for socio-cognitive skills, meaning factual knowledge about our social environment,  such as taking the perspective of another person. To find out, I looked at the relationship between human variability in these skills and variations in the thickness of our participants’ cortices and the plasticity of these measures after training as well as the changes in cortical thickness related to pathology, such as autism.

I was lucky enough to be part of the ReSource Project, a large-scale longitudinal study led by Prof. Tania Singer that investigated, among other things, the effects of socio-affective and socio-cognitive training on behaviour and the brain. I found that it matters what particular skill you train. Training affective skills related to different changes in brain structure relative to training socio-cognitive skills and vice versa. When I investigated the relation between change in brain structure and behaviour, I also found that specific brain regions change depending on how much compassion or understanding of others our participants developed. Using only the baseline data, I found that differences in individual’s empathy modulated structural networks related to socio-affective processing, whereas differences in perspective-taking skills are accompanied by changes in socio-cognitive networks. These findings were in line with my research on autism spectrum disorder, a pathology that particularly affects social skills. I found that in autism the brain structures responsible for socio-cognitive processing are impaired, but not those for socio-affective processing. This could explain why it’s hard for affected people to gain factual knowledge about their social surroundings.

What interests you about this field of research?

I am interested in finding out how we are able to understand others. Specifically, I am interested in the relationship between our biology and our social behavior, and the biological mechanisms that cause behavioral differences between people. More generally spoken, I enjoy working on research projects, analyzing data, and trying to interpret the data in comparison with the existing literature. Finally, I hope that my work helps others as broader understanding of the biological mechanisms underlying social skills therapies and educational programs could be designed and applied in clinical and educational settings in order to improve well being.

Your award-winning thesis is in the bag, what’s next?

I’m currently working with Prof. Simon Eickhoff at the Jülich Research Centre, where I’m involved in various projects on genetics and the brain. This is also a very intriguing and complex topic. I’m also expecting my second child, so naturally my first priority is to prepare for the new addition to our family this summer. Apart from that, I hope to do meaningful research, improve my skills and develop research plans that combine my interests and help others to do the same.

Emiliano Zaccarella, Department of Neupsychology

Could you explain to us what is special about your work?

My research is inspired by the defining truism of human language—the capacity to produce and understand an infinite number of sentences using a finite set of combinatorial rules. A prominent hypothesis in linguistic theory states that humans are endowed with a maximally simple yet flexible enough combinatorial mechanism, Merge, which would alone account for the infinite generation of word combinations. This human-specific mechanism works on abstract word categories. Merge takes as input, for example, a noun like “ship” and a determiner like “this” and combines them to form a new object, “this ship”. Once another element comes in, the verb “sinks” for example, it is attached to the previous object via the same mechanism, to form the sentence “the ship sinks”.

My work has been a first attempt to understand from a neurobiological perspective how the Merge mechanism for language and its internal computations, such as stringing or labeling, are implemented in the mature brain. Using a stepwise reductionist approach, with functional magnetic resonance imaging, (fMRI), I first broke complexity down to a three-word level to explore how Merge creates minimally recursive phrases and sentences such as, “this ship sinks”. I then moved to the most fundamental two-word level using pseudo-nouns, for example, “this firk”, to directly assess the universal invariant nature of Merge when no additive mechanisms are involved, as well as to observe the spatial organization of its internal subroutines.

I first demonstrated that Merge builds linguistic structures out of single words within a highly confined anterior-ventral brain region within the pars opercularis, located in the left inferior frontal cortex. Second, the functional activity for Merge strictly follows sub-regional parcellations proposed for the area, therefore calling for a redefinition of pars opercularis from a multimodal area to a macro-region with internal localizable functional profiles. Third, I found that the functional localization across subjects is highly consistent within the area, thereby approaching the universality claim made for the Merge mechanism in linguistic theory.

These findings enabled me to sketch a testable neuroanatomical model for Merge in language which lies at the interface between linguistic theory, neurobiology of language and language evolution. Older and less specialized regions of the frontal operculum and the insula implement simple stringing sub-routines within the system, while the pars opercularis translates them into human-specific labelled structures.

What is your motivation for being in this research field?

I follow the intuition that while language is the most complex cognitive ability we are endowed with, its underlying simplicity can help us discover the most fundamental characteristics of human nature.

Your award-winning thesis is in the bag, what’s next?

I will be busy working as a postdoctoral fellow in the department of Neuropsychology at the MPI CBS  for the next couple of years. Together with brilliant doctoral students, we are now working on modality-independent aspects of the Merge mechanism—testing, for example, sign language speakers. We are also trying to establish causal relationships between the different brain regions of the combinatorial mechanism during on-line simple phrasal processing across different languages. We are evaluating the contribution of semantic information to structure formation. Overall, my far-reaching goal is to derive a comparative neurobiological account of the Merge mechanism and categorical abstraction in language, including the mature brain, the developing brain and non-human brains. Most of what I have reached so far would have not been possible without my present and past collaborators here at the MPI and from other research institutions in Europe, United States, China and Japan.