University of Illinois Urbana-ChampaignUnited States
Ting Lu is an Associate Professor at the University of Illinois at Urbana-Champaign in the School of Biomedical and Translational Sciences, focusing on microbial synthetic biology and systems biology. Their research bridges biology, engineering, and physics to reprogram cellular functionalities through gene regulatory networks. Ph.D. in Biophysics, University of California at San Diego (2007) B.S. in Physics, Zhejiang University (2002) Ting Lu's work explores microbial ecosystems, synthetic gene circuits, and their applications in biotechnology and medicine. By combining experimental approaches with mathematical modeling, they investigate bacterial communication networks, metabolic pathways, and spatial dynamics in microbial communities. Selected research trends include microbial consortia engineering for bioremediation and bioproduction, complexity reduction in microbiomes, and predictive modeling of synthetic gene networks. Their publications span high-impact journals such as Nature Communications , Nature Chemical Biology , and eLife . Fellow, American Institute for Medical and Biological Engineering (2022) Future Insight Prize (2021) Donald Biggar Willett Faculty Scholar (UIUC) (2020) NIH Maximizing Investigators' Research Award (2019) NSF CAREER Award (2015) AHA National Scientist Development Grant (2012) Ting Lu's lab has received grants from NIH, NSF, ONR, and industry partners. They offer undergraduate research opportunities in synthetic and systems biology, and teach advanced courses such as BIOE 430 - Intro Synthetic Biology and BIOE 432 - Systems Biology .
Mayo Clinic College of Medicine and ScienceUnited States
Mark R. Pittelkow is a Professor of Dermatology at the Mayo Clinic, holding a primary appointment as a Consultant in the Department of Dermatology. He completed his MD at Mayo Medical School and advanced training through Mayo Graduate School of Medicine and Northwestern University. His research focuses on cutaneous lymphomas, photoprotection, and skin cancer, with leadership roles in international guidelines (ISCL/EORTC). He contributes to clinical trials, medical education, and interdisciplinary research through affiliations like the Mayo Clinic Comprehensive Cancer Center and Regenerative Biotherapeutics. Education: MD (Mayo Medical School), MS (Biological Sciences, Northwestern), BA (Northwestern University). Research spans cutaneous lymphoma classification, immunology, and translational dermatology. Notable publications address staging systems for mycosis fungoides/Sezary syndrome and photoprotection strategies. His work integrates clinical practice with molecular mechanisms, such as JAK inhibitor responses in lichen planus. Labs/Teams: Collaborates with Mayo Clinic Cancer Center and interdisciplinary groups in immunotherapy and regenerative medicine. Supervises clinical trials and postdoctoral training programs.
Kristin Bernard, Ph.D. (University of Delaware, 2013), is an Associate Professor of Clinical Psychology at Stony Brook University’s Department of Psychology. Her research focuses on the neurobiological consequences of early adversity, parent-child relationships, and the efficacy of early parenting interventions such as Attachment and Biobehavioral Catch-up (ABC). She collaborates with Power of Two, a NYC-based nonprofit, and leads the Developmental Stress and Prevention Lab. Current grants include studies on epigenomics, maternal attachment representation, and community-based ABC interventions. Dr. Bernard’s work bridges clinical and developmental psychology, emphasizing prevention science and translational research. Education: Ph.D. in Clinical Psychology, University of Delaware, 2013. Research Interests: Child maltreatment, neurobiological impacts of early adversity, parenting interventions, psychobiology of attachment, and intervention efficacy. Her lab investigates mechanisms linking caregiving quality to child outcomes, including cortisol regulation, brain development, and behavioral compliance. Lab & Partnerships: Directs the Developmental Stress and Prevention Lab, focusing on high-risk populations. Collaborations include Power of Two for ABC implementation and NYC agencies like the Administration for Children’s Services. Current projects explore neighborhood influences on parenting (Geography of Parenting Study) and neural correlates of parenting behavior (SNAP study). Grants & Funding: Principal Investigator on NIH-funded projects (R03 HD099372, R01 MH119310) and co-PI on Stony Brook’s seed grants. Projects examine accelerated aging biomarkers and intervention effectiveness in community settings. Publications: Over 50 peer-reviewed articles and a co-authored book on ABC interventions. High-impact journals include Psychoneuroendocrinology , Development and Psychopathology , and Child Development .
Andre Levchenko is the John C. Malone Professor of Biomedical Engineering at Yale University, with secondary appointments in the Department of Neurosurgery and affiliations with the Cancer Signaling Networks, Immunology, and the Yale Program in Neurodevelopment and Regeneration. His research focuses on systems biology, signal transduction, and cell-cell communication, utilizing microfluidics and computational modeling to study cancer progression, stem cell behavior, and neurological disorders. PhD, Columbia University MEng, Moscow Institute of Physics and Technology Levchenko's work explores how cells process dynamic signals to make critical decisions, particularly in glioblastoma migration, organoid development, and cardiovascular tissue engineering. His lab develops innovative microfluidic platforms and mathematical models to dissect multicellular communication and signaling networks. Recent publications highlight his contributions to understanding YAP-driven cancer invasion , NOTCH signaling in angiogenesis , and metabolic regulation of hypoxia responses . He has pioneered methods for organoid modeling and single-cell analysis , advancing precision in biological signaling studies. Scientific Awards : Computational Molecular Biology Post-Doctoral Fellowship (Burroughs Wellcome Fund) National Academies Keck Futures Conference Invitee Distinguished Guest Lecturer, University of Virginia American Asthma Foundation Early Excellence Award Fellow, American Institute for Medical and Biological Engineering Levchenko leads the Levchenko Lab at the Yale Systems Biology Institute, collaborating with institutions like Mayo Clinic and Yale Cancer Center. His research has received recognition in Faculty of 1000 and multiple journal highlights.
Michael Yeager, PhD, serves as an Associate Clinical Professor in the School of Medicine at the University of Colorado Denver, focusing on cardiopulmonary pathophysiology with emphasis on pulmonary hypertension and heart failure mechanisms. He completed his PhD at the University of Colorado Health Sciences Center in 2002, establishing foundational expertise in vascular biology. His research program investigates immunological and molecular drivers of pulmonary vascular disease, particularly the roles of autoantibodies, fibrocytes, and inflammatory cascades in disease progression. Analysis of his 14 publications (2012-2015) reveals consistent exploration of biomarker discovery, vascular remodeling, and immune dysregulation across pediatric and adult pulmonary hypertension. Key methodological approaches include proteomics, animal modeling, and molecular interrogation of cellular stress responses, with significant translational implications for personalized therapeutic strategies. Professional recognitions include: Outstanding Faculty award from Tau Beta Pi (2019) Chancellor's Teaching Recognition Award from the University of Colorado (2016) Dr. Yeager maintains active clinical research collaborations at Children's Hospital Colorado while mentoring within the medical school curriculum. His work bridges basic science discovery with clinical application through ongoing investigations into endothelial dysfunction and inflammatory mediators. Affiliated with the Department of Medicine, he contributes to pulmonary vascular research initiatives and participates in professional societies including the American Thoracic Society, American Heart Association, and T21 Research Society.
Dr. Giulia Biancon is an Assistant Professor Adjunct in the Department of Medical Oncology and Hematology at Yale School of Medicine. She holds a PhD from the University of Milan (2019) and is a member of the Halene Lab, focusing on RNA biology and hematologic malignancies. Her research combines high-throughput methodologies to study RNA mechanisms in diseases like myeloid leukemias and splicing factor mutations. Education: PhD in Molecular Biology from the University of Milan (2019). Research Interests: RNA splicing, stress granules in cancer, epitranscriptomics, clonal hematopoiesis, and the interplay between genetic mutations and cellular pathways in blood cancers. Awards: 2024 Eclipse Award, 2022 ASH Abstract Achievement Award, and 2022 RNA Society Best Poster Award. Her work has been published in journals like Cell Reports , Blood , and Molecular Cell . Labs/Teams: Principal member of the Halene Lab and coordinator at the Yale Center for RNA Science and Medicine. Collaborates with institutions like the SeroNet network for immunology studies.
Thomas R Overton serves as Department Chair and Professor of Dairy Nutrition and Management in the Department of Animal Science at Cornell University's College of Agriculture and Life Sciences (CALS). He also directs PRO-DAIRY, an extension program focused on enhancing dairy farm profitability and efficiency in New York through research-based strategies for transition cow management. Education: Doctorate, University of Illinois, 1998 Master of Science, University of Illinois, 1994 Bachelor of Science, Cornell University, 1991 Dr. Overton's research centers on the transition period (late pregnancy to early lactation) in dairy cows—the most critical phase for health and productivity. His work integrates nutritional physiology with practical farm applications, targeting hypocalcemia management, protein supplementation strategies, inflammation control, and biomarker validation for metabolic health. This research directly informs his extension efforts through PRO-DAIRY, which delivers actionable knowledge to dairy producers and industry professionals. Analysis of his 15 most recent publications (2022-2024) reveals consistent emphasis on transition cow nutrition, with growing focus on metabolic analytics, precision feeding, and real-world herd management. His work bridges controlled studies at Cornell's Ruminant Center with observational research on commercial New York dairy farms. Scientific Awards: 2024 Nutrition Professionals Applied Dairy Research Award (American Dairy Science Association) 2010 CALS Extension/Outreach Team Award (PRO-DAIRY) 2007 Foundation Scholar Award (American Dairy Science Association) 2007 CALS Extension/Outreach Team Award Dr. Overton advises undergraduate and graduate students in Animal Science while leading PRO-DAIRY's extension initiatives. His program secures industry partnerships and grants focused on improving dairy farm sustainability through nutritional science. The July 2025 'Farm of the Future' showcase at Cornell's Ruminant Center exemplifies his commitment to translating research into practical innovation. He operates within Cornell's PRO-DAIRY program and the Cornell University Ruminant Center—a living laboratory for dairy technology testing—collaborating closely with industry stakeholders to address emerging challenges in dairy production.
David Erickson is the SC Thomas Sze Director and Sibley College Professor at Cornell University's Sibley School of Mechanical and Aerospace Engineering. He also holds a joint professorship in the Division of Nutritional Sciences. His research focuses on global health technologies, medical diagnostics, microfluidics, photonics, nanotechnology, and energy systems. He previously served as Associate Dean of Engineering for Research and Graduate Programs. Erickson leads the NIH-funded PORTENT Center for Point-of-Care Technologies in Global Health and has co-founded companies like Dimensional Energy and VitaScan to commercialize diagnostic and energy technologies. Education: B.Sc., Mechanical Engineering, University of Alberta (1999) M.A.Sc., Mechanical Engineering, University of Toronto (2001) Ph.D., Mechanical Engineering, University of Toronto (2004) Postdoctoral Scholar, Electrical Engineering, California Institute of Technology (2005) Research Interests: Erickson’s work spans global health diagnostics , nanobio applications , and clean energy innovation . He develops portable medical devices for low-resource settings, including smartphone-integrated diagnostic tools for malaria, iron deficiency, and cancer. His lab also pioneers photothermal reactors for CO2 conversion into sustainable fuels. Key areas include: Point-of-care testing for infectious diseases and nutritional deficiencies Nanofluidic and optofluidic technologies for biomolecular analysis Solar-driven energy systems for carbon-neutral fuels Awards: Presidential Early Career Award for Scientists and Engineers (2011) Fellowships from the Optical Society, ASME, and Canadian Academy of Engineering Carbon X-Prize Finalist (2019) for Dimensional Energy’s CO2-to-fuel technology Grants & Industry Collaboration: Erickson’s research is funded by NIH, NSF, ARPA-E, DOE, and USAID. His lab’s innovations have spun off start-ups addressing global health and energy challenges. Notable projects include: - Portable cancer diagnostics in sub-Saharan Africa using mobile phone-based systems - Solar-powered CO2 conversion reactors tested in Wyoming and Arizona Labs & Teams: The Erickson Lab collaborates with the Cornell Atkinson Center for Sustainability and the McGovern Center for Entrepreneurship. Key initiatives include the PORTENT Center and the Dimensional Energy CO2-to-fuel project.
David H. Sherman is the Hans W. Vahlteich Professor of Medicinal Chemistry at the University of Michigan, holding joint appointments in the College of Pharmacy (Department of Medicinal Chemistry), Medical School (Microbiology & Immunology), and College of Literature, Science, and the Arts (Chemistry). He leads the Sherman Lab at the Life Sciences Institute and co-founded the Natural Products Discovery Core. His research focuses on natural product discovery, biosynthetic pathways, and drug development for infectious diseases, cancer, and neurological disorders. Education: PhD in Synthetic Organic Chemistry from Columbia University (1981), BA in Chemistry from UC Santa Cruz (1978). Postdoctoral research at MIT (1984). Research interests include microbial secondary metabolites, enzymatic catalysis (e.g., C-H functionalization, polyketide assembly), and high-throughput drug screening. He pioneered a microbial natural product library with over 50,000 samples. Current projects emphasize developing macrolide antibiotics and advancing compounds toward clinical trials through the Natural Products Biosciences Initiative. Collaborations span global institutions, with a focus on biodiversity conservation and capacity-building in low-income nations. He has mentored 67 PhD students, 60 postdocs, and 85+ undergraduates, fostering interdisciplinary training in chemical biology and microbial biochemistry. Labs/Teams: Sherman Lab (Life Sciences Institute), Center Member at Samuel and Jean Frankel Cardiovascular Center, Center for Computational Medicine and Bioinformatics, Rogel Cancer Center.
Jenny Ouyang is an Associate Professor in the Department of Biology at the University of Nevada, Reno , where she also serves as Director of the Ecology, Evolution and Conservation Biology graduate program. She earned her B.S. and B.A. from the University of California, Irvine (2007), followed by M.A. and Ph.D. in Ecology and Evolutionary Biology from Princeton University (2009, 2012). Her research focuses on the ecology and evolution of physiological systems , particularly how hormonally regulated traits enable organismal adaptation to environmental changes like urbanization , light pollution , and endocrine stress responses . Education: Ph.D., Ecology and Evolutionary Biology, Princeton University (2012) M.A., Ecology and Evolutionary Biology, Princeton University (2009) B.S., Biology, University of California, Irvine (2007) B.A., French, University of California, Irvine (2007) Her work integrates neuroendocrine mechanisms with ecological contexts to understand phenotypic flexibility and epigenetic adaptation in birds. Recent projects examine how artificial light at night disrupts circadian rhythms, hormonal profiles, and parental behaviors across urban-rural gradients. She has secured major grants including the NSF CAREER award (2022) for studying urbanization and NIH COBRE funding (2017) as part of a neuroscience team. Key collaborations include Dr. Maria Echeverry at Universidad Pontificia Javeriana in Colombia through her 2023 Fulbright award . The Ouyang Lab combines natural and laboratory experiments to investigate stress physiology, with recent papers analyzing glucocorticoid responses to urbanization, gene expression patterns under light pollution, and epigenetic reorganization in response to environmental stressors. Her publications span top journals like Proceedings of the Royal Society B , Biology Letters , and Ecology Applications , where her 2022 paper on lead pollution and reproduction was highlighted by ESA and Swedish Radio. Scientific Awards & Recognition: US Fulbright Scholars Award (2023) NSF CAREER grant (2022) NIH COBRE grant (2017) as team member Advising students like Valentina Alaasam (NSF GRFP awardee) and Ivan Celso Carvalho Provinciato (Dean's Merit Fellowship)
Britt Adamson is an Associate Professor in the Department of Molecular Biology and the Lewis-Sigler Institute for Integrative Genomics at Princeton University, where she serves as Director of the Undergraduate Program in Quantitative and Computational Biology. Her lab investigates molecular networks in human cells with focus on stress response mechanisms and genome editing technologies. She received her B.S. in Biology from the Massachusetts Institute of Technology (2005) and Ph.D. in Genetics and Genomics from Harvard University (2012), followed by postdoctoral training at UCSF under Jonathan Weissman supported by a Damon Runyon Cancer Research Foundation Fellowship. Adamson's research centers on how cells organize stress response networks during DNA damage and endoplasmic reticulum stress, developing CRISPR-based functional genomics and single-cell sequencing tools to map molecular behaviors. Her work bridges fundamental cell biology with therapeutic applications in genome editing. Analysis of her 15 most recent publications reveals dominant themes in precision genome editing (prime/base editing optimization) and systematic dissection of DNA repair pathways through combinatorial CRISPR screening. Her lab consistently integrates computational approaches with high-resolution experimental techniques to uncover context-dependent cellular behaviors. Her scientific recognitions include: Damon Runyon Cancer Research Foundation Postdoctoral Fellowship Princeton IP Accelerator Award (2025) STAT Who to Know: 10 Scientists leading a new generation of gene editors (2024) Adamson actively mentors eight graduate students (including alumni Ann Cirincione and Jun Hussmann) and two postdocs, with research funded through institutional awards and collaborative grants. Her lab's technological developments have enabled projects spanning virology, immunology, and developmental biology. The Adamson Lab operates within Princeton's Lewis-Sigler Institute for Integrative Genomics, fostering an interdisciplinary environment that merges cell biology, genomics, and computational science. Current projects focus on improving prime editing efficiency and understanding stress response adaptation in disease contexts.
Anirban Paul is an Associate Professor in the Department of Neuroscience and Experimental Therapeutics at Pennsylvania State University, affiliated with the Penn State Neuroscience Institute. His research focuses on cellular and molecular mechanisms of GABAergic inhibitory circuits, with particular emphasis on interneuron biology and its implications in neurological disorders. Dr. Paul's research spans multiple neuroscience domains, with primary focus on GABAergic inhibitory circuits and interneuron biology. His work investigates how specific neuron subtypes, particularly Chandelier cells and cortical interneurons, contribute to brain function and dysfunction. He has made significant contributions to understanding the role of these cells in schizophrenia, Alzheimer's disease, and other neurological conditions. His research integrates molecular, cellular, and systems-level approaches to uncover fundamental mechanisms of neural circuit assembly, plasticity, and function. Key areas include RNA regulation in neuronal development, transcriptomic subtypes of inhibitory neurons, and cell-type specific vulnerabilities in neurodegenerative diseases. His research portfolio demonstrates consistent productivity with publications spanning from 2003 to 2025, showing an evolving focus from basic molecular neuroscience to translational research in neurological disorders. Recent work emphasizes single-cell analysis techniques and the role of specific interneuron populations in disease mechanisms, particularly in schizophrenia and Alzheimer's disease. His publications appear in high-impact neuroscience journals including Neuron, BMC Biology, and Frontiers in Cellular Neuroscience. Dr. Paul has received the NARSAD Young Investigator Award (2018), recognizing his promising research in neuroscience. His scientific contributions have been supported by multiple competitive grants from prestigious organizations including the National Institute on Aging (NIA) and the Brain and Behavior Research Foundation. He serves as Principal Investigator on multiple active research projects, including two major grants from the National Institute on Aging focused on cell-type specific risk and resilience in Alzheimer's disease and aging (2021-2024 and 2024-2026), as well as previous projects from the Brain and Behavior Research Foundation investigating Chandelier cells in schizophrenia. His research program demonstrates sustained funding and scientific leadership in the field of interneuron biology and its clinical implications.
Elizabeth Bernstein is a Professor of Women's, Gender & Sexuality Studies and Professor of Sociology at Barnard College, Columbia University, where she has been a faculty member since September 2002. Her work bridges sociological theory with feminist analysis, focusing on the intersections of gender, sexuality, and political economy. Bernstein directs significant research initiatives including the Gender Justice and Neoliberal Transformations Working Group, a transnational collaboration among thirteen scholars examining gender justice in contemporary global contexts. She is currently developing a new book project titled "Imagining Immunity: Precarious Bodies and the Governance of Gendered Dis-ease," which explores immunological metaphors in understanding bodily risk and suffering. B.A., University of California, Berkeley M.A., University of California, Berkeley Ph.D., University of California, Berkeley Professor Bernstein's research focuses on the political economy of the body, gender, and sexuality, with particular attention to sexual commerce, sex trafficking, and neoliberal governance. Her work employs ethnographic methods to examine how intimate relations become sites of economic exchange and political regulation. She investigates how concepts of authenticity, freedom, and rights are mobilized in debates about sexual commerce and trafficking. Bernstein's scholarship critically engages with feminist theory, carceral politics, and transnational governance frameworks, challenging conventional approaches to sex work and trafficking that often reinforce punitive systems rather than advancing gender justice. Analysis of Bernstein's scholarly output reveals a consistent trajectory examining the intersections of gender, sexuality, and political economy within neoliberal frameworks. Her work demonstrates increasing attention to transnational governance mechanisms and their impact on intimate relations and bodily autonomy. A notable trend is her critical examination of how anti-trafficking campaigns often employ carceral logic that undermines feminist goals of gender justice. Her scholarship consistently challenges binary frameworks that position sex work solely as exploitation or liberation, instead analyzing the complex economic, political, and social dynamics that shape sexual commerce globally. Bernstein's research has received significant recognition through prestigious awards including: Distinguished Book Award, American Sociological Association, Sociology of Sexualities Section (2020) for "Brokered Subjects" Honorable Mention, Society for the Study of Social Problems Global Division Book Award (2019) Norbert Elias Prize, Norbert Elias Foundation (2009) Distinguished Book Award, American Sociological Association, Sex and Gender Section (2009) Her work has also been supported by major funding organizations including the Institute for Advanced Study, National Science Foundation, Social Science Research Council, AAUW, and Mellon Foundation. As a principal investigator along with Janet Jakobsen for the Gender Justice and Neoliberal Transformations Working Group, Bernstein leads a significant collaborative research initiative sponsored by the Barnard Center for Research on Women. Her grant portfolio demonstrates sustained support from major research institutions, reflecting the significance of her work in gender studies and sociology. While specific student advisees aren't listed in the available materials, her role as a full professor at Barnard College indicates extensive mentorship of undergraduate and likely graduate students in Women's, Gender & Sexuality Studies and Sociology. Bernstein co-leads the Gender Justice and Neoliberal Transformations Working Group, a collaboration among thirteen scholars working transnationally on questions of gender justice. This initiative represents a significant research collective examining how neoliberal policies reshape gender relations globally. Her work with the Barnard Center for Research on Women provides institutional support for this transnational feminist research network, facilitating scholarly exchange and collaborative publication projects that advance critical perspectives on gender, sexuality, and political economy.
Vadim Cherezov, the Ester Dornsife Chair in Biological Sciences and Professor at the University of Southern California (USC), leads groundbreaking research in membrane protein structure and function. Affiliated with the Bridge Institute, Department of Chemistry, and Michelson Center for Convergent Bioscience, his work focuses on GPCRs, ion channels, and transporters—critical targets for drug discovery. His team leverages advanced techniques like Lipidic Cubic Phase (LCP) and Serial Femtosecond Crystallography (SFX) at XFEL facilities to solve high-resolution structures under physiological conditions. Institutional Affiliations: Bridge Institute, USC Michelson Center, Department of Chemistry, Department of Pharmacology and Pharmaceutical Sciences. Key Collaborations: Katritch Lab, Kuhn Lab, NIH, European XFEL. His research explores the role of lipids in modulating GPCR function, addressing diseases like Alzheimer’s, diabetes, and cancer. By solving the structure of the A 2A adenosine receptor via sulfur SAD phasing at XFEL, Cherezov’s lab demonstrated de novo phasing without heavy atoms. This breakthrough enables structural studies of previously intractable membrane proteins. Scientific Awards & Grants: NIH R01 GM108635, U54 GM094618, U54 GM094599, R01 GM095583 Science Signaling Breakthroughs of the Year (2014) Cherezov mentors a dynamic team, including postdocs (e.g., Dong-Gyun Kim), graduate students (e.g., Behnaz Davoudinasab), and alumni (e.g., Benjamin Stauch at Eli Lilly, Nairie Michaelian at Genentech). His lab’s publications span Nature , Science , and Cell , with recent work on Science Advances (2025) addressing ABEL-FRET for GPCR dynamics.
Elizabeth A. Simpson is an Associate Professor in the Department of Psychology at the University of Miami's College of Arts and Sciences. She serves as Associate Director of the Child Division and directs the Social Cognition Laboratory, focusing on infant social and cognitive development through interdisciplinary methodologies. Education: Ph.D. in Psychology (unspecified institution) Key Research Areas: Developmental Psychology, Autism, Social Cognition, Primate Studies, Visual Attention, Infant Behavior Her research investigates individual differences in infant visual attention, social motivation, and physiological markers like salivary oxytocin. Recent studies demonstrate: Stability of attentional patterns from newborn to 14 months Sex differences in early face detection Links between oxytocin levels and social affect in infants Neurophysiological markers in newborns later diagnosed with ASD Scientific awards include the NSF CAREER grant for neonatal imitation research. She contributes to open science initiatives through the ManyBabies consortium and develops remote eye-tracking methods for broader accessibility. Current lab work explores: Parent-infant affective interactions during still-face episodes Predictive power of early attentional biases Development of pathogen avoidance behaviors Cross-species comparisons of social cognition