My research program broadly explores how the internal and external environment influences an organism’s phenotype. I focus my work on highly evolved animal behaviors – namely, complex sociality and cognition. These traits require specialized integration of the social and physical environment to produce adaptive responses. As such, my research aims to uncover the physiological mechanisms that mediate social behaviors and cognition. Using integrative and comparative approaches, I apply work in the laboratory and field to address the mechanistic underpinnings of complex, ecologically relevant behaviors.
A major aim of my research is to understand the cognitive processes that free-living animals use to navigate their environment. I am especially interested in the neuroendocrine mechanisms that mediate learning and memory. To test ecologically relevant hypotheses, I developed cognitive assays for use in the field, use state of the art radio frequency technology, and employ experimental endocrine techniques.
My work thus far has found previously undescribed hormonal mechanisms of memory regulation. In Florida Scrub Jays (Aphelocoma coerulescens) moderate levels of glucocorticoids (steroid hormones associated with the physiological stress response) is associated with “over consolidation” of long-lasting fear-based memories, while low and high concentrations led to memory decay and generalization; too much or too little physiological stress leads to “fuzzy” memories. These novel findings highlight the importance of studying cognition in ecologically relevant contexts.
A major goal in organismal biology is to understand how and why animals use different strategies to survive and reproduce. I approach this challenge from an ultimate and proximate perspective: First, how does evolution shapes variation in life-histories among species? Second, what causes individuals of the same species to use alternative life-history strategies? To answer these questions, I draw on natural history and consider how the external (social and ecological) and internal (hormonal and genetic) environments of organisms interact.
My work has shown that the development of the hypothalamic-pituitary-adrenal (HPA) axis (a major regulator of the physiological stress-response) correlates with vocal mimicry ability among song-birds, a possible adaptive response to the negative effects of stress on learning. I have also found that growth and survival is significantly influenced by the El Niño Southern Oscillation (ENSO) and GC exposure in a tropical passerine, the lance-tailed manakin (Chiroxiphia lanceolata). Similarly, telomere length during development and adult hormonal stress-responsiveness predicts social status in lance-tailed manakins.