Theses and Dissertations

Date of Award


Document Type


Degree Name

Master of Science (MS)



First Advisor

Dr. Karl S. Berg

Second Advisor

Dr. Julie Mustard

Third Advisor

Dr. Daniele Provenzano


The Social Intelligence Hypothesis (SIH) proposes that navigating complex societies requires increased neural processing to monitor shifting relationships. SIH evolutionary focus of brain size variation in adults originally ignored the developmental frameworks leading to increased sociality. I studied the ontogeny of early sibling interactions in wild Green‐rumped Parrotlets (Forpus passerinus) in a Venezuelan population that exhibited large variation in brood size and engaged in elaborate social interactions and complex social learning during nestling development. To test if nests of varying brood sizes exhibit differences in social complexity, I quantified the number and strength of sibling play partnerships, as a proxy for social bonds, and constructed social networks. Indices of social connectedness increase with brood size but not sibling age hierarchies. Highly connected siblings also learned vocal signatures earlier in development than less connected siblings, reflecting that social interactions affect at least one parameter of cognitive development.


Copyright 2019 Caleb Michael Mand Arellano. All Rights Reserved.