This experiment proposal is designed to research how different sensory inputs (visual, auditory, and tactile) from different social relationship groups (peers, parents, spouse) may affect perception of loneliness. The importance of peers and parents for juveniles, and spouses for adults will be addressed. The experiment will use zebra finch songbirds as the model to provide further insight into human research. Circulating cortisol will be measured as higher loneliness is associated with greater stress, and therefore higher cortisol levels (Levine, Zagoory-Sharon, Feldman, Lewis, & Weller, 2007). The results are predicted based on existing literature. For juveniles, it is expected that loss of any component of sensory input from social relationships will put them at risk of having at least medium loneliness. Hearing parents may exert the biggest impact on stress and loneliness, while being able to see peers is predicted to be the least influential. For adults, all sensory inputs from a partner are crucial as well. Affectionate communication and positive support show the most priority. No difference between males and females were anticipated. We expect the human to have similar patterns as the zebra finch because their social relationships are comparable. Implications drawn from this experiment in further design and establishment of interventions for reducing human loneliness are discussed.