Bullying and Lifelong Scars

Abstract

Abstract Junior blue-foot and human siblings contradict the conventional expectation that stressful early environments do lasting developmental damage. Although junior blue-foots suffer violent subordination, partial starvation, slow growth, and high levels of stress hormone due to abuse by elder siblings, important developmental impacts never materialize. During adulthood, juniors show no deficits in defense of territory, annual survival, cellular immunity, age and date of first breeding, or the number of fledglings produced through age 16 years. Similarly, although one-third of junior human siblings suffer physical, psychological, or relational aggression from siblings on a weekly basis, affecting self-esteem, loneliness, anxiety, interpersonal stress, and depression, rigorous studies found no effects on the major personality traits in adulthood: emotional stability, extraversion, agreeableness, conscientiousness, and imagination. Both species may have evolved developmental resilience to the stresses of sibling conflict, a predictable challenge of infancy, and similar resilience has been observed in other wild birds.