However, few studies focus exclusively on personality plasticity in older adults, as they also face various life changes (Maiden, Peterson, & Caya, 1999). A longitudinal study conducted by Maiden, Peterson, and Caya (1999) is significant in measuring personality change among older adults through a sample of older women, with an average age of eighty. Maiden, Peterson, and Caya (1999) hypothesized that personality change occurs predominantly in periods in which the conditions of one's existence change dramatically, anticipating moderate change. Participants were sampled multiple times, revealing that when negative life changes were made, the personality followed suit. For example, Maiden, Peterson, and Caya (1999) found that participants felt less extraverted when they suffered from poor health. Likewise, participants indicated that nervousness and irritability intensified, also due primarily to unwanted life changes. The conclusions drawn by Maiden, Peterson and Caya (1999) allow them to confirm their hypothesis. Therefore, the plasticity of an individual's personality throughout his life, even in its final stages, is undeniable