The Stages of Life: Which One of the 4 Are You In?

This article is an excerpt from the Shortform book guide to "The Good Life" by Robert Waldinger and Marc Schulz. Shortform has the world's best summaries and analyses of books you should be reading.

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What are the four main stages of life? Why is it important to understand these stages?

The Good Life by Robert Waldinger and Marc Schulz defines the stages of life as adolescence, young adulthood, midlife, and late life. They argue that understanding these stages will help you better meet the challenges you’re facing in your life and be more empathetic to people in different life stages.

Discover more about the stages of life so you can understand yourself and others better.

Understanding the Life Stages

Waldinger and Schulz explain that the stages of life begin with adolescence, which occurs between the ages of 12 and 19 and is characterized by a struggle to establish one’s identity. Adolescents benefit greatly from having supportive adults in their lives, as these adults serve as exemplars of different lives one might live. However, adolescents themselves tend to prioritize relationships with their peers as they navigate friendships and start to have intimate, romantic relationships.

(Shortform note: Psychologist Erik Erikson also proposes that adolescence (12-18) is characterized by a struggle to establish one’s identity. Erikson suggests that this struggle manifests in two main areas: sexual relationships and occupational concerns (such as what they want to do with their lives). If an adolescent successfully overcomes this struggle, she will develop what Erikson calls “fidelity”—the ability to feel like herself while still conforming to societal expectations. Parents can contribute to this process by not comparing teens to other people. Additionally, set boundaries without attacking your kid; for example, don’t criticize their friends, as your child will interpret these criticisms as a personal attack.)

After adolescence comes young adulthood, which tends to occur between the ages of 20 and 40. Waldinger and Schulz write that young adults tend to experience a lot of stress as they struggle to find their footing in their careers and possibly create new families. Young adults need to be careful not to overwork themselves and neglect other people in their lives, such as their friends or their parents.

Midlife usually occurs between the ages of 41 and 65. Waldinger and Schulz assert that midlife can seem stable to the point of being boring, as people in midlife usually have established careers and families. But people in midlife are often plagued by the thought that they haven’t done enough with their lives—even though their lives are half over. Getting beyond this concern requires that people in midlife reach the “generativity” stage, which is characterized by a focus on making a positive impact on others rather than a focus on improving one’s own life.

(Shortform note: Erikson defines generativity slightly differently, arguing that it’s a desire to leave a legacy, and he points out that most people achieve it through parenthood—though you can also achieve it through other means. Erikson adds that if you are successful in your quest for generativity, you’ll develop “care,” the sense that you matter to others.)

Finally, late life usually begins after the age of 66. Waldinger and Schulz explain that people in this stage are often preoccupied with how well they’ve lived, how well they can live the remainder of their lives, and the legacy they’ll leave. People in this stage tend to be happy, as they’ve gained the perspective necessary to prioritize what matters and ignore small stressors that don’t. But they must make an effort to maintain relationships that may naturally dissipate as they stop doing certain activities like working. They must also learn to accept any help they may need.

(Shortform note: In Being Mortal, Atul Gawande suggests that older people don’t accept help due to the type of help provided. He explains that older people tend to focus on what will make them happy in the present, but the people caring for them have a future-oriented outlook. As a result, caregivers may support medical interventions that extend the elderly person’s life or suggest that she create new relationships to replace those that naturally dissipate, even though she would prefer interventions that improve how well she feels in the present and wants to prioritize her oldest, deepest connections instead.)

Daniel Levinson’s Stages of Adult Life

Like Waldinger and Schulz, psychologist Daniel Levinson divided human life into four main stages. But his stages consisted of 1) childhood and adolescence, 2) early adulthood, 3) middle adulthood, and 4) late adulthood, and they are primarily directed toward the stages of men’s lives.

According to Levinson’s theory, the first important stage is early adulthood, which generally occurs between 17 and 45. This stage features two important transitions: the early adult transition period (17-22), during which you first leave your family and set out on your own, and the age 30 transition (28-33), during which you evaluate your current state to determine whether you’ve made the right choices or need to pivot. In this stage, Levinson highlights the importance of having a mentor—someone who can help you achieve your life goals—rather than the importance of not working too much or neglecting your other relationships.

Middle adulthood begins around 40 and lasts until around 60. During this stage, the realization of your mortality sparks a midlife transition (40-45), during which you question your current career and relationships and may upend them in search of greater meaning. Finally, late adulthood begins at 60 and kicks off a period of trying to accomplish any goals you haven’t reached yet and leave an impactful legacy.

The Stages of Life: Which One of the 4 Are You In?