“Cognitive decline” as a variable in hiring is just ageism

The idea that you shouldn’t hire people over 40 due to cognitive decline is a misconception. While some specific cognitive functions may change with age, overall cognitive ability and job performance don’t necessarily decline. In fact, older workers often bring significant advantages to the workplace.

Cognitive Changes with Age

The changes in cognitive abilities as people age are complex and not a straightforward decline. Different types of intelligence and skills are affected in different ways.

Fluid Intelligence: This type of intelligence involves the ability to reason and think flexibly, solve new problems, and process information quickly. It tends to peak in early adulthood (around age 25) and may show a gradual, minor decline afterward. This is the kind of intelligence that’s often measured in IQ tests and can be associated with reaction time and multitasking.
Crystallized Intelligence: This refers to the accumulated knowledge and skills gained over a lifetime. It includes vocabulary, general knowledge, and practical experience. Crystallized intelligence typically continues to improve well into a person’s 60s and 70s. This means that while an older person may take slightly longer to process new information, their vast store of knowledge and experience gives them a significant advantage in areas like problem-solving, strategic thinking, and mentoring.

Advantages of Hiring Experienced Workers

Older workers bring many valuable qualities to an organization that often outweigh any minor changes in fluid intelligence.

Experience and Expertise: A person over 40 has spent years, if not decades, honing their skills and accumulating knowledge in their field. This makes them highly effective at their jobs and valuable mentors for younger employees.
Decision-Making: Studies show that older adults are often better at strategic learning and decision-making. Their extensive life and work experience allow them to filter out less important information and focus on what matters.
Higher Engagement: Research has found that work engagement often increases with age. Older workers tend to have a strong sense of purpose and are often more motivated and committed to their roles.
Emotional Regulation and Soft Skills: As people age, they often develop better emotional regulation and stronger “people skills.” This leads to more stable, collaborative, and professional working relationships.
Retention and Stability: Older employees tend to be more loyal and have a lower turnover rate, which saves companies significant time and money on recruitment and training.

Fluid and Crystallized Intelligence: The foundational concepts were developed by psychologist Raymond Cattell.

Cattell, R. B. (1963). Theory of fluid and crystallized intelligence: A critical experiment. Journal of Educational Psychology, 54(1), 1–22.

Cognitive Aging and Job Performance: Research in this area examines how age-related cognitive changes relate to performance in the workplace.

Kanfer, R., & Ackerman, P. L. (2004). Aging, adult development, and work motivation. Academy of Management Review, 29(3), 440–458.
Salthouse, T. A. (2010). Major issues in cognitive aging. Frontiers in Psychology, 1, Article 20.
Hedge, J. W., & Borman, W. C. (Eds.). (2007). The aging workforce: Realities, myths, and implications. American Psychological Association.

Work Engagement and Age: Studies that look at how employee motivation and engagement change over a career.

Ng, T. W. H., & Feldman, D. C. (2012). The relationship of age to ten dimensions of job performance. Journal of Organizational Behavior, 33(3), 351–371.

Soft Skills and Emotional Regulation in Older Workers: Research that highlights the development of non-technical skills with age.

Carstensen, L. L. (1995). Evidence for a two-factor model of emotional regulation. Journal of Personality and Social Psychology, 69(1), 163–175. (This is a foundational work on socioemotional selectivity theory, which explains why older adults often have better emotional regulation and social relationships).