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Cohort Effect in Psychology: Definition and Examples

The cohort effect refers to the influence of a person’s generation or birth cohort on their attitudes, beliefs, behaviors, and life experiences.

Cohorts are groups of individuals who share a common historical or social context, such as those born in the same time period, raised in the same cultural environment, or experienced a similar event or social phenomenon. 

The cohort effect is important in psychology because it can help explain why individuals from different generations may have different values, attitudes, and behaviors. 

For example, a cohort of people who grew up during the Great Depression may be more frugal and conservative with money than a cohort of people who grew up during a time of economic prosperity.

Similarly, a cohort of people who grew up during a time when smoking was socially acceptable may have different attitudes toward smoking than those who grew up when smoking was widely recognized as harmful. 

By understanding the cohort effect, psychologists can gain insight into how historical and cultural factors shape individual development and behavior and how these factors may influence how people respond to interventions and treatments.

How the Cohort Effect Impacts Research

The cohort effect can have different implications for longitudinal and cross-sectional research methods

Longitudinal Research

In longitudinal research, the same group of individuals is followed over a period of time. The cohort effect can be a significant factor in longitudinal research because it allows researchers to track how attitudes, beliefs, and behaviors change within a particular group over time. 

Longitudinal studies can provide a more accurate picture of developmental changes. This is because they allow researchers to control for cohort effects by examining changes in individual participants over time.

However, longitudinal studies can also be time-consuming and expensive to conduct, and the sample may not be representative of the larger population if the cohort is not randomly selected.

Cross-Sectional Research

In cross-sectional research, data is collected from individuals of different ages or cohorts at the same point in time. The cohort effect can also have an impact on cross-sectional research because it may be difficult to distinguish between age-related changes and cohort-related changes. 

For example, if a cross-sectional study shows that younger people are more likely to use social media than older people, it could be due to a cohort effect where younger people were exposed to social media from a younger age.

Alternatively, it could be due to an age-related effect, where younger people are generally more tech-savvy than older people. 

The cohort effect can have important implications for both longitudinal and cross-sectional research, and researchers must carefully consider the potential impact of cohort effects when designing and interpreting their studies.

Examples of the Cohort Effect

Some examples of the cohort effect include:

Attitudes Toward Marriage

Attitudes toward marriage have shifted over time, with younger generations being more likely to delay marriage and prioritize personal fulfillment over social expectations. This cohort effect has been attributed to changing social norms, increased education levels, and greater economic independence.

Technology Use

Cohort effects can also influence technology use. For example, older generations may be less comfortable with technology and have lower rates of social media use than younger generations who grew up with it.

Health Behaviors

Health behaviors can also be influenced by cohort effects. For example, Baby Boomers are more likely to smoke cigarettes and consume alcohol than younger generations, while younger generations may be more likely to engage in physical activity and practice healthy eating habits.

Gender Roles

Attitudes toward gender roles have changed over time, with younger generations being more likely to reject traditional gender roles and embrace gender fluidity.

This cohort effect has been attributed to changing social norms, greater exposure to diversity and inclusion, and greater awareness of gender issues.

How to Minimize the Cohort Effect

While it is not possible to completely eliminate the cohort effect, there are several ways that researchers can minimize its impact:

Use a Longitudinal Study Design

Longitudinal studies can help control for the cohort effect by examining changes within individuals over time, rather than comparing different groups of individuals.

Randomly Select Participants

Randomly selecting participants from a population can help ensure that the cohort is representative of the larger population and minimize the impact of cohort effects.

Control for Demographic Factors

Researchers can control for demographic factors such as gender, ethnicity, and socioeconomic status, which can help minimize the impact of cohort effects by isolating specific factors that may be driving differences across cohorts.

Use Statistical Techniques

Statistical techniques such as age-period-cohort (APC) analysis can help disentangle the effects of age, period, and cohort, and provide a more accurate understanding of how different factors contribute to changes over time.

Consider Multiple Cohorts

Researchers can examine multiple cohorts simultaneously to compare how different cohorts are changing over time and identify patterns of change that may be specific to a particular cohort.

By using these methods, researchers can minimize the impact of the cohort effect and gain a more accurate understanding of how individuals and groups change over time.


Atingdui, N. (2011). Cohort effect. In: Goldstein, S., Naglieri, J.A. (eds) Encyclopedia of Child Behavior and Development. Springer, Boston, MA.

Kennison, R.F., Situ, D., Reyes, N., Ahacic, K. (2016). Cohort effects. In: Pachana, N. (eds) Encyclopedia of Geropsychology. Springer, Singapore.

Keyes, K. M., Utz, R. L., Robinson, W., & Li, G. (2010). What is a cohort effect? Comparison of three statistical methods for modeling cohort effects in obesity prevalence in the United States, 1971-2006Social Science & Medicine (1982)70(7), 1100–1108.