Kimberly Kirkpatrick Ph.D.

The Power of Everyday Choices

Self-Control

Gender Effects on Self-Control

Behavioral interventions promote self-control in both males and females.

Posted Feb 08, 2020

By Kelsey Panfil and Kimberly Kirkpatrick

A failure to include both genders in clinical and pre-clinical research analyses can result in detrimental health outcomes. Historically, most scientific research has focused on testing males, with only rare studies including females.

For example, the U.S. Food and Drug Administration (FDA) released a statement last year recommending women take half the previously prescribed dose of a common insomnia drug. The original research was conducted with men and led to incorrect recommendations for women. More recent results showed that women eliminated the insomnia drug from their bodies more slowly than men, increasing the risk for impairment the following morning. The key lesson is that clinical and pre-clinical (e.g., animal) research including both genders is essential for ensuring optimal health outcomes.

Evaluation in men and women is especially important when they differ in underlying behaviors. Impulsivity differs in men and women. Men make more impulsive choices when the rewards are real, while women make more impulsive choices when the rewards are hypothetical.

Impulsivity is related to a wide range of problematic behaviors, such as substance abuse, gambling, and poor diet. In addition, there are sex differences in the prevalence of these problems and the progression to disease. For example, women progress from use to abuse of alcohol faster than men, but men are more likely to meet criteria for abuse (Randall et al., 1999). Issues with self-control underlie many costly problems for men and women. To improve decision-making, we must evaluate treatments in both men and women.

Previous pre-clinical research has not directly compared female and male treatment outcomes following time-based interventions. We examined a fixed interval intervention in female and male rats. Rats perform well in behavioral studies that last for several months, and the methods for measuring behavior in rats can be easily related to humans.

During the intervention, the rats received repeated exposure to 10-second and 30-second delays to food rewards. The rats in the control condition received food rewards immediately. Across the intervention and control conditions, female rats were more self-controlled than males when offered a choice between a small reward after a short delay and a larger reward after a longer delay.

In addition, the intervention consistently increased self-control compared to the control group. Analyses that incorporated data from both the original experiment and its replication showed that there are no consistent differences between male and female responses to the intervention. This indicates that although females are less impulsive overall than males, they are similarly responsive to time-based intervention treatment.

Kim Kirkpatrick
Males and females show a similar response to behavioral interventions on average, but males are less variable than females.
Source: Kim Kirkpatrick

Time-based interventions successfully improve self-control in children and adults with and without developmental disabilities (e.g., Schweitzer & Sulzer-Azaroff, 1988). These interventions are reliably effective in male rats (Smith, Marshall, & Kirkpatrick, 2015) and show promising evidence in female rats (Stuebing, Marshall, Triplett, & Kirkpatrick, 2018). The effects of these interventions are typically long-lasting, specifically up to nine months in male rodents (Bailey, Peterson, Schnegelsiepen, Stuebing, & Kirkpatrick, 2018).

Our study is the first to directly compare male and female rats after a time-based intervention, which has not yet been done in humans. Our results suggest that extended exposure to waiting improves self-control, which is an important predictor for physical health and personal finances (Moffitt et al., 2011).

Practice waiting may not be the only component of the intervention that improves health outcomes. The intervention provides prolonged experience with specific time intervals. Rats may learn to time these delays during the intervention and utilize timing information to make better choices.

Previous research shows that rats that made more impulsive choices also had poorer timing ability (Smith et al., 2015). Future research is needed to understand whether the timing information, practice waiting, or a combination of both results in the increases in self-control. Understanding what component(s) of the intervention produce the improvement to self-control is paramount for translating this intervention for use in men and women.

FDA Drug Safety Information the Use of Insomnia Drugs by Women

Diet-Induced Impulsivity 

References

Bailey, C., Peterson, J. R., Schnegelsiepen, A., Stuebing, S. L., & Kirkpatrick, K. (2018). Durability and generalizability of time-based intervention effects on impulsive choice in rats. Behavioural Processes, 152, 54-62.

Moffitt, T. E., Arseneault, L., Belsky, D., Dickson, N., Hancox, R. J., Harrington, H., . . . Caspi, A. (2011). A gradient of childhood self-control predicts health, wealth, and public safety. Proceedings of the National Academy of Sciences, 108(7), 2693-2698.

Randall, C. L., Roberts, J. S., Del Boca, F. K., Carroll, K. M., Connors, G. J., & Mattson, M. E. (1999). Telescoping of landmark events associated with drinking: a gender comparison. Journal of Studies on Alcohol and Drugs, 60(2), 252-260.

Schweitzer, J. B., & Sulzer-Azaroff, B. (1988). Self-Control: teaching tolerance for delay in impulsive children. Journal of the Experimental Analysis of Behavior, 50(2), 173-186.

Smith, A. P., Marshall, A. T., & Kirkpatrick, K. (2015). Mechanisms of impulsive choice: II. Time-based interventions to improve self-control. Behavioural Processes, 112, 29-42.

Stuebing, S. L., Marshall, A. T., Triplett, A., & Kirkpatrick, K. (2018). Females in the forefront: Time-based intervention effects on impulsive choice and interval timing in female rats. Animal Cognition, 21(6), 759-772.