To Flush or Not to Flush? Part III

Further In-depth Understanding of the Human Capacity to Act Model

Previously in this three-blog series, we discussed how the Human Capacity to Act (HCA) Framework could be used by researchers to learn about what influences people to dispose of Pharmaceuticals and Personal Care Products (PPCPs) the way that they do. PPCPs get into the environment through flushing and other improper disposal methods and studies have shown that the best way to influence people to change their behavior is by affecting them at the social level. This can be done by educating people about the potential negative influence of their actions and starting a discussion about this within communities.


Figure 4

Figure 4. Human Capacity to Act (HCA) Framework


When understanding HCA, the larger the area of the triangle, the more likely a person will change their behavior. With institutional choice having the largest area of the triangle, it shows a greater expected change for behavior change, followed by social proof, and then rational choice at the very top. According to this triangle concept, rational choice has the smallest impact on behavior change, though many agencies and organizations base their outreach and education on rational choice.

Let’s take a look at potential everyday situations:

  • Rational choice: You’re a chain smoker and you see a commercial that says “stop smoking, it’s bad for your health”… does this make you quit smoking cold turkey?
  • Social proof: You move to Corvallis, OR and because most of the people around are OSU Beaver fans, it is easy for you to automatically become one too.
  • Institutional choice: You wear your seatbelt every time you’re in the car because there is a seatbelt law and you may be fined if you don’t wear it.

Now, let’s take a look at a PPCPs example situation:

You look into your medicine cabinet and see a handful of prescription medications that you no longer need or use. What do you do with them? Here’s how the Human Capacity to Act Framework would work in this scenario:

  • Rational choice: You remember seeing a poster at the bus stop that said, “Don’t flush your medication down the drain!” You think that since a poster was made with this message in such strong command words that it must be valid and that you should listen to whomever made that poster. This thought process can be attributed to the assumption that people want to do what is right and that decisions are based off of what people care about. It was mentioned in blog two that typically when someone doesn’t do something, those around them will assume that they simply don’t care about the cause.
  • Social proof: You’re chatting with your neighbor and he tells you about the medication collection boxes where he was able to dispose of a bag of unused medication safely at the law enforcement office in town. Since other people seem to be able to easily do this, it would be achievable for you too. Also, the fact that others are taking the time to protect the environment and waterways by properly dispose of medication, you too can afford to do this.
  • Institutional choice: There is a law against throwing away or flushing your unused medication down the drain and a fee is imposed (hypothetical situation). You avoid flushing simply to avoid paying the fine in this situation.

In the case of institutional choice, you want to avoid being fined for throwing away or flushing your unused medication, so you decided to just keep them in your medicine cabinet longer. In the rational choice situation, you see the poster tell you what not to do, but how much influence does that really have on your decision? Convenience is a huge factor in rational choice – you could think that just flushing a few pills down the drain won’t hurt much. Social proof brings into perspective that when you are unsure of what to do in a situation, you look to the people you trust around you to help make your behavior choice. A person’s experiences and stories can have a great influence on the everyday decisions they make.


“The challenge lies in a willingness to do things differently than we have in the past” (Hungerford & Volk, 1990).


Routine and convenience have become influencing factors in the decisions we make today, but those are usually driven by individual intentions. With community and trusted networks around, they can become the new source of united intentions. Because responsible behavior is important in the face of PPCPs in the environment, the Human Capacity to Act Model is a new model that displays that education on the community level can lead to PPCP stewardship actions.


This blog is the third part of a three-blog series introducing a model and detailing its use through the example of PPCP disposal. As we conclude the series, readers can reflect with a few questions to discuss on your own, with friends, or even in the comments section of this blog: How can you apply the Human Capacity to Action Model in your life? How have you come to the decision to dispose of your unused medications?



Credit to: Jennifer Lam, Samuel Chan, Tania Siemens, and Kayla-Maria Martin


Resources:UpClose Interviews: A behind the scenes look at the researchers working on the topic of PPCPsOSU extension survey 2014: This survey looks into where Oregonians go to for information and want to invest additional funding on different environmental/natural resources, hazards, economic, academic/professional development, youth and human health issues.Ruben Anderson’s blog “a Small and Delicious Life”: The idea of compassionate systems to address the frustration and failure of behavior change

Oregon Drug Collection Box locations (PDF)



Literature Cited (all three blogs):

Anderson, R. (2013). Compassionate systems. Invasive Species Forum. Lecture conducted from Invasive Species Council of BC, Richmond, British Columbia.

Daughton, C. G. (2004). PPCPs in the environment: future research—beginning with the end always in Hungerford, H. R., & Volk, T. L. (1990). Changing learner behavior through environmental education. The journal of environmental education, 21(3), 8-21.

Frey, T. (2013). Our alarming culture of pill people and future trends in healthcare. Retrieved June 23, 2014, from

Hungerford, H. R. , & Volk, T. L. (1990). Changing learner behavior through environmental education. Journal of Environmental Education , 21(3), 8-21.

King County (2013). Brightwater Treatment Plant- a clean water treatment facility. Wastewater Treatment; King County, Washington.

Lam, Jennifer, et al. (2014). Dose of reality: What can we learn from pet owners in veterinary and education professions to guide more effective environmental stewardship of pharmaceutical and personal care products (PPCPs)? AMERICAN WATER RESOURCES ASSOCIATION (AWRA) National Conference “Social Science of Emerging Contaminants”. Nov. 3, 2014. Tyson’s Corner, VA.

McLeod, K. L., & Leslie, H. M. (2009). Why ecosystem‐based management. In K. L. McLeod & H.M. Leslie (Eds.), Ecosystem‐Based Management for the Oceans. Washington, D.C.: Island Press.

Morace, J. L. (2012). Reconnaissance of contaminants in selected wastewater-treatment-plant effluent and stormwater runoff entering the Columbia River, Columbia River Basin, Washington and Oregon, 2008-10. US Department of the Interior, US Geological Survey.

OSU extension (2014). OSU extension statewide survey. Retrieved April 30, 2014, from

Piore, A. (2013) Blissed-out on Prozac. Nautilus. Issue 7 Chapter 1: Available at:

Zhang Y, Geißen SU, Gal C. Carbamazepine and diclofenac: removal in wastewater treatment plants and occurrence in water bodies. Chemosphere 2008;73:1151–61.

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About Danielle Goodrich

I am a senior studying Environmental Science and Zoology at OSU. I started at Oregon Sea Grant in summer 2013 as a PROMISE Intern and I was then offered to continue to help with the WISE program and other projects.
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