Why do people say they are willing to do something and they don’t do it? In marketing, we study how to predict the buyers’ purchasing behavior by determining the consumers’ attitude towards a brand. Unfortunately, our behavior is not always consistent with our intention. Humans are hard to predict.

Roshi & Rahman (2015), for instance, found that despite the positive attitude of customers towards sustainability, “there is little evidence to suggest that purchase of green products has increased”. That happens because general attitudes do not predict specific behaviors accurately. Attitudes are just one of the factors that influence behavior.

Dr. Icek Ajzen, psychologist and professor emeritus at the University of Massachusetts, explains why: there are several constructs regarding attitudes. To understand them, Ajzen created The Theory of Planned Behavior (TPB).

In marketing research, the TPB is used to predict specifically defined behaviors, with a specific action, context, and time frame. An example of a survey question applying the TPB may be:

From 1 to 7, how likely are you to buy green products, in the restaurants on campus, during fall term?

However, according to Ajzen’s theory, the answers to the survey can be affected by three factors:

Behavioral beliefs: about the likely consequences of the behavior.

Normative beliefs: about the normative expectations of others.

Control beliefs: about the factors that facilitate or hinder the behavior

The following scenario is an excellent example to understand the role of a contributing factor, such as the Perceived Behavioral Control:

Jane’s intention to buy a new car this week will likely decrease because she’s not receiving any salary this month. Jane knows she doesn’t have enough money.

Likewise, here is an example of a Subjective Norm affecting behavior:

Jane wants to donate her savings to charity this summer but her best friends are planning a vacation together. Jane doesn’t want to upset her best friends.

The above contributing factors were also studied to predict condom use in college students.

A report by the Centers for Disease Control, CDC.gov/std/, estimates that “nearly 20 million new STIs cases occur every year in the United States (US) with 50% of those cases occurring among young people ages 15–24 years old.” Using the Theory of Planned Behavior, Dr. Matthew Asare, from Northern Kentucky University, studied condom use behavior among 218 college students.

Dr. Asare’s report shows that, in college, sometimes, attitude and behavior are not correlated, and this factor contributes to the sexually risky behavior and increasing rate of sexually transmitted diseases:

“The participants had high favorable attitude toward condom use as it was evident in their mean score of 50.55 (SD = 19.19)”.

Nevertheless, “over 93% of respondents had sexual intercourse in the past three months; 59% of them did not use a condom. A total of 51% had sex with more than one partner in the past three months. More surprisingly, 9% did not use condoms.”

The Theory of Planned Behavior does not assume that consumers’ behavior is rational. There are contributing factors, such as attitudes, subjective norms, and perceived control that can be distorted by biases, wishful thinking, or mental states like paranoia.

Please share with me any experience in this matter. I’m here to listen.

Ivanna Planet - 45 posts

Ivanna is a marketing specialist whose passion is traveling to exotic destinations. As a journalist in Latin America, she has reported news on business and politics.