Effects of Heuristic-Systematic Information Processing About the Flu and the Flu Vaccination

Despite receiving flu vaccination campaign messages every year, only about 46.8% of United States (US) residents received the vaccine during the 2016-2017 flu season. People have different levels of risk perception of hazardous events based on their knowledge and experiences. Accordingly, this study examined the different ways in which individuals perceive risks and benefits through exposure to health information campaigns.

As author SangHee Park explains, psychological barriers such as fears over vaccine safety and efficacy can cause low coverage of the flu vaccination and lead to misperceptions of flu vaccination. For instance, individuals may mistakenly perceive that they can get the flu from the shot; that the vaccination causes side effects; and that it is not necessary for young people to get the shot. These misperceptions are also created and reinforced by the mass media, which by failing to discuss the safety and efficacy of the vaccine without providing conclusive information can create mistrust and raise doubts. It is suspected that despite the well-documented benefits of the vaccination, many people may not be aware of the benefits of the flu vaccine. Information sources can affect risk perceptions and the tendency to engage in the risk management behaviour endorsed by the source.

Park offers a literature review - first on the topic of risk perception. Applying previous research, she hypotheses that higher risk perception of the flu leads to higher perceived benefits of the flu vaccination (H1a) and to lower risk perception of the flu vaccination (H1b). Second, she examines prior research on the heuristic-systematic model (HSM), which involves processing of risk information based on individuals' past experiences and observations (rather than the more analytic systematic information processing). When individuals perceive a risk as being an important issue to their life (higher motivation), they use systematic information processing, although they might lack the ability to comprehend and processes it. Larger gaps of information and lower abilities to understand information are found to be strongly related to heuristic information processing. The present study hypothesises: that a heuristic message generates a higher risk perception of the flu (H2a) and flu vaccination (H2c) than a systematic message; that a systematic message generates a higher benefit perception of the flu vaccination than a heuristic message (H2b); and that a systematic message generates a higher intention to get the flu vaccination than a heuristic message (H2d). Noting that people with more vaccination knowledge are more likely to ask a physician about vaccination information, the study also examines how expert vs. non-expert sources affect perception of the flu and flu vaccination, generating several additional hypotheses (e.g., that a message coming from an expert source generates higher risk perception of flu illness than a message coming from a non-expert source - H3a). 

This investigation applied a 2 (message framing: heuristic vs. systematic) × 2 (sources: expert, vs. non-expert) factorial experimental. The experiment manipulated 2 different types of messages (heuristic information messages and systematic information messages), and US Centers for Disease Control and Prevention (CDC) information from 2 different providers (an expert source and a non-expert source). The manipulated message was in the form of a 7-paragraph essay that provided general information about the flu and flu vaccination. The systematic information processing message provided probabilities of risk, specifically scientific information about flu vaccination and the flu. The heuristic information message provided metaphors and narratives about flu and flu vaccination. The expert source study manipulated risk information coming from a doctor on a hospital website; the non-expert risk information came from an unknown individual on a blog site discussing flu information from the CDC.

Only 3 participants (1.7%) of the 178 who were included in the final analysis correctly answered all 11 questions about knowledge of flu vaccination. Twenty participants (11.24%) agreed with one item: Diseases like autism, multiple sclerosis, and diabetes might be triggered through vaccinations. Ninety-three participants responded that they did not know the answer to this question. This result showed that due to this fear, participants might not get vaccinated against the flu. Other findings:

• Participants who had higher risk perception of the flu illness and the flu mortality had the highest benefit perception of flu vaccination.
• Higher risk perception of the flu vaccination led to low risk perception of the flu vaccination.
• Higher risk perception of flu illness led to higher benefit perception of flu vaccination, whereas risk perception of the flu did not lead to an increased level of risk perception of flu vaccination.
• Between groups who received a heuristic message and a systematic message, there were no statistically significant differences in the level of risk perception of the flu, in the level of risk perception of flu mortality, in the level of benefit perception of flu vaccination, or in the level of intention to get the flu vaccine. However, participants who received a heuristic message perceived higher risk of flu vaccination than a systematic message.
• Participants who received a message coming from an expert source are more likely to get the flu vaccine than those receiving a message from a non-expert source.

In discussing the findings, Park stresses that, when people analyse benefits and risks of a health issue, information processing requires analytical information processing ability. For instance, when people perceive the benefits of health issues, they analyse information based on scientific facts, source expertise, their own experiences, observations, and the experience and/or observations of others. However, when people perceive risks, they focus more on just the risks, even though the information may not be based on scientific facts and/or professional opinions due to a lower ability for interpreting information. Therefore, heuristic messages with an expert source were found in this study to be more effective on benefit flu vaccination perception and flu vaccination intention than other messages.

These findings indicate that health campaigns need to discuss the benefits of the flu vaccination based on scientific evidence. Park stresses that health campaigns should consider literacy levels in order to increase the level of understanding of health information, especially when presenting health statistics. She recommends testing information sufficiency for achieving positive effects from heuristic and systematic information processing, because the level of motivation to learn about the flu and the flu vaccination may affect the understanding of the information.