Australian science and Mathematics School
What extent does the route of
persuasion influence an audience’s
heart rate?
Melanie Bennett
July 2014
Introduction
Smoking contains chemicals that can negatively affect a person’s body. Advertisements are using a variety of
techniques to persuade the public’s attitude’ on smoking to encourage people to quit or not start. There are
two routes of persuasion used in advertisement; central and peripheral (Spencer & Hartstone, 2007). Central
route persuades by making the audience think carefully about the message. Peripheral route persuades by
using cues associated with pleasure, beauty and emotional response.
A group of year 12 students participated in an experiment to observe how the route of persuasion of an
advertisement would influence a participant’s emotional response. This investigation was based on studies
such as ‘Central and peripheral routes to persuasion: An individual Difference Perspective’ by the American
Psychological Association. The aim of the investigation was to explore which route of persuasion in antismoking advertisements would evoke a stronger emotional response. Participants were divided into two
groups and were exposed to anti-smoking advertisements using a central or peripheral route of persuasion.
Group 1 were exposed to a central route of persuasion and group 2 were exposed to a peripheral route of
persuasion. Participants were instructed to measure their heart rate after exposure to test the effectiveness of
the advertisements at evoking emotional responses.
The independent variable was the route of persuasion used in the advertisement; central or peripheral route.
The dependent variable was the heart rate of participants after exposure measured in beats per minute. A
number of possible extraneous variables were kept constant such as the method participants used to measure
their heart rate, the age of participants and the type of advertisement used.
Hypothesis:
People who view the advertisement with a central route of persuasion will have a higher heart rate than those
viewing the advertisement with a peripheral route of persuasion.
Results
Heart Rate (Beats per Minute)
Influence of route of Persuasion on
Heart Rate
75
70
65
60
55
50
Central Route
Peripheral Route
Route of Persuasion
Graph 1: A column graph representing the mean heart rate of 2 groups exposed to either anti-smoking advertisements
with a central or peripheral route of persuasion
Discussion
Interpretation
Graph 1 represents the mean heart rate of groups exposed to advertisements with different routes of
persuasion. Group 1 had a mean heart rate of 60 BPM. Group 2 had a mean heart rate of 72 BPM. The trend
shows the mean heart rate of those exposed to the peripheral route of persuasion was higher than those
exposed to the central route of persuasion.
From the trend in graph 1, the hypothesis ‘People who view the advertisement with a central route of
persuasion will have a higher heart rate than those viewing the advertisement with a peripheral route of
persuasion’, was not supported. The difference in the mean heart rate between participants exposed to
advertisements with a peripheral route of persuasion compared to central routes of persuasion suggest the
peripheral routes of persuasion have a greater impact on heart rate.
The standard deviation of the group exposed to a central route of persuasion was 10. It is unlikely that a
different sample size would produce notable differences in results because the low standard deviation
suggests there were no significant outliers in the results.
Evaluation
The mean difference of heart rate in groups exposed to peripheral and central routes of persuasion was 12;
this does not appear significant. The small difference suggests there may be a lack in the effectiveness of both
advertisements sources, messages, channels of communication or the validity and reliability of results.
Validity and Reliability
The experimental design tested the heart rate of participants exposed to advertisements with either
peripheral or central routes of persuasion. The standard deviation suggested there were no significant outliers
in the results. The experimental design kept all participants in the same environment which may have
improved the reliability. However, the results can’t prove reliable unless repeated experiments produce similar
results; a second, similar group of participants should be tested to support the reliability of results.
To ensure the validity of the experiment, the data collected was objective quantative. The data was collected
by the participants to prevent misinterpretation of results by the interpreter or other participants. However,
many participants had difficulty measuring their heart rates and hadn’t measured heart rates before. This may
have caused participants to measure their heart rates inaccurately. This inaccuracy could have substantially
affected the results because results are not accurately based on their true heart rates. If the experiment was to
be repeated, the heart rates should be tested someone who has experience measuring heart rates.
Sample Size and Representativeness
The experiment was focused on the influence of routes of persuasion in anti-smoking advertisements on heart
rate. The sample size of 35 students was not varied or large enough to represent a population besides year 12
ASMS students. The results could not represent people of a different age because heart rate slows down as a
person ages (Stern, Behar & Gottlieb, 2003).
Year 12 psychology students at the ASMS were used as the sample size. It is likely that the sample size could
represent a population of senior students because ASMS students have a variety in culture and the experiment
used random allocation; these are important aspects to consider when representing a population of senior
students.
Strengths
The main strength of the experimental design was the prevention of variance in heart rate affecting the
results. Differences in weather, stress and age can affect participant’s hearth rate. Extraneous variables that
may influence heart rate such as noise and temperature were kept constant to ensure changes in heart rate
were only influenced by the route of persuasion.
The experimental design also prevented the placebo effect from influencing results. This occurs when a
participant’s response is influenced by their expectations of how they are supposed to respond (Spencer &
Hartstone, 2007). To ensure responses were only influenced by the independent variable, participants were
randomly allocated into groups with no knowledge of it were a control group and no knowledge of the
investigations purpose.
Weaknesses
Firstly, there was a lack of consistency in the amount of time participants were viewing the advertisements.
Time exposure may affect the emotional response obtained. An improvement would be to use a video
advertisement instead of a picture to ensure participants viewing time is consistent.
Secondly, the design used an objective form of measurement; heart rate to decrease the risk of
misinterpretation by the interpreter. However, heart rate may not be a valid way of measuring emotional
responses because heart rates vary between people. An improvement would be to measure the heart rate
before and after viewing the advertisement to calculate the change in heart rate to measure the emotional
response.
Lastly, the experimental design may not apply to the real world but using a qualitative investigation design
may effectively explore more in depth into how anti-smoking advertisements in every day life may have
affected participants.
Ethics
The participant’s well being was the main consideration before conducting the investigation. Participants had
the right to their privacy, therefore, no personal details were disclosed and each participant was allocated a
random number to ensure data from participants were anonymous. Participant’s confidentiality was disclosed
effectively due to the participants being spread out and their numbers being hidden from one another. All
participants voluntarily signed a consent form stating that they wanted to take part; a small concern is that
participants felt obliged to participate because the experiment was a part of an assignment. Participants had a
right to withdraw from the experiment and this was also expressed prior to the investigation. Informed
consent procedures are a large part of ethical considerations; however, procedures were not discussed in
detail prior to the procedures due to knowledge of the investigation possibly influences the results. However,
after the experiment took place, participants were debriefed; by being informed of the purpose and given
support as a result of any distress experienced during participation.
Conclusion
The aim of the investigation was to explore which route of persuasion in anti-smoking advertisements would
evoke stronger emotional responses. The emotional response was measured as the heart rate of participants
after expose to an advertisement. It was hypothesised that ‘People who view the advertisement with a central
route of persuasion will have a higher heart rate than those viewing the advertisement with a peripheral route
of persuasion’. The trend in the results did not support to hypothesis. Although the results produced were
likely to be reliable, the results may not be applicable in the real world and heart rate may not be a valid value
to measure emotional responses. Additional testing with an improved method may gain insight into which
route of persuasion is more effective at evoking emotional responses in anti-smoking adverts.
Bibliography
Petty, RE & John, CT 1988 ‘Central and Peripheral Routes to Persuasion: An individual Difference Perspective’,
Journal of Personality and Social Psychology, vol, 46 no. 1, pp. 69-81, viewed 10 July 2014,
<http://psychology.uchicago.edu/people/faculty/cacioppo/jtcreprints/pc84a.pdf>
Spencer, P & Hartstone, M 2007, ‘Psychology Stage 2’, John Wiley & Sons Australia, Queensland, pp. 12 – 61
Stern, S, Behar, S & Gottlieb, S 2003, ‘Aging and Diseases of the heart’, American Heart Association, viewed 10
July 2014, <http://circ.ahajournals.org/content/108/14/e99.full.pdf+html>
Word Count: 1505