Identifying Structural Features of Radio:
Orienting and Memory for Radio Messages
Robert F. Potter
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Doctoral Candidate
Annie Lang
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Associate Professor
Paul Bolls
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Graduate Student
Department of Telecommunications
Institute for Communication Research
Indiana University
(812) 855-5824
Paper submitted to the Theory and Methodology Division
of the Association for Education in Journalism and Mass Communication.
Baltimore, MD
March, 1998
Please Review This Version Identifying Structural
Features of Radio:
Orienting and Memory for Radio Messages
Abstract
This paper examines the ability of nine different structural and content
features of radio to
elicit orienting responses from radio listeners. It further tests the effect of
the orienting response on
listeners' memory for information presented immediately following the orienting
eliciting feature.
Results show that eight of the nine features elicit orienting responses. On
average, memory is better
for information presented following those features than it is for information
presented before the
features. Identifying Structural Features of Radio:
Orienting and Memory for Radio Messages
Are there features of broadcast radio which can affect how audio messages
are cognitively
processed by listeners? Previous research has demonstrated that structural
features of video
messages can be manipulated by producers to influence audience members'
cognitive processing
(Anderson, 1983; Basil, 1994; Calvert, Huston, Watkins & Wright, 1982; Geiger &
Reeves, 1993;
Grimes, 1990; Gunter, 1987; Lang, Dhillon & Dong, 1995) but results of this work
have not been
extended to other media such as radio. Radio producers have acknowledged the
important role
structural features such as sound effects and vocal delivery play in capturing
audience attention
(Keith, 1990; Siegal, 1992). However, specific investigations into which
structural features
influence cognitive processing of radio messages have not been conducted. The
goal of this study is
to identify possible structural features of radio messages and examine their
influence on the
processing of message information.
Over the last 20 years research has attempted to identify the structural or
formal features of
television which alter television viewers' attention to and memory for
television messages. This
work began in the seventies with studies examining what aspects of children's
television caused
children to look at the TV (Anderson, Levin, & Lorch, 1977, Anderson, Lorch,
Field, & Sanders,
1981, Anderson, 1983). It was suggested (Singer 1980) that many of the formal
features of
television identified in this research were actually eliciting orienting
responses from child viewers.
An orienting response (Lynn, 1966) is a reflexive attention response
characterized by a
group of behavioral and physiological responses including looking toward the
stimulus that elicited
the response, a slowing of the heart rate, and an increase in skin conductance.
Further research determined that many structural features of television,
including cuts (Lang,
Geiger, Strickwerda, & Sumner, 1993), negative video (Lang, Newhagen, & Reeves,
1998), video-
graphics (Thorson & Lang, 1992), and movement (Lang, 1990, Reeves, Thorson,
Rothschild,
McDonald, Hirsch, & Goldstein, 1985) all elicited orienting in attentive
television viewers.
What was not clear, was whether the increase in attention elicited by these
structural features
increased or decreased memory for the messages (Anderson, 1983; Singer, 1980).
One view was
that these momentary increases in attention would automatically increase memory
for the messages.
The other view was that these involuntary responses would distract viewers from
the message
content and focus their attention instead on the peripheral or structural
aspects of the message.
Research investigating this question suggests that both things can happen
depending on how hard the
viewer is working to learn the content contained in the message.
For example, Thorson and Lang (1992) showed that when television viewers
were watching
easy or familiar content, memory for that content improved immediately following
a video-graphic
which elicited an orienting response. However, when the content was difficult
or unfamiliar,
memory decreased following the video-graphic. Similarly, Lang et al. (1993)
demonstrated that
when the content on either side of a cut was related, memory following the cut
increased. However,
when the content on either side of the cut was unrelated, memory decreased.
Similar results have
been found when looking at memory for television messages as a function of how
many structural
features they contain. If the content of a message is not demanding, then
viewers' memory for that
content improves when the message contains many structural features and elicits
many orienting
responses. However, if the message content is demanding, then memory for the
content of the
message is lower if there are a lot of structural features in the message (Lang,
Bolls, Potter, &
Kawahara, in press).
To date, this model has been applied almost exclusively to studying
television messages.
Very little research has been done to determine if these same effects might be
found in media other
than television. Potter, Bolls, and Lang (1997) conducted a study to determine
if radio listeners
exhibited orienting responses to structural features of radio. In that study,
several radio structural
features were combined to determine if listeners exhibited cardiac orienting
responses to these
combined structural features. The answer was yes.
This paper extends that work by examining individually the specific
structural features,
which were combined in the previous study, to determine if they elicit orienting
responses in radio
listeners. Nine different structural features and sound effects were combined
in the previous study to
test the basic orienting hypotheses. The nine features are voice changes,
commercial onsets, silence,
jingle onsets, laser sound effects, a channel changing sound effect, a phone
ringing, a funny voice,
and a sexual word.
It is expected that at least some of these structural and content features
of radio will elicit
orienting in radio listeners. If this occurs, then listeners should exhibit a
decrease in heart rate and
an increase in skin conductance following the structural feature of interest.
Thus:
H1: Heart rate should decrease immediately following the onset of an
identified structural or
content feature.
H2: Skin conductance should increase immediately following the onset of an
identified
structural or content feature.
This paper goes on to test the effects of these sound effects on radio
listeners' memory for the
content occurring immediately before and immediately after the various
structural and content
features. Given the nature of the stimulus (light radio content taped directly
off-air) it is expected
that listeners will not find the content to be demanding. If that is the case,
then the orienting
responses should increase memory for information immediately following the
identified structural
feature. This leads to:
H3: Information presented immediately after the onset of an identified
structural or content
feature will be recognized better than information presented immediately before
such a feature.
H4: Information presented immediately after the onset of an identified
structural or content
feature will be recognized faster than information presented immediately before
such a feature.
Methodology
Subjects
Subjects were college students enrolled in one of three telecommunications
courses at a
major Midwest university. Each subject received course credit for their
participation. Thirty-eight
subjects participated in the experimental protocol.
Stimulus Preparation and Description
The experimental design called for the creation of audio stimuli containing
elements
believed to cause orienting responses in radio listeners. Both structural and
content elements were
chosen. The structural features chosen for investigation were: laser sound
effects, voice changes (the
onset of a different speaker), commercial onsets, and silence. The more content
oriented features
chosen were a funny voice, a jingle onset, a telephone ringing, the sound of
someone changing
stations, and the presence of sexual content.
The final twelve minute stimulus tape included seven audio messages. Six
of these messages
were recorded off the air in a Midwest college town. The seventh message was a
rock and roll song
recorded directly from compact disc.
Four tape orders were constructed using the seven messages. All of the
structural features of
interest occurred during the six non-song messages. The song was the fourth
element in all four tape
orders, with the six broadcast messages being placed in different logical orders
around it. No
broadcast message appeared exclusively before or exclusively after the song.
Also no two broadcast
messages were adjacent to each other in more than one tape order.
The tape orders were transferred onto the audio track of a VHS videotape
which had been
blacked and time coded. This allowed the exact location of the features to be
determined.
Dependent Variables
The dependent variables in this study are heart rate, skin conductance, and
recognition
accuracy. Heart rate and skin conductance were used to indicate if orienting
occurred. If orienting
occurs there should be a significant deceleration of the heart occurring in the
six seconds following
onset of the structural feature (Lang, 1990) and a significant increase in skin
conductance (Lynn,
1966) immediately following the feature. Memory for the content of the messages
was measured
using a forced choice reaction time recognition test. This means both percent
accuracy of recognition
and speed of recognition can be ascertained.
Experimental Procedure
There were four experimenters who conducted this study; each followed the
same
experimental protocol designed to obtain data on human reactions to and memory
for television,
computer media, and radio. The radio protocol reported in this section was
always the second set of
procedures subjects participated in.
Prior to the subjects arrival, a series of safety checks was conducted on
the data collection
equipment to ensure the safety of the subjects. Only one subject participated
in the experiment at a
time. Each was greeted by the experimenter, who then explained that the purpose
of the study was
to gain a better understanding of how human beings react to the media,
specifically television and
computers. After obtaining informed consent, Beckman AG/AGCL electrodes were
applied to the
subject's arms and hands to measure heart rate and skin conductance.
The first set of procedures involved either watching a set of television
messages or
interacting with a computer monitor and keyboard. After these procedures were
completed, subjects
were told that the researcher needed to take about ten minutes to do some
calculations on the data
which had just been collected. The researcher told the subject that, in the
meantime, radio messages
would be played for them to listen to.
After the radio messages were played, subjects participated in other
portions of the protocol
dealing with the television and computer interactions. When these were
completed, subjects were
given a recognition memory test for the radio messages. This test consisted of
listening to 3-second
portions of audio messages. The subjects were told that some of the portions
were from messages
they had heard previously, and others were not. Using a joystick held in their
dominant hand,
subjects were instructed to answer as soon as they knew whether or not they had
heard the portion
earlier in the experiment.
After the entire protocol was completed, subjects were debriefed, thanked,
and dismissed.
Apparatus
Heart rate and skin conductance were collected from the subjects as they
listened to the radio
stimulus. The stimulus tape was played by a Panasonic videocassette recorder
through the speakers
of a 19-in. television placed approximately 5 feet from the subject. The
videocassette recorder,
experimenter, and physiological recording equipment were separated from the
subject by an 8-foot
wooden wall.
The lab was controlled by a 386 computer with a LabMaster AD/DA board
installed.
Coulbourne physiological equipment was used in the collection of data. Heart
rate was measured as
the milliseconds between heart beats and was analyzed as the average heart rate
per second. Skin
conductance data were collected as an analog signal sampling at 10 times per
second.
Recognition responses were recorded using a Sidewinder joystick. Subjects
would press the
"yes" button on the joystick if they had heard the audio segment before, and the
"no" button if they
had not. Recognition results were coded for accuracy and response latency on a
386 computer using
the Slimy Recognition/Reaction Time program (Newhagen, 1993).
Analyses
The heart rate data were analyzed using a mixed N (Repetitions) X 7
(Seconds) X 4 (Order)
ANOVA. The within subjects factors were repetitions (with N levels representing
the number of
times an individual feature occurred) and Seconds (with 7 levels, representing 1
second prior and 6
seconds following feature onset). The number of repetitions of the feature
varies from 1 to 5
depending on which feature is being analyzed. The stimulus tape included 5
voice changes, 2
examples of silence, 2 production effects, 2 commercial onsets, 2 jingles, 1
channel change, 1 phone
ring, 1 sexual content, and 1 funny voice. The between subject factors was Order
(with four levels
representing the presentation orders). Missing heart rate data were re-coded to
the mean heart rate
across subjects for that second. 8 values out of 6840 were missing, resulting
in 0.12% of the heart
rate data being re-coded to the mean.
The skin conductance analysis was done on the change scores; that is, the
extent to which
skin conductance levels changed after the onset of the structural features
(Dawson, Schell, & Filion,
1990). The data were analyzed using a N (Repetitions) X 4 (Seconds)X 4 (Order)
ANOVA. The
within and between subjects factors for this analysis were the same as above
except that the Seconds
factor had 4 levels, representing the change scores for the 4 seconds following
the feature onset. Due
to researcher error during data collection, skin conductance data from three
subjects were missing.
Therefore, n=35 for the skin conductance analysis.
The recognition data were analyzed using an N (Repetitions) X 2 (Position)
X 4 (Order)
ANOVA. The within and between subjects factors for this analysis were the same
as above except
for the Position within subjects factor which had two levels, before and after.
These levels
corresponded to whether the 3-second audio portion being tested occurred before
or after the
structural feature.
Power
As discussed above, the number of repetitions for the individual structural
features varies
from 1 to 5. As a result, the power to detect effects varies. Those analyses
with four or five
repetitions are much more powerful than those with a single repetition. Because
the goal is to begin
to explore which structural features may elicit orienting and because for
several of these features
power is quite low, the .10 level of alpha has been designated as significant
for this study.
Results
Hypothesis 1
This hypothesis predicted that heart rate should decrease immediately
following the onset of
an identified structural or content feature. Using trend analysis, significant
heart rate decelerations
were found for voice changes (F(1,29) = 5.244, p<.066), commercial onsets
(F(1,29)=8.01,
p<.008), jingle onset (F(1,29)=3.03, p<.093), silence (F(1,29)=3.24, p<.082),
production effects
(F(1,29)=3.24, p<.018), phone ringing (F(1,29)=2.86, p<.10), funny voice
(F(1,29)=4.973,
p<.033) and sexual content (F(1,29)=10.05, p<.003. A significant deceleratory
trend was not found
for the station change sound effect. Thus, eight of the nine features tested
showed significant cardiac
deceleration following onset. Combining the features in an overall analysis
also yielded a significant
quadratic heart rate deceleration ( F (1,29)=13.32, p<.001). This combined
effect is shown in
Figure 1.
Hypothesis 2
This hypothesis predicted that skin conductance should increase immediately
following the
onset of an identified structural or content feature. This hypothesis was not
supported for any of the
individual features, though the means are in the expected direction for six of
the nine effects. When
all the features are combined, there is a significant increase in skin
conductance (F(3,81)=2.77,
p<.047, epsilon squared = .06) which is shown in Figure 2.
Hypothesis 3
This hypothesis predicted that information presented immediately after the
onset of an
identified structural or content feature will be recognized better than
information presented
immediately before such a feature. The results of this analysis are shown in
Table 1. Of the nine
features tested three showed significant effects in the predicted direction:
voice change
(F(1,34)=14.61, p<.001), funny voice (F(1,34)=3.86, p<.058), and sexual content
(F(1,34)=4.39,
p<.044). For all of these, recognition was better following the feature than it
was before the feature.
Commercial onsets also elicited a significant effect but in the opposite
direction from that predicted
(F(1,34)=5.11, p<.030) with 54% recognition for information presented after the
commercial
compared to 77% before. The remaining five features all had means in the
correct direction but did
not reach significance. When combined, however, the overall effect was
significant (F(1,34) = 9.15,
p<.005), with listeners recognizing 71% of the content before a feature compared
to 77% after.
Hypothesis 4
This hypothesis predicted that listeners would reach their recognition
decisions faster for
information presented following a feature than they would for information
presented before a
feature. The results of this analysis are presented in Table 2. This
hypothesis was supported for
only two of the features, voice change (F(1,34)=6.48, p<.016) and jingle onset
(F(1,34)=8.85,
p<.005). In both of these instances, latency to recognition was faster for
information presented
following the feature than it was for information presented before the feature.
For two other
features, commercial onset (F(1,34)=73.81, p<.001) and station change
(F(1,34)=5.12, p<.030) this
effect was significant but in the wrong direction. For the remaining five
features the effect was not
significant. The overall combined effect was also not significant (F<1).
Discussion
Overall the results of this study suggest that radio listeners, like TV
viewers, have orienting
responses to structural and content features of the medium. Further, there is
evidence that these
orienting responses do increase memory for the information that follows them.
First, it seems to be fairly clear that radio listeners have orienting
responses to structural
features. Eight of the nine features tested in this study showed significant
cardiac orienting
responses (i.e., a significant quadratic deceleration of heart rate following
the structural features).
While the skin conductance data did not yield significant results for the
individual tests, the overall
combined test did show a significant increase in skin conductance.
The effects of those orienting responses on memory is, not surprisingly,
less clear cut.
Overall, memory is somewhat better for information occurring after the feature
than it is for
information occurring before the feature, as predicted. The main exception
occurs for commercial
onsets and several possible explanations might be offered for this. First, as
discussed previously, it
has been demonstrated (Lang, Geiger, Strickwerda, & Sumner, 1993) that when
processing
television messages, memory for information following a cut decreases if the
information is
semantically unrelated to what was occurring before the cut. This lack of
relation is exactly the
condition tested by commercial onsets in radio. The beginning of a commercial
usually introduces
completely new and unrelated information to the listening audience. Thus,
following the onset of a
completely unrelated message, memory may decline as it does in television. A
second possibility is
that listeners may be actively avoiding paying attention to commercials.
The latency results do not strongly support the notion that information
presented
immediately following a structural feature is somehow more available than
information presented
before the feature. However, this may partially be an effect of the design.
For example, for voice
changes which occurred within a single message with related content and for
which there are several
repetitions there is a significant effect in the predicted direction. It may be
that there are too many
uncontrolled content factors and insufficient power in this design to see
latency effects consistently
across these features. It is probably too early to conclude that no such effect
exists.
Practically, it seems safe to conclude that both structural and content
features in radio do
elicit orienting and that when content is not very demanding those orienting
responses may increase
memory for information occurring immediately following the feature. Further,
even a fairly
innocuous and common feature like voice change appears to consistently elicit
both orienting and
improved memory. This may mean that, despite the low cost, using only one
announcer or anchor to
deliver a radio advertisement or news story may be a poor production strategy.
Results from this
study suggests even a very small production effect (like the addition of a
second voice) appears to
significantly increase listeners' memory. This study also suggests that the
addition of sound effects
(phones ringing and stations changing) also appear to increase attention and
memory. Finally things
which are distinctions, like funny voices or sexual words, also appear to elicit
orienting and improve
memory for the content of the message. References
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Table 1: Mean recognition accuracy for information presented before and after
the structural feature.
Structural Feature
Before After F df p
Funny Voice .771 .914
3.86 1,34 .058
Station change .514
.600 <1 1,34 .373
Commercial onset .771 .543
5.11 1,34 .030
Jingle onset .715
.786 1.98 1,34 .170
Phone ringing .943
.886 <1 1,34 .422
Laser effect .629
.714 1.21 1,34 .280
Sexual content .857
.971 4.39 1,34 .044
Silence .672
.729 2.32 1,34 .137
Voice change
.552 .762 14.61 1,34 .001
All .706 .771
9.15 1,34 .005
Table 2: Mean latency to reaction time for information presented before and
after the structural
feature.
Structural Feature
Before After F df p
Funny Voice 3162 3128
<1 1,34 .865
Station change
3037 3429 5.12 1,34 .030
Commercial onset 2408
4153 73.81 1,34 .000
Jingle onset 2955
2533 8.85 1,34 .005
Phone ringing 3013
2877 1.08 1,34 .307
Laser effect 3277
3106 1.01 1,34 .322
Sexual content 2678
2745 <1 1,34 .664
Silence 2978
3178 .72 1,34 .402
Voice change
3284 3049 6.48 1,34 .016
All 3041 3068
<1 1,34 .542
Figure 1: Average heart rate change over time following a structural or content
feature Figure 2: Average Skin Conductance over time following a structural or
content feature
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