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The effect of brand on EEG modulation: a study on mineral water1
Claudio Lucchiari, Gabriella Pravettoni
Università degli Studi di Milano
Abstract
In many cases, consumers develop tight relationships with their preferred brands and goods.
Companies aim at developing strong and positive emotional relationships between their brands and
their customers. When they succeed, the brand is immediately recognized and it becomes more
difficult to be _replaced by competitors. Previous studies have suggested the existence of a
relationship between brand evaluation and a reward-related functional circuit.
The aim of the present study is to gauge brain responses to different mineral water brands. In
particular, we were interested in analyzing the impact of brand attachment on brain modulation.
We hypothesized that brand evaluation is associated with the processing of reward, and then that the
brain oscillatory activity may be found to be modulated by different expectations, based on previous
experiences.
Time-frequency analyses of the EEG oscillatory activity were performed on 26 healthy subjects (13
males and 13 females) during water intake of differently labeled mineral water.
Our results confirmed that brand processing is joined with the activity of the frontocentral reward-
related network. Beta activity, , seems to be modulated by the experience of pleasure associated to a
favorite brand. Consequently, theta modulation seems to reflect the lack of this experience.
In conclusion, our study showed how exposure to a brand can affect EEG modulation. Additionally,
a possible relationship between brand evaluation and reward processing is confirmed.
Keywords: EEG, spectral analysis, neuromarketing, cortical correlates of brand
TEXT
1 This is a pre-print version. To consult and to cite the final version: Lucchiari, C., & Pravettoni, G. (2012).
The Effect of Brand on EEG Modulation. Swiss Journal of Psychology, 71(4), 199-204.
According to one of the microeconomics models’ assumptions, the experience of pleasure
associated to one particular product depends on its intrinsic characteristics (and, consequently, on
its main ingredients and their combination) apart from the state of mind of a consumer. Indeed, it is
clear that the pleasure associated with tasting some food or beverage depends on individual
conditions such as mood or motivation in that given time. Nevertheless, as the results of different
studies on this subject confirm, the above assumption has proven to be disputable. As a matter of
fact, it was determined that it was possible to modify the consumer’s experience on a particular
food or beverage by altering the way the product is presented and not its intrinsic properties , i.e. its
context features. Actually, the marketing and advertising tend to affect exactly these context
features. A beverage can be presented in such a way to extol only some characteristics It is possible,
for instance, to elicit a relative evaluation (comparing one product with another) instead of
revealing its absolute value. In particular, the consumption of one particular brand can be associated
with the specific expectations on the consumers’ part. It means that there is a feasibility to modify
the level of consumer’s enjoyment experienced by consumption of a particular product
manipulating their expectations towards this product. This phenomenon, known as brand
attachment, may induce a consumer to buy in a privileged way one particular product considering it
to be the most pleasant in consumption. For example, one’s favorite beverage is generally
considered more appealing compared with a beverage equally tasteful but unfamiliar.
In this framework Lee, Frederick and Ariely (2006) have examined the role of expectations in
evaluating the taste of beer using a blind vs. overt taste test. They found that the taste experience
can be affected by contextual factors, such as the presence of a secret ingredient able to generate
specific expectations. Similar results have been already described by Allison’s pioneering work in
this area of research (Allison, 1964). A famous brand may induce subjects to develop positive
anticipations about the beer to be tasted, generally evaluated to be more pleasant than a comparable
but unknown beer. The same phenomenon was confirmed in cinemas; Klaaren, Hodges and Wilson
(1994) found that spectators’ judgment can be strongly influenced by their expectations based on
previous descriptions.
More recently, the study of Shiv, Carmon and Ariely (2005) showed that it is possible to increase
consumers’ cognitive performance by a high price attribution to an energy drink. In this case, the
price/quality heuristics seems not only to be able to modify taste evaluations, suggesting the
relationship higher price-better quality, but it also seems to influence the relative effect of a product;
expensive products seem to produce higher self-perceived effects. These results demonstrate that
communication and marketing strategies are worthwhile investments.
In addition to behavioral data, many researchers shifted their attention to the neuronal determinants
of marketing actions. Plassman, O’Doherty, Shiv and Rangel (2008) have experimentally shown
that offering to taste some wine with the price of 5$ to non-expert consumers and, then, offering the
same wine priced at 90$, led to a substantial change of participants’ pleasure experience. The
participants judged the more expensive sample more tasteful.
So, it turned out that this difference in evaluation is associated with an activation of different
cortical areas. In fact, the medial orbitofrontal cortex turned out to be more active only when the
sample of wine was considered to be the better one, even if in both cases the wine was the same.
Consequently, different brain activities, in particular different activations of the medial orbitofrontal
cortex responsible for pleasure or hedonic experience encoding, may correspond to the same taste
stimulations. This means that better evaluation of more expensive wine is not just simple pretence
or social adjustment, but rather is related to the fact, that the brain represents the experience in a
different way.
More generally, Hubert and Kenning (2008) showed how the evaluation of a particular product and
experience associated with it can be correlated with the function of the circuit which includes
amygdala and orbitofrontal cortex, modulated by the dopaminergic system and different prefrontal
areas. Dalli, Romani and Gistri (2006) provided evidence for the existence of an asymmetric brain
response to liked and disliked brands. In particular, the amygdale activation appeared to be
associated to liked brands, while disliked brands activated a more heterogeneous fronto-temoral
network. McClure, Li, Tomlin, Cypert and Montague (2004), using an fMRI paradigm based on
covert and overt taste tests, demonstrated a different modulation of dorsolateral prefrontal cortex
during the evaluation of a famous brand drink in comparison to a drink without a label . Taken
together, several studies suggest that brand evaluation can be correlated with the activity of a
reward-related system. Thus, we supposed that marketing actions can broadly modulate prefrontal
cortex activity and that this modulation can be measured by means of EEG. This methodology
allows for analyzing the dynamics of neural activity with a high temporal resolution. Brain
oscillations were used as a powerful tool to analyze different cognitive processes (Basar, Basar-
Eroglu¸, Karakas, Schiirman, 1999; 2001). In particular, since theta (4-8 Hz) and beta (14-30)
activities are generally considered to be EEG correlates of the reward processing system, these
frequency ranges may be of particular interest for our study.
The theta rhythm activity (4-8 Hz), was associated with the thalamocortical loop function related to
evaluation of post decision feedbacks (Lucchiari and Pravettoni, 2010, Christie and Tata, 2009,
Cohen et al. 2007), and more generally, with the evaluation of one’s own decision. Theta activity
has been associated with negative feedback. Conversely, some studies (Marco-Pallares at al., 2008)
suggested the relationship between beta modulation and reward evaluation. We supposed that
modulation of theta and beta rhythms of the frontal cortical areas may be related with the
modulation of specific marketing actions.
We were particularly interested to find out what kind of influence the brand value of some products
may have on one’s experience of pleasure and on their related cortical correlates. For this purpose,
we decided to make an experiment using bottled mineral water. Previously, similar experiments
were conducted on drinks with particular intrinsic characteristics like wine, beer, soft drinks, etc.
Yet, these characteristics may be considered basically unique (these may vary a lot from one type of
wine to another) and such taste differences may influence the registered cortex values. Besides that,
the reaction to wine or to any other alcoholic drinks may be different from one person to another
due to incidental reasons or consumers’ personal characteristics. Thus, we chose a rather neutral
product for this experiment while still representing a defined market of reference. In Italy, millions
of bottled water is sold every year. additionally, there are a lot of products with wide price range
and the consumers usually have their strong brand preferences in this field. So, most consumers
choose almost always the same brand, showing the presence of a brand attachment effect.
Previous studies have identified several brain areas activated by water intake. In particular, insula,
opercular, cingulated and orbito-frontal cortices have been found to respond when water is in the
mouth (Arujo, Kringelbach, Rolls, McGlone, 2003). These areas are differently modulated by the
the affect component of water taste (pleasureness vs. unpleasureness), but this activation do not
correlate with taste intensity, that is its pure sensorial component (Kringelbach, O’Dohert, Rolls
and Andrews, 2003).
The insula response to water is also modulated by temperature (Craig et al. 2000). Thus, we decided
to deliver the water at the same temperature (20 ºC), varying only the brand parameter.
Since brand attachment may be affected by some consumer characteristics such as gender, we
expected to find a gender pattern in brain modulation due to brand processing.
For the present experiment we have chosen to study the consumers of still water in order to exclude
evaluation of intrinsic factor of CO2 concentration, which varies from one sparkling water to
another.
Following the study by McClure and Colls (2004) we aimed at evaluating behavioral and neural
responses to mineral waters when presented anonymously and labeled. Furthermore, we wanted to
study the correlation between preference, expressed by subjective evaluations, and corresponding
brain signals. As opposed to McClure and Colls (2004) we used EEG instead of fMRI. The use of
another methodology allowed us to capture different aspects of the examined neural processes such
as the temporal sequence of activated brain areas. We hypothesized that a favorite brand may act as
safety clue from the environment. Thus, goods recognized as safe may be processed as being non-
risky or privileged
Hence, we expected to find:
1) Water labeled with the favorite brand to be more appreciated on subjective judgment;
2) Brand related cortical activity to be similar to the well known reward mechanisms; so, as we
may observe in gambling tasks, we expected to find different cortical responses to familiar
brand, subjectively considered as non-risky and unknown and then potentially risky
products.
Method
Subjects
Eighty persons were contracted within the University of Milan. These 80 participants have been
given a questionnaire to identify their lifestyle, preferences and the way of consuming of different
foodstuffs, including mineral bottled water. Twenty six subjects (13 men and 13 women with an
average age = 24.5, S.D.= 2.4) have participated in the study. Selection criteria were as follows:
preferences for clear still bottled water, familiarity with bottled water market, absence of
neurological diseases, right hand use, no alcohol or drug abuse. Thirty-two subjects were selected
but four of them declined the invitation to participate in this study due to scheduling problems.
Procedure
The subjects were seated at a desk on a comfortable chair. In front of them there were different
glasses with straws. During this exercise a subject was provided with a certain glass identified by a
specific brand of water (the brand was clearly stated during each trial; furthermore, the glass was
filled with water by a researcher every time from a clearly visible bottle). So, the subject was asked
to try this water (5 ml each try), to taste it for 5 seconds and, after that, to fill in a set of visual
analogical scales (VAS) related to water’s different qualities (taste, freshness, lightness, pleasure
experienced).
For each subject three types of water were used: the subject’s favorite water (individualized through
the questionnaire filled in by the subject in the pre-experimental stage), an unknown sub-brand
water (discount) and another brand of water of very well-known and high-quality. Each type of
water was tasted and evaluated 10 times, in two different sessions. Each session included 5
evaluations of each type of water. After each evaluation there was an interstimulus interval of 5
seconds left. The medium duration of each session was equal to 4.25 minutes. Between the first and
the second session there was a break of 5 minutes, during which each subject was assigned a
distracting and enjoyable brain-training-like task of medium cognitive loading. The water
temperature was constantly monitored and kept at the room temperature (20 ºC). The differently
labeled bottles were filled in advance with the same mineral water. Subjects were trained to push a
button with a finger of the right hand to trigger EEG recordings after each water intake. They were
also trained to look at fix point in the center of the screen after trigger activation and to avoid
movements before the next glass.
The EEG was recorded with a 32-channel DC amplifier (Cadwell system). An ElectroCap with
Ag/AgCl electrodes was used to record EEG from active scalp sites referred to earlobe (10/20
system of electrode placement). Additionally, two electro-oculogram (EOG) electrodes were placed
on the outer sides of the eyes. The data was recorded using sampling rate of 250 Hz and filtered
with a bandpass of 0.01–50 Hz. The impedance of recording electrodes was monitored for each
subject prior to data collection and it was kept below 5 kΩ.
Trials with base-peak EOG amplitude and post-EOG amplitude of more than 50µV amplifier
saturation or with a baseline shift exceeding 200 µV/s were automatically rejected off-line. After
EOG correction and visual inspection only artifact-free trials were took into consideration. Fourteen
electrodes were used for the next statistical analysis (4 central, Fz, Cz, Pz, Oz; 10 lateral, F3, F4,
C3, C4, T3, T4, P3, P4, 01, 02). The data was recorded for each epoch and triggered every second
after water intake. In order to study time–frequency behavior of the electrical activity elicited by
water intake, single trial data was convoluted using a complex Morlet Wavelet: w(t, f0) = (2πσ2 t )
−1/2 e−t2/2σ2 t e2iπf0t.
The relation f0/σf (where σf = 1/(2πσt)) was set to 6.7 (Tallon-Baudry et al., 1997). Time-varying
changes of energy (convolution between wavelet and signal to the square) in the studied frequencies
(from 1 to 40 Hz; linear increase) with respect to baseline were computed for each trial and
averaged for each subject in order to figure out the grand average afterwards. Mean values of power
increase/decrease for the different conditions (favorite, known and unknown brands) were obtained
for the three midline electrode locations (Fz, Cz, Pz). Since our main hypothesis was that a brand
manipulation may have an effect similar to a reward, we replicated here the data analysis used in
previous reward-related studies (Lucchiari and Pravettoni 2010, Marco-Pallares et al. 2008).
The ANOVA test was used to test hypothesis. For all the ANOVAs, degrees of freedom were
Greenhouse–Geisser corrected where appropriate.
All the statistical analyses were performed using SPSS 17.0 software.
Results
Behavioral measures
We measured the impact of brand information on subject experience by comparing the mean values
of reported ratings for water when administered with different brands. We found significant
differences for the three conditions (see figure 1). In particular, the liking (F (2,25) = 23.607, p = .
000), pureness (F (2,25) = 22.174, p =.001) and lightness (F (2,25) = 22.512, p =.001) were rated
differently. Pairwise comparisons showed that the favorite brand was rated significantly higher in
liking (t (25) = 12.490, p = .000), pureness (t (25) = 8.170, p =.000) and lightness (t (25) = 10.101, p
= .000) than the unknown brand. Favorite brands were scored higher in liking also with respect to
known brands (t (25) = 17,456, p = .000). No differences were found in freshness ratings. As a
result of gender comparison, we found out that women reported higher ratings in liking of their
favorite brand (t (24) = 9.195, p =.001).
Figure 1 here
Time-frequency analysis
The time–frequency analysis of the three conditions indicated a clear enhancement of theta activity
(4–8 Hz) between 50 and 450 ms after water intake at Fz electrode. In particular, the most
pronounced increase was found for the unknown brand (see figure 2).
Figure 2 here
Considering other frequency bands, we found out an increase in the mid-beta (8-22 Hz) for the
favorite brand between 450 and 900 ms (see figure 3).
Figure 3 here
An ANOVA of the mean power change for the theta frequency band (4–8 Hz, time-window 50–450
ms) was performed including brand type (favorite, unknown, known) and electrode (midline
locations: Fz, Cz, Pz) as within-subject factors. Significant effects were found for brand type
(F(2,50) = 4.23, p = .001), electrode (F(2,50) = 4.08, p = 0.025) and for the interaction between
brand type × electrode (F(4,100) = 3.45, p =.005). A significant increase of the theta frequency was
present at the frontal electrode (see figure 2). A Contrast analysis revealed that the difference was
significant between Fz and Pz (F (1,25) = 6.721, p = .0.01) and Fz and Cz (F (1,25) = 5.654, p = .
024), but not between Cz and Pz (F (1,25) = 2.127, p = .125). The favorite brand also showed to
have a higher impact on theta activity. In fact, contrast analysis revealed a significant difference
between favorite and known brands (F (1,25) = 4.922, p = .034) as well as between favorite and
unknown brands (F (1,25) = 5.786, p =.002). Also known and unknown brands were found to
differently modulate the theta activity (F (1,25) = 5.239, p = .019).
A mixed ANOVA was performed using brands (favorite, known, unknown) as within-factor and
gender as between factor in order to verify the existence of gender differences in theta modulation.
As a result, no gender effect was found.
The most pronounced difference in power change in the mid-beta band (18–22 Hz) between favorite
brand and the other brands was observed in the 450–900 ms time-window. The corresponding
ANOVA performed in this time-window (450–900 ms) showed a main effect of brand type (F(2,50)
= 4.89, p = .000), which reflects the increase of the mid-beta power (18–22 Hz) in favorite brand
trials when compared to other trials. In fact, contrast analysis showed a significant difference
between favorite and known brands (F(1,25) = 5.012, p = .011) and between favorite and unknown
brands (F(1,25) = 5.989, p = .003). A frontocentral scalp distribution was observed (electrode
condition F(2,50) = 3.63, p = .025; interaction between brand type x electrode, F(4,100) = 2.38, p =
.032). In particular mid-beta Fz activity was found to be significantly higher with respect to Pz (F
(1,25) = 6.345, p = .000). No significant differences were found between Fz and Cz, even though
mid-beta showed higher increase in Fz.
A mixed ANOVA was performed using brands (favorite, known, unknown) as within factor and
gender as between factor in Fz electrode in order to verify the existence of gender differences in
mid-beta modulation. The brand type resulted significant in terms of gender interaction (F (2, 48) =
3.123, p = .022). In particular, mid-beta showed higher power increase in known and favorite
brands (see figure 4) in women with respect to men.
Figure 4 here
Conclusion
This exploratory study showed how the brand influence can be revealed by means of
electrophysiological data analysis. In particular, we provide evidence for how taste of favorite
mineral water modulates frontal electrode sites activity in very different ways when compared to
tasting the same water but labeled as another brand. Besides that, the present study showed that by
means of marketing actions, it is possible to obtain different evaluations for the same water from the
same subject. Known brands, in fact, were considered purer and lighter. Further, the experience of
pleasure was correlated to the brand manipulation, similarly to other studies conducted on different
goods (i.e, Rao and Monroe, 1989). Moreover, our data has shown significant differences in
electrode sites recordings as a result of brand manipulation. In particular, it seems to be plausible to
infer a relationship between the degree of theta band change and the experience of pleasure caused
by the taste of a familiar brand. Unknown brands labeled water, considered low-quality and
subjective bad tasting was in fact associated to an increase of theta activity, similar to the one
observed during processing of negative feedback (Marco-Pallares et al., 2008). Since the parameters
that have been shown to affect brain response to water intake, as the temperature in particular (de
Arujo et al., 2003; Craig et al. 2000), were kept constant, the different electrophysiological
modulations found may be directly associated to brand manipulation. The fact that marketing
actions may modulate brain response is consistent with previous studies where neuroimaging
techniques were used (Plassman et al., 2008; Hubert and Kenning, 2008).
Taken together, the above data highlights that the brand assumes both symbolic and biological
values. The brand, in fact, identifies something well known and reliable: a safety option. Thus, the
brand seems to be a kind of marker, which is able to drive our behavior. A safe and reliable source
of water in nature represents an environment resource to keep in mind with particular attention as it
may be essential, especially to avoid potential dangers (like an unsafe potentially fatal food source).
The brand seems to work in the same way, but for one slight difference: the brand is not necessarily
associated to a healthy product or its way of consumption, such as drinking alcohol, smoking or the
use of legal or illegal drugs. Many people, for instance, declare to prefer a branded medicine to
some generic medicine due to a better efficacy, even if some part of its efficacy can be generated
by the brand effect, which seems to cure headache better than anonymous medicine (Wager, 2005).
The same can be related to food and drink consumptions. A famous brand may generate a positive
evaluation, motivating an over consumption of calories or of unhealthy goods.
Linking the response of pre-frontal cortices to brand evaluation to the reward neural circuit, allows
us to suggest that unhealthy nutrition habits may be, at least partially, correlated to marketing
actions that associate brands with safe, non-risky behaviors, so eliciting approaching brain
responses.
Our study addressed also gender differences, a key characteristic of consumers’ research. In fact,
it’s well-known that males and females are differently influenced by a particular type of advertising
messages.
The existence of gender differences in behavior was supported both by economical and
neuropsychological literature (e.g , Croson, Gnezzy, Gnezzy, 2009, Jausovec and Jausovec, 2008)..
There was evidenced, in particular, that the gender difference affects numerous cerebral areas (e.g.
the hippocampus and the amygdale) as well as cognitive and emotional processes.
All of the above considerations should not be overlooked when the purchasing behavior is studied.
If we consider, for example, the emotions’ role to be fundamental for decision-making on
purchasing of some particular goods, we cannot ignore analyzing the gender differences on the way
they face the emotional experiences. Our data seem to confirm a different action of brand
manipulation in men and women, at least in mineral water choice. Even if it’s not yet very clear
what this different activation means, it is plausible to suggest that women are more affected by
brand attachment.
Naturally, the present study has research constraints that limit the generalizability of our data. First
of all our sample has exiguous participants’ number, and secondly the electrophysiological measure
used (EEG modulation) does not permit easy and direct interpretations. In fact, though the EEG in a
direct measure of neurons functions, with high time resolution, it has a poor spatial resolution and
presents a number of technical and methodological limitations. Since there are only a few studies on
this topic so far, and given the exploratory nature of our study, more research needs to be carried,
including the use of different brain imaging methods.
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Figure 1. Difference of water ratings between brands
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
freshness
pureness
lightness
Liking
favourit e
unknown
known
Figure 2. Theta changes in power at Fz in 50-450 time window.
.
Figure 3. Beta changes in power at Fz in 50-450 time window
Figure 4. Gender differences in mid-beta (18-22 Hz) modulation in the time-window 450-900 ms
after water intake at Fz.
