Enkephaloglyphs and Marketing Research
Enkephaloglyphs represent spectral signatures of electric brain
activity. What does this mean? What is a spectral signature? Spectral
signatures are better known from astronomy. Quite a bit of knowledge of
astronomy and astrophysics is based on a mathematical transformation named
frequency analysis. For example atom-absorption-spectrometry provides
information on the composition of distant stars. It is also possible to
decompose light in its single colours by use of a prism. We are dealing then
with spectral colours, which consist of particular frequencies given in waves
per second (named as hertz (Hz)). Within the field of capturing electric brain
activity called electroencephalography (EEG), as Hans Berger, the discoverer of
human brain electricity, named it, it stands for a transformation of the
signals from time dependency into frequency dependency. The result consists in
a power-density-spectrum. More details will be given later. This kind of
approach using frequency analysis is the base for the mapping of brain
electricity as realized in the software-hardware combination of neo-CATEEM®.
This idea of using an additive color mixture of spectral colors for depiction
of all frequencies of an EEG within one map (an idea of Hans Carlos Hofmann) is
not only still up to date but has put us into the position to create what we
now call a spectral signature of electric brain activity or an Enkephaloglyph
(Fig. 1 gives an example from a recent marketing research project dealing with
web surfing of bank portals).
Fig. 1 Information content of an enkephaloglyph
showing numeric content of the current frequency pattern of 10 subjects (bar
chart on the left side of the figure) as well as the resulting averaged map.
Please remark significant increases of electric power at frontal sites
represented by electrode positions F7 and F8 (cognitive process of 364
milliseconds duration). Eye tracking (right) provided the documentation of a
“hot spot” representing the location, where the majority of the subjects looked
at in this moment.
With the extension of the CATEEM® system into the direction
of higher time resolution completely new applications have arisen for example
within marketing research as control for success of commercials or pitch-perimeter
advertising during sport events. Just imagine, your TV program is interrupted
by a commercial. After some reaction of disappointment you decide to watch
“this nonsense” since you don`t have a better idea for the moment. In addition,
you never know the duration of the advertisements. But these commercials are
sometimes very short (about 10 s) but nevertheless may be very efficient. The
advertising industry always is very keen to receive hints on the individual
success of their spots or pitch-perimeter advertisements. Since, as we shall
see later, electric brain activity mirrors our interior with respect to
cognitive as well as emotional features, its analysis can give us information with
respect to individual and averaged resonances. In order to correlate electric
activity to single scenes of a film or commercial, time resolution must be well
beyond one second. Since the original CATEEM® provided only a time
resolution of 4 s, as practiced now for 20 years, this time resolution has not been
good enough for this purpose.
In the past we had concentrated only on analyzing the averaged electric
brain activity with regard to a certain time. That means, we averaged the
electric signal over a time of several minutes and median activity was depicted
as a map. Normally, this kind of activity was shown as difference to a baseline
value recorded under the condition of open eyes. This has been used for a long
time to characterize drug actions. But what about those ultra-quick processes,
which we relate to single thoughts? Thanks to a genious idea of the physicist
and mathematician Hans-Carlos Hofmann (with whom I work together for more than
a quarter of a century) we are able to record the electric features of the
brain now with a time resolution of 364 milliseconds. That means we receive
about 3 pictures of brain activity per second. This enables us to relate
particular scenes from films to the electric pattern in a very exact way. One
could say that we capture the reaction of the TV watching people nearly as
quick as thoughts come and go.
It has been known for a long time that one can record the electric
reaction of the brain in the presence of acoustic or visual stimuli. However,
administration of a large number of stimuli and averaging their response is
needed. This kind of analysis of brain electric activity is known under the
heading of “evoked potentials” in the neurophysiological literature. I have
dedicated my effort for many years to this kind of analysis. Inspired by the
work of Polich and colleagues my team succeeded to present this kind of brain
responses as maps. For example we presented acoustic stimuli 1 second apart
from each other during about 5 minutes. High frequency tones were alternated
with low frequency tones (1:5) and subjects were asked to count the more seldom
tones. Using this approach one can check the ability to concentrate quite well
because the brain processes both kind of responses in a different way. From the
difference one can calculate the degree of attention. However, this kind of analysis
asks for several minutes of testing and the result consists in an average
response. From this approach it became obvious that the brain needed about 300
to 360 milliseconds of processing time, which is age dependent. Since this kind
of signal is depicted as a positive wave, it has been denominated as “P300” in
the literature. This means, that quantitative analysis of single responses to
acoustic or visual stimuli would ask for such short time of analysis.
Unfortunately, this kind of signal escapes detection in the EEG trace because
of the small signal to noise ratio, which means that you cannot see it during
the course of conventional EEG recording (only as averaged signal as mentioned
above).
However, we have seen that frequency analysis is a valuable tool for
describing electric brain activity in an exact manner. By coding single frequency ranges into a map by use of spectral colours
the result can be depicted graphically in order to describe brain functions.
After twenty years of practicing frequency analysis of this kind of signal a
solution was detected, which allows spectral analysis of these ultra-short
grapho-elements of the EEG and depict them graphically according to existing
algorithms used already twenty years ago. Based on a sweep time of 364
milliseconds we are now well within the desired velocity of mental processes
and thoughts. The result of spectral analysis of the EEG has been named an Enkephaloglyph by myself “(enkephalo”
comes from ancient Greek language and means “what is in the head”; a glyph is a
kind of pictogram, namely a graphic description in form of a signature).
Enkephaloglyphs are electric correlates thought to mirror or reflect psychic
processes like cognition and emotion among other mental processes. In any case
they represent the electric response of our brain to acoustic or visual
stimuli.
One of the problems arising with the availability of the new ultra-fast
technology was the interpretation of the obtained Enkephaloglyphs. A picture
can tell you more than a thousand words, as a German phrase puts it. That means
also that during presentation of pictures or movies it is very important to
know where the eyes look at. What part of the picture or video catches our
attention? A solution was found by combining our EEG with another
well-established technology. Within marketing research other scientists
succeeded in developing a method, which now is known under the name of “eye tracking”.
Basically, this method registers eye movements and projects its coordinates
with high time resolution as a spot on the picture or movie under examination.
The momentarily recorded eye-gaze is documented continuously as i.e. a red spot
on the video presentation (s. Fig. 2).
In the case of concomitant recording of the EEG, both films - representing
the EEG and the eye tracking – can be synchronized. Practically, the
eye-tracking system transmits a trigger at begin of the presentation which is
seen on the EEG recording by means of our newly developed Windows based neo-CATEEM®.
By it synchronization is achieved in a very accurate way. By use of a film cut
program depiction of focused attention of a subject with a time resolution of
364 milliseconds per sweep is achieved. It allows to relate the brain`s
electric response to a visual challenge to a very short eye-gaze.
The combination of these two physiological methods opens completely new
perspectives for example in marketing research. If evaluation and control of
success of advertising like commercials or presentation of logos as well as
pitch-perimeter advertising during sport events was only accessible in a very
rough manner, the combination of eye tracking and neo-CATEEM®
provides now the possibilities of individual quantitative analysis. First
results show that the electric response of the brain differs quite a bit
depending on the momentary eye-gaze. Prominent differences are seen between the
sport events and gazes on pitch-perimeter advertising. Even the extent of the
qualitative reaction as well as quantitative differences to presentations of single
companies can be evaluated. On the other side similar enkephaloglyphs were
recorded in different subjects with respect to identical advertising
presentations. An example of a subject watching different advertisements is
documented in Fig. 2 (see also videos on YouTube). It is very interesting that
in both cases slow delta and theta activity increases at the lateral cortex
(the frequencies of EEG waves have been named historically according to the
Greek alphabet). Taking a look on the details of frequency changes one can see
a central increase of alpha1 waves (depicted as yellow color) and a reaction on
the electrode position F3 representing the frontal brain during watching the
Mercedes presentation. One can conclude from this that a thought-association
has occurred since similar enkephaloglyphs have been observed during
recognition of subjects. Obviously, the goal of the advertisement had been
reached. Further studies will lead to construction of a library of
enkephaloglyphes allowing extended interpretations.
Fig. 2 Ultra short electric reactions on advertisements. Upper part:
Pitch perimeter advertising during a socker game with significant increase of
central beta waves (blue) and increase of delta, theta and alpha1 waves (red,
orange and yellow, respectively) at the forebrain. Lower part: Reaction during
a gaze on an advertisement of “Mercedes” (red spot represents momentary gaze),
which is quite similar to the reaction on “Gazprom” but not identical.
Further information on the technology is provided at http://www.mewicon.at and its use in research
at http://www.neurocode-ag.com
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