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.