Typical EEG Dependences on Psychotype According to MBTI

At the end of the previous decade, Dario Nardi of the University of Los Angeles used electroencephalography to study brain activity in people of different psychological types according to Myers-Briggs theory (MBTI) while they performed a wide range of tasks. It turned out (as was to be expected) that psychotype largely determines typical patterns of cerebral cortical activity. Nardi’s results were included in his book “Neuroscience of Personality”. Since the MBTI type system is closely related to socionics (both developed from Jung’s theory), here I will attempt to map these results onto the basis of socionics, comment on them, and draw parallels with the results of other authors. But for this purpose it will first be necessary to bring the two theories (socionics and MBTI) to a certain common denominator, because there are nevertheless some differences between them.

The main one concerns the interpretation of the rationality/irrationality dichotomy, its close MBTI analogue Judging/Perceiving, and the order of the strong functions in theoretical models of the psyche. Both models have a primary and a subordinate function, with one of them in the extraverted attitude and the other in the introverted attitude (in socionics, black and white functions). But in socionics, the rationality/irrationality dichotomy is determined by the leading (first in the model) function, whereas in MBTI the J/P dichotomy is determined by the extraverted function, even if it is the second (subordinate) function in the model. This is argued on the grounds that only the extraverted function can ensure a person’s activity in society, whereas the introverted one works rather “for internal use”; thus extraversion and introversion in MBTI are directly linked to the opposition activity (activeness) – reflection (reflection of the external world).

Proceeding from this difference between the two models, some socionists argue that the J/P dichotomy is not an analogue of socionic rationality/irrationality (more precisely, they coincide for extraverts but differ for introverts, as a result of which, for example, INTJ turns out to be analogous to ILI rather than LII, while the J/P dichotomy itself is an analogue of dynamics/statics). On the other hand, descriptions of IJ types are closer to descriptions of socionic intro-rationals, IP to intro-irrationals, and the description of the J/P dichotomy itself differs from socionic rationality/irrationality only in some details, while overall their essence approximately coincides.

It is precisely for these reasons that I adhere to a different view of type correspondence. I consider the J/P dichotomy an approximate analogue of rationality/irrationality, and the types from the two typologies to approximately correspond to one another. I consider the difference between the models of the psyche to be a consequence of the fact that the functions included in them are not identical to one another. Taking INTJ as an example: its first function is Ni, its second is Te (because of the latter it is a J type despite having a leading irrational function). But (attention!) – these are not the socionic and ! These are different functions.

Indeed, in socionics the color of functions is completely unrelated to their (social) activity/passivity. For types with base , , , the color of the base function does not in any way prevent the latter’s social activity (the only exception here is perhaps base , and even then, in my opinion, rather because of a poor understanding of this function’s social action). In general, all TIMs are socially more active precisely through their base functions, regardless of their color; as for the creative function, here I showed that it incorporates the social motivation of the base function, as a result of which it works “in the mode” of the latter rather than in its own mode. Projecting this understanding onto the MBTI model, we find that the parallel with Model A should not be drawn according to the order of functions, but in a completely different way. More precisely, the extraverted function in the MBTI model, which determines activity in society, should be regarded not as the socionic “black” function but as the base function, irrespective of its position in the model, whether it is first or second. Similarly, the introverted function should be regarded as subordinate to the base function, or as an analogue of the creative function in Model A. The extraversion/introversion of the base function, in turn, repeats the type’s extraversion/introversion. For example, in the INTJ model, 1-Ni, 2-Te is equivalent to base socionic logic, specifically introverted logic – .

As a result, the indices “e” before a strong MBTI function should be read as “socionic base”, and “i” as “socionic creative”. Or, equivalently: Se, Ne are “irrational” sensing/intuition, while Si, Ni are “rational” sensing/intuition (the rationality consists in their working “under the command” of a base rational function). Similarly, Te, Fe are rational logic/ethics, while Ti, Fi are irrational logic/ethics (under the command of an irrational base function). At first glance, this “crossed” identification of concepts from the two typologies seems unnecessarily complicated. But below I will show that precisely with this identification, some of D. Nardi’s results receive a very clear and precise interpretation within socionics, including agreement with the neurophysiological explanation of rationality/irrationality in V. Talanov’s terms.

What are these results? For people with strong Se, Ne (= P types), a fairly characteristic EEG pattern consists of rapid, relatively disorderly (in appearance) “flaring up” and fading of activity in most areas of the cortex at different frequencies. Nardi calls it “Christmas lights”, probably referring to blinking electric lights (I would call this pattern a “disco”). Sensing types differ from intuitive types mainly in having a lower amplitude of electrical activity, but the picture is equally “blinking” and disorderly (according to Nardi, “tennis hop”). As for types with strong Si, Ni (J types), a completely different pattern is typical of them – the so-called “state of flow”, consisting in synchronization of the activity rhythms of (almost) the entire cortex for a relatively long period of time (on the order of several minutes; sensing types also differ from intuitive types in having a lower signal amplitude). This difference is very substantial, and it can be explained by the fundamental difference between two activating systems of the brain that, according to Talanov, constitute the basis of the rational and irrational temperaments: the mesencephalic and thalamic systems. The former “produces” activation that is relatively stable over time (tonic), whereas the latter produces a component that changes rapidly in response to external events (phasic). It is not difficult to see here precisely the distinction between the “state of flow” and “Christmas lights” patterns.

Fig. 1. EEG patterns “state of flow” (left) and “Christmas lights” (right). Below - color designations of the dominant frequency of the EEG spectrum.

Very interesting results were obtained for the rational functions, more precisely, for the localization of the latter in the cerebral cortex. It turned out that the thinking/feeling (Thinking/Feeling) dichotomy is completely unrelated to the brain hemispheres, contrary to what the majority of socionists believed and still believe. But here again a substantial difference between J and P types emerged. Thus, for strong Te, Fe (J types), it was found that both of these functions are associated with high activity in the speech areas of the left hemisphere (areas T3, Fp1 in Fig. 2). The functions Ti, Fi (in P types), by contrast, turned out to be localized in different cortical regions, but again bilaterally: Ti in the parietal and premotor cortex (P3, P4, F3, F4), Fi in the temporal and inferior frontal cortex (T3, T4, T5, F7, F8 in different types). I believe that the separation of Ti areas from Fi areas goes back to the separation of the two streams of visual information in the cortex: the dorsal stream (from the occipital to the parietal cortex) and the ventral stream (to the temporal cortex). Indeed, in the ventral stream an emotional component is extracted from visual information (emotions associated with a given object), while in the dorsal system sensory information is “schematized”, reduced to a simplified scheme of the positions of objects, contours, and directions of movement (aspects , ). For more on the two systems of visual perception, see, for example, Wikipedia. Here I also consider it important that the described “logical” and “emotional” cortical areas were found specifically for Ti, Fi, that is, for irrational, or perceiving, logic/emotion. Incidentally, this result of Nardi’s did not come as a surprise to me, because back in 2011 I hypothesized the existence of “perceiving” logic/ethics and their connection specifically with the dorsal and ventral visual systems (see here).

Fig. 2. Standard placement and designation of electrodes in electroencephalography, together with the dominant functions of the corresponding cortical areas (according to D. Nardi).

I will also note that Nardi’s results contain no information about sensory and intuitive areas of the cortex; the localization of T, F was established, while that of S, N was not. Generally speaking, sensory association areas have been fairly well studied by neurophysiologists, which cannot be said of intuition, if only because of its extremely vague representation in science. I hypothesized that the inferior parietal and superior temporal areas (Brodmann areas 40, 39), associated with language, mathematical abilities, and so on, should properly be called intuitive. However, with the electrode placement standard in electroencephalography, these areas fall at the junction of T5 and P3 (on the left), possibly even “capturing” part of T3 (similarly on the right – T6, P4, T4). As a result, signals from this potentially “intuitive” area are mixed with signals from other (logical, emotional) regions above and below, and are additionally “smeared” across several electrodes. Nardi identified regions P4, T6, F7 as potentially related to intuition, but this is considerably less than for logic and emotions. It is very likely that an experiment using a different, more suitable electrode placement (even if “contrary to EEG standards”) will be able to establish accurately the presence of an intuitive area in the region indicated above. It may also be worth placing additional electrodes in the frontal parts of the cortex, because, for example, the important Broca’s area falls at the junction of Fp1, F7 and, possibly, F3.

Among Nardi’s more important results, the data on the balance of left- and right-prefrontal-cortex activity came as a surprise to me: the left PFC turned out to be more active in EJ and IP types, while the right PFC was more active in IJ and EP types, or, in socionic terms, according to the dynamics/statics dichotomy. At present I do not know how to interpret this result. Here I dealt with the problem of hemispheric asymmetry, but, first, I linked it to the Reinin process/result dichotomy and, second, I regarded not the outer surface of the cortex as responsible for it, but the cingulate cortex located deeper inside, whose activity (like that of all other parts of the brain not facing the skull) is not reflected in the EEG at all. Thus, the question remains open. As a hypothesis, I will suggest that the separation of left/right PFC activity is related to the operation of the functions of the mental and vital rings of Model A.

It should also be noted that Nardi established a relationship between extraversion/introversion and electrical cortical activity in the absence of external stimuli: in introverts it is substantially higher, and when stimuli are presented it is also higher than in extraverts. The hypothesis that such a relationship exists was proposed by Eysenck long ago; Nardi’s results merely confirmed it.

Fig. 3. Typical patterns of cortical activity in extraverts and introverts in the absence of external stimuli and in their presence.

Finally, the search for a relationship between psychotype and the type of activity during which a person easily enters the “state of flow” described above, with synchronized activity of all cortical areas, may prove very promising (in my view). I wrote that it occurs more often in J types; but P types can also enter it, although less often. For example, in types with base Se, a crisis situation in which decisions must be made quickly triggers state of flow. Nardi showed that different psychotypes tend to enter this state when solving different tasks: Si when recalling past events, Ni, conversely, when thinking about the future. A person can also enter state of flow when doing favorite and long-familiar work (for example, a singer sings his own song; but if he sings another song, one less familiar to him, he will not enter this state). This point gave rise to an interesting hypothesis for me: a person can enter state of flow when the Ego block is operating under the control of the base function. More precisely, the hypothesis is that it is precisely the dominant base function (and only it!) that is capable of synchronizing the operation of all the other functions, putting them “at its service”, not suppressing them completely but merely synchronizing them and loading them with its own tasks. (Incidentally, this hypothesis may give rise to a fairly precise instrumental method for determining TIM by means of EEG.) Similarly, it may turn out that when functions from other blocks of Model A dominate, analogues of state of flow are possible in which the cortex is also synchronized, but at a different rhythm frequency. Nardi gave examples of such states when a person feels depressed (low frequency), happy (higher frequency), or intellectually excited (still higher frequency, see Fig. 4). Thus, it is possible that such states are caused by the dominance, respectively, of the Superego, Superid, and Id blocks over all the other functions. However, for now this is merely a hypothesis requiring verification.

Fig. 4. Analogues of “state of flow” in different psychological states (according to D. Nardi).

Ivan Popov, 2013