Existential Neuroscience: a field in search of meaning

What separates prior from subsequent is exactly nothing. This nothing is absolutely impassable, just because it is nothing...

–Jean-Paul Sartre, Being and Nothingness (p. 28).

If you read the journal Social Cognitive and Affective Neuroscience (SCAN), you might think that Existential Neuroscience is a hot new field, since three recent papers on the topic have been published there. Can it provide profound new insights into the human condition? From what I can tell, these references to a formal discipline of “Existential Neuroscience” are based entirely on terror management theory, which was developed by Greenberg and colleagues in the 1980s (Greenberg et al., 1986; Rosenblatt et al., 1989). How does this relate to existentialism?


“Existence precedes essence” (Sartre, 1946).

But first, what is Existentialism? The Stanford Encyclopedia of Philosophy is reluctant to admit that it's an actual philosophy, rather than a literary or artistic trend:

By the mid 1970s the cultural image of existentialism had become a cliché, parodized in countless books and films by Woody Allen. It is sometimes suggested, therefore, that existentialism just is this bygone cultural movement rather than an identifiable philosophical position; or, alternatively, that the term should be restricted to Sartre's philosophy alone.

Stanford Encyclopedia eventually tells us that the most distinctive aspect of existentialism is that standard notions of identity are wrong:

The fundamental contribution of existential thought lies in the idea that one's identity is constituted neither by nature nor by culture, since to “exist” is precisely to constitute such an identity. It is in light of this idea that key existential notions such as facticity, transcendence (project), alienation, and authenticity must be understood.

The first known account of “Existential Neuroscience” (EN) was written by mirror neuron researcher Dr. Marco Iacoboni in 2006 (PDF).¹ It was published as a book chapter in Social Neuroscience: Integrating Biological and Psychological Explanations of Social Behavior (Harmon-Jones & Winkielman, 2007). Thus, EN appears to be a branch of Social Neuroscience.

But what is Existential Neuroscience, exactly? A group of French intellectuals discussing brain research in a cafe while smoking and sipping espresso? An authentic neuroscience of utter freedom that embraces a state of perpetual despair² over the meaninglessness of existence? Or independent groups of German-speaking neuroscientists who scan subjects while they ponder death?

Sartre and Friends

If you guessed the latter, you'd be correct.  More precisely, EN thus far consists of neuroimaging studies of mortality salience, as you might expect by its reliance on terror management theory (TMT).³  Therefore, EN should be called “Fear of Death” Neuroscience. TMT holds that when people are confronted with their own mortality, they respond in ways to boost their self-esteem, reinforce their own values, and punish outsiders.

In an ironic twist for the existentialist neuroscientists, however, Existentialism rejects science as means of understanding what it is to be human. Here's Sartre on the futility of science:

From the outset physiology is condemned to understand nothing of life since it conceives life simply as a particular modality of death, since it sees the infinite divisibility of the corpse as primary, and since it does not know the synthetic unity of the "surpassing towards" for which infinite divisibility is the pure and simple past. Even the study of life in the living person, even vivisection, even the study of the life of protoplasm, even embryology or the study of the egg can not rediscover life; the organ which is observed is living, but it is not established in the synthetic unity of a particular life; it is understood in terms of anatomy—i.e., in terms of death.

-Jean Paul Sartre, Being and Nothingness (p. 348).

Even if one is a firm believer in the potential of neuroscience to lead to better treatments for mental illness, it's hard to envision what brain research can tell us about a philosophical system opposed to science (or most other philosophies, for that matter). Can we imagine what a Taoist Neuroscience or an Epicurean Neuroscience would be like? Not to mention the prospect of a Nihilist Neuroscience or a Post-Structural Neuroscience...

By necessity, a true Existential Neuroscience must deal with human beings as the focus of study, since the withdrawal reflex of Aplysia might not be a valid model of existential angst. It's unlikely we'll see circuit models and optogenetic studies of the alienated self any time soon. As currently formulated, EN has more concrete goal: to study one specific element of existentialist thought that might be more closely related to Heidegger's views (see Quirin et al., 2012).

This leads us to the most recent of the EN studies in SCAN (Silveira et al., 2013), which I'll discuss in some detail. This study is based on a different reaction to mortality salience, one that is derived from evolutionary psychology: the drive to reproduce. The heterosexual participants in the study viewed attractive opposite-sex faces and made decisions about whether they would like to meet them (a proxy for sexual desire) after being primed by death-related words (or not). Already, this seems like a bridge too far, but let us go on.

Sixteen female and 16 male subjects participated in this fMRI experiment. They viewed a series of attractive faces (as judged by an independent group of participants) and decided, in separate blocks, if the faces were attractive or not (explicit evaluation) or whether they'd like to meet the person or not ("implicit" evaluation). The task was cued at the beginning of a block by the words Meet? or Attractive? Participants make their choice when the ? appears on the monitor. Below is an example of the implicit no-prime condition shown to the male subjects.

Fig 1 (Silveira et al., 2013).

The participants viewed a blank screen before each face is presented, instead of viewing control words that are unrelated to death. The lack of such a control condition is problematic, as we'll see later. For comparison, an example of the death-prime condition is illustrated below.

modified from Fig 1 (Silveira et al., 2013). I added two English translations for the original German exemplars that were given in the text .


Here we can see the participants are reading words, a condition that entails a number of visual, lexical (e.g., decoding the letter string), and semantic (meaning-related) processes that are completely absent from the no-prime condition. Therefore, we can't know if any differential brain activation in the death-prime vs. no-prime conditions is caused by reading a word (any word) or by comprehending a specific reference to death, thereby triggering mortality salience.

To compound matters, the study used block design methodology, so the discrete hemodynamic responses to prime presentation or face presentation or the decision screen could not be determined, as in an event-related design. The figure below shows the death-prime vs. no-prime comparison for male participants (left) and female participants (right), who did not differ from each other.

Fig. 2 (Silveira et al., 2013). Increased neural activation when viewing attractive opposite-sex faces after death-related compared to no priming in (A) men and (B) women. lPFC = lateral prefrontal cortex.


The figure shows activation in the left anterior insula and adjacent inferior prefrontal cortex, which are known to be involved in language, particularly in coordinating speech (known as articulatory planning). Although such activity is usually associated with speaking aloud, left anterior insula activation has also been observed during silent reading. To reiterate, the present result may be due to the absence of any words in the no-priming condition. This interpretation is opposed to Silveira et al.'s claim that the activity "reflects an approach-motivated defense mechanism to overcome concerns that are induced by being reminded of death and dying."

Another wrinkle in the authors' world view is the fact that the death-priming manipulation increased interest in meeting an attractive member of the opposite sex only in males (76% vs. 68% in the no-prime condition) and not in females (47% vs. 48%). It's hard to know how the approach-motivated defense mechanism is operating in women, since it didn't increase their desire to meet potential [fictitious] partners.

It seems a stretch, then, to claim:

Thus insular activation suggests an increase in mating motivation under mortality salience. This interpretation is in accordance with previous findings that mortality salience motivates the formation of romantic relationships as well as reproductive desire.

Hardly. The female participants expressed no greater interest in even meeting potential partners (no less having babies with them), and yet their insular activations were highly similar to those seen in the male participants (who may or may not have shown greater reproductive desire, as this was not queried or investigated in any way).

In sum, I don't know if we've learned anything about existentialism, or sex and death, or even mortality salience and the left anterior insula.

C'est la guerre.

I emerge alone and in anguish confronting the unique and original project which constitutes my being; all the barriers, all the guard rails collapse, nihilated by the consciousness of my freedom. I do not have nor can I have recourse to any value against the fact that it is I who sustain values in being. Nothing can ensure me against myself, cut off from the world and from my essence by this nothingness which I am. I have to realize the meaning of the world and of my essence; I make my decision concerning them—without justification and without excuse.

-Jean Paul Sartre, Being and Nothingness (p. 39).

Footnotes

¹ Iacoboni called EN a “Quiet Revolution” (that to me seems more like embodied cognition... which has not been quiet in announcing itself to the world):

In fact, some empirical work in the neuroscience of sociality seems to suggest - quietly, but resolutely - that the assumptions of the subject/world, inner/outer dichotomy, of representations independent of the things they represent, and of the atomism of the input may not be easily applied in some cases. Thus, rather than the picture of a meaning-giving brain that looks at the outside world and makes sense of it with a reflective and analytic approach, what emerges from some work in social cognitive neuroscience is the view of a human brain that needs a body to exist in a world of shared social norms in which meaning originates from being-in-the-world. This view is reminiscent of motives
recurring in at least one flavor of what is called existential phenomenology (Heidegger 1927). For this reason, I call this view existential neuroscience.

² Despair:

What sets the existentialist notion of despair apart from the conventional definition is that existentialist despair is a state one is in even when he isn't overtly in despair. So long as a person's identity depends on qualities that can crumble, he is considered to be in perpetual despair. And as there is, in Sartrean terms, no human essence found in conventional reality on which to constitute the individual's sense of identity, despair is a universal human condition.

³ One might consider that Iacoboni's studies of existential mirror neurons fall under a different branch of EN; they're not cited by the "fear of death" faction and vice versa.


References

Greenberg, J., Pyszczynski, T., & Solomon, S. (1986). The causes and consequences of a need for self-esteem: A terror management theory. In R. F. Baumeister (Ed.), Public self and private self (pp. 189 –212). New York: Springer-Verlag.

Quirin M, Loktyushin A, Arndt J, Küstermann E, Lo YY, Kuhl J, & Eggert L (2012). Existential neuroscience: a functional magnetic resonance imaging investigation of neural responses to reminders of one's mortality. Social cognitive and affective neuroscience, 7 (2), 193-8. PMID: 21266462

Rosenblatt A, Greenberg J, Solomon S, Pyszczynski T, Lyon D. (1989). Evidence for terror management theory: I. The effects of mortality salience on reactions tothose who violate or uphold cultural values. J Pers Soc Psychol. 57(4):681-90.

Silveira S, Graupmann V, Agthe M, Gutyrchik E, Blautzik J, Demirçapa I, Berndt A, Pöppel E, Frey D, Reiser M, & Hennig-Fast K (2013). Existential neuroscience: Effects of mortality salience on the neurocognitive processing of attractive opposite-sex faces. Social cognitive and affective neuroscience PMID: 24078106

Jean-Paul Sartre, 1905–1980