Neurodualism... People Assume that the Brain Affects the Mind more than the Mind Affects the Brain, & distort claims about the brain from the wider culture to fit their dualist belief that minds and brains are distinct, interacting entities

Neurodualism: People Assume that the Brain Affects the Mind more than the Mind Affects the Brain. Jussi Valtonen, Woo-kyoung Ahn, Andrei Cimpian. Cognitive Science ,September 7 2021. https://doi.org/10.1111/cogs.13034

Abstract: People commonly think of the mind and the brain as distinct entities that interact, a view known as dualism. At the same time, the public widely acknowledges that science attributes all mental phenomena to the workings of a material brain, a view at odds with dualism. How do people reconcile these conflicting perspectives? We propose that people distort claims about the brain from the wider culture to fit their dualist belief that minds and brains are distinct, interacting entities: Exposure to cultural discourse about the brain as the physical basis for the mind prompts people to posit that mind–brain interactions are asymmetric, such that the brain is able to affect the mind more than vice versa. We term this hybrid intuitive theory neurodualism. Five studies involving both thought experiments and naturalistic scenarios provided evidence of neurodualism among laypeople and, to some extent, even practicing psychotherapists. For example, lay participants reported that “a change in a person's brain” is accompanied by “a change in the person's mind” more often than vice versa. Similarly, when asked to imagine that “future scientists were able to alter exactly 25% of a person's brain,” participants reported larger corresponding changes in the person's mind than in the opposite direction. Participants also showed a similarly asymmetric pattern favoring the brain over the mind in naturalistic scenarios. By uncovering people's intuitive theories of the mind–brain relation, the results provide insights into societal phenomena such as the allure of neuroscience and common misperceptions of mental health treatments.

7 General discussion

We investigated intuitive theories of minds and brains in five studies with both lay participants and professional psychotherapists. We hypothesized that when reasoning about minds and brains, people rely on neurodualism—a hybrid intuitive theory that assimilates aspects of physicalist beliefs into pre-existing dualist intuitions, attributing more causal power to the brain over the mind than vice versa.

In all experiments and across several different tasks involving both thought experiments and naturalistic scenarios, untrained participants believed that interventions acting on the brain would affect the mind more than interventions acting on the mind would affect the brain, supporting our proposal. This causal asymmetry was strong and replicated reliably with untrained participants. Moreover, the extent to which participants endorsed popular dualism was only weakly correlated with their endorsement of neurodualism, supporting our proposal that a more complex set of beliefs is involved. In the last study, professional psychotherapists also showed evidence of endorsing neurodualism—albeit to a weaker degree—despite their scientific training and stronger reluctance, relative to lay participants, to believe that psychiatric medications affect the mind.

Our results both corroborate and extend prior findings regarding intuitive reasoning about minds and brains. Our results corroborate prior findings by showing, once again, that both laypeople and trained mental health professionals commonly hold dualistic beliefs. If their reasoning had been based on (folk versions of) a physicalist model, such as identity theory or supervenience, participants should not have expected mental events to occur in the absence of neural events. However, both lay participants and professional psychotherapists did consistently report that mental changes can occur (at least sometimes) even in situations in which no neural changes occur.

Our findings also extend prior findings by demonstrating that intuitive theories of minds and brains are considerably more complex than has previously been acknowledged. While it is widely agreed that dualistic beliefs are common (Ahn et al., 2017; Bloom, 2004; Forstmann & Burgmer, 2015; Miresco & Kirmayer, 2006; Mudrik & Maoz, 2014; Stanovich, 1989), how exactly people reason about the mind and brain in relation to each other has remained unclear. Our findings show that the fuller picture of intuitive theories is more nuanced than a mere belief that the mind and the brain are separate interacting entities. That intuitive theories can contain aspects of both popular-dualist and physicalist beliefs helps to explain why people's beliefs often seem internally inconsistent: While people often agree with the statement that the mind is not separable from the brain, they also endorse the view that the mind is not fundamentally physical (Demertzi et al., 2009). Similarly, even professional neuroscientists—who presumably endorse physicalist views—commonly discuss the brain in terms that conflict with physicalism (Greene, 2011; Mudrik & Maoz, 2014). Inconsistencies such as these are to be expected if people intuitively think of the mind as neither purely physical nor entirely independent of the brain, but rather embrace aspects of both of those views simultaneously. In fact, it is not uncommon for intuitive theories to take the form of hybrids that incorporate novel beliefs into existing theories whose original core is not lost even as the theories become increasingly complex (e.g., Hussak & Cimpian, 2019; Shtulman & Lombrozo, 2016).

Moreover, the current study sheds light on what this hybrid theory looks like. The results suggest that even if (and when) people are dualists, they perceive the brain neither as causally irrelevant for the mind nor as unresponsive to mental changes, but rather see the brain as a more commanding and robust causal agent than the mind. Future research will hopefully be able to capture further subtleties in intuitive theories of minds and brains. It seems likely that if researchers search for more fine-grained options than dichotomous dualist/antidualist positions in lay intuitions, increasingly fine-grained aspects may become visible.

7.1 Broader implications for theory and practice

7.1.1 Relation to the popular allure of neuroscience

Our findings may help to explain the intense fascination that the general public and mass media show for neuroscience research (Beck, 2010; O'Connor, Rees, & Joffe, 2012). If the general public is reluctant to believe that changes in the mind always correspond to changes in the brain, neuroscience findings showing that what happens in our minds happens in our brains as well contradict this belief and may thereby be particularly intriguing. Neurodualism may also help explain why people find brain-related statements informative in the context of psychological explanations even when the statements are irrelevant (Weisberg, Keil, Goodstein, Rawson, & Gray, 2008; Fernandez-Duque, Evans, Christian, & Hodges, 2015). Conceivably, the intuitive tendency to privilege causal patterns in the brain-to-mind direction (i.e., neurodualism) may bias people to perceive causal brain-to-mind connections even when none exist, which may in turn make the addition of neuroscience evidence to a psychological explanation seem informative. Also consistent with this argument, Fernandez-Duque et al. (2015) found that (popular) dualistic beliefs alone did not predict their participants’ reasoning in these contexts. In future research, it would be useful to test whether endorsement of neurodualism does predict the tendency to view information about the brain as particularly explanatory even in cases where it is not.

On a different note, some authors have suggested that the allure of neuroscience explanations is not specific to beliefs about minds and brains but related to a more general preference for reductive information. Hopkins, Weisberg, and Taylor (2016) found that across different scientific disciplines, people generally preferred explanations that referred to processes perceived as more fundamental, even when these processes were logically irrelevant to the explanation. According to this view, information about the brain may be seen as particularly informative because it is perceived as operating at the next level of analysis below psychological phenomena (Fernandez-Duque, 2017). It seems likely, however, that the neurodualist intuitive theory identified in the present research and this general preference for reductive information are independent inputs into the public's fascination with neuroscience explanations. Importantly, neurodualism itself is not a reductionist theory: For instance, people report that changes in mental states are only sometimes accompanied by changes in brain states (see Studies 3–5). Beliefs such as these are not easily interpreted as evidence that people are treating the terms “mind” and “brain” as referring to the same phenomenon at different levels of analysis. A more plausible account is that a neurodualist intuitive theory and the preference for reductive explanations are two independent factors contributing to the public appeal of neuroscience.

7.1.2 Implications for reasoning about mental illness and health

The current results may help to make sense of common beliefs regarding treatment efficacy in mental health. When people think that the source of a mental health issue such as depression is in the brain, they perceive psychological interventions as less likely to be helpful (Ahn et al., 2017; Deacon & Baird, 2009; Kemp et al., 2014). The belief that a psychological treatment cannot be effective if the problem is reflected in brain processes is at odds with both a physicalist view of the mind and the empirical evidence (e.g., Linden, 2006; Lozano, 2011; Deacon, 2013). These beliefs are unfortunate from a practical viewpoint as well because prognostic beliefs often predict treatment outcomes (Rutherford, Wager, & Roose, 2010). That is, pessimistic expectancies can become self-fulfilling prophecies: Neurobiological causal attributions are associated with both lower treatment expectations and poorer psychosocial treatment outcomes in depression (Schroder et al., 2020). Our findings suggest that part of the reason for these effects may lie in the intuitive theories people use for reasoning about the mind and brain. Biological causal explanations may foster pessimism about the efficacy of psychotherapy partly because of an underlying intuitive theory ascribing relatively little power to the mind over the brain.

Fortunately, targeted education about the malleability of neurobiological factors in depression can help reduce prognostic pessimism and strengthen patients’ beliefs about their own ability to regulate their moods in depression (Lebowitz & Ahn, 2015), suggesting that these intuitions are not fixed or immutable. In future work, it would be worthwhile to investigate whether interventions that target people's intuitive theories of the relation between the mind and brain could also help mitigate the negative consequences of biological attributions for disorders such as depression.

While participants in our studies were reluctant to believe that acting on the mind can result in changes in the brain, they were more willing to endorse that acting on the brain can result in changes in the mind. This may help, in part, to explain why Western societies have so enthusiastically come to favor neurobiologically centered approaches to mental illness despite people's dualistic intuitions. Pharmacological treatments have become the predominant societal response to mental health conditions over the past decades. Although it is widely agreed that an adequate response to mental distress needs to address several nonreducible levels, Western cultures have allowed “the biopsychosocial model to become the bio-bio-bio model,” in the words of a previous president of the American Psychiatric Association (Sharfstein, 2005). Arguably, neither the enthusiasm nor the scale at which this approach has been implemented is easy to explain from a purely evidence-based perspective (Deacon, 2013; Whitaker & Cosgrove, 2015; UN Human Rights Council, 2017; Lacasse & Leo, 2005; Healy, 2015; Moncrieff & Cohen, 2006), and its success has been controversial at best (Danborg & Gøtzsche, 2019; Gøtzsche, Young, & Crace, 2015; Haslam & Kvaale, 2015; Hengartner, 2020; Ioannidis, 2019; Jakobsen et al., 2017; Munkholm, Paludan-Müller, & Boesen, 2019; Sohler et al., 2015). Why, then, do we continue to operate based “on faith that neuroscience will eventually revolutionize mental health practice,” if “[d]ecades of extraordinary investment in biomedical research have not been rewarded with improved clinical tools or outcomes” (Deacon, 2013, p. 858)? While numerous societal and institutional factors undoubtedly affect the situation in all its complexity (e.g., Moncrieff, 2006; Whitaker & Cosgrove, 2015), from a strictly cognitive perspective, it is conceivable that our intuitive theories—in particular, our willingness to believe in the brain as an asymmetrically powerful causal agent that can influence the mind—may have contributed and made the public prone to believe overstated neuroscientific claims. In a self-reinforcing cycle, the widescale implementation of any neurobiologically centered practices likely also loops back and shapes people's intuitive theories in ways that further increase the appeal of these practices.

7.1.3 Relation to the broader historical context

The intuitive theories documented here are undoubtedly a product of the current historical context: Several authors have suggested that many cultures are undergoing a transition toward understanding mind–brain relations in more materialistic terms (e.g., Mudrik & Maoz, 2014). As scientific inquiry has progressed, we as a culture have increasingly come to believe that it is the brain which controls faculties formerly associated with the soul, such as memory, language, and emotion. If the suggestion is correct that we are in the process of intuitively giving up the mind's and/or soul's functions to material brains (Greene, 2011), it is interesting to consider what are “the soul's last stands”—the most immaterial of our nonphysical capacities, the ones not yet outsourced to the brain.

7.2 Conclusion

It is important to keep in mind that, philosophically, the mind–body problem remains an unresolved paradox. Although materialist and physicalist views have been the working assumption of contemporary psychologists and neuroscientists and also the prevailing position in philosophy over the past decades, this does not mean that the original mind–body problem itself was resolved. It remains, to this day, extremely difficult to see how, if the mind is a nonphysical thing and the body is a physical thing, one could simply just be the other (or how they could interact, if we are dualists). It is helpful to remember that not only the general public but also (at least some) contemporary philosophers find the claim inherently implausible that the mind simply is a physical thing (e.g., Westphal, 2016). What people think the mind is, however, and how exactly they think it is related to the brain seems worth investigating further, both for theoretical and practical reasons.