In those split seconds when people witness others in distress, neural pathways in the brain support the drive to help through facets of imagination that allow people to see the episode as it unfolds and envision how to aid those in need, according to a team of Boston College researchers.
The underlying process at work is referred to as episodic simulation, essentially the ability of individuals to re-organize memories from the past into a newly-imagined event simulated in the mind.
Neuroimaging helped the researchers identify multiple neural pathways that explain the relationship between imagination and the willingness to help others, researchers from Boston College and the University of Albany, SUNY, reported recently in the journal Social Cognitive and Affective Neuroscience.
The team explored two separate brain regions with different functions: the right temporoparietal junction (RTPJ), a key brain region thought to be involved in representing the minds of other people, also known as “perspective-taking”; and the medial temporal lobe (MTL) subsystem, a set of brain regions that support the simulation of imagined scenes.
The study discovered evidence for the direct impact of scene imagery on willingness to help, according to Boston College Associate Professor of Psychology Liane Young, a co-author and the principal investigator on the project.
While study participants imagined helping scenes, neural activity in MTL predicted overall willingness to help the person in need, according to the article, “A role for the medial temporal lobe subsystem in guiding prosociality: the effect of episodic processes on willingness to help others,” which was published in the journal’s April 14 edition.
“If we are able to vividly imagine helping someone, then we think we’re more likely to actually do it,” said Young, director of the Morality Lab at BC.
“Imagining the scenery surrounding the situation can also prompt people to take the perspective of the people in the situation who need help, which in turn prompts prosocial action.”
This may be because of a phenomenon known as imagination inflation, where humans use the vividness of their imagination as a kind of cue to estimate the likelihood of an event, according to the co-authors, which also included former BC postdoctoral researcher Brendan Gaesser, now an assistant professor of psychology at the University of Albany, SUNY, research assistants Joshua Hirschfeld-Kroen and Emily A. Wasserman, and undergraduate research assistant Mary Horn.
The team set out to learn how the capacity to simulate imagined and remembered scenes of helping motivate individuals to form more altruistic intentions.
The goal was to uncover the cognitive and neural mechanisms that explain the relationship between episodic simulation and the enhanced willingness to help those in need.
In the first experiment, which allowed the team to look at both brain regions, the researchers collected functional brain images as people imagined and remembered helping others in hypothetical scenarios.
In the second experiment, while people were imagining helping another person, the team used transcranial magnetic stimulation (TMS) to disrupt activity in their right temporoparietal junction (RTPJ), a key brain region thought to be involved in representing the minds of other people.
Neuroimaging revealed that the willingness to help was also predicted by activity in the RTPJ, a critical node that’s involved in taking the perspective of other people, according to the researchers.
However, in the second experiment, when the team used TMS to temporarily inhibit activity in the RTPJ, they found that the altruistic effect of vividly imagining helping remained significant, suggesting that this effect doesn’t depend exclusively on perspective-taking.
“We had initially expected that higher neural activity in the medial temporal lobe subsystem would be associated with a greater willingness to help,” the team reported.
“Surprisingly, we found the opposite: the more activity a person had in their MTL subsystem while they were imagining helping scenes, the less willing they were to help the person in need.”
This contradiction may be explained by lower MTL activity reflecting greater ease of imagining episodes, and that ease of imagination means that participants are more willing to help.
Consistent with this account, the team found that when participants reported finding it easier to imagine or remember helping episodes, they also tended to report being more willing to help the person in need.
Young and Gaesser recently found in a separate study, led by BC postdoctoral researcher Jaclyn Ford and Professor Elizabeth Kensinger, that vividly remembering helping was associated with making more generous donations in the wake of the 2013 Boston Marathon bombing. Next steps in the research will further connect the lab’s neuroimaging approach with measures of real-world altruistic behavior.
Humans often collaborate, coordinate and help each other in times of need.
Research in social neuroscience and psychology has focused on investigating how the processes underlying our perceptions of people in need, their mental states and our subsequent emotional reactions contribute to prosociality (Coke et al., 1978; Decety, 2005; Singer and Lamm, 2009; Batson, 2011; Rameson et al., 2012; Waytz et al., 2012; Zaki and Ochsner, 2012; Marsh, 2016).
Great progress has been made in revealing how neural mechanisms associated with various social-cognitive processes, including theory of mind/mentalizing (Masten et al., 2011), representing individual victims (Genevsky et al., 2013), affect-sharing (Singer and Lamm, 2009; Hein et al., 2010) and positive empathy (Morelli et al., 2015), can inform decisions to help others.
But, helping involves more than representing and reacting to a person in isolation: it involves a specific event unfolding in time and place, in which the person is embedded. While person-centric accounts of prosociality have yielded key insights, they do not address the potential importance of how the helping event itself is represented.
Thus, the current work aims to investigate the following questions:
Does it matter not just how we represent the person in need, but how we represent the episodic details of helping?
Can neural systems that support episodic simulation (imagining hypothetical and future events) and episodic memory (remembering past events) contribute to our willingness to help others?
Episodic representation involves consciously experiencing an unfolding sequence of details (e.g. people, objects) in a specific place as an event or scene (Schacter et al., 2008).
Whereas episodic memory is retrospective, episodic simulation is less anchored to a temporal direction, including imagining possible future events (Atance and O’Neill, 2001; Seligman et al., 2013; Szpunar et al., 2014), atemporal fictitious events (Hassabis et al., 2007; Summerfield et al., 2009, 2010) and counter-factual events (De Brigard et al., 2013). A large body of neuroimaging work (Addis et al., 2007; Szpunar et al., 2007; see Benoit & Schacter, 2015 for meta-analysis) and patient studies (Tulving, 1985; Klein et al., 2002; Hassabis et al., 2007; D’argembeau et al., 2008; Addis et al., 2009; Berryhill et al., 2010; de Vito et al., 2012; Race et al., 2011) has established that episodic simulation and memory recruit many of the same brain regions, including the medial temporal lobes (MTLs), medial prefrontal cortex (mPFC), posterior cingulate cortex (PCC), lateral temporal cortex and lateral parietal cortex, commonly referred to as the default network (Raichle et al., 2001; Buckner and Carroll, 2007; Spreng et al., 2009).
This network is comprised of dissociable subsystems (i.e. the core, dMPFC and MTL subsystems) that show different patterns of connectivity at rest and support different component processes (Andrews-Hanna et al., 2010; Andrews-Hanna et al., 2014).
The core subsystem is extensively connected to all other regions across the default network.
The dMPFC subsystem, comprised of the dMPFC, lateral temporal cortex and temporal pole, is recruited for semantic knowledge, mental state content and narrative processing.
Most pertinent to the present study is the MTL subsystem, comprised of the hippocampus, parahippocampus, retrosplenial cortex, posterior inferior parietal lobule and, to some extent, the ventral medial prefrontal cortex (vMPFC), is critical for imagining and remembering events.
The MTL subsystem is particularly engaged when participants generate episodes specific in time and place and is sensitive to scene construction (i.e. the need to embed an event within a spatial context; Andrews-Hanna et al., 2010; Addis et al., 2011; Madore et al., 2016; Tamir et al., 2016; Palombo et al. 2018).
While cognitive neuroscientists have learned a great deal about the brain systems supporting episodic processes, little is known about their potential contribution to social cognition, broadly and prosociality, more specifically.
Emerging behavioral evidence finds that imagining future events and remembering past events can facilitate prosocial intentions to help a person in need: participants were more willing to help a person in need after imagining helping in that situation or remembering helping in a related situation (Gaesser et al., 2015; Gaesser and Schacter, 2014; Gaesser et al., 2017a, 2017b).
A shared cognitive mechanism has been suggested to underlie the similar effects of both imagining and remembering on prosocial intentions. Initial evidence has come from behavioral measures suggesting that, as the imagined and remembered helping scene becomes more vividly represented, the accessibility of the helping event and subjective plausibility that one will help in that situation increases.
Relatedly, amnesic patients with damage to the MTL, often characterized by parallel deficits in imagining future events and remembering past events, have been shown to exhibit prosocial deficits in some cases (Beadle et al., 2013).
While the MTL subsystem may directly influence prosocial intentions by heightening access and the subjective plausibility of a helping episode, another possibility is that the MTL subsystem guides prosocial intentions by interacting with other person-focused mechanisms previously shown to impact prosociality.
Indeed, we have recently found behavioral evidence that an effect of episodic simulation on prosocial intentions and decision-making may be partially attributed to an increase in considering the mental states of the person in need (i.e. theory of mind akin to mentalizing, perspective-taking) for the person in need (Gaesser et al., 2018).
For example, imagining or remembering a helping episode may recruit theory of mind, making it easier to consider the thoughts and feelings of the person in need embedded within the imagined or remembered episode.
On this account, imagining and remembering helping a person in need may elicit enhanced activity in the network of regions that support theory of mind (akin to mentalizing or perspective-taking), such as the right temporal parietal junction and dorsal mPFC (Saxe and Wexler, 2005; Scholz et al., 2009; Young et al., 2010; Zaki and Ochsner, 2012; Hill et al., 2017).
Here, we investigated the neural basis of the prosocial effect of episodic processes using functional magnetic resonance imaging (fMRI; Experiment 1) and transcranial magnetic stimulation (TMS; Experiment 2) in order to examine whether neural regions engaged during episodic simulation and episodic memory can guide a willingness to help others.
Across both experiments we used a theory of mind functional localizer to independently define each participant’s theory of mind network to interrogate (Experiment 1) and disrupt (Experiment 2) activity in this network.
Because no such functional localizer exists for episodic simulation and episodic memory, we instead targeted the MTL subsystem coordinates independently defined in previous work using functional connectivity (Andrews-Hanna et al., 2010) and associated with imagining and remembering specific episodes or scenes (Andrews-Hanna et al., 2010; Addis et al., 2011; Madore et al., 2016; Tamir et al., 2016; Palombo et al., 2018).
Given that the MTL subsystem of the default network supports constructing mental scenes of episodic experiences, one possibility is that activity within the MTL subsystem would inform a willingness to help.
Another possibility is that generating episodic experiences recruits theory of mind, and it is instead activity within the theory of mind network that informs a willingness to help.
Thus, the present study sought to investigate the neural basis of the prosocial effect of episodic processes and gain insight into the underlying mechanism.
More information: Brendan Gaesser et al, A role for the medial temporal lobe subsystem in guiding prosociality: the effect of episodic processes on willingness to help others, Social Cognitive and Affective Neuroscience (2019). DOI: 10.1093/scan/nsz014
Journal information: Social Cognitive and Affective Neuroscience
Provided by Boston College