The neural reuse theory has proven remarkably generative and supportive of research activity on embodied cognition, motivation, and behavior. We first present and discuss recent research evidence consistent with a “conceptual scaffolding” principle that is in harmony with the neural reuse perspective. We then discuss how conceptual development in neuroscience and empirical research in social psychology may collaborate in fathoming the neural structure of grounded cognition.
Anderson (Reference Anderson2014) notes that conceptual metaphors – structure and logical protocols from one domain guiding and structuring those in another (e.g., life is a journey, love is war) – may be only one “side effect” (p. 26) of the neural reuse process on a larger scale. Evidence from social and consumer psychology on embodied forms of judgment and behavior suggests that higher-order mental conception is not built from the more basic functional models as “prototypes” (Anderson Reference Anderson2014, p. 17) as much as it is built upon (associatively connected to) the biological groundings of the primal functions, sharing their neural substrates by reuse. Several lines of research provide support for this proposition.
The conceptual scaffolding account (Williams et al. Reference Williams, Huang and Bargh2009), which was influenced by and is in harmony with the neural reuse principle, argues that more abstract concepts and complex, higher-order mental functions (person perception, self-esteem, value judgment) grow organically from and are hence “built upon” the more fundamental, innate needs, such as for survival, safety, and resource acquisition (consumption). The “built upon” notion leads directly to the assumption that associative connections will be formed between the concrete and the abstract concepts or goals, associations that remain intact throughout the lifespan. This in turn leads to hypotheses regarding the use of physical level concepts in describing more abstract social and psychological phenomena, as documented by extant theory and research on metaphor use (Lakoff & Johnson Reference Lakoff and Johnson1980; Landau et al. Reference Landau, Meier and Keefer2010). Social relationships (a close relationship, a warm father, a sweet thing to do) are commonly described in physical terms, and we easily understand each other when these terms are used. But the “scaffolded” associative connections play an even larger role than in language alone, as many studies have now documented how activation of the physical level concepts (such as by holding something warm, or feeling something rough) spreads along these associative connections to activate and influence analogically related psychological and social level judgments and motivations as well.
For example, research in the sensorimotor domain shows that higher-level social judgments are influenced by concrete physical sensory experiences (Ackerman et al. Reference Ackerman, Nocera and Bargh2010; Krishna Reference Krishna2012). Ackerman et al. (Reference Ackerman, Nocera and Bargh2010) found that incidentally touching something rough or smooth (rough or smooth backing on the clipboard they were using) influenced participants to rate a social interaction they read about as having gone more roughly or smoothly. Schaefer et al. (Reference Schaefer, Heinze and Rotte2014) replicated this effect across 96 different social interaction scenarios, in the context of an fMRI study in which participants touched something rough or smooth prior to reading each of the scenarios. Schaefer et al. (Reference Schaefer, Heinze and Rotte2014) replicated the rough-smooth priming effect but showed further that the extent of activation of the somatosensory cortex caused by the physical experiences correlated significantly with the extremity of the social judgment of the smoothness of the social interactions.
Moreover, just as cold ambient temperatures and physical objects (e.g., ice cubes) cause a person to feel physically colder, so too does “social coldness” in the form of rejection by others cause a person to actually feel and become physically colder (IJzerman et al. Reference IJzerman, Gallucci, Pouw, Weissgerber, Van Doesum and Williams2012). Physical warmth (as from holding something warm) causes people to become more socially warm (generous, trusting: Inagaki & Eisenberger Reference Inagaki and Eisenberger2013; Williams & Bargh Reference Williams and Bargh2008), and holding something cold causes people to act with less generosity and lower levels of trust in behavioral economic games (Kang et al. Reference Kang, Williams, Clark, Gray and Bargh2011). And again, neuroscience studies have shown that the degree of activation of the brain regions that respond to the physical level experience are correlated with the extent of the obtained effect in the more abstract social or psychological domain. In the case of physical warmth and coldness, the same regions of insula become active upon physical and social warmth experiences – holding something warm or texting to one's family and friends (Inagaki & Eisenberger Reference Inagaki and Eisenberger2013) – and upon physical and social coldness experiences (Kang et al. Reference Kang, Williams, Clark, Gray and Bargh2011). Moreover, the same homeostatic mechanisms are activated in the two forms of warmth or coldness: Just as one seeks warmth when cold, Zhong and Leonardelli (Reference Zhong and Leonardelli2008) demonstrated that after an experience of social exclusion (coldness), participants more often wanted a hot drink or warm food for lunch, compared with an iced drink or cold cuts.
That physical level experiences such as a warm bowl of soup can effectively substitute for missing feelings of social warmth (as after exclusion or rejection by others) is reminiscent of Kurt Lewin's early theory of goal substitution, as originally studied by his student Mahler (see Wicklund & Gollwitzer Reference Wicklund and Gollwitzer1982). If a desired goal cannot be met, then substitute activities can often, at least temporarily, satisfy (and turn off) that goal. And so socially rejected participants more strongly prefer physically warm beverages or lunch dishes (Zhong & Leonardelli Reference Zhong and Leonardelli2008). Other studies show similar goal substitution effects, even at the abstract level of political values and attitudes.
For example, we all have a need to feel in control of our lives and important (goal-related) outcomes; when this need is threatened (such as when our economic resources are low) people tend to compensate by identifying more strongly with larger, more powerful social entities such as the government or a supernatural, powerful God (Kay et al. Reference Kay, Gaucher, Napier, Callan and Laurin2008). Other, more physical level needs show the same goal substitution effect. Immigrants to one's culture can be viewed as analogous to external germs and viruses entering one's own physical body. Satisfying the goal of disease prevention, such as by getting a flu shot or by washing one's hands with antibacterial disinfectant, would hence be expected to substitute for the more abstract goal of defending one's culture by anti-immigration attitudes. Several studies indeed showed that participants who had been inoculated against the flu virus (and reminded of that fact) had less negative attitudes toward immigration than nonimmunized participants; and in another study, those given a chance to use disinfectant hand wipes also then had less negative immigration attitudes (Huang et al. Reference Huang, Sedlovskaya, Ackerman and Bargh2011).
Similarly, in the case of another basic physical-level motivation, consumption of food, more abstract (and modern-day) consumption goals would be expected to be “built upon” or “reuse” that more fundamental motive. In harmony with that prediction, Xu et al. (Reference Xu, Schwarz and Wyer2015) have shown that not only do hungry participants tend to buy more food at the grocery store, as previous studies had shown, but they also buy more of everything, even non-food items at a department store. The goal of consumption or acquisition of resources in general appears therefore to be built on the more fundamental (and survival relevant) goal of food consumption – such that when that food consumption goal is active (that is, when the person is hungry), the more abstract consumption goals are also more active. Not only is it a good idea, from a pragmatic economic standpoint, to having something to eat before going to the grocery store (Gilbert et al. Reference Gilbert, Gill and Wilson2002), but it also appears to be a good idea before doing any kind of shopping.
There are cultural and individual differences in the use of particular metaphors, and these would be expected to moderate when the physical-to-abstract influences on judgments and behavior will occur. Some metaphors, such as the warm-cold one, appear from the neuroscience research (as well as social psychological research on impression formation; see Fiske et al. Reference Fiske, Cuddy and Glick2007) to be hard-wired and universal, but other metaphors appear in some cultures and not in others. This suggests that more than one mechanism might underlie the metaphorical effects; some might be hard-wired, whereas others are culturally based and semantic, reflecting linguistic customs (Meier et al. Reference Meier, Schnall, Schwarz and Bargh2012b).
At the individual difference level, the recent development of the Metaphor Usage Measure (MUM; Fetterman et al. Reference Fetterman, Bair, Werth, Landkammer and Robinson2016) shows that a person's tendency to use metaphors in his or her everyday communications to others is related to the probability that their behavior will be influenced by analogous physical experiences. The authors' previous research had shown that eating sweet foods was related to having a “sweet” personality (kind, thoughtful, selfless) and also that people in general were more likely to behave “sweetly” after having consumed sweet foods or drink (Meier et al. Reference Meier, Moeller, Riemer-Peltz and Robinson2012a). Research on validation of the MUM scale showed that the more a given individual tended to use metaphors (in general) in common speech, the stronger the correlation in their daily lives between how much sweet foods and drinks they consumed and how many “sweet” behaviors they performed that day. Hence, the extent to which associative connections have formed between the physical and social levels of a concept influences both the use of the metaphorical use of the physical concept in language and its degree of influence (when activated by relevant physical experience) on analogous forms of social behavior.
Anderson's (Reference Anderson2014) innovative model of neural reuse has been of tremendous help in understanding the basis for the numerous and often remarkable findings of physical experiences on higher-level judgments and behavior over the past decade. This body of evidence, especially its increasing focus on mechanism and individual difference moderators, will be important for sorting out the several distinctive theoretical frameworks that have emerged to account for the metaphorical or analogical influence of the body over the mind. These include evolutionary (Kaschak & Maner Reference Kaschak and Maner2009), linguistic and symbolic (Boroditsky Reference Boroditsky2001), simulation-based and perceptually grounded (Barsalou Reference Barsalou2008), as well as culturally situated (Cohen & Leung Reference Cohen and Leung2009; Oyserman Reference Oyserman2011). Some of these theories rely more heavily on a semantic or linguistic mechanism, whereas others emphasize a goal-based evolutionary exaption (Anderson Reference Anderson, Hardy-Vallee and Payette2008b) of functional units in service pursuit of the same ultimate underlying end-state – the ancient concerns of survival and prosperity, consisting of the same basic set of primal challenges: self-conservation, social affiliation, mating, and power (Kenrick et al. Reference Kenrick, Maner, Butner, Li, Becker and Schaller2002). As embodiment and neural reuse theory and research themselves evolve together in the years to come, a better understanding of the underlying mechanisms and contextual moderators of embodiment and metaphor effects will certainly be gained by staying mindful of new developments in the theory and research on neural reuse.
The neural reuse theory has proven remarkably generative and supportive of research activity on embodied cognition, motivation, and behavior. We first present and discuss recent research evidence consistent with a “conceptual scaffolding” principle that is in harmony with the neural reuse perspective. We then discuss how conceptual development in neuroscience and empirical research in social psychology may collaborate in fathoming the neural structure of grounded cognition.
Anderson (Reference Anderson2014) notes that conceptual metaphors – structure and logical protocols from one domain guiding and structuring those in another (e.g., life is a journey, love is war) – may be only one “side effect” (p. 26) of the neural reuse process on a larger scale. Evidence from social and consumer psychology on embodied forms of judgment and behavior suggests that higher-order mental conception is not built from the more basic functional models as “prototypes” (Anderson Reference Anderson2014, p. 17) as much as it is built upon (associatively connected to) the biological groundings of the primal functions, sharing their neural substrates by reuse. Several lines of research provide support for this proposition.
The conceptual scaffolding account (Williams et al. Reference Williams, Huang and Bargh2009), which was influenced by and is in harmony with the neural reuse principle, argues that more abstract concepts and complex, higher-order mental functions (person perception, self-esteem, value judgment) grow organically from and are hence “built upon” the more fundamental, innate needs, such as for survival, safety, and resource acquisition (consumption). The “built upon” notion leads directly to the assumption that associative connections will be formed between the concrete and the abstract concepts or goals, associations that remain intact throughout the lifespan. This in turn leads to hypotheses regarding the use of physical level concepts in describing more abstract social and psychological phenomena, as documented by extant theory and research on metaphor use (Lakoff & Johnson Reference Lakoff and Johnson1980; Landau et al. Reference Landau, Meier and Keefer2010). Social relationships (a close relationship, a warm father, a sweet thing to do) are commonly described in physical terms, and we easily understand each other when these terms are used. But the “scaffolded” associative connections play an even larger role than in language alone, as many studies have now documented how activation of the physical level concepts (such as by holding something warm, or feeling something rough) spreads along these associative connections to activate and influence analogically related psychological and social level judgments and motivations as well.
For example, research in the sensorimotor domain shows that higher-level social judgments are influenced by concrete physical sensory experiences (Ackerman et al. Reference Ackerman, Nocera and Bargh2010; Krishna Reference Krishna2012). Ackerman et al. (Reference Ackerman, Nocera and Bargh2010) found that incidentally touching something rough or smooth (rough or smooth backing on the clipboard they were using) influenced participants to rate a social interaction they read about as having gone more roughly or smoothly. Schaefer et al. (Reference Schaefer, Heinze and Rotte2014) replicated this effect across 96 different social interaction scenarios, in the context of an fMRI study in which participants touched something rough or smooth prior to reading each of the scenarios. Schaefer et al. (Reference Schaefer, Heinze and Rotte2014) replicated the rough-smooth priming effect but showed further that the extent of activation of the somatosensory cortex caused by the physical experiences correlated significantly with the extremity of the social judgment of the smoothness of the social interactions.
Moreover, just as cold ambient temperatures and physical objects (e.g., ice cubes) cause a person to feel physically colder, so too does “social coldness” in the form of rejection by others cause a person to actually feel and become physically colder (IJzerman et al. Reference IJzerman, Gallucci, Pouw, Weissgerber, Van Doesum and Williams2012). Physical warmth (as from holding something warm) causes people to become more socially warm (generous, trusting: Inagaki & Eisenberger Reference Inagaki and Eisenberger2013; Williams & Bargh Reference Williams and Bargh2008), and holding something cold causes people to act with less generosity and lower levels of trust in behavioral economic games (Kang et al. Reference Kang, Williams, Clark, Gray and Bargh2011). And again, neuroscience studies have shown that the degree of activation of the brain regions that respond to the physical level experience are correlated with the extent of the obtained effect in the more abstract social or psychological domain. In the case of physical warmth and coldness, the same regions of insula become active upon physical and social warmth experiences – holding something warm or texting to one's family and friends (Inagaki & Eisenberger Reference Inagaki and Eisenberger2013) – and upon physical and social coldness experiences (Kang et al. Reference Kang, Williams, Clark, Gray and Bargh2011). Moreover, the same homeostatic mechanisms are activated in the two forms of warmth or coldness: Just as one seeks warmth when cold, Zhong and Leonardelli (Reference Zhong and Leonardelli2008) demonstrated that after an experience of social exclusion (coldness), participants more often wanted a hot drink or warm food for lunch, compared with an iced drink or cold cuts.
That physical level experiences such as a warm bowl of soup can effectively substitute for missing feelings of social warmth (as after exclusion or rejection by others) is reminiscent of Kurt Lewin's early theory of goal substitution, as originally studied by his student Mahler (see Wicklund & Gollwitzer Reference Wicklund and Gollwitzer1982). If a desired goal cannot be met, then substitute activities can often, at least temporarily, satisfy (and turn off) that goal. And so socially rejected participants more strongly prefer physically warm beverages or lunch dishes (Zhong & Leonardelli Reference Zhong and Leonardelli2008). Other studies show similar goal substitution effects, even at the abstract level of political values and attitudes.
For example, we all have a need to feel in control of our lives and important (goal-related) outcomes; when this need is threatened (such as when our economic resources are low) people tend to compensate by identifying more strongly with larger, more powerful social entities such as the government or a supernatural, powerful God (Kay et al. Reference Kay, Gaucher, Napier, Callan and Laurin2008). Other, more physical level needs show the same goal substitution effect. Immigrants to one's culture can be viewed as analogous to external germs and viruses entering one's own physical body. Satisfying the goal of disease prevention, such as by getting a flu shot or by washing one's hands with antibacterial disinfectant, would hence be expected to substitute for the more abstract goal of defending one's culture by anti-immigration attitudes. Several studies indeed showed that participants who had been inoculated against the flu virus (and reminded of that fact) had less negative attitudes toward immigration than nonimmunized participants; and in another study, those given a chance to use disinfectant hand wipes also then had less negative immigration attitudes (Huang et al. Reference Huang, Sedlovskaya, Ackerman and Bargh2011).
Similarly, in the case of another basic physical-level motivation, consumption of food, more abstract (and modern-day) consumption goals would be expected to be “built upon” or “reuse” that more fundamental motive. In harmony with that prediction, Xu et al. (Reference Xu, Schwarz and Wyer2015) have shown that not only do hungry participants tend to buy more food at the grocery store, as previous studies had shown, but they also buy more of everything, even non-food items at a department store. The goal of consumption or acquisition of resources in general appears therefore to be built on the more fundamental (and survival relevant) goal of food consumption – such that when that food consumption goal is active (that is, when the person is hungry), the more abstract consumption goals are also more active. Not only is it a good idea, from a pragmatic economic standpoint, to having something to eat before going to the grocery store (Gilbert et al. Reference Gilbert, Gill and Wilson2002), but it also appears to be a good idea before doing any kind of shopping.
There are cultural and individual differences in the use of particular metaphors, and these would be expected to moderate when the physical-to-abstract influences on judgments and behavior will occur. Some metaphors, such as the warm-cold one, appear from the neuroscience research (as well as social psychological research on impression formation; see Fiske et al. Reference Fiske, Cuddy and Glick2007) to be hard-wired and universal, but other metaphors appear in some cultures and not in others. This suggests that more than one mechanism might underlie the metaphorical effects; some might be hard-wired, whereas others are culturally based and semantic, reflecting linguistic customs (Meier et al. Reference Meier, Schnall, Schwarz and Bargh2012b).
At the individual difference level, the recent development of the Metaphor Usage Measure (MUM; Fetterman et al. Reference Fetterman, Bair, Werth, Landkammer and Robinson2016) shows that a person's tendency to use metaphors in his or her everyday communications to others is related to the probability that their behavior will be influenced by analogous physical experiences. The authors' previous research had shown that eating sweet foods was related to having a “sweet” personality (kind, thoughtful, selfless) and also that people in general were more likely to behave “sweetly” after having consumed sweet foods or drink (Meier et al. Reference Meier, Moeller, Riemer-Peltz and Robinson2012a). Research on validation of the MUM scale showed that the more a given individual tended to use metaphors (in general) in common speech, the stronger the correlation in their daily lives between how much sweet foods and drinks they consumed and how many “sweet” behaviors they performed that day. Hence, the extent to which associative connections have formed between the physical and social levels of a concept influences both the use of the metaphorical use of the physical concept in language and its degree of influence (when activated by relevant physical experience) on analogous forms of social behavior.
Anderson's (Reference Anderson2014) innovative model of neural reuse has been of tremendous help in understanding the basis for the numerous and often remarkable findings of physical experiences on higher-level judgments and behavior over the past decade. This body of evidence, especially its increasing focus on mechanism and individual difference moderators, will be important for sorting out the several distinctive theoretical frameworks that have emerged to account for the metaphorical or analogical influence of the body over the mind. These include evolutionary (Kaschak & Maner Reference Kaschak and Maner2009), linguistic and symbolic (Boroditsky Reference Boroditsky2001), simulation-based and perceptually grounded (Barsalou Reference Barsalou2008), as well as culturally situated (Cohen & Leung Reference Cohen and Leung2009; Oyserman Reference Oyserman2011). Some of these theories rely more heavily on a semantic or linguistic mechanism, whereas others emphasize a goal-based evolutionary exaption (Anderson Reference Anderson, Hardy-Vallee and Payette2008b) of functional units in service pursuit of the same ultimate underlying end-state – the ancient concerns of survival and prosperity, consisting of the same basic set of primal challenges: self-conservation, social affiliation, mating, and power (Kenrick et al. Reference Kenrick, Maner, Butner, Li, Becker and Schaller2002). As embodiment and neural reuse theory and research themselves evolve together in the years to come, a better understanding of the underlying mechanisms and contextual moderators of embodiment and metaphor effects will certainly be gained by staying mindful of new developments in the theory and research on neural reuse.