Social Neuroscience Notes PDF

Preview

Summary

Introduction to social neuroscience...

Description

Ian Morton, 2007

This past summer (June-August, 2007) I participated in Bryn Mawr's Summer Science Research Fellowship Program, working for ten weeks in Paul Grobstein's lab along with friends and colleagues Rebecca Woodruf, Heather Fetting and Ashley Dawkins. In addition to contributing to collaborative, inquiry-based discussions (see PGLab-Summer2007 and Brain Stories), I pursued independent research, seeking to get a foundation in the developing field of social neuroscience. Here I offer a summary of my findings with the intent of offering a generalized understanding of what social neuroscience entails. Additionally, I hope to expand upon this page as my research continues and encourage anyone to offer his/her own thoughts and insight into this topic.

What is "Social Neuroscience?" Social Neuroscience is a term applied to an emerging field of study concerned with identifying the neural processes underlying social behavior/cognition. However, the field extends beyond a search for neurochemicals and brain regions that cause behavior; social neuroscience seeks to better understand the relationship between the brain and (social) behavior (W  aldrop, 1993; Decety & Keenan). This relationship is reciprocal: the brain affects social cognition and behavior, and social cognition/behavior affects the brain (I nsel & Dernald, 2004). The underlying question of social neuroscience, then, is how do the agents of this dyadic relationship influence one another? From this question a multitude of increasingly specified questions arise, but all of which seek to examine some aspect of the nature of the social brain-behavior dyad. The brain is an immensely complex system and it is becoming increasingly evident that the brain does not operate completely via feed-forward, hierarchical processes, stemming from discrete brain “centers”(Adolphs, 2003). Rather, the brain operates on parallel networks of both feed-forward and feedback loops, distributed across the brain (W  aldrop, 1993). As behavior is a result of the brain, it too is highly complex, influenced by numerous factors, both neurological and environmental in nature (Insel & Dernald, 2004). Due to the complexity of both brain and behavior, dogmatically adhering to classical scientific methods (rigidly controlled hypothesis-testing experiments) will not suffice. Controlling for the multitude of factors seems out of the question, thus making it virtually impossible to reach any absolute conclusions (Adolphs, 2003). It seems that the best hope for progress in social neuroscience will be the search for overarching patterns of brain-behavior through identifying converging results from diverse studies (Adolphs, 2003; Raichle, 2003; I nsel & Dernald, 2004; Decety & 

Keenan).Seeking fully objective conclusions about the social brain solely within the laboratory may hinder the field more than it would benefit its progress. Consequently, social neuroscience is best served through interdisciplinary research. Researchers from across fields such as cognitive neuroscience, social psychology, psychiatry, sociology, and philosophy, are all contributing to this ongoing examination of the brain and the social condition. Research within this field should include studies of brain function and organization (Young, 2001; G  allese, 2003; Insel & Dernald, 2004; A  modio & Frith, 2006), functional imaging studies (Raichle, 2003; Heatherton  et al . , 2004), case studies (A. Demasio, 1995; Dobbs,  2007), animal studies (Y  oung, 2001; Insel & Dernald, 2004; Miller, 2007), lesion studies (A. Demasio, 1994), behavior studies (M  iller, 2007), meta-analyses (Zhou et al . , 2005; Amodio  & Frith, 2006) and perhaps additional techniques not yet devised. Social neuroscience can therefore be understood as an interdisciplinary field that seeks to better understand the relationship between brains and social cognition and behavior through the use of various experimental techniques and converging results. Some Key Terms/Theories: To date, several provocative and influential theories have emerged from the study of social cognition and behavior. As a part of understanding social neuroscience, it is important to examine the current directions in which research is headed, the predominant theories that are in play, and state of our current understanding of the “social brain.” Not only should one understand these theories, but also one should also critically examine their implications, the validity of their foundations and assumptions, and the nature of how research is approaching these topics. Imitation: Imitation is precisely as it sounds; it is the duplication of an observed behavior. However, as simple as it is to define, the precise mechanisms of imitation remain contentious (Brass & Heyes, 2005). A predominant view describes imitation as a behavior whereby an individual translates an observed, external action of an Other into an internal pattern of neuromuscular activity that produces an equivalent action, thereby implying intentionality (M  eltzoff & Decety, 2003; Brass & Heyes, 2005). Meltzoff believes that infants are born with an innate capacity to imitate, which supplies them with a powerful learning tool in the social environment (Melzoff & Decety, 2003).Further, the mechanisms of imitation may play a decisive role in the development of theory of mind (Meltzoff & Decety, 2003). Theory of Mind (ToM):

(Also referred to as mentalization and mind reading ) Theory of Mind refers to the cognitive ability to attribute states of mind such as desire, intention and emotion to other people (and to oneself) as a means for predicting their behavior (Apperly, I.A., 2007). The cognitive ability to recognize and understand that others behave in a goal-oriented manner is a valuable tool for surviving in a social environment, as it allows individuals to predict the actions of others and therefore to manipulate and influence their behavior (Gallese, 2003). As ToM involves the recognition that others have mental states and perceptions that are distinct and independent of one’s own, of which one cannot have any direct knowledge, one can only have a “theory” of the other’s mind. ToM is an essential cognitive ability for successful social existence and has thus been a major focus of cognitive social neuroscience research. From the research with ToM, two major theoretical mechanisms have been proposed: Simulation Theory and Theory Theory (Vogeley K et al . , 2001). Simulation Theory (ST): Simulation Theory is one of two leading theories as to what serves as the basis for ToM capacity. According to ST, the capacity for ToM is based in one’s ability to take on another’s perspective via simulation, the cognitive act of placing oneself in another’s mental “shoes” (G  allese, 2003; Vogeley K et al. , 2001). According to Gallese, simulation is embodied  in the sense that the process of mentally modeling the behavior of other draws upon the very cognitive modeling used to shape one’s own  behavior (G  allese, 2003). Similarly, Vogeley et al . argue that in process of simulation, the mechanisms used for one’s own motivations, emotions and rationality are employed to imagine the motivations and emotions of the Other (Vogeley K et al . , 2001). Thus in ST, one not only takes the perspective of the Other, but also projects one’s own subjectivity onto the Other. Theory Theory (TT): TT proposes that one’s ability to understand and predict the behavior of others is dependent on the employment of a social knowledge base, often called folk psychology , to infer the mental states of others (Stich & Nichols, 1993; Gallese, 2003). Thus, one’s social understanding of another is accomplished entirely and solely through mental metarepresentations, contrary to the notion of embodied simulation inherent to ST (G  allese, 2003). Folk Psychology: Folk psychology refers to a theoretical framework about the social world (Stich & Nichols, 1993). It is a body of theories or principles, constructed automatically and unconsciously throughout one’s ontogenic development; one continually creates, tests, and revises theories about the social world (Gopnik & Meltzoff, 1997). As folk psychology refers to a body of

theories which serves as the foundation for TT, it is occasionally used synonymously with theory of mind.

Resources: Note: a DOI (Digital Object Identifier) is an identifier for a body information located on a digital network. That is, DOIs refer to the body of information itself, not just a URL where the body of information can be found. DOIs remain constant for a specific intellectual property, such as an article, and can be resolved using http://dx.doi.org. Resolving a DOI will supply information on the body of information such as its title and where it can be found digitally (a URL). For further information on the DOI system, visit h ttp://www.doi.org/.

Meeting of minds: the medial frontal cortex and social cognition David M. Amodio and Chris D. Frith Amodio, David M., and Chris D. Frith. "Meeting of Minds: the Medial Frontal Cortex and Social Cognition." Nature  Reviews Neuroscience 7 (2006): 268-277. http://www.nature.com/nrn/journal/v7/n4/full/nrn1884.html

In their paper, David Amodio and Chris Frith incorporate a wide range of meta-analysis research across fields associated with social cognition along with anatomical characteristics of the medial frontal cortex (MFC) and neighboring regions to draft proposal for the various roles of the MFC in social cognition. While the anatomy is somewhat specific and the number of study results covered vast, giving the paper an overwhelming effect, upon careful reading the layman can extract the major proposals of this paper. The authors present a theoretical model of the MFC that seems well founded in the current research, but which remains to be confirmed. However, their proposal could offer a valuable foundation for drafting future research on the role of the MFC in social cognition. Further, such a detailed analysis of the MFC and its subdivisions is beneficial when juxtaposed with other theoretical works concerning social cognition that may or may not implicate the involvement of MFC activity. According to Amodio and Frith’s model, the MFC is important for guiding behavior based on anticipated value within a social context. The posterior rostral region (prMFC), the most caudal of the regions of concern, is associated with a process of internal monitoring of response

selection, thus regulating behavior in terms of the predicted value of possible actions. The orbital region (oMFC) guides behavior in terms of the value of possible future outcomes. Finally, the anterior region (arMFC), lying between the two and most caudally positioned, has been associated with self-knowledge, person knowledge and mentalizing. The authors go on to argue that within the overall architecture of the MFC, processes become more abstract and complex in more rostral/anterior regions. The activity of posterior MFC regions appears to be associated with given information such as a felt sense of pain while anterior regions are concerned with more abstract representations of experience such as sensing that a loved-one is in pain (empathy), a process independent of sensory input. The authors propose that the arMFC is responsible for meta-cognitive processes of reflecting on feelings, intentions and values linked to outcomes and actions, thereby implicating its crucial role in empathy, morality and reputation, all key aspects of social cognition.

Discrete hierarchical organization of social group sizes W.-X.Zhou, D. Sornette, R. A. Hill and R. I. M. Dunbar Zhou, W. -X., D. Sornette, R. A. Hill, and R. I. M. Dunbar. "Discrete Hierarchical Organization of Social Group Sizes." Proc.  R. Soc. B 272 (2005): 439-444. PubMed. Haverford, Haverford. http://www.journals.royalsoc.ac.uk/content/wu7p7urhf381m1yd/

The “social brain hypothesis” suggests that group sizing is somewhat limited by cognitive factors such as the volume of neural material available for processing complex social information and dynamics. When groups attempt to extend beyond their cognitive boundaries, social stability suffers and groups fall apart. In this paper the authors make their own contribution to the ongoing discussion of grouping patterns in humans, identifying a hierarchy of social group sizes. Typically humans have a small core group of friends (the ‘support clique’). This core group is part of a larger sympathy group of friends, which in turn is part of the larger band. Bands, as termed in reference to hunter-gatherer societies, consist of a dynamic group of individuals, but which are all pulled from a common pool of people, the clan. The clan in turn is part of the megaband, which is a subgroup of the overall tribe. Using quantitative analysis of social networks from census data from various countries, the authors found that between these successive groupings there was a constant scaling ratio of about 3. That is they found that support cliques had a mean size of 4.6, sympathy groups a mean size of 14.3, bands 42.6 etc.

From these results the authors propose that humans form groups according to a distinct hierarchy with a preference for a scaling ratio of about 3. To support the quantitative analysis the authors also did a systematic analysis that took into account all the data, not just the means, as well as analysis of a third data set. In each case, they observed a scaling ratio of about 3. The data presented here is interesting as it shows a common scaling ratio for hierarchical group organizations from a diverse set of data, thereby suggesting that this is more than coincidental. Similar organization is observed in other facets of human life such as the military and stock market. One is left to wonder if this form of structuring is innate to human cognition, or perhaps the limits of human cognition. While this paper is not necessarily neural in nature, it suggests a neural basis and has implications for how we understand the neural processes of social understanding and categorization. How might this discrete hierarchical processing of social networking relate to the evolution of the social brain?

How The Brain Processes Social Information: Searching for the Social Brain Thomas R. Insel and Russel D. Dernald. Annural  Review of Neuroscience. 2004;27:697-722. DOI: 1 0.1146/annurev.neuro.27.070203.144148 In this paper, Insel and Dernald describe some of the recent studies related to the processing of social information with the intent of highlighting some of the neural mechanisms that appear to be specialized for social cognition. While the bulk of research covered in this paper does not pertain directly to humans, the correlations between specific neural mechanisms and particular aspects of social behavior observed in model organisms can offer some general insight into how the nervous system shapes behavior and vice versa. With these general concepts in mind, future research can be shaped to more precisely understand the neural correlates of social behavior and could shed new light on the role of the human nervous system in social cognition thereby offering potential benefits for better understanding neurological social disorders. The authors also critically consider the research they present in their paper and offer questions and ideas to help shape future experiments. Insel and Dernald call upon research that illustrate both ways in which social behavior can be influenced by physiological processes and ways that social behavior and perception can influence physiological processes. This is an important concept to highlight, that it is the interplay between one’s physiology and one’s environment that shapes behavior, not one or the other. With this in mind, the authors recognize that studying social neuroscience is difficult, as results can be skewed/misleading depending on the context (environment, social) of the experiments. However, Insel and Dernald believe that a blend of multiple studies will allow us to

begin defining the circuitry of the “social brain” and could thus help us to better understand how the brain operates within the social world. Additionally, in their paper the authors present a simplified and theoretical model for mammalian social processing.

The Neurobiology of Social Recognition, Approach, and Avoidance Larry J. Young The neurobiology of social recognition, approach, and avoidance. Biological Psychiatry, Volume 51, Issue 1, 2001: Pages 18-26. http://dx.doi.org/10.1016/S0006-3223(01)01268-9 In this paper, Young discusses three main rodent models that are valuable for understanding the basic neural mechanisms involved with social processing, approach and avoidance. First, studies with oxytocin knockout (OTKO) mice suggest that the amygdala, rich in OT receptors, differentially processes social versus nonsocial information, but requires the presence of OT in order to do so. Young’s research with voles was the first to illustrate the direct correlation of the regional distribution and density of neuropeptide receptors with unique sets of social behavior. Young observed a high concentration of OT and vasopressin (AVP) receptors in regions associated with the dopamine reward system in highly social voles, but found low concentrations in the same regions of nonsocial voles. Young infers that OT and AVP promote social behavior in social voles through activation of the neural circuitry of reward thus reinforcing highly social behavior, while nonsocial voles, not expressing significant receptor distribution in regions connected to reward, do not receive the same motivation for social behavior. Finally, studies with hamsters suggest that corticotropin releasing factor (CRF) is involved in the expression of social avoidance and submissive behavior. While the studies presented by Young do not directly pertain to human systems, they provide valuable correlations between basic neural mechanisms and social behavior that may help to elucidate the role of the brain in the social behavior of humans. Young clearly presents the observations from rodent systems and does well at relating the observations to human systems and conditions. In particular, this paper could offer new and better ways to understand the human condition of social anxiety. Young’s work with voles implicates the importance of brain organization, a result of genetic sequence, for shaping behavior. It therefore seems plausible that individual variation in organization of the dopamine system would result in different predispositions for social behavior, including prosocial, affiliative behavior or nonsocial, anxious behavior. What roles might OT, CRFs and the amygdala play in prosocial versus socially anxious behaviors? While this paper can be useful for better understanding the neural machinery behind social approach and avoidance, one should not be misled to believe that brain organization solely determines human behavior. It should rather be understood that the brain

creates strong dispositions for certain sets of behavior, which get reinforced or inhibited with experience in the world.

Investigating the cognitive neuroscience of social behavior Ralph Adolphs. Neuropsychologia. 2003;41(2):119-26. DOI: 1 0.1016/S0028-3932(02)00142-2 Ralph Adolph wrote his paper to complement several featured papers from this issue of Neuropsychologia, which cover some recent findings pertaining to social knowledge and behavior. Adolph did not intend to review the neurobiology of these articles, but rather to outline and discuss key issues provoked by these papers that pertain to the field of social neurobiology as a whole. This paper begins with a brief presentation of the featured articles, in which Adolph discusses the benefits offered by different techniques utilized in each, such as functional imaging, while also illustrating that results from a single study are incomplete and inconclusive. Adolphs’ intent is to show that social neuroscience differs from other “strict” scientific fields in both theory and methodology. Indi...