pain associated with rejection by others (DeWall et al., 2012). Figure 2.8 includes fMRI images obtained in an investigation of brain activity during exposure to social versus nonsocial objects. Later on we will highlight additional fMRI studies that have identified neural correlates to key social behaviors.
Figure 2.8 Social Versus Nonsocial Brain Activation
Source: Mitchell, J. P., Heatherton, T. F., & Macrae, C. N. Distinct neural systems subserve person and object knowledge. Proceedings of the National Academy of Sciences of the United States of America, 99(23), 15238-15243. Copyright © 2002 National Academy of Sciences, U.S.A.. Reprinted with permission.
Other Methods
GSR, EEG, MEG, MRI, and fMRI have been among the most popular approaches to understanding the physiological bases of social behavior. However, researchers have also used positron emission tomography (PET), the physical induction of lesions directly on the brain, transcranial magnetic stimulation (TMS), and other methods (Beadle & Tranel, 2011; Decety & Cacioppo, 2011; Todorov, Fiske, & Prentice, 2011). PET provides an alternative way of imaging the brain that, like fMRI, examines blood flow. However, PET is a more invasive approach in that it utilizes injected radioactive or other substances and consequently makes it somewhat less appealing to social psychologists. Both lesion induction and TMS are disruptive techniques in that they impair normal functioning of the brain in order to see the effects of psychological processes. Lesioning involves causing irreversible damage to the brain, raising obvious ethical concerns. For this reason, lesion studies are usually conducted on animals or on humans who have already experienced brain trauma outside the laboratory (Beadle & Tranel, 2011). Had Gage’s severe brain injury occurred today, he would have been a prime candidate for one of these studies!
TMS uses a magnetic field to create an electric current that stimulates targeted areas of the brain and temporarily prevents normal functioning. For example, one study used TMS to briefly shut down the mirror neuron system in order to verify its role in imitating others (described earlier and again in Chapter 8). Researchers found that people’s ability to imitate others was significantly hampered, thus providing additional evidence of the function of mirror neurons (Heiser, Iacoboni, Maeda, Marcus, & Mazziotta, 2003).
Multimethods
Each of these techniques—like all research methods—has its strengths and weaknesses. Therefore, social psychologists prefer to use more than one method to investigate social behavior. As a result, our understanding of the neuroscience of social behavior is more comprehensive and sophisticated (Ochsner, 2007; Wager & Lindquist, 2011). As we will see later, the principle of combining multiple research methods to examine a common phenomenon in order to strengthen our knowledge of social behavior applies more broadly to all methods of inquiry.
Think Again!
1 What is a galvanic skin response?
2 What are the advantages of fMRI?
3 Why is it important to use multiple methods for studying the brain?
Social Neuroscience And The Fundamental Questions
By now the importance of the studying the brain for understanding social behavior should be clear. As appealing and important as social neuroscience is, one can, however, be easily seduced by the ahhh! factor and captivated by the beauty and power of these powerful technologies (Satel & Lilienfeld, 2013). In fact, we may even be tempted to reduce social behavior to its brain biology and point to a particularly vivid region on a multicolored, three-dimensional brain image and claim there it is, the root of prejudice (or some other social behavior)! However, the brain processes that occur during social behavior are just one component of a much larger social psychological explanatory framework with multiple levels of analysis. In other words, we cannot even come close to an adequate understanding of social behavior if we engage in such reductivism—which is the assumption that we need only study the brain to understand the causes of social behavior. Many prominent social neuroscientists have argued instead the importance of examining social behavior from multiple perspectives (Decety & Cacioppo, 2011; Lieberman, 2010). The unique contributions of social neuroscience to our understanding of specific social behaviors are important, but they are only part of the story. Indeed, social neuroscience, in addition to deepening our understanding of social behaviors, is highly relevant to the six fundamental questions of human existence.
Free Will
Research in social neuroscience is probably most relevant for the question of free will. In fact, a number of prominent research programs have challenged the notion that humans are in conscious control of our mental and behavioral processes (Baer, Kaufman, & Baumeister, 2008; Gazzaniga, 2011). If scientists can pinpoint the biology of nonconscious processes, and if these processes can predict social behavior without needing to factor in the conscious mind, then does it make any sense for us to talk about free will (Bargh, 2008; Baumeister, 2008)? For many social psychologists, the answer is yes: Even if we do not actually have free will, both the experience of free will and the reasons people believe in it are important for understanding social behavior (Baumeister, 2008). For example, a person who believes that he has the free will to shape his future is more likely to persist in the face of failure than is someone who thinks that he is powerless and that his fate has already been decided (Dweck, 1999).
Applying Social Neuroscience to Law
Can fMRI Detect Lies?
As you’ll see in the remainder of this text, social neuroscience has wide applications in social psychology and beyond. Recently, researchers have been studying whether or not fMRI can be used in law enforcement and the courts, specifically to detect deception in suspects and witnesses (Langleben & Moriarty, 2013). Given the challenges people face in detecting lies on their own (which are discussed in Chapter 5), law enforcement has sought a foolproof, technological solution. How might an fMRI identify lies? Briefly, it has been proposed that there are discernable differences in brain processes when people tell the truth versus when they do not (Bizzi et al., 2009). The short answer is that neuroscientists largely agree, at least at this time, the fMRI is unable to identify such differences (Bizzi et al., 2009; Ganis, Kosslyn, Stose, Thompson, & Yurgelun-Todd, 2003; Langleben & Moriarty, 2013). Some of the criticisms include the following:
Different types of lies may show different brain activation patterns, and therefore no single brain “signature” for deception exists.
Existing research has involved only very small samples.
Lying in a laboratory setting is artificial and not reflective of real-world conditions, and consequently, generalizability to non-experimental situations is low.
In addition to the scientific concerns, questions have been raised regarding the ethics of using an fMRI for lie detection: Would it violate the Fifth Amendment prohibition of forced self-incriminating testimony? Would it violate the Fourth Amendment protection from warrantless search?
Figure 2.9 fMRI as
