This is My Brain on Social Cognition
By Bob Spunt
I’m an odd breed of Social Psychologist known as a Social Cognitive Neuroscientist. I am this way because of two basic beliefs about people like you and me. The first is that our brains make our minds, and the second is that our minds are made to live in a social world. The former belief is at the heart of the discipline of Cognitive Neuroscience, while the latter is at the heart of the discipline of Social Psychology. When you put these disciplines together, you not only get a mouthful of syllables, you also gain the power to use neuroimaging methods such as functional magnetic resonance imaging (fMRI) to view what is happening inside a person’s head while they do the work of social cognition. My own studies using fMRI have allowed me to photograph hundreds of other people’s brains on social cognition. Recently, I got the opportunity to photograph my own brain on social cognition. I’m here to tell you the story of how I was able to do this. By the end of my story, you may find that you’ve learned a thing or two about how fMRI can be used to measure the inner workings of not just my social mind, but everyone’s social mind, including you, too.
How to Photograph the Social Mind
Figure 1. Two forms of proof that I have a brain. Panel a shows three photographs taken from a structural MRI scan of my head that took 5 minutes to complete. Panel b shows three photographs from a functional MRI scan of the same areas of my head. This scan took just 1 second to complete and contains information about the regions of my brain that were most active during that 1 second period. Hence, by collecting many of these scans back-to-back, I can see how my brain activity is affected by second-to-second changes in what I was doing, thinking, or feeling during the scan. This is the basic logic of photographing the mind with an MRI machine.
Three basic ingredients are needed to photograph the inner workings of the social mind. The first is a living brain to view. Fortunately, I not only have a brain, but I’m also alive. The second ingredient we’ll need is a camera for taking photographs of the inside of my head. The camera I used is an MRI machine, namely, a Siemens Trio 3.0 Tesla located at the Caltech Brain Imaging Center. The top panel in Figure 1 shows three sections (or slices) from one of the 3D pictures taken of me during my MRI session. This is from an anatomical scan that took about 5 minutes to complete. Although it proves that I have a brain inside of my head, it does not provide any information about what my brain was doingwhile the scanner was busy taking the picture. To get this kind of functional information, I underwent another kind of MRI called echoplanar imaging (EPI). You can see one of my EPIs in the bottom panel of Figure 1. The pixel intensity in these images provides a measure of what is known as Blood Oxygenation Level Dependent (BOLD) signal. To make a long story short: In order to do their work, brain regions need oxygen, which is delivered via the bloodstream. Importantly, oxygen is routed to different brain areas on the basis of need: When activity in a brain region increases, the body responds by delivering more oxygen to that region; when brain activity decreases, the body responds by delivering less oxygen to that region. These changes in “blood oxygenation” are the basis of the BOLD signal. Critically, whereas my anatomical image took 5 minutes to produce, each one of my EPIs took just 1 second to produce. Hence, by acquiring EPIs consecutively while I use my brain, I can detect changes in BOLD signal that are caused by momentary changes in what is on my mind.
Our third and final ingredient is a method for experimentally controlling when social cognition is on my mind, and when it isn’t. This is the independent variable (IV) that I will use to cause changes in the dependent variable (DV), that is, BOLD signal. Of the three ingredients, this is the most important, because without it I’d have no way to understand what it was that I was looking at when I finally get to examining my brain images. To illustrate the problem here, imagine you’re about to undergo an fMRI for 5 minutes. I give you the following instructions: “Just close your eyes and relax. Do not fall asleep.” Now, ask yourself: What would you be doing, thinking, and feeling during that 5 minute period? Maybe you’d focus on your breathing, or the sound of the running scanner, or the visual images that occasionally pop into your head. Maybe you’ll reflect on a recent conversation with a friend, or worry about an upcoming deadline. Maybe you’ll fall asleep even though I told you not to. Maybe you’d do all of those things, yet at different times during your scan. Who knows? Certainly not me. Thus, when I get to looking at your brain activity, I’ll no doubt be seeing your brain doing something, but I’ll have no idea what for. That is, I won’t know what was on your mind at the time each image was being acquired.
Fortunately, experimentally controlling social cognition is one of the many things I learned to do in the Social Psychology doctoral program at UCLA. At this point, I should stop saying “social cognition” – which is too broad and abstract to be scientifically tractable – and start speaking in terms of the specific part of social cognition my research focuses on, namely, the ability to make attributions about human behavior (Malle, 2007; Heider, 1958). To make sure we’re all on the same page regarding what I mean by attribution, take a quick moment to answer the following question about me: “Why did this Social Cognitive Neuroscientist guy write this post?” If you’re like most people, you’ll have no problem rifling off a variety of plausible answers to this question, such as “He’s trying to teach others about his profession“, “He thought he’d acquire some kind of fame“, and the uninformative (yet still attributional) “He’s doing it because he wants to do it”. Even if you didn’t come up with your own answer, you probably appreciate the plausibility of the answers I provided, and this is illustrated by an implausible answer: “He wants to fall in love”. Our ability to construct and evaluate attributions about behavior is a fundamental part of how we understand the social world. What is happening inside our heads when we do this?
To photograph my own ability to make attribution, I need to be able to control when I am (and am not) using that ability. In my first fMRI studies of attribution, published with Matt Lieberman while I was at UCLA, I used a natural method for putting attribution on other people’s brains: I presented them with either verbal descriptions, photographs, or videos of human behavior, and I asked them to answer the attributional question: “Why is the person doing it?” While this is clearly a method for putting attribution on the brain, it no doubt puts quite a lot of other things on the brain too, and many of these things have little to do with attribution per se. For example, consider how much your mind had to do to answer the attributional question I asked you to answer above, including: (1) moving your eyes while you read the sentence; (2) recognizing the individual words and comprehending the overall meaning of the sentence; and (3) retrieve the knowledge and words necessary to verbalize your answer. None of these cognitive processes arespecific to answering why-questions, since they’re also involved in answering basically any question I might pose to you now. This fact is particularly problematic in fMRI studies, since the EPIs contain information about basically everything that is on a person’s mind, regardless of whether it is or isn’t essential to the explicit task the person is performing. Hence, to get a clear photograph of attribution (and only attribution), I needed a control question that did not require attributional processing to answer, but which required all of the other cognitive processes involved in the attribution condition. Fortunately, the question “Why is the person doing it?” has a natural opposite: “How is the person doing it?” For example, the control question for the one I posed to you earlier would simply be: “How did this Social Cognitive Neuroscientist guy write this post?” Even though you don’t know exactly how I wrote this post, you can probably appreciate the plausibility of an answer like “He used a computer” and the implausibility of an answer like “He rode a bicycle“. Hence, to separate brain activity that is specific to attribution from brain activity that is involved in answering questions in general, I can measure brain activity associated with answering both why- and how-questions, and then simply subtract the latter from the former (for a critical discussion of this idea of “cognitive subtraction”, see Friston et al., 1996).
Why-questions to put attribution on the brain, and how-questions to take it (and only it) off the brain. In Social Psychology, the comparison of why and how questions is known as the Why/How Task (Fujita, Trope, Liberman, & Levin-sagi, 2006; Freitas, Gollwitzer, & Trope, 2004; Strack, Schwarz, & Gschneidinger, 1985). In the version of the task I performed, I answered a series questions about a set of photographs showing familiar human behaviors. Every photograph appears twice, once for a how-question, and once for a why-question. In cognitive psychology, this is known as an attentional manipulation; in social psychology, I imagine this would also be called a construal manipulation. These are similar ways of saying that what differs across the two question types is not the stimulus I am looking at (i.e., the photograph), but rather the manner by which I attend to, interpret, or construe that stimulus.
I had the necessary ingredients: a brain (me), a camera to view my brain in use (fMRI), and an experimental method to put attribution on and off my brain (Why/How Task). My social mind was ready to have its photo taken. Here’s a brief description of my experience. Upon entering the room housing the MRI scanner, I put on earplugs to protect my ears from the loud noises produced by the scanner while it is running. Then, I lied down on a reasonably comfy table attached to the front of the scanner and my head was snugly postioned inside a 32-channel head coil that looks like a cage-like structure. A mirror was placed on top of the head coil such that I was able to see a monitor positioned at the back of the scanner, which would be used to visually present the Why/How Task to me. My left hand held a squeeze ball that I could use to sound an alarm in the case of an emergency, and my right hand held a button box that I would use to make my responses. After setting me up with all of this equipment, I was moved deep into a 60 cm wide tube (the scanner bore). Even though I’ve been inside an MRI machine more than 10 times in my lifetime, I still felt a little claustrophobic when I first entered that tight little space. This quickly dissipated, and in no time I was using my brain to answer Why and How questions about people in photographs. The Why/How Task took just over 5 minutes to complete. Altogether, my MRI session took about 30 minutes to complete.
Getting My Social Mind’s Photos Developed
Figure 2. Relating what I was seeing and doing to what my brain was doing. During my fMRI scan, I saw color photographs of human behavior and sometimes answered Attributional Questions (panel a) and sometimes answered Factual Questions (panel b) about them. Given that the timeseries of the two Question Types are different, each would be predicted to produce a different pattern of brain activity across time (panel c). Thus, I can determine which regions are more strongly related to one Question Type over another. Moreover, I can determine which regions are related to answer both Question Types. Panel d shows actual timeseries data extracted from my visual cortex.
To develop my mind’s photographs, I’d have to deal with the data first. Immediately after I finished performing the Why/How Task, a single data file was saved to my computer that contained important information about my performance of the Why/How Task, including when the different types of questions occurred, how long it took me to give my answers, and what answers I actually gave. Although that data file weighs in at a meager 7 KB (i.e., 0.007 MB), it is critical for developing my photos because it tells me what my mind was up to at the time each image was being collected. This is illustrated in the first two panels of Figure 2, which shows when I was and wasn’t answering the two types of questions for each of the 300+ images that were collected every second of the scan.
At 7 KB, the behavioral data is easy to process. Unfortunately, the MRI data files are another story entirely. Each whole-brain image file weighs in at just under 1 MB. This is already a lot more data than my behavioral data file, and for good reason: Each image contains 358,400 different volumetric pixels (calledvoxels), each containing information about different parts of the 3D space that my head was placed within. Yet, this is just one of over 300 images of the same size. The result is 300 MB worth of raw data for a task that took just over 5 minutes to complete.
Before I could even begin to analyze my fMRI data, I had to preprocess my images. To minimize the risk of losing you to some other blog that doesn’t contain the words “realignment”, “segmentation”, and “diffeomorphic”, I will keep this short. Preprocessing is as important to fMRI data analysis as it is frustrating, tedious, and distracting to most fMRI researchers. It’s important because the raw data contains many sources of noise that must be minimized in order to improve your chances of seeing the signal you really care about. In my case, I care about changes in BOLD signal that are caused by changes in the kind of question I was answering. The image timeseries contains these changes, no doubt, but they also contain changes caused by a host of other factors, for instance, head motion. Figure 3 is a 30-second video of functional data from the front of my face (the two circles at the bottom are my beautiful blue eyes) for the entire duration of the Why/How Task, and shown at 10 times the actual speed. Here, pixel brightness corresponds to signal strength. It’d be great if this also meant that pixel brightness corresponds to strength of brain activity. Yet, clearly it doesn’t. Just take a look at how much signal change occurs in and around my eyes whenever I blink. If simply moving my eyelids can cause that much signal change, just think how much would be caused by moving my entire head. Because of this, most fMRI studies will literally throw out a participant’s data if they moved their head more than a tenth of an inch! Fortunately, I was virtually a cadaver in there.
Figure 3. Bob’s Brain, Hard at Work. If you look close enough, you can see the mind-body problem.
To detect brain activity that is specifically associated with the attribution process, I needed to know when my brain was and wasn’t on attribution. Fortunately, my behavioral data file allows me to know what kind of question I was answering at the time that every one of my 300+ images was being collected. This, in turn, allows me to predict brain activity changes that are caused by changes in the task I was performing. As you can see in panel c of Figure 2, the timeseries of the two Question types would be expected to produce different patterns of brain activity across time (panel c). Panel d shows actual timeseries data extracted from my visual cortex, which was active regardless of the kind of question I was answering. This shouldn’t be surprising, since every question required visually attending to color photographs of complex social scenes.
Figure 4. Brain activity maps of my left hemisphere while answering attributional (why) and factual (how) questions. The rightmost map is what is known as a contrast map, and produced by subtracting the activity map for factual questions from the activity map for attributional questions. In all maps, yellow/red indicates a positive relationship while blue indicates a negative relationship. The top row shows the lateral (side) surface of the hemisphere (imagine looking at me while I’m facing to my right). The bottom row shows the medial (inside) surface of the hemisphere (imagine looking at me while I’m facing to my left, and suddenly the right half of my head is removed).
Whereas both why and how questions demand the same kinds of visual processing, they critically differ in their demand on attributional processing. By determining which regions are more strongly associated with answering why questions compared to answering how questions, I can see what’s happening inside my head that is specific to attribution. Figure 4 visualizes how this is done. The two images on the left show the strength of the relationship between each question type and every region of the left hemisphere of my brain. Notice that the two question types result in brain activity patterns that are generally pretty similar. This reflects the fact that the two question types are, by design, very similar in the demands they placed on my mind: Not only can you see strong activity in my visual cortex for both question types, but you can see strong activity in my left motor cortices that is due to the right hand finger presses I made when responding to the task.
To see how why and how questions differ, I simply subtract the latter from the former. This is the Why > How contrast shown in the rightmost map in Figure 4. This map is unthresholded, thus it shows regions that showed similar levels of activity across the two question types, as well as regions that actually showed a stronger response to how than to why questions. To get those pretty lava blobs you see in publications and in the press, I can statistically threshold the map so that I see the regions that were positively and reliably associated with answering attributional (relative to factual) questions. This map is shown in the top panel of Figure 5. Yup, that’s me. Or rather, that’s me using my ability to make attributions about human behavior. Now that’s a selfie I can get behind.
This is Our Brain on Social Cognition
Let’s see how I compare to a photo of the typical person’s brain on attribution, shown in the bottom panel of Figure 5. This map is essentially an average of the Why > How contrast from a separate sample of 59 healthy adults, all of whom performed the same task while undergoing fMRI. It shows that I used most of the same brain regions that the typical person uses when doing the task. I honestly did not expect my results to look as typical as this. After all, I wrote the test. I had taken the test many times before. I was familiar with all of the photographs, and wrote all of the questions. Yet, I used largely the same parts of my intellect to perform the task as a person who is taking the test for the first time.
Figure 5. This is Our Brain on Social Cognition. Panel a shows the regions of my brain’s left hemisphere that were specifically activated when I was answering attributional questions about people, as opposed to when I was answering factual questions about the same people. Panel b displays the same comparison measured in a group of over 50 healthy adults who performed the same task.
Here’s how I explain this strange observation: Making attributions is so natural for the typical person – me included – that the best way for me to approach the task was to just use this ability in same way I use it to make sense of the people I interact with and think about outside of the scanner. Given that such social sense-making is a near constant part of living in human society, I’d say that most of us spend a large part of our entire lives taking – and passing – attribution tests. And when we do, the studies I’ve conducted so far suggest that nearly everyone uses the same parts of their brain to answer all kinds of different attributional questions (Spunt & Adolphs, In Press; Spunt & Lieberman, 2012b; Spunt & Lieberman, 2012a; Spunt, Satpute, & Lieberman, 2011; Spunt, Falk, & Lieberman, 2010). To give just a few examples, my work suggests we use the same cognitive ability to make attributions for both a person’s intentional actions and their emotional facial expressions, and regardless of whether we’re watching their behavior or simply reading about it. In ongoing work, I am examining how attributional processing breaks down in autism spectrum disorders, as well as in people with lesions to parts of the brain thought to be important to social cognition.
But, all that is another story. For now, I’ll conclude by confessing that, stereotypically, I did go into psychology partly because I thought it would help me understand myself. Early on in my research career, I did some research on indecisiveness, and that was definitely motivated by my own difficulties with handling decisions. But I never really saw my research on attribution as a case of “re-search is me-search”. That is, until now.
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