Humans aren’t the only lonely species. Monkeys may be lonely too.

January 14, 2015February 9, 2015Eliza Bliss-Moreau

More than two decades of research demonstrates that people who have more social connections do better—in terms of their general health, ability to recover from illness, and longevity (for a classic, oft cited study, see here; for a review, here; for popular press coverage and a lovely long read on human loneliness, here). Perhaps unsurprisingly, it’s not just the number of people you’re connected to that matters for your well-being. Whether people’s social relationships meet their social needs also has critical importance for health outcomes regardless of how many social connections they have (for reviews of this literature see here, here, and here). That is, it’s possible to be well-connected socially and still feel totally alone in the world. It is also possible to have very few social relationships but not feel lonely at all.

Exciting new evidence illustrates that we humans might not be the only ones to experience loneliness—rhesus macaque monkeys may as well. As part of an interdisciplinary team, Dr. John Capitanio examined the social behavior of adult male macaques at the California National Primate Research Center and identified three different patterns. Some monkeys engaged in a lot of social interactions with other males, adult females, and younger monkeys. Other monkeys did not engage in a lot of social interactions at all. What’s critical some of these “lowly social” monkeys seemed fairly content with their lot in life—they went about their daily business without trying to build new relationships.

The other lowly social monkeys did seem to care about their lot in life, however. They often physically approached adult females and younger animals, presumably in an effort to initiate an interaction. Similarly, the monkeys would walk by those animals to see what they were doing, even when trying not to engage with them. The fact that these behaviors were observed with adult females and younger monkeys suggests that these “lonely” adult male monkeys may have been looking for easy social relationships (because of how macaque societies are structured, relationships between adult males can be challenging). This heightened social interest persisted when evaluated 1.5 years later. In other words, there were monkeys who appeared to chronically desire social relationships but did not manage to make them happen—a potential monkey homologue of human loneliness. What’s more, as Capitanio points out, these lonely monkeys may be better models for human loneliness than previous animal models because the phenomenon emerged spontaneously in the context of large naturalistic social groups, rather than as a result of experimentally separating animals.

In and of itself, the finding that nonhuman animals might have the capacity to be lonely is an interesting one. It suggests that experiencing a mismatch between one’s social realities and one’s social desires is evolutionarily old, raising questions about what function loneliness might have served for our ancestors.

But perhaps more importantly, animal models of human psychological phenomena, such as a monkey model of loneliness, are critical to understanding the biological processes that contribute to them. Nonhuman primate (e.g., monkey) models are particularly important for understanding human function and dysfunction because we share so many biological and social features. Monkey models allow for precise experimental control (e.g., the ability to manipulate social environment, diet, sleep-cycles, etc.), intensive long-term longitudinal studies (i.e., the ability to track and evaluate many individual animals over the course of their entire lives), and the development of causal biological models. Understanding biological mechanisms is critical for developing effective early interventions and treatments for deleterious psychological experiences. Studying lonely monkeys may therefore unearth the biological and social processes that can be harnessed to help lonely humans in the future.

Photo: Adult male rhesus monkey at the CNPRC eating a zucchini. Photo Credit: Kathy West, CNPRC.

The Social Brain: Thinking about Others

December 17, 2014January 1, 2015Steve Chang

Our lives are greatly dependent on other people around us. As the holiday seasons approach, many of us are reminded that there are so many people whom we care about and who care about us. For some people, this time of the year may remind them of the loved ones who might no longer be around them. We are highly social animals, and we cannot escape this fact. Sociality creates, defines, and drives who we are.

Many scientists agree that the complexity of social environments was one of the key factors that actively steered primate brain evolution. This is of course supported by a seminal hypothesis known as the social brain hypothesis by Robin Dunbar. This hypothesis was primarily generated by the observations that there is a strong positive correlation between the brain size and the social group size across different primates (monkeys, apes, and humans). In a nutshell, larger the social group size became, the bigger the brain size became. It’s definitely not a stretch to state that social processing is one of the very most important functions carried out by our brains (especially in the parts of our brain called neocortex).

Animals that live in social groups are indeed very sensitive to information about other individuals in their societies. Processing social information can take many forms. Just to give some everyday examples, we constantly pay attention to what other people think of us, and vice versa. We are also very aware of things happening to others. We often feel happy, sad, angry, or jealous when we learn about others. Basically, it’s up to our brain to parse out the information about self and others in order to influence our future actions. Not surprisingly, this process is powerfully shaped by emotional feelings generated by different social information.

Neuroscientists are now hoping to unlock the mystery behind the “social brain”. This is a daunting task especially since social processing, by nature, is a product of numerous associations among sensory/motor, cognitive, and emotional processes. One of the big questions that many neuroscientists are asking is whether there are dedicated brain circuits for social processing. The alternative is that the neural circuits already being used for non-social processing also handle social functions. The answer still remains elusive, but the experiments asking questions about the social brain are becoming more sophisticated and more rigorous (which is exciting). We recently discussed how preexisting brain areas for carrying out non-social functions might have been repurposed and extended to serve social functions in primates. It remains to be seen whether some parts of the brain are newly expanded to accommodate exclusively social functions.

Let’s return to how the brain might process the information about others. In a recent study, we tested how the neurons in the brain that carry the information about one’s rewards (e.g., getting money, delicious food, etc.) respond when another individual is rewarded. In a task where monkeys got to choose whether they shared a reward with another monkey, we found that different parts of the prefrontal cortex (an area of the brain that is highly developed in humans and other primates) signal juice rewards received by an actor monkey and a recipient monkey in distinctive manners. Some neurons only care about one’s own reward outcome, but there are also other types of neurons that track the reward outcome of another individual either exclusively or in conjunction with one’s reward outcome. In another recent study, Matt Roesch and colleagues found that when a rat observes the rewarding event of another rat, dopamine is released in a brain region important for reinforcement learning. One important conclusion to be made from these and other recent studies (e.g., a, b, c) is that the brain structures that typically process one’s own information also signal the information of other individuals either by the same neurons or distinct “other” types of neurons.

The field investigating the mystery behind the social brain is rapidly growing. It would be fascinating to know more about how internal states, such as those regulated by emotion, control the way by which social information is computed. The success of our adventures into the social brain will critically depend on collective efforts by scientists who study human participants and non-human animals so that we can discover the complexities behind human social cognition as well as concurrently discover fundamental neuronal mechanisms in animal models. New exciting knowledge awaits us.

 photo credit: https://m.flickr.com/#/photos/kymberlyanne/2687290741/

Do talk to strangers

July 30, 2014January 2, 2015Kristen Lindquist

If you’re a New Englander, a city-dweller, an introvert, or just put a lot of stock in your mother’s admonitions to avoid talking to strangers, then you’re going to think what I’m about to say is crazy. You should talk to strangers more, and there’s scientific evidence to support it. Now I know what you’re thinking. Small talk is tedious! If you talk to that person on the street, you’ll be stuck there forever. Plus, he’s most likely crazy, going to mug you, or both. Be that as it may, scientific research suggests that it will make you happier to make a connection with other members of humankind.

In a newly published paper, Nick Epley and Juliana Schroeder at the University of Chicago asked participants in a Chicago-area train station to do one of three things on their commute: one group was asked to strike up a conversation with the person next to them, one group was asked to do their normal commute routine (which let’s be honest, probably involves ruminating about the coming toils of the day, or what you’re going to make for dinner that night) and one group was asked to sit in solitude. At the end of the train ride, the authors measured how happy the commuters felt. They found that small talk is apparently not so tiresome after all. Participants who chatted with a train-mate reported feeling more positive compared to participants who sat in solitude and participants who did their normal commute thing. Now perhaps what’s most interesting about these findings is precisely what I suggested at the beginning of this post—the idea of chatting with someone sounds, well, at best a little tedious and at worst just downright terrible. As a dyed-in-the-wool New Englander, I can assure you that this is my expectation when the person next to me in the supermarket checkout line starts expounding on the recent weather or extolling the virtues of my choice in yogurt. Epley and Schroeder’s participants also predicted that they’d feel pretty unimpressed at sharing trivial tidbits with another human being on the train. Funnily enough, they also predicted that solitude would be rather blissful. Not so.

These findings are interesting not just because they offer a new tactic for improving your commute, but because they strike at the heart of what social scientists and emotion researchers have known for some time. People need other people. Indeed, social connection is probably one of the most important keys to health and well-being. A famous study by Nobel Laureate Daniel Kahneman found that having intimate relations (with another person) and being with friends makes people happier than almost all other things, including relaxing, eating, exercising, napping, even taking care of their kids (you’ll note that spending time with kids doesn’t quite count as the type of “spending time with people” we’re referring to here—this effect is probably moderated by the dirty diapers, constant feedings, rides to soccer practice and fights amongst siblings that makes interactions with these small people less than blissful). John Cacioppo, also from the University of Chicago, has found that perceived loneliness is related to depression, poor health and even mortality. And what’s lonelier than being surrounded by a sea of people and not making connection with a single one? So find a good joke, start caring about the vagaries of the weather, and reach out and chat with someone.

Is Facebook getting you down?

July 23, 2014January 2, 2015Kristen Lindquist

What better for a first blog post about emotions than a discussion of how the internet (may be) shaping our emotions? By now, you’ve probably heard about the Facebook study that was published in the Proceedings of the National Academy of Science that purportedly shifted people’s emotions by altering the content of their news feeds. If you haven’t seen it yet, this paper produced a lot of uproar (mostly on Facebook). People have variably decried it as unethical, not novel, or not evidence that people’s emotions were actually shifted. If you haven’t read it, here’s a précis: The authors selected a group of Facebook users and selectively reduced the amount of positive posts that were displayed in their newsfeed (e.g., removed posts like “I’m so happy I got the new job!” “We’re so glad to welcome our new baby!”) or selectively reduced the amount of negative posts that were displayed in their newsfeed (e.g., removed posts like “I really hate when some as*hole takes your parking spot at work!” “People disgust me!”). The authors then measured how much Facebook users in each condition posted positive or negative information themselves using an automated dictionary that codes words as positive or negative. What they found was that people who saw less positive stuff posted less positive stuff and more negative stuff, and people who saw less negative stuff posted less negative stuff and more positive stuff. Now if the authors really shifted people’s emotions then this is cool, but maybe not so surprising. It’s like saying that the people around you affect your mood. Think of that whiny co-worker who you want to avoid because life just seems a little more terrible when he’s around. It’s the same effect. Of course it’s made more interesting by the fact that it occurred on a massive scale and through—gasp—the internet!

But other questions remain about the study and its findings. I’ve been asked, so did they really change people’s emotions? Unfortunately, this question is quite the quagmire in the science of emotion. It turns out that there is no single measure in science that can tell you exactly what someone is feeling. You could hook them up to a heart rate monitor, measure the sweat on their skin, measure their respiration, put them in a brain scanner and you still couldn’t know exactly what they were feeling, beyond the fact that they were feeling something and maybe whether they were feeling generally activated v. sleepy or pleasant v. unpleasant. Thus, despite all our technology, the best way to know what someone is feeling is to ask them. Obviously hooking up Facebook users around the world to physiological recording devices was not an option for the authors, and they didn’t ask their unknowing participants how they felt either. So all we know from the experiment is that seeing fewer positive or negative posts changed the way that people used emotion words themselves. This could be the result of a change in participants’ perceptions of norms (i.e., “it’s not cool to humble brag on my Facebook page if my friends don’t do it”). Or it could be “emotional contagion” as the authors suggest—in the absence of positive information on Facebook feeds around the world, people’s days were just a bit grayer.

So in sum, why did this study get so much attention if it showed that—guess what—the people around us affect our emotions (or at least the nature of the emotion words we use in our Facebook posts)? It’s because people felt played. They felt taken advantage of. That Big Brother was toying with their emotions. Yet what people fail to realize is that their emotions are always being played. Every advertiser, politician, journalist, author, and salesperson in the world is constantly trying to play our emotions, for good or bad. Emotions are involved in every single moment of your waking life and are shifted by myriad unseen influences, not least of which is the Facebook newsfeed we (choose to) be glued to. At least Facebook technically told you it reserves the right to manipulate you (although see Eliza’s post for the broader ethical considerations at stake here when this happens in an experimental context). Not so much can be said for the used car salesman who relies on emotion-based tactics to get you to walk off the lot with a lemon. So if Facebook is getting you down, wait a minute and someone else will shift your mood.