Twitter is either an indispensible professional and personal tool, or the downfall of humanity, depending on who you believe. But to Scott Golder and Michael Macy from Cornell University, it is something more: an unparalleled source of data. The duo has used the popular social networking site to eavesdrop upon the world’s moods, as they rise and fall throughout the day and across the week. By analysing half a billion tweets from 2.4 million people in 84 different countries, they turned Twitter into a giant global mood ring.
They found that, on average, people wake up in a good mood, which falls away over the course of the day. Positive feelings peak early in the morning and again nearer midnight, while negative feelings peak between 9pm and 3am. Unsurprisingly, people get happier as the week goes on. They’re most positive on Saturdays and Sundays and they tend to lie in for an extra two hours, as shown by the delayed peak in their positive feelings. The United Arab Emirates provide an interesting exception. There, people work from Sunday to Thursday, and their tweets are most positive on Friday and Saturday.
This might seem obvious, but previous studies have arrived at conflicting results about our mood cycles. For example, psychologists have variously said that positive feelings peak: just once, 8 to 10 hours after waking; once at noon and once in the evening; and once in the afternoon and again in the evening. Different studies have also claimed that negative feelings are most common in the morning, afternoon or evening… or don’t have any daily cycles all!
Most of these studies involved small numbers of American undergraduates, who were asked to remember their feelings hours or days ago. These small samples and imprecise measures might explain why the results have been so inconsistent. On top of that, students are hardly representative of the wider population, especially since they’re constrained by academic schedules.
Twitter was an obvious way of circumventing these problems. It’s popular around the world, people use it to voluntarily report their feelings without any reminders, and they do so in a timely (and time-stamped) way. The experimenters don’t ever have to prompt or even meet their volunteers. They just sit back and collect the data.
This is the second study to use Twitter to track broad changes in mood. The first focused solely on the United States and although widely reported last year, it has not been published yet. Golder and Macy’s attempt is larger in scope. They sampled 400 English tweets from every Twitter account created between February 2008 and April 2009. The messages – around 509 million of them – spanned two years.
The duo analysed them with a programme called Linguistic Inquiry and Word Count (LIWC), which hunted for words that betray a number of different positive and negative feelings. The programme’s vocabulary is calibrated using texts from journals, novels, conversation recordings, blog posts and more, in both American and British English. It may not be up-to-date with the latest internet slang, but it’s certainly diverse in its scope.
You might think that counting positive and negative words is a fairly crude way of looking at tweets. For example, the programmes might recognise “good” as being positive, even if it was part of a neutral phrase (“good morning”) or a negative one (“not good”). But Golder and Macy found that both of these misdirecting uses are far less common than people might assume, and certainly too rare to skew the results. For example, “good” appears in 1 in 20 tweets, but it’s only preceded by “not” in 1 in 2000 of them. Likewise, including smileys and emoticons did little to change the shape of the world’s moods.
The mood graphs suggest that sleep gives us a chance to reboot our moods from the stress of a working day, and weekends are doubly refreshing for our emotions. And people show the same emotional cycles around the world even though they might come from different cultures and countries (including the UK, USA, Canada, India, Australia, New Zealand and various African nations).
By looking at when people were most likely to tweet, Golder and Macy separated their sample into morning people, afternoon people, evening people and night owls. The first three groups were fairly similar in their mood cycles, but the night owls – who were most active between midnight and 6am – were very different. Their morning peak of positivity happened two hours after everyone else and they didn’t have a second peak at night. Instead, they had two peaks of negative feelings – once in the morning when everyone else’s negative feelings are ebbing, and another later at night.
Golder and Macy also looked at how the tweets varied with the seasons. The length of the days had no effect on their emotional content; instead, it’s the relative change in daylight hours that matter. Our tweets are (very slightly) more positive at the spring equinox, when the days start to lengthen more quickly, than at the summer solstice when the days are actually at their longest. Negative feelings, however, don’t seem to change with the seasons. The fabled “winter blues” are more due to fewer positive feelings than more negative ones.
Relying on tweets raises its own problems, but this is still a decent step beyond small, questionnaire-based studies. Twitter’s users are not representative of the general population, but they certainly represent a broader spectrum of society than American college students. Tweets only show the emotions that people are willing to express, rather than the ones they actually feel, but you could say the same for the questionnaires used in most psychological experiments.
The data set is not perfect, but it compensates for that in its size and breadth. Looking at the world’s moods may be a simple first step, but Golder and Macy have demonstrated how scientists can mine social networks for data on those slipperiest of experimental subjects: people.
Reference: Golder & Macy. 2011. Diurnal and Seasonal Mood Vary with Work, Sleep, and Daylength Across Diverse Cultures. Science http://dx.doi.org/10.1126/science.1202775
September 29th, 2011 at 7:14 pm
It seems to me that people who tweet might themselves not be exactly a random cross-section of the society. For instance, there is a much lower likelihood that somewhere over 40 is present on Twitter than someone under 40. And even for those, the people who are less technologically savvy are absent. There is no reason to think that the mood cycle of people over 40 is the same as the mood cycle of those under 40 though of course it may turn out to be. I think the study could possibly correct for this by checking in what proportions different sections of society are represented on Twitter and correcting for it, provided this information is individually available.
September 29th, 2011 at 7:54 pm
I go back to what I said at the end of the piece: “Twitter’s users are not representative of the general population, but they certainly represent a broader spectrum of society than American college students.”
No one has suggested that this is a random cross-section, but it’s a much MUCH better data set than the ones we previously had.
September 29th, 2011 at 8:58 pm
I’m curious if the medium affects the message. I use Twitter to vent/bitch/etc. It is my outlet during the day to vent. I am only one person, but my tweets would all fall into the sarcastic/angry/unhappy set. These also during occur during working hours.
Mornings and evenings I am with my family, and the tweets fall off.
My point is, this survey assumes users are always tweeting according to their overall mood. Work may piss me off, and I vent, but it doesn’t mean I am unhappy. Conversely, when I am happy, I am not in the mood to tweet because I don’t think my happy moments are interesting to share.
Many people use twitter like the media reports on news. Conflict is interesting, boring happiness is not.
September 30th, 2011 at 1:21 am
It’s cool that you can see a shift in happy feelings in counties that have their weekend on different days. It’s interesting how the night owls have such a strong timeshift in their morning peak too.
September 30th, 2011 at 2:33 am
Really interessing study. I think that due to the great numbers it might be as reliable as one could get, although I agree with Catelli_NOU regarding the most postitive and negative feelings being topped of. But it think those don’t matter anyhow: it is the trend that is of interest, not the exeptions. I think Sebastian will be surprised how many people over 40 are on twitter: especially in the scientific community. Most of my timeline is over 40.
September 30th, 2011 at 8:44 am
For me, the issue is that all of the data is self-reported. The trend seems to show that people feel better in the morning but it really shows that people say they feel better. There is an artificiality to social media, a performance aspect where people put on their best face, or their worst. I wonder if the authors considered this or if the LIWC is robust enough to take this into account.
September 30th, 2011 at 9:13 am
Again, I’ll point out that ALL the previous data has also been self-reported, and under artificial experimental conditions under the behest of a researchers. At least here, it’s self-reported but spontaneously so.
This is not a perfect data set, by any means. It is, however, a far far better data set than anything we previously had.
October 1st, 2011 at 11:57 am
That’s fascinating and especially interesting in the way that weekend feelings correspond across cultures. I’m also interested in the differences with night owls (knowing one or two). I’m still following your blog avidly though commenting infrequently because I’ve been busy for some time with the publishing process. My new novel is now available for pre-order & coming out very soon, early next year! So I’ve also been busy revamping my website to showcase it.
October 1st, 2011 at 2:43 pm
Actually, it’s not wrong to point out the self-reported nature of the data because the medium may exaggerate the feeling of an audience. In an experimental study, you’re told your name will never be reported. Your audience is thus the research team (only a few people) and for the few-month span of the study. On twitter, your audience is dozens or even hundreds of followers, and you are invested in their opinion of you for the long haul (open-ended time span). For a large-scale study like this where people do seem to report both positive and negative moods, it probably doesn’t matter, but for a more fine-grained analysis of content I would be wary.
October 1st, 2011 at 11:21 pm
This is very silly … not everyone tweets about their life and feelings or only that, nor is every tweeter a person . People tweet what they want to share . Statistics like these are bogus.
Just because we want to know something doesn’t mean it is there to be found.
The assumption of this study is that tweeters actually tweet their moods (all of them). While true for some, that’s a huge assumption. Some tweeters are tweeting about their agenda, not their feelings, be it politics, or career, or hobbies, or philosophy, or passions and interests. or where they are, or what they had for lunch. How do you pick out mood, much less accurately, in all of what is tweeted?
How and why do people use twitter and when? Is it our voice or our ears? I suspect that our use of twitter evolves.
November 4th, 2011 at 5:58 am
We are trying to map the mood of the world. Starting with iPhone users and then moving to Android and the web. We have been working on this project for almost two years now, and it has been a long road. Lots of gear shifting and direction changing. We finally feel like we are making some progress.
It is nice to see that others are interested in this area too.