# Are emoji sequences as informative as text?

Something I’ve been thinking about a lot lately is how much information we really convey with emoji. I was recently at the 1​st​ International Workshop on Emoji Understanding and Applications in Social Media and one theme that stood out to me from the papers was that emoji tend to be used more to communicate social meaning (things like tone and when a conversation is over) than semantics (content stuff like “this is a dog” or “an icecream truck”).

I’ve been itching to apply an information theoretic approach to emoji use for a while, and this seemed like the perfect opportunity. Information theory is the study of storing, transmitting and, most importantly for this project, quantifying information. In other words, using an information theoretic approach we can actually look at two input texts and figure out which one has more information in it. And that’s just what we’re going to do: we’re going to use a measure called “entropy” to directly compare the amount of information in text and emoji.

### What’s entropy?

Shannon entropy is a measure of how much information there is in a sequence. Higher entropy means that there’s more uncertainty about what comes next, while lower entropy means there’s less uncertainty.  (Mathematically, entropy is always less than or the same as log2(n), where n is the total number of unique characters. You can learn more about calculating entropy and play around with an interactive calculator here if you’re curious.)

So if you have a string of text that’s just one character repeated over and over (like this: 💀💀💀💀💀) you don’t need a lot of extra information to know what the next character will be: it will always be the same thing. So the string “💀💀💀💀💀” has a very low entropy. In this case it’s actually 0, which means that if you’re going through the string and predicting what comes next, you’re always going to be able to guess what comes next becuase it’s always the same thing. On the other hand, if you have a string that’s made up of four different characters, all of which are equally probable (like this:♢♡♧♤♡♧♤♢), then you’ll have an entropy of 2.

TL;DR: The higher the entropy of a string the more information is in it.

### Experiment

#### Hypothesis

We do have some theoretical maximums for the entropy text and emoji. For text, if the text string is just randomly drawn from the 128 ASCII characters (which isn’t how language works, but this is just an approximation) our entropy would be 7. On the other hand, for emoji, if people are just randomly using any emoji they like from the set of emoji as of June 2017, then we’d expect to see an entropy of around 11.

So if people are just  using letters or emoji randomly, then text should have lower entropy than emoji. However, I don’t think that’s what’s happening. My hypothesis, based on the amount of repetition in emoji, was that emoji should have lower entropy, i.e. less information, than text.

#### Data

To get emoji and text spans for our experiment I used four different datasets: three from Twitter and one from YouTube.

I used multiple datasets for a couple reasons. First, becuase I wanted a really large dataset of tweets with emoji, and since only between 0.9% and 0.5% of tweets from each Twitter dataset actually contained emoji I needed to case a wide net. And, second, because I’m growing increasingly concerned about genre effects in NLP research. (Like, a lot of our research is on Twitter data. Which is fine, but I’m worried that we’re narrowing the potential applications of our research becuase of it.) It’s the second reason that led me to include YouTube data. I used Twitter data for my initial exploration and then used the YouTube data to validate my findings.

For each dataset, I grabbed all adjacent emoji from a tweet and stored them separately. So this tweet:

Love going to ballgames! ⚾🌭 Going home to work in my garden now, tho 🌸🌸🌸🌸

Has two spans in it:

Span 1:  ⚾🌭

Span 2: 🌸🌸🌸🌸

All told, I ended up with 13,825 tweets with emoji and 18,717 emoji spans of which only 4,713 were longer than one emoji. (I ignored all the emoji spans of length one, since they’ll always have an entropy of 0 and aren’t that interesting to me.) For the YouTube comments, I ended up with 88,629 comments with emoji, 115,707 emoji spans and 47,138 spans with a length greater than one.

In order to look at text as parallel as possible to my emoji spans, I grabbed tweets & YouTube comments without emoji. For each genre, I took a number of texts equal to the number of spans of length > 1 and then calculated the character-level entropy for the emoji spans and the texts.

#### Analysis

First, let’s look at Tweets. Here’s the density (it’s like a smooth histogram, where the area under the curve is always equal to 1 for each group) of the entropy of an equivalent number of emoji spans and tweets.

Text has a much high character-level entropy than emoji. For text, the mean and median entropy are both around 5. For emoji, there is a multimodal distribution, with the median entropy being 0 and also clusters around 1 and 1.5.

It looks like my hypothesis was right! At least in tweets, text has much more information than emoji. In fact, the most common entropy for an emoji span is 0: which means that most emoji spans with a length greater than one are just repititons of the same emoji over and over again.

The YouTube data, which we have almost ten times more of, corroborates the earlier finding: emoji spans are less informative, and more repetitive, than text.

### Which emoji were repeated the most/least often?

Just in case you were wondering, the emoji most likely to be repeated was the skull emoji, 💀. It’s generally used to convey strong negative emotion, especially embarrassment, awkwardness or speechlessness, similar to “ded“.

The least likely was the right-pointing arrow (▶️), which is usually used in front of links to videos.

If you’re interested, the code for my analysis is available here. I also did some of this work as live coding, which you can follow along with on YouTube here.

For future work, I’m planning on looking at which kinds of emoji are more likely to be repeated. My intuition is that gestural emoji (so anything with a hand or face) are more likely to be repeated than other types of emoji–which would definitely add some fuel to the “are emoji words or gestures” debate!

# How do we use emoji?

Those of you who know me may know that I’m a big fan of emoji. I’m also a big fan of linguistics and NLP, so, naturally, I’m very curious about the linguistic roles of emoji. Since I figured some of you might also be curious, I’ve pulled together a discussion of some of the very serious scholarly research on emoji. In particular, I’m going to talk about five recent papers that explore the exact linguistic nature of these symbols: what are they and how do we use them?

### Dürscheid & Siever, 2017:

This paper makes one overarching point: emoji are not words. They cannot be unambiguously interpreted without supporting text and they do not have clear syntactic relationships to one another. Rather, the authors consider emoji to be specialized characters, and place them within Gallmann’s 1985 hierarchy of graphical signs. The authors show that emoji can play a range of roles within the Gallmann’s functional classification.

• Allography: using emoji to replace specific characters (for example: the word “emoji” written as “em😝ji”)
• Ideograms: using emoji to replace a specific word (example: “I’m travelling by 🚘” to mean “I’m travelling by car”)
• Border and Sentence Intention signals: using emoji both to clarify the tone of the preceding sentence and also to show that the sentence is over, often replacing the final punctuation marks.

Based on an analysis of a Swiss German Whatsapp corpus, the authors conclude that the final category is far and away the most popular, and that emoji rarely replace any part of the lexical parts of a message.

### Na’aman et al, 2017:

Na’aman and co-authors also develop a hierarchy of emoji usage, with three top-level categories: Function, Content (both of which would fall under mostly under the ideogram category in Dürscheid & Siever’s classifications) and Multimodal.

• Function: Emoji replacing function words, including prepositions, auxiliary verbs, conjunctions, determinatives and punctuation. An example of this category would be “I like 🍩 you”, to be read as “I do not like you”.
• Content: Emoji replacing content words and phrases, including nouns, verbs, adjectives and adverbs. An example of this would be “The 🔑 to success”, to be read as “the key to success”.
• Multimodal: These emoji “enrich a grammatically-complete text with markers of
affect or stance”. These would fall under the category of border signals in Dürscheid & Siever’s framework, but Na’aman et all further divide these into four categories: attitude, topic, gesture and other.

Based on analysis of a Twitter corpus made of up of only tweets containing emoji, the authors find that multimodal emoji encoding attitude are far and away the most common, making up over 50% of the emoji spans in their corpus. The next most common uses of emoji are to multimodal:topic and multimodal:gesture. Together, these three categories account for close to 90% of the all the emoji use in the corpus, corroborating the findings of Dürscheid & Siever.

### Wood & Ruder, 2016:

Wood and Ruder provide further evidence that emoji are used to express emotion (or “attitude”, in Na’aman et al’s terms). They found a strong correlation between the presence of emoji that they had previously determined were associated with a particular emotion, like 😂 for joy or 😭 for sadness, and human annotations of the emotion expressed in those tweets. In addition, an emotion classifier using only emoji as input performed similarly to one trained using n-grams excluding emoji. This provides evidence that there is an established relationship between specific emoji use and expressing emotion.

### Donato & Paggio, 2017:

However, the relationship between text and emoji may not always be so close. Donato & Paggio collected a corpus of tweets which contained at least one emoji and that were hand-annotated for whether the emoji was redundant given the text of the tweet.  For example, “We’ll always have Beer. I’ll see to it. I got your back on that one. 🍺” would be redundant, while “Hopin for the best 🎓” would not be, since the beer emoji expresses content already expressed in the tweet, while the motorboard adds new information (that the person is hoping to graduate, perhaps). The majority of emoji, close to 60%, were found not to be redundant and added new information to the tweet.

However, the corpus was intentionally balanced between ten topic areas, of which only one was feelings, and as a result the majority of feeling-related tweets were excluded from analysis. Based on this analysis and Wood and Ruder’s work, we might hypothesize that feelings-related emoji may be more redundant than other emoji from other semantic categories.

### Barbieri et al, 2017:

Additional evidence for the idea that emoji, especially those that show emotion, are predictable given the text surrounding them comes from Barbieri et al. In their task, they removed the emoji from a thousand tweets that contained one of the following five emoji: 😂, ❤️, 😍, 💯 or 🔥. These emoji were selected since they were the most common in the larger dataset of half a million tweets. Then then asked human crowd workers to fill in the missing emoji given the text of the tweet, and trained a character-level bidirectional LSTM to do the same task. Both humans and the LSTM performed well over chance, with an F1 score of 0.50 for the humans and 0.65 for the LSTM.

So that was a lot of papers and results I just threw at you. What’s the big picture? There are two main points I want you to take away from this post:

• People mostly use emoji to express emotion. You’ll see people playing around more than that, sure, but by far the most common use is to make sure people know what emotion you’re expressing with a specific message.
• Emoji, particularly emoji that are used to represent emotions, are predictable given the text of the message. It’s pretty rare for us to actually use emoji to introduce new information, and we generally only do that when we’re using emoji that have a specific, transparent meaning.

If you’re interested in reading more, here are all the papers I mentioned in this post:

#### Bibliography:

Donato, G., & Paggio, P. (2017). Investigating Redundancy in Emoji Use: Study on a Twitter Based Corpus. In Proceedings of the 8th Workshop on Computational Approaches to Subjectivity, Sentiment and Social Media Analysis (pp. 118-126).

Dürscheid, C., & Siever, C. M. (2017). Beyond the Alphabet–Communication of Emojis. Kurzfassung eines (auf Deutsch) zur Publikation eingereichten Manuskripts.

Gallmann, P. (1985). Graphische Elemente der geschriebenen Sprache. Grundlagen für eine Reform der Orthographie. Tübingen: Niemeyer.

Na’aman, N., Provenza, H., & Montoya, O. (2017). Varying Linguistic Purposes of Emoji in (Twitter) Context. In Proceedings of ACL 2017, Student Research Workshop (pp. 136-141).

Wood, I. & Ruder, S. (2016). Emoji as Emotion Tags for Tweets. Sánchez-Rada, J. F., & Schuller, B (Eds.). In Proceedings of LREC 2016, Workshop on Emotion and Sentiment Analysis (pp. 76-80).

# Where 👏 do 👏 the 👏 claps 👏 go 👏 when 👏 you 👏 write 👏 like 👏 this 👏?

You may already be familiar with the phenomena I’m going to be talking about today: when someone punctuates some text with the clap emoji. It’s a pretty transparent gestural scoring and (for me) immediately brings to mind the way my mom would clap with every word when she was particularly exasperated with my sibling and I (it was usually along with speech like “let’s go, let’s go, let’s go” or “get up now”). It looks like so:

This innovation, which started on Black Twitter is really interesting to me because it ties in with my earlier work on emoji ordering. I want to know where emojis go, particularly in relation to other words. Especially since people have since extended this usage to other emoji, like the US Flag:

Logically, there are several different ways you can intersperse clap emojis with text:

• Claps 👏  are 👏 used 👏 between 👏 every 👏 word.
•  👏 Claps 👏 are 👏 used 👏 around 👏 every 👏 word. 👏
•  👏 Claps 👏 are 👏 used 👏 before 👏 every 👏 word.
• Claps 👏 are 👏 used 👏 after 👏 every 👏 word. 👏
• Claps 👏 are used 👏 between phrases 👏 not words

I want to know which of these best describes what people actually do. I’m not aiming to write an internet style guide, but I am hoping to characterize this phenomena in a general way: this is how most people who do this do it, and if you want to use this style in a natural way, you should probably do it the same way.

Data

I used Fireant to grab 10,000 tweets from the Twitter streaming API which had the clap emoji in them at least once. (Twitter doesn’t let you search for a certain number of matches of the same string. If you search for “blob” and “blob blob” you’ll get the same set of results.)

Analysis

From that set of 10,000 tweets, I took only the tweets that had a clap emoji followed by a word followed by another clap emoji and threw out any repeats. That left me with 260 tweets. (This may seem pretty small compared to my starting dataset, but there were a lot of retweets in there, and I didn’t want to count anything twice.) Then I removed @usernames, since those show up in the beginning of any tweet that’s a reply to someone, and URL’s, which I don’t really think of as “words”. Finally, I looked at each word in a tweet and marked whether it was a clap or not. You can see the results of that here:

The “word” axis represents which word in the tweet we’re looking at: the first, second, third, etc. The red portion of the bar are the words that are the clap emoji. The yellow portion is the words that aren’t. (BTW, big shoutout to Hadley Wickham’s emo(ji) package for letting me include emoji in plots!)

From this we can see a clear pattern: almost no one starts a tweet with an emoji, but most people follow the first word with an emoji. The up-down-up-down pattern means that people are alternating the clap emoji with one word. So if we look back at our hypotheses about how emoji are used, we can see right off the bat that three of them are wrong:

• Claps 👏  are 👏 used 👏 between 👏 every 👏 word.
•  👏 Claps 👏 are 👏 used 👏 around 👏 every 👏 word. 👏
•  👏 Claps 👏 are 👏 used 👏 before 👏 every 👏 word.
• Claps 👏 are 👏 used 👏 after 👏 every 👏 word. 👏
• Claps 👏 are used 👏 between phrases 👏 not words

We can pick between the two remaining hypotheses by looking at whether people are ending thier tweets with a clap emoji. As it turns out, the answer is “yes”, more often than not.

If they’re using this clapping-between-words pattern (sometimes called the “ratchet clap“) people are statistically more likely to end their tweet with a clap emoji than with a different word or non-clap emoji. This means the most common pattern is to use 👏 a 👏 clap 👏 after 👏 every 👏 word, 👏  including  👏 the  👏 last. 👏

This makes intuitive sense to me. This pattern is mimicking someone is clapping on every word. Since we can’t put emoji on top of words to indicate that they’re happening at the same time, putting them after makes good intuitive sense. In some sense, each emoji is “attached” to the word that comes before it in a similar way to how “quickly” is “attached” to “run” in the phrase “run quickly”. It makes less sense to put emoji between words, becuase then you end up with less claps than words, which doesn’t line up well with the way this is done in speech.

The “clap after every word” pattern is also what this website that automatically puts claps in your tweets does, so I’m pretty positive this is a good characterization of community norms.

So there you have it! If you’re going to put clap emoji in your tweets, you should probably do 👏 it 👏 like 👏 this. 👏 It’s not wrong if you don’t, but it does look kind of weird.

# Do emojis have their own syntax?

So a while ago I got into a discussion with someone on Twitter about whether emojis have syntax. Their original question was this:

As someone who’s studied sign language, my immediate thought was “Of course there’s a directionality to emoji: they encode the spatial relationships of the scene.” This is just fancy linguist talk for: “if there’s a dog eating a hot-dog, and the dog is on the right, you’re going to use 🌭🐕, not 🐕🌭.” But the more I thought about it, the more I began to think that maybe it would be better not to rely on my intuitions in this case. First, because I know American Sign Language and that might be influencing me and, second, because I am pretty gosh-darn dyslexic and I can’t promise that my really excellent ability to flip adjacent characters doesn’t extend to emoji.

So, like any good behavioral scientist, I ran a little experiment. I wanted to know two things.

1. Does an emoji description of a scene show the way that things are positioned in that scene?
2. Does the order of emojis tend to be the same as the ordering of those same concepts in an equivalent sentence?

As it turned out, the answers to these questions are actually fairly intertwined, and related to a third thing I hadn’t actually considered while I was putting together my stimuli (but probably should have): whether there was an agent-patient relationship in the photo.

Agent: The entity in a sentence that’s affecting a changed, the “doer” of the action.

• The dog ate the hot-dog.
• The raccoons pushed over all the trash-bins.

Patient: The entity that’s being changed, the “receiver” of the action.

• The dog ate the hot-dog.
• The raccoons pushed over all the trash-bins.

## Data

To get data, I showed people three pictures and asked them to “pick the emoji sequence that best describes the scene” and then gave them two options that used different orders of the same emoji. Then, once they were done with the emoji part, I asked them to “please type a short sentence to describe each scene”. For all the language data, I just went through and quickly coded the order that the same concepts as were encoded in the emoji showed up.

Examples:

• “The dog ate a hot-dog”  -> dog hot-dog
• “The hot-dog was eaten by the dog” -> hot-dog dog
• “A dog eating” -> dog
• “The hot-dog was completely devoured” -> hot-dog

So this gave me two parallel data sets: one with emojis and one with language data.

All together, 133 people filled out the emoji half and 127 people did the whole thing, mostly in English (I had one person respond in Spanish and I went ahead and included it). I have absolutely no demographics on my participants, and that’s by design; since I didn’t go through the Institutional Review Board it would actually be unethical for me to collect data about people themselves rather than just general information on language use. (If you want to get into the nitty-gritty this is a really good discussion of different types of on-line research.)

## Picture one – A man counting money

I picked this photo as sort of a sanity-check: there’s no obvious right-to-left ordering of the man and the money, and there’s one pretty clear way of describing what’s going on in this scene. There’s an agent (the man) and a patient (the money), and since we tend to describe things as agent first, patient second I expected people to pretty much all do the same thing with this picture. (Side note: I know I’ve read a paper about the cross-linguistic tendency for syntactic structures where the agent comes first, but I can’t find it and I don’t remember who it’s by. Please let me know if you’ve got an idea what it could be in the comments–it’s driving me nuts!)

And they did! Pretty much everyone described this picture by putting the man before the money, both with emoji and words. This tells us that, when there’s no information about orientation you need to encode (e.g. what’s on the right or left), people do tend to use emoji in the same order as they would the equivalent words.

## Picture two – A man walking by a castle

But now things get a little more complex. What if there isn’t a strong agent-patient relationship and there is a strong orientation in the photo? Here, a man in a red shirt is walking by a castle, but he shows up on the right side of the photo. Will people be more likely to describe this scene with emoji in a way that encodes the relationship of the objects in the photo?

I found that they were–almost four out of five participants described this scene by using the emoji sequence “castle man”, rather than “man castle”. This is particularly striking because, in the sentence writing part of the experiment, most people (over 56%) wrote a sentence where “man/dude/person etc.” showed up before “castle/mansion/chateau etc.”.

So while people can use emoji to encode syntax, they’re also using them to encode spatial information about the scene.

## Picture three – A man photographing a model

Ok, so let’s add a third layer of complexity: what about when spatial information and the syntactic agent/patient relationships are pointing in opposite directions? For the scene above, if you’re encoding the spatial information then you should use an emoji ordering like “woman camera man”, but if you’re encoding an agent-patient relationship then, as we saw in the picture of the man counting money, you’ll probably want to put the agent first: “man camera woman”.

(I leave it open for discussion whether the camera emoji here is representing a physical camera or a verb like “photograph”.)

So people were a little more divided here. It wasn’t quite a 50-50 split, but it really does look like you can go either way with this one. The thing that jumped out at me, though, was how the word order and emoji order pattern together: if your sentence is something like “A man photographs a model”, then you are far more likely to use the “man camera woman” emoji ordering. On the other hand, if your sentence is something like “A woman being photographed by the sea” or “Photoshoot by the water”, then it’s more likely that your emoji ordering described the physical relation of the scene.

## So what?

So what’s the big takeaway here? Well, one thing is that emoji don’t really have a fixed syntax in the same way language does. If they did, I’d expect that there would be a lot more agreement between people about the right way to represent a scene with emoji. There was a lot of variation.

On the other hand, emoji ordering isn’t just random either. It is encoding information, either about the syntactic/semantic relationship of the concepts or their physical location in space. The problem is that you really don’t have a way of knowing which one is which.

Edit 12/16/2016: The dataset and the R script I used to analyze it are now avaliable on Github.