2018-01-28

# Getting started

1. Worksheet with code to edit: benschmidt.org/Vectors.Rmd

Benschmidt.org/UNC

Choose 2 or 3 sources.

1. “r/books,” 2016
2. “r/The_Donald,” 2016
3. “r/politics,” 2016
4. GloVe. A widely-used set of embeddings which contains millions of words in the full version.
5. RMP: All the reviews of faculty members from RateMyProfessors.com
6. Hansard: Several different sets of debate transcriptions from the British parliament.
• ## Rstudio and R Markdown

Post-its

Green: Working away on the task. Red: Stuck on something; help! White: If I’m typing, it’s to check the Huffington Post

Task now: Using the sources at benschmidt.org/UNC, successfully run the first block of code.

``````library(wordVectors)

# What are word embeddings?

## Terms

• Word Embedding: A general strategy for treating words as numbers.
• Word2Vec: An algorithm that performs a particularly useful word embedding.
• wordVectors: an actual program you can run inside Rstudio to do this yourself.

Word embeddings place words into space that does the following:

1. Approximate semantic distance as spatial distance for computation.
2. Approximate frequent relationships as vectors in space.

Predicting words from context.

Source: Conor McDonald

A two-dimensional reduction

Two dimensions is not enough! Neither is 3! 3d embeddings (a bad idea)!

Word2Vec uses a few hundred dimensions for each word. Here are some.

::
country V1 V2 V3 V4 V5 V6
France Germany wine 0.01500453 0.06001414 -0.04239146 0.018186183 0.046422540 -0.031893139 0.08340119 0.06336951 -0.05403588 0.009556154 0.002588225 0.033243816 0.016695607 -0.063688305 0.002391649 0.007973551 -0.026276992 0.048410353

Word Embeddings and Topic Models

• Word embeddings try to create a detailed picture of language in a corpus: topic models try to simplify the vocabulary in each text into a higher level abstraction than an individual word.

Topic Models are better than word embeddings because:

1. They represent documents as important elements and let you make comparisons across them.
2. They can handle words with multiple meanings sensibly.
3. They let you abstract away from words to understand documents using broad measures.

Word embeddings are better than topic models because

1. They retain words as core elements and let you make comparisons among them.
2. They make it possible (not easy) to define your own clusters of interest in terms of words.
3. They let you abstract away from documents to understand words.

# WEMs: Word similarities

``````
library(wordVectors)

# Creating Models

## What Algorithm should I use?

Major options are:

• word2vec: Fast, general-purpose, laptop-friendly.

• GloVe: Better theoretical grounding, better if you’re running many models of different dimensionality on a server. Scales poorly.

But at this point, you could go crazy

Swivel, Poincaré (hierarchical) embeddings, Bernoulli Embeddings, and more.`\_(ツ)_/¯`

## What Algorithm should I use?

Short Answer: word2vec with skip-gram negative sampling.

Probably using my R package or gensim for python

Word2Vec on small (less than 1 million words) corpora

1. Think again

2. Try greatly expanding the window–default is 12 but try 50,

3. Run many iterations. A hundred, maybe. If your model trains in less than a minute, it’s probably no good.

Some notes on preparation:

• You must have a single text file.
• For anything less than a massive corpus, lowercasing is a good idea.
• Bundling bigrams together can be helpful.
• the `prep_word2vec` function in my package handles all this, somewhat slowly.

# Relationships

Semantic vectors have meaning

“Capitalness” (?)

Creating a relational vector

``male_female = model[["man"]] - model[["woman"]]``

OR

``male_female = model %>% extract_vectors(~ "man" - "woman")``
``````teaching_vectors %>% closest_to("hola")

hola       espanol         todos    fantastico        porque
-4.440892e-16  5.419217e-01  5.561170e-01  5.582298e-01  5.584173e-01
interesante          buen     simpatico           muy     profesora
5.646364e-01  5.702220e-01  5.703893e-01  5.707483e-01  5.709447e-01``````
``````teaching_vectors %>% closest_to(teaching_vectors[["hola"]]-teaching_vectors[["spanish"]])
##        hola          hi goodmorning    mmmmmkay      wassup       hello
##   0.2541650   0.6992011   0.7123197   0.7195401   0.7225225   0.7289345
##       todos         uhm   hahahahah        quot
##   0.7447951   0.7485577   0.7516170   0.7620057``````

# Frontiers: rejection and de-biasing

Example from “Semantics derived automatically from language corpora necessarily contain human biases,” Caliskan-Islam et al.

“Semantics derived automatically from language corpora necessarily contain human biases,” Caliskan-Islam et al.

Translations to English from many gender-neutral languages such as Finnish, Estonian, Hungarian, Persian, and Turkish lead to gender-stereotyped sentences. For example, Google Translate converts these Turkish sentences with genderless pronouns: “O bir doktor. O bir hems ̧ire.” to these English sentences: “He is a doctor. She is a nurse.”

“Semantics derived automatically from language corpora necessarily contain human biases,” Caliskan-Islam et al.

We demonstrate here for the first time what some have long suspected (Quine, 1960)—that semantics, the meaning of words, necessarily reflects regularities latent in our culture, some of which we now know to be prejudiced.

“Semantics derived automatically from language corpora necessarily contain human biases,” Caliskan-Islam et al.

First, our results suggest that word embeddings don’t merely pick up specific, enumerable biases such as gender stereotypes (Bolukbasi et al., 2016), but rather the entire spectrum of human biases reflected in language. […] Bias is identical to meaning, and it is impossible to employ language meaningfully without incorporating human bias.

Alternative: (Schmidt 2015, Bolukbasi et al., 2016):

What’s new here is not that bias is finally proven, but that we manipulate around it.

``````genderless = news %>%
reject(news[["he"]] - news[["she"]]) %>%
reject(news[["man"]] - news[["woman"]]) %>%``````

## Changes in similarities in an unbiased space

Debiased pairs from rateMyProfessors

``````#   [1] "he->she"                       "hes->shes"
#   [3] "himself->herself"              "his->her"
#   [7] "grandpa->grandma"              "dude->chick"
#   [9] "wife->husband"                 "grandfather->grandmother"
#  [13] "fatherly->motherly"            "brother->sister"
#  [15] "actor->actress"                "grandfatherly->grandmotherly"
#  [17] "father->mother"                "genius->goddess"
#  [19] "arrogant->snobby"              "priest->nun"
#  [21] "dork->ditz"                    "handsome->gorgeous"
#  [23] "atheist->feminist"             "himmmm->herrrr"
#  [25] "kermit->degeneres"             "mans->womans"
#  [27] "hez->shez"                     "himmm->herrr"
#  [29] "trumpet->flute"                "checkride->clinicals"
#  [31] "gay->lesbian"                  "surgeon->nurse"
#  [35] "monsieur->mme"                 "jolly->cheerful"
#  [37] "jazz->dance"                   "wears->outfits"
#  [39] "girlfriends->boyfriends"       "drle->gentille"
#  [41] "gentleman->gem"                "charisma->spunk"
#  [43] "egotistical->hypocritical"     "cutie->babe"
#  [45] "wingers->feminists"            "professore->molto"
#  [47] "gruff->stern"                  "demonstrations->activities"
#  [49] "goofy->wacky"                  "coolest->sweetest"
#  [51] "architect->interior"           "sidetracked->frazzled"
#  [53] "likeable->pleasant"            "grumpy->crabby"
#  [55] "charismatic->energetic"        "cisco->cna"
#  [57] "masculinity->gender"           "girlfriend->boyfriend"   ``````

# Frontiers: alignment

Aligning multiple models.

Diachronic Word Embeddings Reveal Statistical Laws of Semantic Change

Hansard Corpus