Adjectives

​x
 
///fold:
↔​
​
var alpha = 1; // rationality parameter
​
var utterances = ["expensive", ""];
var cost = {
  "expensive": 1,
  "": 0
};
var utterance_prior = function() {
  return utterances[discrete(map(function(u) {return Math.exp(-cost[u]);}, utterances))];
};
​
var meaning = function(utterance, price, theta) {
  if (utterance == "expensive") {
    return price >= theta;
  } else {
    return true;
  }
};
​
var literalERP = cache(function(utterance, theta, item) {
  var price_prior = prior(item);
  return Enumerate(function() {
    var price = price_prior();
    condition(meaning(utterance, price, theta));
    return price;
  });
});
​
var speakerERP = cache(function(price, theta, item) {
  return Enumerate(function() {
    var utterance = utterance_prior();
    factor( alpha * literalERP(utterance, theta, item).score([], price) );
    return utterance;
  });
});
​
var listenerERP = function(utterance, item) {
  var price_prior = prior(item);
  var theta_prior = theta_prior(item);
  return ParticleFilter(function() {
    var price = price_prior();
    var theta = theta_prior();
    factor( alpha * speakerERP(price, theta, item).score([], utterance) );
    return {
      price: price,
      theta: theta
    };
  }, 1000);
};
​
// draw graphs
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​
run

 
// experiment data is in fold
///fold:
↔​
​
var prior = function(item) {
​
  // midpoint of bin shown to participants
  var prices = data[item].prices;
​
  // average responses from participants, normalizing by item
  var probabilities = data[item].probabilities;
​
  return function() {
    return prices[discrete(probabilities)];
  };
}
​
vizPrint(
  {
    "coffee_maker": Enumerate(prior("coffee maker")),
    "headphones": Enumerate(prior("headphones")),
    "laptop": Enumerate(prior("laptop")),
    "sweater": Enumerate(prior("sweater")),
    "watch": Enumerate(prior("watch")),
  });
​
run