Backbone: impossible de remplir la collection à partir de données brutes

$(document).ready(function () {
  people = Backbone.Collection([
    {name: "Tim", age: 5},
    {name: "Ida", age: 26},
    {name: "Rob", age: 55}
  ]);
  alert(JSON.stringify(people));
});

causes

Uncaught exception: TypeError: 'this._reset' is not a function
Error thrown at line 23465, column 4 in <anonymous function: Backbone.Collection>(models, options) in http://127.0.0.1:8000/webapp/app.js:
    this._reset();
called from line 481, column 2 in <anonymous function>() in http://127.0.0.1:8000/:
    people = Backbone.Collection([

Backbone 1.1.0, Underscore 1.5.2 (le même avec lodash).