Polymer Behaviour Question

my-element.html

<link rel="import" href="../../bower_components/polymer/polymer.html">
<link rel="import" href="../../bower_components/iron-selector/iron-selectable.html">

<dom-module id="my-element">
  <template>
    <style>
      :host {
        display: block;
      }
    </style>
    <div>Hello from <span>{{items}}</span></div>
  </template>
  <script>
  (function() {
    'use strict';

    Polymer({
      is: 'my-element',
      properties: {
        //nothing to see here
      },
      //by adding this behavior here it means that this element has the 'items' attribute among other things
      behaviors: [Polymer.IronSelectableBehavior], 
      ready:function(){
        console.log(this.items);//my items should be here but no... nothing :(  
      }
    });
  })();
  </script>
</dom-module>

somewhere-else.html

//somewhere else where I can inspect myarray and confirm that is has "things" in it

<my-element items="[[myarray]]" selected="0"></my-element>

If I inspect somewhere-else.html and see its $0.myarray I can see the array filled with objects inside it.
If I inspect my-element.html and see its $0.items I can see an empty array

On somewhere-else element:
$0.myarray
[Object, Object]

On my-element:
$0.items
[]

Hm it's interesting that you see an array at all and not just an undefined if it truly is undefined...

Indeed! I sort of assumed the behavior would initialize the items array tho.

If it's bound to myArray I would think that it would since a binding is just shorthand for saying myElement.items = myArray. Are you able to put together a jsbin to illustrate this? Maybe it's a timing issue

You can use bit.ly/polybin as a starter

Sorry, it took so long..work got in the way! Please have a look:
https://jsbin.com/kazide/edit?html,console,output