Edit in JSFiddle

var contact= new Backbone.Model();

var ContactView = Backbone.View.extend({
    initialize:function(){
        //listen to change event on model
        this.listenTo(contact,'change:firstName',this.render);
    },
    render:function(){console.log('render a change, data changed');}
});

new ContactView();
//change event, fired because we are only listening for firstName
contact.set('firstName','john'); 
contact.set('phone','222-222-2222'); //no change event trigger