This is the code for Pet:
function Pet() {
    this.vitals = new Vitals();
}
function Vitals() {
    this.hunger = 5;
    this.thirst = 0;
    this.emotions = {
        happy: true,
        sad: true
    }
}
Below is the calling and so forth:
$(document).ready(function () {
    var pet = new Pet();
    console.log(pet);
    pet.vitals.emotions.happy = false;
    console.log(pet);
});
This is what I get from the console:

Question: Why is happy false in both readouts, and not just the second one?
 
     
    