javascript closure for_loop

I have been stuck on this for a while. I had also threw in a debugger to see what is actually happening. I think it is something related to closure but not 100% sure.

var names = [ "roy", "nick" ];

var ids = [0, 1];
var people = [];

for ( i in names ){
    people.push({
        name: names[i],
        id: ids[i]
    })
    people[i].ages = {
        this_year: function(){

            var ages = [10, 11];
            return ages[i];
        }
    }
}
console.log(people[0].ages.this_year()); // why not 10

---

Tried using function arguments as suggest by @slebetman, however, i intend to invoke the function later so this wouldn't work..

var names = [ "roy", "nick" ];
var ids = [0, 1];
var people = [];

for ( i in names ){
    people.push({
        name: names[i],
        id: ids[i]

    })
    people[i].ages = {
        this_year: (function(x){
            var ages = [10, 11];
            return ages[x];
        })(i)
    }
}
console.log(people[0].ages.this_year); // 10
console.log(people[0].ages.this_year()); // not a function