This looks like an [unrolled loop](https://en.wikipedia.org/wiki/Loop_unwinding#Static.2FManual_Loop_Unrolling); which is a pretty cool technique for performance optimization, but it's also a little verbose.

What if we used a [forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach)?

```
['first_name', 'last_name'].forEach(function(fieldName) {
  $('#' + fieldName).val(response[fieldName]);
})'
```