var customerTypeFields = [];
    customerTypeFields['Individual'] = ['First Name(s)', 'Last Name', 'Date of Birth'];
    customerTypeFields['Limited Company'] = ['Name', 'Company Number'];
    customerTypeFields['Partnership'] = ['Name', 'Company Number'];

    $('#customer-type-selector').chosen().change( function() {
        var visibleFields = customerTypeFields[$(this).children("option[value='" + $(this).attr('value') + "']").text()];
        console.log(visibleFields);
        $.each(visibleFields, function(i, field) {
            $('#customer-features').find('input[data-feature-type=' + field + ']').parent().parent().show();
        });
    });

Uncaught Error: Syntax error, unrecognized expression: input[data-feature-type=First (s)]

(...)  .find('input[data-feature-type="' + field + '"]')  (...)