After spending ages looking for the ‘right’ way to set the ‘humanized’ name for an ActiveRecord attribute (seeing as human_attribute is deprecated),  it seems The Way now is to do this with locales.
Specifically, having something like this in your config/locales/en.yml
activerecord:
    attributes:
      model_name:
        attr_name: “Your mother”
…and this will make all the model errors [...]