What may cause request parameters to appear as nested parameters

Here my params are nested utf8 wraps press_release which in turn wraps venue, venue_country, etc.
What causes this behavior?

 {"utf8"=>"✓",
"authenticity_token"=>"qR82bEuyDUS6XD1dxylozc96nGH0kxk/ew+sUe95LT9s+8G9PJqAr06khj0bE9SEPElcinsWxe0Kgzppzq1g0w==",
"press_release"=>
{"venue"=>"",
"venue_country"=>"US",

utf8 and authenticity_token are at the "root" level of the params hash, at the same level as press_release. They are peers. Press release contains two child attributes and their values, because that's the way your form was set up. By default, when you use

  <%= form_for @foo do | f | %>

to start off your form, you are going to get a set of parameters like

  { ... "foo" => { "name" => "Bar", "style" => "Baz" } ... }

in return.

Walter

Thanks