diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index e38d8aecf5..980d132051 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,13 @@
+*   Calling `update_attributes` will now throw an `ArgumentError` whenever it
+    gets a `nil` argument. More specifically, it will throw an error if the
+    argument that it gets passed does not respond to to `stringify_keys`.
+
+    `Example:`
+
+        @my_comment.update_attributes()  # => raises ArgumentError
+
+    *John Wang*
+
 *   Remove Oracle / Sqlserver / Firebird database tasks that were deprecated in 4.0.
 
     *kennyj*
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
index 75377bba57..53ce5f4952 100644
--- a/activerecord/lib/active_record/attribute_assignment.rb
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -13,7 +13,9 @@ module ActiveRecord
     # of this method is +false+ an <tt>ActiveModel::ForbiddenAttributesError</tt>
     # exception is raised.
     def assign_attributes(new_attributes)
-      return if new_attributes.blank?
+      if !new_attributes.respond_to?(:stringify_keys)
+        raise ArgumentError, "When assigning attributes, you must pass a hash as an argument."
+      end
 
       attributes                  = new_attributes.stringify_keys
       multi_parameter_attributes  = []
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index ee0150558d..a3a7d338d1 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -92,7 +92,7 @@ class AttributeMethodsTest < ActiveRecord::TestCase
 
   def test_set_attributes_without_hash
     topic = Topic.new
-    assert_nothing_raised { topic.attributes = '' }
+    assert_raise(ArgumentError) { topic.attributes = '' }
   end
 
   def test_integers_as_nil
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 30dc2a34c6..6cd3e2154e 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -419,10 +419,6 @@ class PersistenceTest < ActiveRecord::TestCase
     assert !Topic.find(1).approved?
   end
 
-  def test_update_attribute_does_not_choke_on_nil
-    assert Topic.find(1).update(nil)
-  end
-
   def test_update_attribute_for_readonly_attribute
     minivan = Minivan.find('m1')
     assert_raises(ActiveRecord::ActiveRecordError) { minivan.update_attribute(:color, 'black') }
@@ -701,6 +697,17 @@ class PersistenceTest < ActiveRecord::TestCase
     assert_equal topic.title, Topic.find(1234).title
   end
 
+  def test_update_attributes_parameters
+    topic = Topic.find(1)
+    assert_nothing_raised do
+      topic.update_attributes({})
+    end
+
+    assert_raises(ArgumentError) do
+      topic.update_attributes(nil)
+    end
+  end
+
   def test_update!
     Reply.validates_presence_of(:title)
     reply = Reply.find(2)