diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index e813629855..d583d48b54 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -62,6 +62,11 @@ module ActiveModel
     CALLBACKS_OPTIONS = [:if, :unless, :on, :allow_nil, :allow_blank, :strict]
     MESSAGE_OPTIONS = [:message]
 
+    class << self
+      attr_accessor :i18n_full_message # :nodoc:
+    end
+    self.i18n_full_message = false
+
     attr_reader :messages, :details
 
     # Pass in the instance of the object that is using the errors object.
@@ -375,7 +380,7 @@ module ActiveModel
     def full_message(attribute, message)
       return message if attribute == :base
 
-      if @base.class.respond_to?(:i18n_scope)
+      if self.class.i18n_full_message && @base.class.respond_to?(:i18n_scope)
         parts = attribute.to_s.split(".")
         attribute_name = parts.pop
         namespace = parts.join("/") unless parts.empty?
diff --git a/activemodel/lib/active_model/railtie.rb b/activemodel/lib/active_model/railtie.rb
index a9cdabba00..0ed70bd473 100644
--- a/activemodel/lib/active_model/railtie.rb
+++ b/activemodel/lib/active_model/railtie.rb
@@ -7,8 +7,14 @@ module ActiveModel
   class Railtie < Rails::Railtie # :nodoc:
     config.eager_load_namespaces << ActiveModel
 
+    config.active_model = ActiveSupport::OrderedOptions.new
+
     initializer "active_model.secure_password" do
       ActiveModel::SecurePassword.min_cost = Rails.env.test?
     end
+
+    initializer "active_model.i18n_full_message" do
+      ActiveModel::Errors.i18n_full_message = config.active_model.delete(:i18n_full_message) || false
+    end
   end
 end
diff --git a/activemodel/test/cases/railtie_test.rb b/activemodel/test/cases/railtie_test.rb
index ff5022e960..ab60285e2a 100644
--- a/activemodel/test/cases/railtie_test.rb
+++ b/activemodel/test/cases/railtie_test.rb
@@ -31,4 +31,24 @@ class RailtieTest < ActiveModel::TestCase
 
     assert_equal true, ActiveModel::SecurePassword.min_cost
   end
+
+  test "i18n full message defaults to false" do
+    @app.initialize!
+
+    assert_equal false, ActiveModel::Errors.i18n_full_message
+  end
+
+  test "i18n full message can be disabled" do
+    @app.config.active_model.i18n_full_message = false
+    @app.initialize!
+
+    assert_equal false, ActiveModel::Errors.i18n_full_message
+  end
+
+  test "i18n full message can be enabled" do
+    @app.config.active_model.i18n_full_message = true
+    @app.initialize!
+
+    assert_equal true, ActiveModel::Errors.i18n_full_message
+  end
 end
diff --git a/activemodel/test/cases/validations/i18n_validation_test.rb b/activemodel/test/cases/validations/i18n_validation_test.rb
index ea462d9e07..1c62e750de 100644
--- a/activemodel/test/cases/validations/i18n_validation_test.rb
+++ b/activemodel/test/cases/validations/i18n_validation_test.rb
@@ -12,6 +12,9 @@ class I18nValidationTest < ActiveModel::TestCase
     I18n.load_path.clear
     I18n.backend = I18n::Backend::Simple.new
     I18n.backend.store_translations("en", errors: { messages: { custom: nil } })
+
+    @original_i18n_full_message = ActiveModel::Errors.i18n_full_message
+    ActiveModel::Errors.i18n_full_message = true
   end
 
   def teardown
@@ -19,6 +22,7 @@ class I18nValidationTest < ActiveModel::TestCase
     I18n.load_path.replace @old_load_path
     I18n.backend = @old_backend
     I18n.backend.reload!
+    ActiveModel::Errors.i18n_full_message = @original_i18n_full_message
   end
 
   def test_full_message_encoding
@@ -42,7 +46,20 @@ class I18nValidationTest < ActiveModel::TestCase
     assert_equal ["Field Name empty"], @person.errors.full_messages
   end
 
+  def test_errors_full_messages_doesnt_use_attribute_format_without_config
+    ActiveModel::Errors.i18n_full_message = false
+
+    I18n.backend.store_translations("en", activemodel: {
+      errors: { models: { person: { attributes: { name: { format: "%{message}" } } } } } })
+
+    person = Person.new
+    assert_equal "Name cannot be blank", person.errors.full_message(:name, "cannot be blank")
+    assert_equal "Name test cannot be blank", person.errors.full_message(:name_test, "cannot be blank")
+  end
+
   def test_errors_full_messages_uses_attribute_format
+    ActiveModel::Errors.i18n_full_message = true
+
     I18n.backend.store_translations("en", activemodel: {
       errors: { models: { person: { attributes: { name: { format: "%{message}" } } } } } })
 
@@ -52,6 +69,8 @@ class I18nValidationTest < ActiveModel::TestCase
   end
 
   def test_errors_full_messages_uses_model_format
+    ActiveModel::Errors.i18n_full_message = true
+
     I18n.backend.store_translations("en", activemodel: {
       errors: { models: { person: { format: "%{message}" } } } })
 
@@ -61,6 +80,8 @@ class I18nValidationTest < ActiveModel::TestCase
   end
 
   def test_errors_full_messages_uses_deeply_nested_model_attributes_format
+    ActiveModel::Errors.i18n_full_message = true
+
     I18n.backend.store_translations("en", activemodel: {
       errors: { models: { 'person/contacts/addresses': { attributes: { street: { format: "%{message}" } } } } } })
 
@@ -70,6 +91,8 @@ class I18nValidationTest < ActiveModel::TestCase
   end
 
   def test_errors_full_messages_uses_deeply_nested_model_model_format
+    ActiveModel::Errors.i18n_full_message = true
+
     I18n.backend.store_translations("en", activemodel: {
       errors: { models: { 'person/contacts/addresses': { format: "%{message}" } } } })
 
diff --git a/guides/source/configuring.md b/guides/source/configuring.md
index 7d5ca4b8a7..49c5b0406f 100644
--- a/guides/source/configuring.md
+++ b/guides/source/configuring.md
@@ -305,6 +305,10 @@ All these configuration options are delegated to the `I18n` library.
     config.i18n.fallbacks.map = { az: :tr, da: [:de, :en] }
     ```
 
+### Configuring Active Model
+
+* `config.active_model.i18n_full_message` is a boolean value which controls whether the `full_message` error format can be overridden at the attribute or model level in the locale files
+
 ### Configuring Active Record
 
 `config.active_record` includes a variety of configuration options: