diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index b50cb951e..9d00e6fbf 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -12,6 +12,9 @@
 # reified when subclassed to decorate a resource.
 module ActiveModel
   class Serializer
+    undef_method :select, :display # These IO methods, which are mixed into Kernel,
+    # sometimes conflict with attribute names. We don't need these IO methods.
+
     # @see #serializable_hash for more details on these valid keys.
     SERIALIZABLE_HASH_VALID_KEYS = [:only, :except, :methods, :include, :root].freeze
     extend ActiveSupport::Autoload
diff --git a/lib/active_model_serializers/model.rb b/lib/active_model_serializers/model.rb
index ea10ac881..2ff3d60c5 100644
--- a/lib/active_model_serializers/model.rb
+++ b/lib/active_model_serializers/model.rb
@@ -1,6 +1,7 @@
 # ActiveModelSerializers::Model is a convenient superclass for making your models
 # from Plain-Old Ruby Objects (PORO). It also serves as a reference implementation
 # that satisfies ActiveModel::Serializer::Lint::Tests.
+require 'active_support/core_ext/hash'
 module ActiveModelSerializers
   class Model
     include ActiveModel::Serializers::JSON