diff --git a/lib/finite_machine/hooks.rb b/lib/finite_machine/hooks.rb
index 5007671..26732e5 100644
--- a/lib/finite_machine/hooks.rb
+++ b/lib/finite_machine/hooks.rb
@@ -18,7 +18,7 @@ class Hooks
     def initialize
       @hooks_map = Concurrent::Map.new do |events_hash, hook_event|
         events_hash[hook_event] = Concurrent::Map.new do |state_hash, name|
-          state_hash[name] = []
+          state_hash.compute_if_absent(name) { [] }
         end
       end
     end