diff --git a/.idea/runConfigurations/Scratch_Pad.xml b/.idea/runConfigurations/Scratch_Pad.xml
index 509e9fd0f22..47414f5f051 100644
--- a/.idea/runConfigurations/Scratch_Pad.xml
+++ b/.idea/runConfigurations/Scratch_Pad.xml
@@ -1,12 +1,12 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="Scratch Pad" type="PythonConfigurationType" factoryName="Python">
-    <module name="PsyNeuLink" />
+    <module name="PsyNeuLink (Dropbox)" />
     <option name="INTERPRETER_OPTIONS" value="" />
     <option name="PARENT_ENVS" value="true" />
     <envs>
       <env name="PYTHONUNBUFFERED" value="1" />
     </envs>
-    <option name="SDK_HOME" value="$USER_HOME$/anaconda/envs/gym-forager/bin/python" />
+    <option name="SDK_HOME" value="$USER_HOME$/anaconda/envs/python36/bin/python" />
     <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/Scripts" />
     <option name="IS_MODULE_SDK" value="false" />
     <option name="ADD_CONTENT_ROOTS" value="true" />
diff --git a/psyneulink/core/components/component.py b/psyneulink/core/components/component.py
index 93a60934512..2f4acaebb84 100644
--- a/psyneulink/core/components/component.py
+++ b/psyneulink/core/components/component.py
@@ -163,9 +163,11 @@
 * **reinitialize_when** - the `reinitialize_when <Component.reinitialize_when>` attribute contains a `Condition`. When
   this condition is satisfied, the Component calls its `reinitialize <Component.reinitialize>` method. The
   `reinitialize <Component.reinitialize>` method is executed without arguments, meaning that the relevant function's
-  `initializer<IntegratorFunction.initializer>` attribute (or equivalent -- initialization attributes vary among functions) is
-  used for reinitialization. Keep in mind that the `reinitialize <Component.reinitialize>` method and `reinitialize_when
-  <Component.reinitialize_when>` attribute only exist on stateful Mechanisms.
+  `initializer<IntegratorFunction.initializer>` attribute (or equivalent -- initialization attributes vary among
+  functions) is used for reinitialization. Keep in mind that the `reinitialize <Component.reinitialize>` method and
+  `reinitialize_when <Component.reinitialize_when>` attribute only exist for Mechanisms that have `stateful
+  <Parameter.stateful>` Parameters, or that have a `function <Mechanism.function>` with `stateful <Parameter.stateful>`
+  Parameters.
 
   .. note::
 
@@ -416,7 +418,11 @@ class `UserList <https://docs.python.org/3.6/library/collections.html?highlight=
 
 from psyneulink.core import llvm as pnlvm
 from psyneulink.core.globals.context import Context, ContextFlags, _get_time
-from psyneulink.core.globals.keywords import COMPONENT_INIT, CONTEXT, CONTROL_PROJECTION, DEFERRED_INITIALIZATION, FUNCTION, FUNCTION_CHECK_ARGS, FUNCTION_PARAMS, INITIALIZING, INIT_FULL_EXECUTE_METHOD, INPUT_STATES, LEARNING, LEARNING_PROJECTION, LOG_ENTRIES, MATRIX, MODULATORY_SPEC_KEYWORDS, NAME, OUTPUT_STATES, PARAMS, PARAMS_CURRENT, PREFS_ARG, SIZE, USER_PARAMS, VALUE, VARIABLE, kwComponentCategory
+from psyneulink.core.globals.keywords import \
+    COMPONENT_INIT, CONTEXT, CONTROL_PROJECTION, DEFERRED_INITIALIZATION, \
+    FUNCTION, FUNCTION_CHECK_ARGS, FUNCTION_PARAMS, INITIALIZING, INIT_FULL_EXECUTE_METHOD, INPUT_STATES, \
+    LEARNING, LEARNING_PROJECTION, LOG_ENTRIES, MATRIX, MODULATORY_SPEC_KEYWORDS, NAME, OUTPUT_STATES, \
+    PARAMS, PARAMS_CURRENT, PREFS_ARG, REINITIALIZE_WHEN, SIZE, USER_PARAMS, VALUE, VARIABLE, kwComponentCategory
 from psyneulink.core.globals.log import LogCondition
 from psyneulink.core.globals.parameters import Defaults, Parameter, ParameterAlias, ParameterError, ParametersBase
 from psyneulink.core.globals.preferences.componentpreferenceset import ComponentPreferenceSet, kpVerbosePref
@@ -850,6 +856,8 @@ class Component(object, metaclass=ComponentsMeta):
     componentCategory = None
     componentType = None
 
+    standard_constructor_args = [REINITIALIZE_WHEN]
+
     class Parameters(ParametersBase):
         """
             The `Parameters` that are associated with all `Components`
@@ -935,7 +943,8 @@ def __init__(self,
                  size=NotImplemented,  # 7/5/17 CW: this is a hack to check whether the user has passed in a size arg
                  function=None,
                  name=None,
-                 prefs=None):
+                 prefs=None,
+                 **kwargs):
         """Assign default preferences; enforce required params; validate and instantiate params and execute method
 
         Initialization arguments:
@@ -946,6 +955,11 @@ def __init__(self,
 
         """
 
+        for arg in kwargs.keys():
+            if arg not in self.standard_constructor_args:
+                raise ComponentError(f"Unrecognized argument in constructor for {self.name} "
+                                     f"(type: {self.__class__.__name__}): {repr(arg)}")
+
         self.parameters = self.Parameters(owner=self, parent=self.class_parameters)
 
         context = ContextFlags.COMPONENT
@@ -1005,7 +1019,11 @@ def __init__(self,
         self.paramInstanceDefaults = {}
 
         self.has_initializers = False
-        self.reinitialize_when = Never()
+
+        if kwargs and REINITIALIZE_WHEN in kwargs:
+            self.reinitialize_when = kwargs[REINITIALIZE_WHEN]
+        else:
+            self.reinitialize_when = Never()
 
         self._role = None
 
diff --git a/psyneulink/core/components/mechanisms/mechanism.py b/psyneulink/core/components/mechanisms/mechanism.py
index bac02e13b31..10241dbe7a8 100644
--- a/psyneulink/core/components/mechanisms/mechanism.py
+++ b/psyneulink/core/components/mechanisms/mechanism.py
@@ -1422,6 +1422,7 @@ def __init__(self,
                  name=None,
                  prefs=None,
                  context=None,
+                 **kwargs
                  ):
         """Assign name, category-level preferences, and variable; register Mechanism; and enforce category methods
 
@@ -1487,7 +1488,8 @@ def __init__(self,
                                              function=function,
                                              param_defaults=params,
                                              prefs=prefs,
-                                             name=name)
+                                             name=name,
+                                             **kwargs)
 
         # FIX: 10/3/17 - IS THIS CORRECT?  SHOULD IT BE INITIALIZED??
         self._status = INITIALIZING
diff --git a/psyneulink/core/components/mechanisms/processing/processingmechanism.py b/psyneulink/core/components/mechanisms/processing/processingmechanism.py
index af70f7c14f0..f1d2e30b356 100644
--- a/psyneulink/core/components/mechanisms/processing/processingmechanism.py
+++ b/psyneulink/core/components/mechanisms/processing/processingmechanism.py
@@ -140,12 +140,13 @@ def __init__(self,
                  default_variable=None,
                  size=None,
                  input_states=None,
+                 function=None,
                  output_states=None,
                  params=None,
                  name=None,
                  prefs=None,
                  context=None,
-                 function=None,
+                 **kwargs
                  ):
         """Abstract class for processing mechanisms
 
@@ -162,12 +163,13 @@ def __init__(self,
         super().__init__(default_variable=default_variable,
                          size=size,
                          input_states=input_states,
+                         function=function,
                          output_states=output_states,
                          params=params,
                          name=name,
                          prefs=prefs,
                          context=context,
-                         function=function,
+                         **kwargs
                          )
 
     def _validate_inputs(self, inputs=None):
diff --git a/psyneulink/core/components/shellclasses.py b/psyneulink/core/components/shellclasses.py
index f7753600d4f..3ab1f92b3c8 100644
--- a/psyneulink/core/components/shellclasses.py
+++ b/psyneulink/core/components/shellclasses.py
@@ -103,13 +103,15 @@ def __init__(self,
                  function=None,
                  param_defaults=None,
                  name=None,
-                 prefs=None):
+                 prefs=None,
+                 **kwargs):
         super().__init__(default_variable=default_variable,
                          size=size,
                          function=function,
                          param_defaults=param_defaults,
                          name=name,
-                         prefs=prefs)
+                         prefs=prefs,
+                         **kwargs)
 
     def _validate_params(self, request_set, target_set=None, context=None):
         raise ShellClassError("Must implement _validate_params in {0}".format(self))
diff --git a/psyneulink/core/compositions/composition.py b/psyneulink/core/compositions/composition.py
index 2e3d7cd8850..5d4cc451ed8 100644
--- a/psyneulink/core/compositions/composition.py
+++ b/psyneulink/core/compositions/composition.py
@@ -4888,6 +4888,12 @@ def run(
                 else:
                     execution_autodiff_stimuli[node] = autodiff_stimuli[node]
 
+            for node in self.nodes:
+                if hasattr(node, "reinitialize_when") and node.parameters.has_initializers._get(execution_id):
+                    if node.reinitialize_when.is_satisfied(scheduler=self.scheduler_processing,
+                                                           execution_context=execution_id):
+                        node.reinitialize(None, execution_context=execution_id)
+
             # execute processing
             # pass along the stimuli for this trial
             trial_output = self.execute(inputs=execution_stimuli,
diff --git a/psyneulink/core/globals/environment.py b/psyneulink/core/globals/environment.py
index 003f09a5995..e8cc0713f2a 100644
--- a/psyneulink/core/globals/environment.py
+++ b/psyneulink/core/globals/environment.py
@@ -892,7 +892,7 @@ def run(obj,
             if call_before_time_step:
                 call_with_pruned_args(call_before_time_step, execution_context=execution_id)
 
-            # Reset any mechanisms whose 'reinitialize_when' conditions are satisfied
+            # Reinitialize any mechanisms that has a 'reinitialize_when' condition and it is satisfied
             for mechanism in obj.mechanisms:
                 if hasattr(mechanism, "reinitialize_when") and mechanism.parameters.has_initializers._get(execution_id):
                     if mechanism.reinitialize_when.is_satisfied(scheduler=obj.scheduler_processing, execution_context=execution_id):
diff --git a/psyneulink/core/globals/keywords.py b/psyneulink/core/globals/keywords.py
index 5bf765cde45..88861feea99 100644
--- a/psyneulink/core/globals/keywords.py
+++ b/psyneulink/core/globals/keywords.py
@@ -98,8 +98,8 @@
     'PREDICTION_MECHANISM_TYPE', 'PREFS_ARG', 'PREVIOUS_VALUE', 'PRIMARY', 'PROB', 'PROB_INDICATOR',
     'PROCESS', 'PROCESSING', 'PROCESS_INIT', 'PROCESSES', 'PROCESSES_DIM', 'PROCESSING_MECHANISM', 'PRODUCT',
     'PROJECTION', 'PROJECTION_DIRECTION', 'PROJECTION_PARAMS', 'PROJECTION_SENDER', 'PROJECTION_TYPE', 'PROJECTIONS',
-    'QUOTIENT', 'RANDOM', 'RANDOM_CONNECTIVITY_MATRIX', 'RATE', 'RATIO', 'REARRANGE_FUNCTION',
-    'RECEIVER', 'RECURRENT_TRANSFER_MECHANISM', 'REDUCE_FUNCTION', 'REFERENCE_VALUE', 'REINITIALIZE',
+    'QUOTIENT', 'RANDOM', 'RANDOM_CONNECTIVITY_MATRIX', 'RATE', 'RATIO', 'REARRANGE_FUNCTION', 'RECEIVER',
+    'RECURRENT_TRANSFER_MECHANISM', 'REDUCE_FUNCTION', 'REFERENCE_VALUE', 'REINITIALIZE', 'REINITIALIZE_WHEN',
     'RELU_FUNCTION', 'REST', 'RESULT', 'RESULTS', 'ROLES', 'RL_FUNCTION', 'RUN',
     'SAMPLE', 'SAVE_ALL_VALUES_AND_POLICIES', 'SCALAR', 'SCALE', 'SCHEDULER', 'SELF', 'SENDER',
     'SEPARATOR_BAR', 'SIMPLE', 'SIMPLE_INTEGRATOR_FUNCTION', 'SINGLETON', 'SIZE', 'SLOPE', 'SOFT_CLAMP',
@@ -914,6 +914,7 @@ def _is_metric(metric):
 OUTPUT_TYPE = 'output'
 OVERWRITE = 'overwrite'
 REINITIALIZE = "reinitialize"
+REINITIALIZE_WHEN = "reinitialize_when"
 
 LOW = 'low'
 HIGH = 'high'
diff --git a/psyneulink/library/components/mechanisms/processing/integrator/ddm.py b/psyneulink/library/components/mechanisms/processing/integrator/ddm.py
index a1f247102a7..01dda8d9f07 100644
--- a/psyneulink/library/components/mechanisms/processing/integrator/ddm.py
+++ b/psyneulink/library/components/mechanisms/processing/integrator/ddm.py
@@ -837,7 +837,8 @@ def __init__(self,
                  output_states:tc.optional(tc.any(str, Iterable))=(DECISION_VARIABLE, RESPONSE_TIME),
                  params=None,
                  name=None,
-                 prefs: is_pref_set = None):
+                 prefs: is_pref_set = None,
+                 **kwargs):
 
         self.standard_output_states = StandardOutputStates(self,
                                                            DDM_standard_output_states,
@@ -923,7 +924,8 @@ def __init__(self,
                                   name=name,
                                   prefs=prefs,
                                   size=size,
-                                  context=ContextFlags.CONSTRUCTOR)
+                                  context=ContextFlags.CONSTRUCTOR,
+                                  **kwargs),
         self._instantiate_plotting_functions()
         # # TEST PRINT
         # print("\n{} user_params:".format(self.name))