diff --git a/keras/backend/numpy/core.py b/keras/backend/numpy/core.py
index 1b3e8e408..2e6ea07f0 100644
--- a/keras/backend/numpy/core.py
+++ b/keras/backend/numpy/core.py
@@ -61,15 +61,11 @@ def cond(pred, true_fn, false_fn):
     return false_fn()
 
 
-def vectorized_map(function, elements):
-    if len(elements) == 1:
-        return function(elements)
-    else:
-        batch_size = elements[0].shape[0]
-        output_store = list()
-        for index in range(batch_size):
-            output_store.append(function([x[index] for x in elements]))
-        return np.stack(output_store)
+def vectorized_map(function, x):
+    output_store = []
+    for element in x:
+        output_store.append(function(element))
+    return np.stack(output_store)
 
 
 # Shape / dtype inference util