diff --git a/pysaliency/datasets/scanpaths.py b/pysaliency/datasets/scanpaths.py
index 92ad172..e8e274a 100644
--- a/pysaliency/datasets/scanpaths.py
+++ b/pysaliency/datasets/scanpaths.py
@@ -221,7 +221,7 @@ def concatenate_scanpaths(scanpaths_list: List[Scanpaths]) -> Scanpaths:
         mappings = {scanpaths.attribute_mapping.get(key) for scanpaths in scanpaths_list}
         if len(mappings) > 1:
             raise ValueError(f"Multiple mappings for attribute {key} found: {mappings}")
-        elif len(mappings) == 1:
+        elif len(mappings) == 1 and list(mappings)[0] is not None:
             merged_attribute_mapping[key] = mappings.pop()
 
     return Scanpaths(xs, ys, n, length, scanpath_attributes=scanpath_attributes, fixation_attributes=fixation_attributes, attribute_mapping=merged_attribute_mapping)
\ No newline at end of file
diff --git a/tests/datasets/test_scanpaths.py b/tests/datasets/test_scanpaths.py
index effea4e..040500b 100644
--- a/tests/datasets/test_scanpaths.py
+++ b/tests/datasets/test_scanpaths.py
@@ -299,6 +299,38 @@ def test_concatenate_scanpaths():
     assert concatenated_scanpaths.attribute_mapping == {'attribute1': 'attr1', 'attribute2': 'attr2'}
 
 
+def test_concatenate_scanpaths_no_mapping():
+    xs1 = [[0, 1, 2], [2, 2], [1, 5, 3]]
+    ys1 = [[10, 11, 12], [12, 11], [21, 25, 33]]
+    n1 = [0, 0, 1]
+    scanpath_attributes1 = {'task': [0, 1, 0]}
+    fixation_attributes1 = {'attribute1': [[1, 1, 2], [2, 2], [0, 1, 3]], 'attribute2': [[3, 1.3, 5], [1, 42], [0, -1, -3]]}
+    attribute_mapping1 = {}
+
+    scanpaths1 = Scanpaths(xs1, ys1, n1, length=None, scanpath_attributes=scanpath_attributes1, fixation_attributes=fixation_attributes1, attribute_mapping=attribute_mapping1)
+
+    xs2 = [[0, 1, 2], [2, 2], [1, 5, 4]]
+    ys2 = [[10, 11, 12], [12, 12], [21, 25, 33]]
+    n2 = [0, 1, 1]
+    scanpath_attributes2 = {'task': [0, 1, 0]}
+    fixation_attributes2 = {'attribute1': [[1, 1, 2], [2, 2], [0, 1, 3]], 'attribute2': [[3, 1.3, 5], [1, 42], [0, -1, -3]]}
+    attribute_mapping2 = {}
+
+    scanpaths2 = Scanpaths(xs2, ys2, n2, length=None, scanpath_attributes=scanpath_attributes2, fixation_attributes=fixation_attributes2, attribute_mapping=attribute_mapping2)
+
+    concatenated_scanpaths = concatenate_scanpaths([scanpaths1, scanpaths2])
+
+    assert_variable_length_array_equal(concatenated_scanpaths.xs, VariableLengthArray(xs1 + xs2))
+    assert_variable_length_array_equal(concatenated_scanpaths.ys, VariableLengthArray(ys1 + ys2))
+    np.testing.assert_array_equal(concatenated_scanpaths.n, np.array(n1 + n2))
+    assert concatenated_scanpaths.scanpath_attributes.keys() == {'task'}
+    np.testing.assert_array_equal(concatenated_scanpaths.scanpath_attributes['task'], np.array([0, 1, 0, 0, 1, 0]))
+    assert concatenated_scanpaths.fixation_attributes.keys() == {'attribute1', 'attribute2'}
+    assert_variable_length_array_equal(concatenated_scanpaths.fixation_attributes['attribute1'], VariableLengthArray([[1, 1, 2], [2, 2], [0, 1, 3], [1, 1, 2], [2, 2], [0, 1, 3]]))
+    assert_variable_length_array_equal(concatenated_scanpaths.fixation_attributes['attribute2'], VariableLengthArray([[3, 1.3, 5], [1, 42], [0, -1, -3], [3, 1.3, 5], [1, 42], [0, -1, -3]]))
+    assert concatenated_scanpaths.attribute_mapping == {}
+
+
 def test_concatenate_scanpaths_missing_fixation_attribute():
     xs1 = [[0, 1, 2], [2, 2], [1, 5, 3]]
     ys1 = [[10, 11, 12], [12, 11], [21, 25, 33]]