diff --git a/src/objectliterals.jsdoc b/src/objectliterals.jsdoc
index 289dedd51f..840cbb3584 100644
--- a/src/objectliterals.jsdoc
+++ b/src/objectliterals.jsdoc
@@ -311,9 +311,12 @@
 
 /**
  * @typedef {Object} ol.interaction.SelectOptions
+ * @property {ol.interaction.ConditionType|undefined} addCondition A conditional
+ *     modifier (e.g. shift key) that determines if the selection is added to
+ *     the current selection. Default is when holding the shift key only.
  * @property {ol.interaction.ConditionType|undefined} condition A conditional
- *     modifier (i.e. Shift key) that determines if the interaction is active
- *     or not, default is on mouse click only.
+ *     modifier (e.g. shift key) that determines if the interaction is active
+ *     (i.e. selection occurs) or not. Default is on mouse click only.
  * @property {undefined|function(ol.layer.Layer):boolean} layerFilter Filter
  *     function to restrict selection to a subset of layers.
  */
diff --git a/src/ol/interaction/selectinteraction.js b/src/ol/interaction/selectinteraction.js
index ee157b5049..813e6d1e0f 100644
--- a/src/ol/interaction/selectinteraction.js
+++ b/src/ol/interaction/selectinteraction.js
@@ -28,6 +28,13 @@ ol.interaction.Select = function(opt_options) {
   this.condition_ = goog.isDef(options.condition) ?
       options.condition : ol.interaction.condition.clickOnly;
 
+  /**
+   * @private
+   * @type {ol.interaction.ConditionType}
+   */
+  this.addCondition_ = goog.isDef(options.addCondition) ?
+      options.addCondition : ol.interaction.condition.shiftKeyOnly;
+
   /**
    * Mapping between original features and cloned features on selection layers.
    * @type {Object.<*,Object.<*,ol.Feature>>}
@@ -65,7 +72,7 @@ ol.interaction.Select.prototype.handleMapBrowserEvent =
     if (!goog.isNull(this.layerFilter_)) {
       layers = goog.array.filter(layers, this.layerFilter_);
     }
-    var clear = !ol.interaction.condition.shiftKeyOnly(mapBrowserEvent);
+    var clear = !this.addCondition_(mapBrowserEvent);
 
     var that = this;
     var select = function(featuresByLayer) {