diff --git a/src/instance/properties.js b/src/instance/properties.js
index 428a569..293913d 100644
--- a/src/instance/properties.js
+++ b/src/instance/properties.js
@@ -118,8 +118,8 @@
         if (Array.isArray(value)) {
           log.observe && console.log('[%s] observeArrayValue: register observer [%s]', this.localName, name, value);
           var observer = new ArrayObserver(value);
-          observer.open(function(value, old) {
-            this.invokeMethod(callbackName, [old]);
+          observer.open(function(splices) {
+            this.invokeMethod(callbackName, [splices]);
           }, this);
           this.registerNamedObserver(name + '__array', observer);
         }
diff --git a/test/html/property-array-changes.html b/test/html/property-array-changes.html
index e3950b1..44f0093 100644
--- a/test/html/property-array-changes.html
+++ b/test/html/property-array-changes.html
@@ -29,20 +29,20 @@
               this.a = a;
             },
             aChanged: function() {
-              this.nextTest();
+              this.nextTest(arguments);
             },
             bChanged: function() {
-              this.nextTest();
+              this.nextTest(arguments);
             },
             currentTest: 0,
             getCurrentTest: function() {
               return this['test' + this.currentTest];
             },
-            nextTest: function() {
+            nextTest: function(args) {
               var m = this.getCurrentTest();
               //console.log(this.currentTest);
               if (m) {
-                m.call(this);
+                m.apply(this, args);
               }
               this.currentTest++;
               if (!this.getCurrentTest()) {
@@ -67,13 +67,16 @@
               this.a.push(1);
               this.a.push(2);
             },
-            test4: function() {
+            test4: function(splices) {
               chai.assert.equal(this.a, a1, 'array property is correct value');
               chai.assert.equal(this.a.length, 2, 'noticed array addition');
+              chai.assert.equal(arguments.length, 1, 'only 1 argument when array mutates');
+              chai.assert.equal(splices[0].addedCount, 2, 'addedCount splice correctly sent in splices');
               this.a.shift();
             },
-            test5: function() {
+            test5: function(splices) {
               chai.assert.equal(this.a.length, 1, 'noticed array removal');
+              chai.assert.equal(splices[0].removed.length, 1, 'removed splices correctly sent');
               a.push(55);
               setTimeout(this.nextTest.bind(this), 0);
             },