diff --git a/test/objects.js b/test/objects.js
index 6fc60f1e4..95e5ab829 100644
--- a/test/objects.js
+++ b/test/objects.js
@@ -318,14 +318,14 @@ $(document).ready(function() {
       parent.iElement   = document.createElement('div');\
       parent.iArguments = (function(){ return arguments; })(1, 2, 3);\
       parent.iArray     = [1, 2, 3];\
-      parent.iString    = 'hello';\
-      parent.iNumber    = 100;\
+      parent.iString    = new String('hello');\
+      parent.iNumber    = new Number(100);\
       parent.iFunction  = (function(){});\
       parent.iDate      = new Date();\
       parent.iRegExp    = /hi/;\
       parent.iNaN       = NaN;\
       parent.iNull      = null;\
-      parent.iBoolean   = false;\
+      parent.iBoolean   = new Boolean(false);\
       parent.iUndefined = undefined;\
     </script>"
   );
diff --git a/underscore.js b/underscore.js
index 46f0ef685..e2a2fb260 100644
--- a/underscore.js
+++ b/underscore.js
@@ -614,7 +614,7 @@
     var isNumberA = _.isNumber(a), isNumberB = _.isNumber(b);
     if (isNumberA || isNumberB) return isNumberA && isNumberB && +a == +b;
     // Compare boolean objects by value. The value of `true` is 1; the value of `false` is 0.
-    var isBooleanA = toString.call(a) == '[object Boolean]', isBooleanB = toString.call(b) == '[object Boolean]';
+    var isBooleanA = _.isBoolean(a), isBooleanB = _.isBoolean(b);
     if (isBooleanA || isBooleanB) return isBooleanA && isBooleanB && +a == +b;
     // Compare dates by their millisecond values.
     var isDateA = _.isDate(a), isDateB = _.isDate(b);
@@ -738,7 +738,7 @@
 
   // Is a given value a boolean?
   _.isBoolean = function(obj) {
-    return obj === true || obj === false;
+    return obj === true || obj === false || typeof obj == 'object' && toString.call(obj) == '[object Boolean]';
   };
 
   // Is a given value a date?