diff --git a/chai.js b/chai.js
index ffe12c426..55f7a5ac4 100644
--- a/chai.js
+++ b/chai.js
@@ -932,11 +932,16 @@ module.exports = {
    * ### config.truncateThreshold
    *
    * User configurable property, sets length threshold for actual and
-   * expected values in assertion errors. If this threshold is exceeded,
-   * the value is truncated.
+   * expected values in assertion errors. If this threshold is exceeded, for
+   * example for large data structures, the value is replaced with something
+   * like `[ Array(3) ]` or `{ Object (prop1, prop2) }`.
    *
    * Set it to zero if you want to disable truncating altogether.
    *
+   * This is especially userful when doing assertions on arrays: having this
+   * set to a reasonable large value makes the failure messages readily
+   * inspectable.
+   *
    *     chai.config.truncateThreshold = 0;  // disable truncating
    *
    * @param {Number}
diff --git a/lib/chai/config.js b/lib/chai/config.js
index 36007e8f2..e6f38fff2 100644
--- a/lib/chai/config.js
+++ b/lib/chai/config.js
@@ -34,11 +34,16 @@ module.exports = {
    * ### config.truncateThreshold
    *
    * User configurable property, sets length threshold for actual and
-   * expected values in assertion errors. If this threshold is exceeded,
-   * the value is truncated.
+   * expected values in assertion errors. If this threshold is exceeded, for
+   * example for large data structures, the value is replaced with something
+   * like `[ Array(3) ]` or `{ Object (prop1, prop2) }`.
    *
    * Set it to zero if you want to disable truncating altogether.
    *
+   * This is especially userful when doing assertions on arrays: having this
+   * set to a reasonable large value makes the failure messages readily
+   * inspectable.
+   *
    *     chai.config.truncateThreshold = 0;  // disable truncating
    *
    * @param {Number}