Monday, June 7, 2010

Do you have Change Blindness?

What is considered to be "Change Blindness?" Take a minute and glance over the top picture to your left. Now, take a look at the picture below it. Were you able to speculate the six different in the second picture? If you were unsuccessful, then you have just experienced change blindness. Many people often have trouble detecting the change in details of a picture, unless it is prominent where to look.

The six alterations between the top and bottom pictures are as follows:

  1. Number of Clouds
  2. Number of Whiskers
  3. Expression of Worm's Mouth
  4. Red Flower (detail)
  5. Leaf at the top of the tree
  6. Bird's Foot
Change blindness is defined as "the difficulty in detecting changes in scenes." The signification of attention (or lack thereof) is very crucial in determining change in a picture, scene, or environment. Ronald Rensink conducted experiments pertaining to change blindness, and concluded that pictures had to be alternated from one to the other a number of times until participants were able to detect the difference. However, Rensink also reported that when he added a cue indicating where the particular change or changes took place in the picture, participants were able to notice the change much more quickly.

Change Blindness is not just limited to pictures, this phenomenon can also occur in movies, sitcoms, or commercials. Have you ever watched a movie and noticed that some aspect of a scene, which should remain the same, changes from one shot to the next? This is known as a continuity error; and these errors are spotted by viewers who are "hunting them down" in the film. However, these critics had to watch the film several times to speculate the difference; most people would not notice the difference if they were not looking for them. In films, many people bestow their attention onto motion, which provides a cue that indicates a change is going to occur. However, the appearance or disappearance of an object/detail is when we miss detecting those changes.

In conclusion, we can perceive some things that are apparent, such as gender, or ethnic background, without focused attention; however, that focused attention is necessary and mandatory for detecting many of the details within a scene and the specific objects accompanying that scene!

The video below exhibits change blindness (continuity error) in a short video. See if you can find the change. Good Luck!

Copy & Paste the link below into your Browser:


  1. The topic of change blindness is interesting to me because looking back as a child (and I have to admit, even at 22 years old) I could not wait for the Sunday comics to do the fun activities, and one was the "find the differences between the pictures" - the classic example of change blindness. It was a fun activity as a child to race my friends and sister to see who could find all the differences first (I always won by the way :)). It is interesting that something that was seen as a stupid game is actually a significantly researched area of perception. I also experienced change blindness whenever I would watch television with my grandmother. She was very into soap operas and we loved to sit together and look for differences between the scenes (such as a woman wearing a backwards necklace in one scene and a second later it was worn the correct way). One time my grandmother even noticed a stain that was on a man's shirt in certain scenes, but in others it was gone. If she was alive today I'm sure she would find amusement in the fact that this is an important topic in the area of perception.

  2. This topic is fascinating to me! When reading the book there is an image on two separate changes and it asks you to spot the difference. Unfortunately, after looking for about five minutes, I couldn't spot a single difference. In your picture however, I am able to very quickly spot the differences. I think when the images are placed right above or next to each other the differences are easier to see, but when asked to turn a page and see what your brain interprets as the same image, spotting the differences is much more difficult. There is a game at most bars called mega touch and a game on there that involves finding the differences and it is not easy. These games play tricks on your mind because most of the time the differences are so subtle that they are difficult to find, however sometimes when you are looking for the subtle change you miss the difference that is staring you in the face. Although this is a topic in perception, it can actually be quite fun. I even think that you can train your brain to make your change blindness less and less.