PECS Phase 3: Discrimination Training

Once the child is using PECS and traveling across the room to request four to five different things, Phase 3 can begin. Now the child is ready to move on to requesting a preferred item by choosing from a display of more than one picture, going to the communicative partner and giving that person the picture or symbol of what he is requesting. At this stage it is critical that the child learns to attend to the pictures to become able to discriminate between them.

Components of Phase 3

Discriminating between two pictures
The first step in teaching discrimination is to have the communication book presented with two pictures/symbols on it – one with a known, highly reinforcing item or an item appropriate to the situation and the other a nonpreferred item. If the child is watching a video and the communication partner stops it, we would expect the child to reach for and give the picture for the video to the partner. If the child gives the picture of a nonpreferred item (such as a shirt), the communicative partner gives the child the shirt without any social reaction. If the child continues to give the “nonpreferred” picture, check to see that the child really wants the other item.

The Four-step correction procedure
Some children look at the pictures displayed on their book and quickly learn to discriminate between the picture that goes with the thing they want and the one that does not. For others, this skill does not come easily. They may repeatedly give their partner the wrong picture or continue to give different pictures until their partner gives them what they want.

A strategy to teach children to look at the pictures and select the one that matches the object they want is called the 4-step correction procedure. The procedure goes like this:

If the student does not give the correct picture the second time, stop the training session and use an alternative discrimination strategy. It is important that the student continues to be successful in getting what she wants by giving a picture to a partner.

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Alternative discrimination strategies
If a student is having difficulty learning to discriminate between pictures, it is often helpful to increase the contrast between the picture that is associated with what the student wants and the other pictures in the display. Increasing the contrast between the pictures of the desired object and the nonpreferred object can be accomplished by using one of the following methods.

• Make the picture of the desired object larger than the nonpreferred object
• Use a colored picture of the desired object and a black-and-white picture for the nonpreferred
• Highlight the desired picture by outlining it with a magic marker
• Use a blank card as the other picture in the display
• Make the desired picture 3-dimensional by attaching it to a poker chip or block
• Place the desired picture closer to where you are holding the desired object
• Put the pictures inside the book so the student must open the book to find them
• Turn the book face down so the student must turn it over to find the pictures

Increasing pictures in the display
As the child’s ability to discriminate increased, add pictures/symbols so the child can begin to request from numerous pictures. Begin with highly preferred and less preferred, and move to adding symbols of equally desirable items.

Correspondence check
When the child is able to discriminate between three items, do what is called a “correspondence check” to be sure that the child is requesting and taking the item they are asking for. A simple way to do this is to present the communication book with two pictures and the two items within view. When the child presents the communication partner with one picture, the partner responds with “You want video–take it.” If the child reaches for and takes the videotape, you are assured this is what he wants.

The outcome of phase 3 is that the student selects the picture associated with the object he wants from a display of pictures, approaches a communicative partner and gives him or her the picture.

Key Points

• No verbal prompts are used during this stage
• It is important to vary the position of the pictures or symbols on the communication board until the child has mastered discrimination
• Incidental teaching opportunities should supplement the structured teaching trials throughout the day
• It is important to avoid saying “No” when the child makes a mistake during discrimination training: Instead respond by giving the child what he has requested
• The ongoing documentation of highly reinforcing items continues to be an important part of the PECS training

Helpful Tips

• Keep extra copies of pictures/symbols handy. A filing system using an index box or a plastic hang-up pocket chart is helpful
• Cut out pictures of items from the boxes they come in. They make an instant symbol
• Keep a supply of Velcro on hand; Make symbols sturdier to withstand lots of use by laminating them. Small laminators are quite inexpensive
• Rearrange the location of the symbols on the board so the child does not choose a symbol based on its location
• When the child is able to discriminate between 8-10 symbols/pictures, begin to reduce the size of the symbols so that the book is not overly crowded
• Use a page within the book as a “storage” page for pictures that are used for requests

Note items that are not preferred or even disliked by the student