Understanding Discrimination Training in ABA Therapy


Discrimination training is a key aspect of Applied Behavior Analysis (ABA). It teaches people how to choose one option or stimulus from various stimuli presented to them. This type of training is beneficial for people with autism spectrum disorder (ASD) as they may have limited communication skills or a tendency to get overwhelmed easily. With discrimination training, they learn to hone in on the relevant stimulus in their environment or the context of the situation, while ignoring background details.

Discrimination enhances social skills so people learn to convey their preferences with good conversational abilities. It is fundamental in ABA training because it promotes the development of essential skills like basic communication by focusing on what is important while ignoring irrelevant details.

What is Discrimination Training?

Imagine your life is a multiple-choice exam - for every question, you have a list of answers and you must choose the correct one. Discrimination training will help you circle out the best answer while ignoring the irrelevant options.

As the name suggests, discrimination training literally teaches the learner to ‘discriminate’ or differentiate the relevant or right response from an assortment of responses. The response to the correct stimulus is reinforced, while incorrect responses are not.

For example, if you place a fruit basket on the table and ask the learner to pick out an apple, he would be implementing discrimination training if he actually selects an apple rather than a banana or peach. This simple example shows how people learn to respond to simple instructions or questions by learning discrimination.  Another important outcome of discrimination training is learning where certain behaviors are appropriate and where they are not.  For instance, if you are watching a soccer game, it may be appropriate to yell and cheer on the players.  But if you are watching a movie in a movie theater, that behavior is most likely inappropriate.  Most people learn to discriminate where they can yell and where they cannot, however sometimes people with disabilities need to be taught these nuances specifically.

What are the Types of Stimuli Used in Discrimination Training?

Discrimination training involves two classifications of stimuli - discriminative stimulus and stimulus delta. In simpler words, relevant and irrelevant cues.

Discriminative Stimulus

Discriminative stimulus is the correct, relevant answer that receives reinforcement. In the fruit basket example given earlier, “apple” is the discriminative stimulus because the learner was asked to pick out an apple from the basket. This response was reinforced by the learner getting to enjoy a juicy apple!

Stimulus Delta

On the other hand, stimulus delta refers to all the other, irrelevant cues in a given situation whose choosing behavior is not reinforced. Going back to the fruit basket example, all other fruits in the basket were stimuli delta. If the learner had picked out a banana or an orange, that response would be incorrect and the therapist would not reinforce the response.

Types of Discrimination Training

Discrimination training teaches people how to differentiate between right and wrong responses. The existing skill level of the learners determines where to start to promote their growth and skill development. The ABA therapist can proceed with making a customized plan for them that targets their unique, individual needs, after assessing current abilities

Simple Discrimination

This technique teaches the learner to differentiate between two different stimuli. This is the most common and basic method of teaching discrimination and is essential in everyday life scenarios. 

Here are some examples of simple discrimination in the context of routine scenarios:

  • Choosing a blue pen from a mix of different colored pens
  • Choosing a T-shirt from a collection of turtle necks, button-downs, and plan round neck T-shirts.
  • Putting on a favorite TV channel
  • Choosing milk from tea, coffee, and juice.

Conditional Discrimination

Conditional discrimination teaches individuals to select a stimulus in a given condition or context. It encourages the ability of people to choose a particular response in the presence or absence of certain conditional cues.

For example, wearing a coat when going out. The condition for wearing a coat is stepping out of the house, if the learner is coming inside, he will not choose to put on a coat. This is important for developing the ability to give the most appropriate response depending on the social or environmental context.  Or an even further discrimination would be wearing a coat when the weather is cold, but not when it is hot.

Here are some more examples of conditional discrimination:

  • Saying “good morning” or “good night” depending on the time of the day.
  • Solving a math sum by adding or subtracting according to the given instruction (e.g. when given the problem 2 + 2, providing an answer of 4 rather than another number)
  • Giving the appropriate response to a customer’s query depending on whether they are asking about product information, price, or availability.
  • Following steps in a recipe such as “stir until sauce thickens” or “whisk until soft peaks form”.

Stimulus Fading

In stimulus fading, the stimulus is gradually modified (generally lessened) while the desired response is maintained. This promotes generalized learning by associating a response with a stimulus, not with a specific state of the stimulus. Stimulus fading encourages people to choose a response from a minor or less noticeable cue rather than a prominent prompt.

For example, a child can select a banana when asked to pick out a banana. Stimulus fading might include first pointing to the banana or putting the banana in a prominent place and then fading those prompts.   Gradually and systematically reducing the intensity of the cues and modifying them leads to more adaptive learning as individuals learn to transfer their responses from exaggerated cues to more subtle ones.

Here are more examples of stimulus fading in the context of everyday life situations:

  • Using dotted lines to trace out alphabets then slowly reducing the dotted figures till the letters can be written independently.
  • Delivering a speech from a printout of the entire document to eventually using cue cards with minimal prompts.
  • Reducing detailed step-by-step instructions for a cooking recipe to providing generalized, basic instructions.

Benefits of Discrimination Training in ABA

Discrimination training provides an array of benefits across various educational and personal living domains to people from all age groups. It significantly improves the quality of life and quality of relationships for people as they learn to develop their communication and interpersonal skills.

The following table illustrates how discrimination training translates to real-word scenarios and what skills are developed along the way.

Advantages of Discrimination Training Description Example
Supports adaptive learning Learning to follow instructions Stopping at a red signal or “Stop” sign
Improves differentiation skills Learning to distinguish one stimulus from a pool of stimuli Choosing a red shirt from a variety of colored shirts
Improves decision-making ability Interpreting given information to make an informed decision Choosing to bring an umbrella based on the weather forecast
Increases focus Concentrating on the task at hand without being distracted easily Studying for a school test without being distracted by phone, social media, or the TV
Enhances verbal communication Learning to converse and convey emotions or preferences with the appropriate choice of words or tone Saying no to an offered meal option in a restaurant and placing a different order
Builds self-control and regulates emotions Choosing an appropriate reaction to any news, especially sad or infuriating news Taking deep breaths when angry
Refines social skills Learning how to behave in a social gathering Attending during a conversation or participating in a group discussion
Achieves more independence Learning to complete tasks without constant supervision or instructions Learning a recipe and successfully preparing a meal without a cookbook
Boosts confidence Learning to successfully and appropriately respond to cues to become more certain and proficient Not being afraid to ask for help, initiate a conversation, or present in front of an audience

More Examples Of Discrimination Training

Discrimination training in ABA therapy can help individuals to differentiate between stimuli and respond appropriately, by using these techniques, therapists teach learners the ability to interact with the environment and others more effectively:

Discrimination Between Colors

  • Objective: Teach the child to discriminate between colors using colored cards.
  • Procedure: Present two cards, one red and one blue. Say, "Touch red." If the child touches the red card, provide reinforcement like verbal praise or a small treat. If the child touches the blue card, prompt them gently and repeat the trial. Increase the number of colors as the child improves.

Discrimination Between Shapes

  • Objective: Teach the child to differentiate shapes using shape flashcards.
  • Procedure: Present two cards, one with a circle and one with a square. Say, "Show me the circle." Reinforce the behavior of selecting the circle. Later, present multiple shapes and say, "Point to the triangle." Reinforce correct responses and prompt when there are incorrect ones.

Discrimination Between People

  • Objective: Help the child identify individuals using photos of people.
  • Procedure: Show two photos, one of the child's mother and one of the therapist. Ask, "Who is mommy?" Reinforce pointing to or naming the mother. Increase the number of photos and ask, "Who is Sarah?" Reinforce correct responses and prompt when there are incorrect ones.

Discrimination Between Instructions

  • Objective: Teach the child to follow different instructions using verbal cues.
  • Procedure: Give two instructions, like "Clap your hands" and "Touch your nose." Say, "Clap your hands," and reinforce clapping. Mix several instructions and give them in random order. Reinforce correct responses and prompt or correct as needed.

Discrimination Between Social Cues

  • Objective: Teach the child to recognize social cues using videos or role-playing scenarios.
  • Procedure: Show a video of someone smiling. Ask, "Is this person happy or sad?" Reinforce correctly identifying the emotion. Show various clips with different emotions and ask the child to identify each one. Reinforce correct responses and explain incorrect ones.

When you try to implement these tips, make sure to often provide positive reinforcement for correct responses, use and gradually fade prompts, practice in different settings with varied materials, and track responses to adjust the training plan.


Discrimination training is a crucial part of ABA therapy as it promotes the acquisition of new skills and their development across various domains of life. By teaching people to discriminate between stimuli, you empower individuals to make better decisions and improve their everyday interactions with others. Through implementing reinforcement and gradual stimulus-fading techniques, discrimination training boosts confidence and independence as children learn to navigate life without constant assistance from cues or supervision. In essence, discrimination training lays the foundation for continuous learning and social integration.


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