Posts Tagged ‘learning disabilities’

Part 3 – The Errors we See- Discrimination challenges in children with autism and Learning Disabilities

September 21, 2017 2 comments

The author is a Board Certified Behavior Analyst working with Behavior Momentum India. The views in this blog are his own. I hope to keep in mind parents and therapists as I write and will try to keep the jargon to a minimum. Do feel free to contact me via

In parts 1 and 2 of this series, we saw the various examples and types of errors children with autism and learning disabilities make.  In the concluding part of this series, we will see some proven strategies to overcoming error patterns while teaching receptive language.


Don’t be too sure that the child ‘knows’ – do a counterbalanced assessment with distractors

Firstly it is important not to be satisfied with a confident assertion that the child ‘knows’ and has acquired the targeted discrimination. The first is done by performing a thorough assessment with the target items and distractors counterbalanced across all positions and across the number of times asked for.

For example, if you are testing for discrimination between say a,b and c ( or tiger/ leopard/panther or cup/spoon/ fork for that matter) then a minimum of 18 trial probes will be needed.  a, b and c should appear in each of the three positions in the array equal number of times and the instruction asking the child to select a,b or c should be done an equal number of times for each one in each position. This will help us find out if there is a  position bias in the students responding, a dominant item response or other errors such as win-stay errors.  An example of a counterbalced array is as below for assessments.

Array Position of stimuli Ask For Observer 1 Observer 2
Left Mid Right SD
1 yellow PINK brown   brown
2 PINK yellow brown PINK
3 brown yellow PINK yellow
4 yellow brown PINK yellow
5 brown PINK yellow brown
6 PINK brown yellow yellow
7 brown yellow PINK PINK
8 PINK yellow brown yellow
9 yellow PINK brown yellow
10 yellow brown PINK PINK
11 PINK brown yellow PINK
12 brown yellow PINK brown
13 PINK yellow brown brown
14 brown PINK yellow yellow
15 yellow brown PINK brown
16 brown PINK yellow PINK
17 PINK brown yellow brown
18 yellow PINK brown PINK

I once had a heart-rending situation.  Mom was confident that ‘Of course, my child knows his mom’. With due permissions, I ran a test. when there were 3 ladies, one of them being mom standing at random distances from the child we asked the child to give some item to mom, he would go and give it to the nearest person. The results were not much better when they were equidistant or when we instructed the child to “go to mom”. While the child would engage in play and singing with rhymes and other manners of sharing affection with her, he could not respond based on the instruction, “give this to mom” or ” go and touch mom”

Don’t be too sure that the student ‘knows’ – Are there some inadvertent prompts :

To rule out the possibility of inadvertent prompts a parent or therapist may be giving, it is important to have other people conduct the same set of assessments. If the child succeeds with everyone with a scientific assessment then it is possible to conclude that the discrimination is acquired. If the child is not able to make correct selections at more than chance rate ( only 33% of the times correct when an array of 3 stimuli is used and child is asked to select one randomly) with other people then either there is a failure to generalize, or, more likely the discrimination acquired is faulty.

Re-cap: error patterns exist if:

■Selection is right sometimes – wrong sometimes “ inconsistent”

■Response starts before instruction is given ( the student is basing responses on some ‘rule’ other than listening to you and selecting’)

■Child attends to /looks at a particular stimulus before instruction is given ( Sometimes instructors instruction coincides with child’s pre-selection)

■Responding occurs  without scanning  ( but some do respond well without directly looking)

■Escape behaviors happen  during receptive ID tasks

The first step is to ensure correct level of  discrimination in target selection :It is not a good idea to train fine or nuanced discriminations if grosser discriminations are not in place – Example – subtle shades in colors, words such as meet/ meat , sew/ sue, concept of honest vs dishonest

discrimination applicators-2022599_1280


Some strategies to overcome error patterns in teaching receptive language/  discrimination tasks:

No one procedure is guaranteed to work. but if you give considerable thought to the various options you have and if you are prepared to be flexible and if you take data on correct responding and errors under different strategies you will soon find what would work. For a full tutorial read Grow and LeBlanc (2013) – they have put it all together in the form of a tutorial. You will still need a guidance from an experienced Behavior Analyst for children with severe discrimination problems

  • get an observing/ attending  to the stimuli   before  the student responds :
    • Prompt to attend to the therapist – ” look at me” / other attention getting tactics before issuing instruction
    • It can be a simple prompt to look at each of the stimuli
    • A prompt to attend to a critical feature – match stripes before asking to select zebra from an array of zebra, horse, and deer.
    • student echoes  the instruction to confirm that he has heard it right ( Instructor says “zebra”, student says “zebra” and then proceeds to select Zebra from an array of 3 animals
    • Non-vocal children can make a sign corresponding to the instruction and proceed to make a selection
    • In fine discrimination exercises, example ‘b’ vs. ‘d’ – answer first whether the semi-circle is to the right of the line or to the left
  • Minimize inadvertent prompts from parent or therapist such as
    • eye gaze prompts – look directly at learners face and avoid looking at stimuli while giving instructions
    • A relaxing of facial features when student hovers over the right selection
    • small movements of therapists hands or eye movements
    • patterns of instruction ( example always ‘cow’ first, ‘horse’ second and ‘zebra’ third; position-wise – Right, middle, left)
  • Introduce multiple targets simultaneously – over teaching one may make it difficult to introduce new targets
  • By rotation, cover each target equal number of times within a session
  • Introducing sequentially is not recommended as teaching in isolation, simple discrimination is not likely to help with acquiring subsequent discriminations ( Grow et al., 2011, Gutierrez et al., 2009)
  • Use at least an array of 3 unless you are targeting opposites- with 2, the student has a 50% chance of being right anyways !
  • Improve Behavior consequence – A strong reinforcer for correct response And a loss of privileges or delay to reward – guided by Fisher, Pawich, Dickes, Paden  & Toussaint (2014).
  • If there is a position or side bias – counteract with more trials with success in other positions or increase array size
  • If there is a long history of errors with certain targets consider starting with a new set of targets  altogether

If the responding demonstrates improved discrimination, you are on the right track. Otherwise be flexible, look at the rate of correct and error responses across sessions and with professional guidance attempt an alternate strategy.

Happy teaching discrimination.

Selected References


Fisher, W. W., Pawich, T. L., Dickes, N., Paden, A. R., & Toussaint, K. (2014). Increasing the saliency of behavior–       consequence relations for children with autism who exhibit persistent errors. Journal of applied behavior analysis47(4), 738-748.

Grow, L., & LeBlanc, L. (2013). Teaching Receptive Language Skills. Behavior analysis in practice6(1), 56-75


The Errors we See- Discrimination challenges in children with autism and Learning Disabilities – Part II

The author is a Board Certified Behavior Analyst working with Behavior Momentum India. The views in this blog are his own. I  hope to keep in mind parents and therapists as I write and will try to keep the jargon to a minimum. Do feel free to contact me via

In Part 1 of the series we saw the types of discrimination challenges and issues we run into when teaching children with autism or other learning disabilities.  These are often a part of larger error patterns that children acquire inadvertently because of the way materials are used, the way responses may be prompted or the way they are reinforced. In this second part, we will look at inspecting and understanding error patterns. In part III we will look at strategies to avoid and overcome them.

Most of the receptive language tasks involve :

  • the teacher presenting an array of 3 or more items, asking for one of them
  • prompting and fading prompts if the child does not know the correct response
  • and rewarding ( reinforcing)  correct responses and ignoring incorrect responses.

Several potential errors creep in depending on how the training procedures are run.  Step one, in most cases, we must recognize that the student may not really interested in acquiring the discrimination between purple and Red or Tall and short. We believe, these are useful and functional and set up the teaching environment while the student could only aim to get a reward with minimum effort. The reward can be a preferred item or activity given by the therapist for correct responses or just completing the task as fast as possible and getting away from it all ( Technically. these are called reinforcers that increase future occurrence of the behavior that they follow) !! Behavior Analysts, both researchers, and practitioners have, in studies since the 1960s documented the kind of errors that could happen and newer and newer strategies are still being researched for improving outcomes. Laura & Grow ( 2013), have published a great article which details the type of errors that occur in teaching receptive language and strategies to overcome them.

Most parents and therapists miss the first step- recognizing that there is a problem. After doing a few tests it is very easy to be deluded into believing that the child ‘knows’ what is being taught though he sometimes makes incorrect responses. Some of the error patterns and how they creep in are discussed below:

I bet on a position ( Dominant position bias):

When you place pictures or dolls of cat, dog, and cow in an array and ask for one, say ‘cow’,  the student could adopt several strategies to complete the task which does not require him/her to listen carefully and make a correct selection – One is a position bias. As a student, I go for one particular position more often,  for example, the right most. Soon the therapist/mom inadvertently starts placing the target item there more often in that position, for, after all, the therapist or mom is also rewarded by students correct responses. The mistakes that happen when the target item is in other positions are overlooked and attributed to the student being ‘inconsistent’. In such a strategy, the student can completely avoid paying attention to what the instructor/ therapist/parent is asking to be selected( Technically called the Auditory stimulus presented by an adult which should serve as a discriminative stimulus for the student response).

I bet on a particular target item ( Dominant Response Bias):

Using the same example, possibly because I was taught ‘cow’ first and reinforced several times, even when the new targets of dog and cow are introduced I keep selecting cow more often regardless of what I am asked to select. On the occasions when I am correct, I get rewarded. Sometimes, this too could result in the teacher/ therapist asking for ‘cow’ more often creating an illusion of successful discrimination!

I bet on a familiar looking item :

There was a student who could identify spoon, cup, pen, socks, fork, lunch box, toy, and nearly a dozen such items from an array of 5 different objects. He never made a mistake until his teacher started presenting the array with 2 or more from his ‘known’ list. Then he started making mistakes. In the earlier procedure, the student merely had a rule that is something like ” If I see that familiar one, I will go for it”.

I respond based on body language or other inadvertent cues from the teacher:

While teaching receptive language the teacher may be inadvertently supplying additional cues which indicate where the correct responses lie. The student can be sometimes seen intently looking at the teachers face before selecting the item asked for. Some inadvertent prompts could be

  • the therapist’s eyes  dart at the target item before she asks for it (called eye-prompts or eye-gaze prompts)
  • the target item could be placed closer to the child than the other items, as the student’s hand hovers over an incorrect response the therapist’s features are taut and they relax as he switches to the correct response midway
  • the teacher uses exaggerated intonation correlated to a specific target ( Biiiiiig vs small, nineteen versus nine) but does not fade such intonation prompts.

Switching bias :

The student, after being asked to select big, switches the next response to small ( even if ‘big’ is asked for again) because historically his therapist has always switched the target from the previous teaching trial.

Random responding:

Here the student randomly selects any item without regard to what was asked. Afterall,  in an array of 3, he could be successful 33% of the times and that is fine!

Stimulus Overselectivity:

Stimulus over-selectivity or attending to one part of an item to the exclusion of all other parts of the whole could result in errors. For example, a child who looks only at wheels may find discrimination between a car, a truck and a van difficult.

Generalization Problems:

While discrimination is acquired with specific items taught it has not generalized to novel items 0r contexts.

Laura and Grow in their 2013 article talk about several evidence based strategies to avoid errors and teach receptive identification to children with autism.   These include counterbalanced assessments and presentations, requiring an observing response, avoidance of instructor errors, use of simultaneous targeting versus introducing targets one by one and use of appropriate array sizes.  In addition, Fisher, Pawich, Dickes, Paden and Toussaint (2014) conducted a very important study that explains how and why it is important to manage the consequences of correct responses in relation to errors ( they call it managing the behavior-consequence salience for children with autism who present persistent errors).

We will discuss these strategies to over come error patterns in part II of this blog series.


Selected References

Grow, L., & LeBlanc, L. (2013). Teaching Receptive Language Skills: Recommendations for Instructors. Behavior Analysis in Practice6(1), 56–75.

Fisher, W. W., Pawich, T. L., Dickes, N., Paden, A. R. and Toussaint, K. (2014), Increasing the saliency of behavior-consequence relations for children with autism who exhibit persistent errors. Journal of Applied Behavior Analysis, 47: 738–748. doi:10.1002/jaba.172

The Errors we See- Discrimination challenges in children with autism and Learning Disabilities – Part I

July 22, 2017 1 comment

The author is a Board-Certified Behavior Analyst and works with Behavior Momentum India as a Research Associate, Faculty in teaching Applied Behavior Analysis course sequence and trains therapists who work with children with autism. He attempts to avoid jargon to make topics in Applied Behavior Analysis intelligible to parents of children with autism and learning disabilities, students, and therapists. The views in this blog are his own. This is the first blog and is expected to run into 3 parts because of the vast amount challenges in teaching receptive language to children with autism and recent advances.

David is a 4-year-old boy with developmental disabilities. One day his mom was excited. She was working at training identification of everyday objects from a small array of 3 different objects and he seemed to get it right with 7-8 objects such as a spoon, cup, top and fork wherever they are placed in an array. At the ABA center he went to during the day, his case manager was surprised by mom’s report. At the center, David would only get his identifications right only 25- 30% of the time, around a chance level of success, as if he were selecting randomly. He requisitioned videos of sessions from home and played them a few times over and found that a simplified array of stimuli was being used. There would be the target object, selecting which produced rewards and two other objects such as scissors and crayon that the parent never asked. David had figured that he needs to go for the spoon or the cup whenever they appeared in the array- he did not have to listen to what was asked for and make a discriminated selection. When probed with spoon, cup, and fork in the same array, hi correct selections dropped to chance levels as now the correct response depended on his selection also tallying with what the adult asked for.

Girls who buy nail polish need to know the difference between two shades that are close to each other in appearance- one could be “just her type” and another one not so! Children with autism and learning disabilities often have serious problems mastering discrimination tasks. One of the reasons is making a selection based on one element or feature of an object instead of attending to all the parts. This is called stimulus over selectivity. For instance, a child whose attention is only on wheels may not be able to identify a car if a truck and a van are also present in the array of vehicle pictures. Examples of making a response based on attending to an incorrect part abound. Discrimination training procedures involve the use of rewarding correct responses, prompting and prompt fading procedures and may inadvertently result in responses with errors or prompt dependence.

Let’s look at some more examples of errors. At a simple level, let us say a student is taught to respond to the instruction “touch head” by touching his or her own head. When “touch elbow” is introduced as a next target, the student could proceed to touch his head as soon as he hears the word “touch”. Similar problems exist with training to answer questions such as “what is your name” and  “What is your mother’s name”. The response “David” could be blurted out as soon as “what is” is heard. A child who is taught to answer “air” when asked what does fan give could reply with “air” when asked what does cow give”. It is quite possible that the “what” or “give” part of the question controls the students answer of “air” and not the “fan” or “cow”.

At a certain stage of learning, generalization must stop and discrimination must set in. There could also be a problem of over generalization without discrimination setting in (or being taught). A child taught to request for “hug” from parent’s could request hug from complete strangers. A child who is taught to say “daddy” with her dad’s picture (let’s say dad sports a beard in the picture) starts labeling other pictures of persons with a beard also as “daddy”. Many children on the spectrum who perform discriminative tasks with nouns well, fail when it comes to discriminating even between the basic colors of red, blue, green and yellow. I have come across students who do a perfect job of matching red card to card, blue card to blue card and so on. However, when they are asked to point at the red card or the yellow card or the blue, in an array that has all these cards things start going wrong. There is some other discrimination issue at work here. Discrimination challenges are part of everyday life with all humans. Husbands could buy the wrong gift on the anniversary day, a writer, could place too many, commas in his sentences, or cops could overlook important evidence at the crime site and obsess with non-essentials while the criminal is thriving and on the run. However, with children with autism and other learning disabilities, these problems acquire serious proportions across several areas of their learning and the error patterns could become stronger confounding parents and therapists.
Behavior Analysts use research based methods to identify error patterns, understand why they could occur in discrimination training and use specific strategies to overcome these.I will look forward to examining additional error patterns and the current state of research on how they can be overcome in the next parts of this series on discrimination training.

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