DISCREET TRIALS
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WHAT IS DISCRETE TRIAL TEACHING? (SMITH, 2001)
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The term discrete trial describes the following procedure: SD – Response – Consequence – Intertrial Interval
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As opposed to free-operant procedure: – Organism is “free” to respond at various frequencies – There’s not intertrial interval
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Discrete Trial Teaching/Training (DTT) or Discrete Trial Instruction (DTI) is
one of dozens of behavior analytic teaching strategies It’s a method for individualizing and simplifying instruction to enhance learning Skills are taught in small, structured steps Instruction is typically conducted one-to-one in a distraction-free setting DTT is “one of the most important instructional methods for children with autism” (p. 86)
FIVE PARTS TO A TRIAL IN DTT (SMITH, 2001) • Teacher presents brief, distinctive instruction or question – e.g., “do this”, “what is it?”
• If needed, a prompt is provided after or along with the instruction • Child responds correctly or incorrectly • Teacher provides a consequence (reinforcer, ignore, or correction) • Intertrial Interval – Teacher pauses 1-5 s before presenting the next trial – Data may be recorded at this time
SOME HISTORY… • First well-known model of early behavioral intervention for children with autism was developed by (Ole) Ivar Lovaas in the ’60s and ’70s • Trained in behavior analysis while doing a postdoc with Sidney Bijou in 1958 – Lovaas (1993) credits Bijou with helping him bridge “the gap between behavioral psychology and clinical application” (p. 618)
• Psychology professor at the University of California at Los Angeles (UCLA) • Applied the science of behavior analysis to the treatment of people with autism in a new way, which he now calls the Lovaas Model of ABA (www.lovaas.com) • Video
UCLA YOUNG AUTISM PROJECT (YAP; LOVAAS & SMITH, •
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2003)
Stage 1 (2-4 weeks) - DTT – Establish “instructional control” • Extinguish escape-maintained behavior • Establish history of reinforcement for following directions Stage 2 (1-4 months) - DTT – Direction following – Imitation – Matching, Receptive Object ID – Dressing – Toy play Stage 3 (6+ Months) - DTT, IT – Verbal Im – Expressive labels – Receptive Picture/Action ID – Expand SH and play – Augmentative system if vocal language is not acquired
UCLA YOUNG AUTISM PROJECT (YAP; LOVAAS & SMITH, 2003) •
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Stage 4 (12 months) - DTT, IT, dyads with typical peers – Expressive labels - colors, shapes – Beginning “language concepts” – Recognizing emotions – Beginning sentences (“I want____”; “I see ____”) – Pretend play and peer interaction – Toilet training
Stage 5 (12 months) - DTT, IT, small group, typ PK – – – – – – –
Using “language concepts” Conversation Comprehending stories Perspective-taking Learning from models Working independently Helping with chores
THE “LOVAAS MODEL OF ABA” • Was widely disseminated as a treatment for children with autism in the 80s – Manuals – Program evaluations
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• 2003
Discrete Trial Instruction Model
D S
R C
Instruction Response Consequence Antecedent Behavior Consequence
DISCRETE TRIAL QUICK VOCABULARY • Target—the identified correct response • Distracter—any items/information, other than the target, presented during the task • Field of—refers to the total number of supplies presented at one time, target and all distracters. (Fo3, Fo2)
DISCRETE TRIAL TRAINING DTT involves: 1. Breaking a skill into smaller parts (sub-skills) 2. Teaching one sub-skill at a time until mastery 3. Allowing repeated practice in a concentrated period of time 4. Providing prompting and prompt fading as necessary 5. Using reinforcement procedures
Discrete Trial Training Components •The components of a trial: –Discriminative stimulus (SD): verbal direction, instruction, or cue –Response (R) –Consequence (C) •Stimulus Reinforcer (SR+): If response is correct, the child is reinforced –Inter-trial Interval: pause between trials
D S
R C
DISCRETE TRIAL TRAINING •Initially: –allow mini breaks where the student is given a reinforcer (great time to collect data and prepare materials for next series in addition to monitoring the child’s behavior and reinforce appropriate play); length of mini break should be proportionate to length of work completed –trials can be conducted in series of one to several, depending on the attention span, need for reinforcement, and difficulty of the material
DISCRETE TRIAL TRAINING •Schedule as many sessions in a day as is productive for the child •Allow breaks between sessions •Space sessions out through the day (rather than scheduled back-to-back) •Intersperse instructions from a variety of domains (visual, motor, language, math, motor, visual) •Evenly distribute sessions throughout the week
DISCRETE TRIAL TRAINING •As the student progresses, make the setting as natural as possible –deliberately allow distractions to occur –move to different places for a portion or all of the therapy session / teaching opportunity –gradually provide more complex instructions –vary materials
• Intertrial interval: The time between trials. An intertrial interval begins with the delivery of a consequence (reinforcer or removal of stimulus arrangement) and ends when a stimulus arrangement is presented • Discrete trial session: A discrete trial session involves repeated trials, differential reinforcement and the collection of data on each trial
INTER-TRIAL INTERVAL Is the time between Sr and the next SD Allows a break between teaching interactions Must not be too long or child may stop attending to therapist Should be between 5-7 seconds
COMPONENTS OF DISCRETE TRIAL TEACHING • Establish appropriate attending (child should sit appropriately and quietly, make eye contact, and refrain from engaging in stereotypic behavior) • Present discriminative stimulus (direction or instruction) • Wait a few seconds for the child to respond • Provide either reinforcement contingent upon correct responding, or provide corrective feedback contingent upon incorrect responding or no responding. • Provide intertrial interval (3-5 seconds) during which the child may consume or engage with the reinforcer and data may be collected. • The above sequence is typically repeated ten times
GENERAL GUIDELINES FOR DISCRETE TRIAL TEACHING • Arrange teaching environment to be free is distraction • Have all necessary materials readily available, and keep waiting time to a minimum • Establish appropriate attending behavior prior to providing instruction • Use brief and specific discriminative stimuli, and present them in a clear and directive voice • Present stimuli only once • Use minimal prompts and fade prompts systematically and quickly • Present reinforcement immediately following a correct response in an enthusiastic, upbeat voice • Use behavior specific phrase, e.g. “Good stand up!”
GENERAL GUIDELINES FOR DISCRETE TRIAL TEACHING • Provide frequent opportunities for the child to sample reinforcers • Use a variety of reinforcers • Maximize the number of trials per session to provide ample opportunities for learning • Make sure your teaching pace is appropriate, rather than too slow or too fast • Establish a data collection procedure to measure progress objectively • Take inter-observer agreement frequently to ensure that your data collection procedures are reliable
GRADUATED GUIDANCE • General goal: fade prompts across 10 trials • Begin with least intrusive prompt necessary • Begin to fade when student responds to 3 consecutive trials accurately • If 2 consecutive errors, immediately return to more intrusive prompt level
ERRORS INTERFERE WITH LEARNING • Teaching programs are designed to minimize errors and define back-up procedures if an error should occur • In all instances- errors should be interrupted before they are completed
PROMPT • Any additional guidance, presented with the instruction, which guides the student to make the correct response.
FADING • Gradual removal of prompts until the response occurs in the presence of the original instruction.
FADING PHYSICAL PROMPTS • Example: – FMG: immediate full manual guidance – PMG: immediate partial manual – 2 s delay PMG: 2 second delay partial manual guidance – I: Independent (no prompt)
FADING VERBAL PROMPTS • Example – FVM: Immediate full verbal model: “dog” – PVM: Immediate partial verbal model: “d” – 2 s delay PVM: 2 second delay partial verbal model – I: Independent (no prompt)
DATA COLLECTION • Data are collected on a trial-by-trial basis – +: correct and independent – +p: correct prompted – -: incorrect without prompts – -p: incorrect with prompt – NR: no response
THE DISCRIMINATIVE STIMULUS Must be issued when the child is ready to learn i.e. attending to therapist and therefore has the best chance of being successful Issued in clear language in a clear tone of voice Issued without interruption Issued only once before a response –follow through with the discrete trial before reissuing. Must be consistent across tutors
THE RESPONSE Must be defined prior to trial Should occur within 3-5 seconds Must be clear – no extraneous behaviours
THE RESPONSE • Why is it important to have established criteria to determine the expected behaviour?
A PRE-DEFINED RESPONSE Ensures consistency across tutors Ensures child is not confused – they know exactly what is expected of them and exactly what is being reinforced Ensures consistent data collection
THE RESPONSE • Can you name some different types of response?
MOTIVATIONAL OPERATIONS 1. Alter the effectiveness of reinforcers or punishers = value-altering effect
a) Establishing – EOs – increase effectiveness b) Abolishing – AOs – decrease effectiveness 2. Alter the frequency of operant response classes related to consequences = behaviour-altering effect. a) Evocative – increase responding b) Abative – decrease responding
MOTIVATIONAL OPERATIONS Examples: -Amount of Attention -Performance demands -Access to objects -Amount of Stimulation -Hunger -Pain -Fatigue/Boredom
MANIPULATION OF MOs Satiation will result in reinforcers losing their value and no longer functioning as reinforcers. Deprivation will result in reinforcers increasing in value. Conduct regular reinforcer assessments Limit the availability of reinforcers outside the teaching situation
MANIPULATION OF MOs Keeping the child engaged in activities and providing plenty of social contact and access to tangibles may decrease self-stimulatory, self-injurious and aggressive behaviours induced by EOs such as boredom or deprivation of attention.
MANIPULATION OF MOs Provide access to attention, tangibles and escape contingent upon appropriate behaviours to decrease the need for children to engage in inappropriate behaviours. Reducing failure for the child results in increased access to Sr which may reduce the aversiveness of the teaching situation “to the point at which it may not function as a demand but rather as an opportunity�
RECAP Sr gives child feedback about their response Must be clearly contingent on target behaviour- delivered immediately after a correct R Avoid satiation and use a variety of reinforcers – maintain motivation, prevent obsessions, move towards more naturally occurring reinforcers Reinforcers must be reinforcing! Be aware of MOs
ERROR CORRECTION What do you do if the response is incorrect? Effective error correction is essential to ensure learning and prevent prompt dependency. The discrete trial must be completed before the SD is re-issued i.e., the child must receive feedback about their R before retrial. The child does not receive access to reinforcers for an incorrect response
ERROR CORRECTION Corrective Feedback for an incorrect response may include: “No” “try again” “not quite” “uh-uh” with head shake
ERROR CORRECTION Feedback is issued in a neutral tone of voice - not reinforcing and distinct from feedback for correct R. All signs of reinforcers should be removed (may include eye-contact). “no� is used less often as it can be aversive and de-motivating for the child.
ERROR CORRECTION The “No-Prompt-Unprompted� procedure 2-3 secs after giving corrective feedback, the trial is reissued with a full prompt to show the correct R and give the child access to Sr (at lower level than for a correct R). Trial is then re-presented without extra help to give the child the opportunity to make the correct response independently and receive optimal Sr. procedure is repeated if necessary.
ERROR CORRECTION The item may be randomly re-presented later in the session to test for learning. Procedure may be adjusted according to child’s needs and point in the programme e.g., some children may be given two opportunities to make a correct R before a prompt is brought in (N-N-P-UP) etc A prolonged unstable performance, e.g. if 3rd trial in a row contains an error, returning to an earlier step i.e., reinstating prompts may be necessary.
ERROR CORRECTION • Demonstration • Practice with each other.
FURTHER FEEDBACK You can strengthen learning further by drawing the child’s attention to their correct R and repeating it back to them: e.g., “yes! fire engine!” - emphasising the object label whilst showing the child the correct item “yes! They’re the same!,” - emphasising the word “same” whilst showing the child the two items “yes! It’s yellow!” - emphasising the colour whilst showing the child the yellow item
BE ORGANIZED!! 1. Keep everything you need at the learning area. 2. Each student needs his own set of supplies. 3. Have data sheets ready before you begin instruction.
DIFFERENTIAL REINFORCEMENT • What Is Differential Reinforcement?
DIFFERENTIAL REINFORCEMENT Providing a greater amount of reinforcement for specific types of response, while providing less or no reinforcement for other types of response. Different levels of reinforcement must be clear to the child
DIFFERENTIAL REINFORCEMENT We provide increased levels of reinforcement for: More difficult responses Less prompted responses Independent responses Higher quality responses An item on acquisition/ target item Attention and co-operation
DIFFERENTIAL REINFORCEMENT We provide lower levels of reinforcement for: Easier responses/tasks More prompted responses Lower quality responses Mastered items Poor attention or co-operation
DIFFERENTIAL REINFORCEMENT
• Demonstration • Practice with each other
THE ACQUISITION PROCESS Procedure through which a target item progresses when being taught In most cases within a programme, only one item should be on acquisition at any one time Target items are initially prompted regardless of point of entry into the acquisition process to teach child correct response
PROMPTS AND PROMPTING 1. Physical: physically guiding the child, may be full or partial. 2. Verbal – use of speech to tell child the correct response 3. Gestural – using your body to indicate a correct response 4. Proximity/positional – placing target item closer to child to elicit the correct response
PROMPTS AND PROMPTING 5. Model – therapist models correct response to child for them to imitate 6.Tone of voice/inflection – emphasising a word or sound in the SD to facilitate the correct response 7.Visual – presenting the child with visual stimuli to assist the child in providing the correct response
PROMPTS AND PROMPTING 8. Recency – presenting the target item
in close succession to previously learned item to elicit the appropriate response. 9. Inadvertent! May include any of the above!
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SESSION MANAGEMENT Preparation is vital Review daily records, communication books, teaching plans etc prior to starting Plan a variety of reinforcers, conduct a reinforcer assessment Think about activities for between tasks Organise all teaching materials needed until the next break Know the SD, expected R and level of prompting to be used
SESSION MANAGEMENT Keep it fun! Conduct reinforcer assessments throughout the session Play activities should be varied frequently to maintain interest and fun Aim for an energetic and fun but relaxed atmosphere– how you behave and feel will effect how the child behaves and feels.
SESSION MANAGEMENT Adhere to teaching plans – ensure consistency across the team Keep a careful note of responses, extra help given etc as move through the activity/programme Record data carefully immediately after completion of the activity Leave the classroom as you would like to find it!
CO-OPERATION AND COMPLIANCE
Establishing co-operation is essential for successful learning Success increases the chance of future co-operation by maintaining motivation Issue clear instructions with prompts if necessary Strongly reinforce compliance and calm behaviour immediately
BEHAVIOUR MANAGEMENT Ignore inappropriate behaviours during activities as far as possible: Do not look at the child or attend to the behaviour as far as possible. Do not speak to the child to reprimand or comment on behaviour. Adopt neutral expression. Remove all signs of reinforcers Remove teaching materials and re-set up trial once behaviour has stopped.
BEHAVIOUR MANAGEMENT Child should be allowed to leave the teaching situation contingent on some appropriate behaviour. Increase task demand gradually and stick to teaching plans/ opportunity goals Be aware that children may “test� you if you are new or are carrying out new tasks or in a new setting etc It is essential that you let the child know when they are behaving appropriately by reinforcing them during these times!
BEHAVIOUR MANAGEMENT Remember: Manage CB according to behaviour management guidelines Follow communication protocols Do not put yourself or the child at unnecessary risk of harm Operate within your limits and seek support and guidance when you need it.
AIMS OF DTT Short-term Goals: To teach/increase the fundamental skills or “behavioural cusps� needed for a child to learn: Co-operation Ability to Attend Ability to imitate Early communication skills
AIMS OF DTT Long-term goals: To increase/teach Communication skills Play skills Cognition Social skills Academics and Academic Readiness Self-help/independence
DISCRETE TRIAL TEACHING Some core curricular areas: Non-Verbal Imitation (NVI) Matching Receptive Instructions (RI) Receptive Object Labels (ROL) Fine and Gross Motor Skills Interactive Play Manding and expressive language
CORE CURRICULUM AREAS NVI – develops ability to attend to and imitate others Matching – develops ability to visually discriminate between objects, increases attention to task and facilitates receptive language RI – develops ability to develop receptive language and ability to follow simple instructions
CORE CURRICULUM AREAS ROL – develop receptive language skills, increase vocabulary and provide opportunity to further facilitate expressive language skills Fine Motor – develops attention skills and encourages fine-motor development Interactive Play – develops play and social interaction skills. Goals include: imitation – flexibility – giving –
- manding - duration
CORE CURRICULUM AREAS • Manding – increases ability to initiate requests by using functional communication in natural environment
Verbal Behaviour Tools for assessing skills in children with language and learning deficits and is most commonly used in the process of the development of a behavioral program for children in the autism spectrum. Develop curriculum guides. •ABLLS-R: ABLLS-R stands for Assessment of Basic Language and Learning Skills - Revised. (http://www.partingtonbehavioranalysts.com/page/ablls-r25.html) •VB-MAPP: VB-MAPP stands for The Verbal Behavior Milestones Assessment and Ptlacement Program (http://www.marksundberg.com/vb-mapp.htm) 70
Verbal Behavior • It’s an object of behavior analysis, because of its importance in humans • VBs play a central role in such skills as social interaction, language and cognitive development, problem solving etc.
Features of language Skinner,1957 • Formal properties: language structure, including the topography of VB • Functional properties: these include the cause of a VB A full awareness of language presupposes both of these types of features
Θεωρίες της Γλώσσας • Cognitive approach: language is controlled by internal procedures of perceiving, classifying, encoding and decoding, and storing verbal information (Piaget, 1952;Bloom,1970) • Biological approach: language is hereditary and evident since birth. (Chomsky,1965)
Verbal behavior “Verbal behavior is whatever behavior is
reinforced through the mediation of another person” • A learned behavior • Maintained by the same environmental variables that maintain other non-verbal behaviors
Differences of approaches • Listener and speaker are clearly differentiated • Skinner puts the emphasis on the speaker’s behavior • He doesn’t uses terms like expressive or receptive language
Analysis of verbal behavior is conducted through verbal operants • We analyse verbal operants taking into account MOs, SD, C, whereas classical linguistics deal with words, phrases, sentences etc.
Classification of verbal behaviors Teach all meanings of a word chocolate
Mand Tact Echoic/mimic Intraverbals Receptive RFFC Textual Monorodi 2013, All rights reserved
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Verbal operants Stimulus
Verbal behavior
Result of communication (gain)
Desire or need
Request (mand)
Demand met
I’m thirsty
“Juice”
I’m given a juice
Visual stimulus
You name it (tact)
Social reinforcement
You’re given a picture and you’re asked “what is it?”
“a hen”
“Well done”
Verbal stimulus
Verbal imitation (echoic)
Reinforcement
Say “apple”
“apple”
“bingo!”
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Verbal operants Stimulus
Verbal behavior
Result of communication (gain)
Verbal stimulus
Verbal response (intraverbals)
Social reinforcement
“What’s your name?”
“My name’s Anna”
“My name’s Maria, do you want to play with me?”
Discriminative stimulus
Verbal response different from Social reinforcement the SD itself (Textual)
A text
He reads the text
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“Well done”
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Requests (manding) • How is your student communicating when he’s trying to make you understand what he wants? 1.Does he drag you by the hand? Is he pointing? Is he standing in front of the reinforcer? 2.Is he using one-word utterances? 3.Does he exchange pictures (PECS)? can he use signs? Or both? Monorodi 2013, All rights reserved
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Initial stage • Physical imitation Does he copy (imitate) your actions? 1.Clapping hands? 2.Shooting a ball? 3.Your model for jumping?
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Initial stage • Receptive skills Can he understand phrases? Can he follow commands? 1. Can he follow 5 single verbal commands pertaining to daily living actions? 2. Can he show 10 actions upon the educator’s request? (e.g. “show me ‘sleep’!”) 3. Can he identify 10 objects after their attributes (“show me round and red”) Monorodi 2013, All rights reserved
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Initial stage • Matching Is your student able to match items, pictures, sample shapes, that you give him? 1.Can he match 10 objects with corresponding pictures? 2.Can he match colors with sample drawings? 3.Can he put items on shelves by matching them with other items on the shelves? Monorodi 2013, All rights reserved
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Initial stage • Verbal imitation Does your student repeat after you sounds, words, or phrases you model? 1. Does he imitated vocalizations after the educator? 2. Does he imitate words after the educator? 3. Does he imitate phrases after the educator? Traditional SLT starts from this point!.. Monorodi 2013, All rights reserved
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Articulation deficits • When functional speech is too delayed, articulation cannot be a priority! • You may even never set articulation work as a goal, as other language goals may be a priority • Articulation work is ineffective if your student doesn’t look at you or never imitates • Articulation in such cases cannot improve global functioning or enhance development!
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Intermediate stage • Labeling Can your student name items or actions? 1.Labels 5-10 items when so instructed by the educator 2.Labels 30 actions when so instructed by the educator 3.Names surrounding people
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Advanced stage • Conversational skills (intraverbal precursors) Does your student answer questions, or does he complete phrases with missing words? 1. Does he continues a song when the educator stops? 2. Does he complete phrases like «1,2,3....» 3. Does he answer wh- questions?
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Advanced stage • Academic skills Is your student able to learn how to read, write, count? 1.Does he recognize letters? Or words? 2.Can he do any calculations? 3.Can he identify words he doesn’t understand in a text of 50 words?
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