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System of Least Prompts

Chain Task

Instructional Objective:

When given the verbal direction “Open a can of (content)”, Ted will perform with

95% accuracy for 2 consecutive sessions over 2 consecutive days all the steps in the task

analysis, when reinforced on a VR-3 and respectively on a FR-22 schedule.

Task Sequence and Task Analysis:

The instructional framework will be a total task presentation, when the

interventionist will give Ted the opportunity to perform independently each step of the

task analysis. In order to break this activity into discrete behaviors, I performed the entire

task for myself and noted down the steps that I usually carry out in order to open a can.

The 22 steps of the task analysis are described on page 8.

Instructional Arrangement: 1:1.

Description of subject and prerequisite behaviors:

Ted is a 14 year-old male identified with mild intellectual disabilities and

impairment in fine motor coordination. Ted will be screened in order to assess

prerequisite behaviors. Ted should display the ability to (a) to recognize and respond to

stimuli used as discriminative stimuli during the intervention, (b) voluntary motor control

to perform the task, (c) to adequately perform the target skill, i.e. gross motor abilities to

stand, walk, grasp, pull, and turn his wrist, (d) to remain on task for up to 30 minutes

without interruption, and (e) to have an instructional history with a contingency

reinforcement system.

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Target Stimuli/Materials:

Two sets of materials will be used during the intervention, one for the student to

use, and one for the interventionist. The materials involved in performing the task will

vary, e.g. cans of different sizes, color, with various contents, different can openers,

different sinks, different trainers, different cabinets and drawers from different settings,

such as classroom, school home economics room, learner’s home, etc.

Probes: A number of at least 3 probe sessions will be conducted or until a stable trend

will be established. The teacher will deliver the task direction “Ted, open a can of

(content)” and wait 5 seconds for the student to initiate a response and 8 seconds for the

student to complete the response. If Ted does not perform the correct response, he will be

asked to turn around, and the teacher will perform the step for him. Then, Ted will be

asked to attend to the discriminative stimulus, i.e. the completed previous step, and he

will be given 5 seconds to initiate and 8 seconds to complete his response. Only correct

or incorrect responses will be recorded. Correct responses will result in delivery of the

reinforcer, and incorrect responses will be interrupted.

Procedure Description:

Procedure: A system of least prompts (SLP) will be used to teach Ted to open a can.

Prompt Hierarchy: The SLP procedure will use a 4 level hierarchy of prompts, arranged

from least intrusive to most intrusive amounts of assistance. The last level of prompt in

the hierarchy is a controlling prompt, one that ensures correct responses for each step of

the task analysis. The prompt hierarchy consists of the next levels of prompts:

(1) independent or no assistance;

(2) verbal directions;

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(3) model and verbal directions;

(4) full physical prompt and verbal directions.

Discriminative Stimuli: The discriminative stimulus for the first step in the task analysis

is the task direction delivered by the teacher/interventionist “Ted, open a can of

(content)”. For the remaining 21 steps of the task analysis, the completion of the previous

step will represent the discriminative stimulus for the next step in sequence. The target

stimulus will be present(ed) at each level in the prompt hierarchy.

Specific Active Attentional Cues: The teacher will use specific active attentional cues to

ensure that the student will attend to the critical features of the discriminative stimulus,

such as “Ted, what are you supposed to do?” for step 1, when Ted is required to verbally

respond “(I am supposed to) open a can of (content)”; “Ted, look in the drawer. Where

are you going to look?” for step 7, when Ted is required to verbally answer “(I am

looking for) the drawer”; “Ted, look for the trash can” for step 20, to which Ted is

required to answer “(I am looking for) the trash can”; or simply “Ted, what is next?”,

when Ted is required to verbally describe the next step in sequence.

Prompt Interval: After the presentation of the discriminative stimulus, the teacher will

wait 5 seconds for the student to initiate the target response.

Response Interval: Upon initiation of the correct target response, the teacher will wait 8

seconds for the student to complete his response on all steps of the task analysis, except

step 14, when the teacher will wait 30 seconds for the student to cut the lid of the can.

Possible Student Responses: (1) unprompted corrects, also known as correct

anticipations, are correct responses initiated by the student within 5 seconds, before the

trainer delivers the prompt at a certain level; (2) prompted corrects, also known as correct

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waits, are correct student responses given after the prompt has been delivered; (3)

unprompted incorrects, also known as nonwait errors, are incorrect student responses

exhibited before the prompt was presented, that is within 5 seconds from the presentation

of the target stimulus or completion of the previous step in the task analysis; (4)

prompted incorrects, also known as wait errors, are incorrect student responses performed

after the prompt has been presented; and (5) no response errors are recorded when the

student does not perform any response after the prompt has been presented. Unprompted

and prompted incorrect responses (errors) will be coded as topography (the shape of

student’s behavior is incorrect), duration (student’s response exceeds 8 or 30 seconds, as

previously established), or sequence (student initiates an out of sequence behavior, that

is, a step that does not follow the order of the task analysis steps) errors. Only correct

independent responses will count toward final criterion.

Reinforcer: All correct responses will result in descriptive verbal praise delivered at each

level of the prompt hierarchy on a continuous reinforcement schedule (CRF) until the

student performs independently 60% unprompted correct responses, and on a variable

ratio of every 3 correct responses schedule (VR-3) until the student performs 95%

independent correct responses for one session, after which he will be reinforced on a

fixed ratio of every 22 correct responses (FR-22). If Ted’s performance decreases after

one session of 95% correct responses when reinforced on a VR-3 schedule, the

interventionist will return to the VR-3 schedule of reinforcement until first part of final

criterion will be reached again. The back-up reinforcer will be delivered at the end of the

22 steps of the task analysis, namely the opportunity to consume the content of the

opened can.

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Incidental Information: Following each correct response, the teacher will include in the

consequences, i.e. s/he will add to the descriptive verbal praise, non-targeted information

related to the task, information that will remain consistent for each step of the task

analysis throughout the intervention. For example, after Ted will correctly touch can (step

2), the teacher will say “Good job, Ted. This is a can of (content). A can is made of

metal”; following a correct response on step 6, opening the drawer, the teacher will say

“Yes, this is the drawer under the counter. Drawers can also hold cooking and eating

utensils”, etc.

Error Correction: Unprompted incorrect responses will result in the teacher interrupting

the response, reminding the student that he has to wait if he does not know the correct

response, and delivering the next, more intrusive, level of prompt in the prompt

hierarchy. Prompted incorrect responses will result in the teacher interrupting student’s

response, saying “No”, and delivering the next level of the hierarchy. No responses will

result in the teacher delivering the next level of prompt. If no responses occur or the

student opposes resistance after the presentation of the controlling prompt, i.e. the final

level of prompt in the hierarchy as the most intrusive prompt, the teacher will avoid eye

contact with the student and will not attend to the student for 5 seconds.

Training sessions: The teacher will deliver the task direction and the specific active

attentional cue “Ted, open a can of (content). What are you supposed to do?”. Upon

student’s correct verbal response “(I am supposed to) open a can of (content)”, the

teacher will wait 5 seconds for the student to initiate the first step in the task analysis, i.e.

open the cabinet door. If the student will initiate the target response within 5 seconds, the

teacher will wait 8 seconds for Ted to complete his response and record an unprompted

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correct response if he does open the cabinet door within 8 seconds from initiation and

deliver the reinforcer and incidental information, or an unprompted incorrect if Ted does

not complete the correct behavior within 8 seconds. If Ted does not independently initiate

the correct response within 5 seconds, the teacher will deliver the next more intrusive

prompt in the hierarchy, i.e. the verbal description of the step, the task direction, and will

wait 5 seconds for the student to initiate a correct response. If Ted will initiate the correct

response within 5 seconds and complete it within 8 seconds, the teacher will record a

prompted correct response and will deliver descriptive verbal praise and incidental

information for that step. If Ted will initiate an incorrect response, the teacher will

interrupt his response, deliver the next prompt in the hierarchy and the task direction.

Also, if Ted does not initiate any response within 5 seconds, the teacher will deliver the

the next prompt in the hierarchy, that is, the teacher will model the correct response on

his set of materials while describing the step “Ted, watch me. You are supposed to open

the cabinet door”, followed by the delivery of the task direction. If the student will

initiate the correct response within 5 seconds after the prompt and complete it within 8

seconds from initiation, a prompted correct response will be recorded at level 3 of the

prompt hierarchy. If the student does not initiate a response within 5 seconds from the

presentation of the task direction, complete the correct response within 8 seconds from

initiation, or initiates an incorrect response, the teacher will interrupt the incorrect

response, deliver the task direction again, and the next prompt level in the hierarchy, i.e.

full physical prompt. The teacher will perform the task with the student, hand-over-hand,

and record a prompted correct response for the 4th level of the prompt hierarchy. If Ted

will oppose resistance, a no response will be recorded and the teacher will avoid eye gaze

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and will not attend to the student for 5 seconds. Then, the teacher will perform the step

for the student, on Ted’s set of materials, and wait 5 seconds for Ted to independently

initiate the correct response for the next step in the task analysis. Instruction on each step

will continue in this manner, the teacher delivering descriptive verbal praise and

incidental information for each correct response or interrupting the incorrect response and

delivering the next level of the prompt hierarchy until Ted will complete all steps in the

task analysis. Only independent unprompted correct responses will count toward final

criterion.

Data Collection Methods:

An event recording data collection sheet will be used to record information about

the student and procedural data; the five types of student responses will be recorded by

putting a mark in the appropriate column and row (in the errors column a T will be

recorded for a topographical error, a D for a duration error, a S for a sequence error, or a

O for other behavior); and a summary section with a total number and percent of each

type of response.

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Task Analysis for Opening a Can:

1) Open cabinet door. 2) Touch can. 3) Pick up can. 4) Close cabinet door. 5) Place can on the counter. 6) Open drawer (under the counter). 7) Touch can opener. 8) Pick up can opener. 9) Close drawer. 10) Place can opener on the counter. 11) Detract (open) can opener handles. 12) Place the cutting top (blade) of can opener on the edge of can so that the blade

touches the lid of the can. 13) With left hand, squeeze the can opener handles on the edge of the can until the

blade of can opener penetrates the lid of can (the blade gets into the can). 14) With right hand, turn forward the rotating key of the can opener while continuing

to squeeze its two handles with left hand. Continue turning the can opener key until the lid is cut off completely.

15) Switch can opener to right hand. 16) Position the narrow top (the hook) of can opener on the lid of can. 17) Press the hook against the edge of the lid until part of lid enters the can and the

other part rises on the opposite side. 18) With left hand, grab the lid from the raised edge. 19) Take lid off can. 20) Place lid into trashcan. 21) Place can opener in sink. 22) Stop.