William Dube – Stimulus Overselectivity in DD: Analysis and Remediation

•    NICHD funded research

•    Overselectivity – 1970 – Lovaas first named it

o    Laura schriebman – work

o    Restrictive S control or overselective attention

o    Also a problem in learning for individuals with moderate to severe disabilities of all types

•    Basic research on overselectivity

o    Simple simultaneous discrimination -> S+ and S-

•    Same 3 correct and incorrect on every trial

o    Test trials – individual S presented

o    TD children – all three stimuli were S control

o    1 or 2 as disability is more severe

o    more complexity – more overselectivity

•    effects

o    social relationships

o    generalization

o    prompt dependency

o    language deficits – research literature in the auditory and visual domain

•    Some data from a SPED classroom

o    Child with moderate MR – ID functional sight words

o    Gave identity MTS task to see if he could discriminate

o    All S were presented equally – scored 90% correct

•    Lower when samples began with P – no discrimination

•    Stimulus control by the initial letter?

•    Basic research – delayed MTS with two samples

o    Pretest  for qualifications – must have high accuracy in a delayed MTS with 1 stimulus

•    Ss controls the amount of delay and display

o    Test for overselectivity – 2 stimuli – only one of  the two samples appear in the comparison array – can’t predict which stimuli will appear

•    Use arbitrary forms – 180

•    No way for the student to learn the stimulus compounds

o    Accuracy – if no sample stimulus controls – 33% -> if every sample controls – 100%

o    When samples appeared in the array – children would always be correct

•    Overselectivity – 50-83% accuracy

o    % of scores below 83% compared to PPVT – seems to be related to mental age – similar to Lovaas test with simple discrimination

•    costs Sr to be overselective

•    when compared to the ADOS – OS more prevalent, but not exclusively so

•    Studies of observing behavior – eye tracking with IDD

o    Problem of head immobilization

o    Apparatus with head-mounted imaging systems – headband allows for free head movement

•    Needs to be calibrated – may take some time

•    Shows point of gaze in real time on the data collectors’ computer

o    What is the observing behavior?

•    Frequency

•    Duration

•    Patterns

o    Frequency of observing – define a target area around the stimuli with some variation

•    Nonclinical subject – proportion of trials in which the Ss made observations

•    Most made three – left -> right - > left

•    Few cases where there is one

•    Kids with Intellectual disabilities – most of the kids looked like nonclinical Ss

•    Overselective – only looked at one of the two stimuli

•    When the comparison Ss did not appear in the array – chance level scores

o    Summary – OS is related to incomplete observing behavior

o    Interventions that produce adequate observing behavior produce high accuracy scores

•    Within stimulus prompts often works

•    Intervention – differential observing response – increases the probability of correct responding

o    From the animal literature

o    Different response to each stimulus that should be observed

o    Control observing behavior

o    Verify discrimination of all critical stimuli (e.g., naming or spelling aloud)

o    Identity matching procedure DOR

•    Teach a compound stimulus matching task

•    Verifies observing and discrimination

•    Embedded the task in the observing period

•    Samples presented – do the match – no reinforcement

•    Next touch – comparison array as in the baseline task

•    In JABA

•    Position of S not related

•    Can be overlapping  - all start with the same letter or non overlapping – all stimuli are different

o    Embed simple and complex discriminations

o    Dube 1999, 2007

o    Compound sample – symbol + printed word

•    Comparison stimuli – symbol only or printed word only

•    Constructed response MTS

o    Compound stimuli – Ss selects the “letters” or pieces of the stimuli from an array

o    Gradually elaborate the comparison array to include the left half of the keyboard

o    Compound stimuli – picture + written word

•    Increased accuracy in delayed MTS

•    Visual cues were needed to maintain accuracy

•    If contingencies require Differential observing responses then OS reduced or eliminated

o    When withdrawn – OS occurs again

o    Need flexible options for differential observing response for instructional programs

•    Suggestions

o    Test OS periodically – overlapping S elements in the choice pool

o    Use the compound matching strategy

•    Please get the red socks – red socks and blue socks and red shirt

o    Add DOR requirements as needed

•    Echo spoken cues

•    Naming and spelling aloud

•    Draw the sample, copy the text

•    Constructed response DORs

•    Identity matching – build in tasks within the training tasks