Modeling Verbal Behavior Deficits with the Stimulus Control Ratio Equation, SCoRE

The verbal behavior stimulus control ratio equation, or SCoRE, measures a participant's present level of functional language, and specifically analyzes stimulus over selectivity. SCoRE quantifies the functional verbal repertoire with a single numeric value and prescribes an individualized intervention plan. Children with autism spectrum disorder are susceptible to disproportionate stimulus control over their verbal behavior.

SCoRE analyzes the extent of this disproportionality, and may be used to evaluate other stimulus control discrepancies as well, such as equivalence formations and listener responding. Demonstrating the procedure will be Mariana de los Santos, a board-certified assisted behavior analyst from our laboratory. Begin by arranging tact, mand, echoic, and sequelic experimental conditions to establish functional relations between specific environmental variables and the behavior of the speaker.

Then, escort the participant into the experimental room, and show them to the tact condition area. To assess the tact relation, have the participant engage with toys that are common among young children. At 30-second intervals, point at the item with which the child is currently engaged, and ask them to name the object.

Tally the total number of items labeled by the participant, and consequate with generalized reinforcement. Then, remove access to that particular item, and encourage the participant to engage with another stimulus. Repeat the procedure a total of 10 times to evoke up to 10 different labels from the participant.

Next, to assess the mand relation, select any two of the 10 target items identified in the tact condition, and ask the participant to pick one. Allow the participant to play with the selected item for 30 seconds, then remove the item by placing it out of sight, and prompt for a mand. Score whether or not the participant says the name of the stimulus, and reinforce with access to the preferred item.

Next, to assess the echoic relation, provide an echoic stimulus at 30-second intervals, such as the common name of the item for one of the targets identified in the prior condition. Score whether or not the participant echoes the target response, and consequate with generalized reinforcement. To assess the sequelic relation, provide a fill-in-the-blank stimulus at 30-second intervals for one of the previously identified response targets.

Note:the fill-in-the-blank frame should be specific to how the child played with the item during the tact condition. Then, score whether or not the participant replies with the target response, and consequate with generalized reinforcement. Finally, repeat all four conditions twice more, each time arranging for 10 new response targets, to assess a total of 30 novel responses within each of the four conditions at the end of the verbal operant analysis.

Begin by calculating the strength for all bivergent and trivergent sources of multiple control by summing the percentages for each individual operant. Starting with the sum of all four verbal operants, rank order the level of stimulus control from greatest to least. Once the operant strength has been rank ordered across singular and multiple sources of control, extract the fading steps that pertain to each verbal operant while preserving the response strength hierarchy.

Next, condition relational flexibility with referent-based instruction by converging mand, tact, echoic, and sequelic relata, and be careful not to omit any steps of prompt fading. To do this, first show the ball to the participant, but do not give it to them. Tell the participant:You roll the ball, you roll the?

After the participant says:Ball. Reinforce correct responding with access to the ball and verbal praise. Good job!

When responding is stable, fade the prompt level even further. For example, while engaged with a ball, restrict access to the ball while showing it to the participant. Provide target response:say ball.

Say ball.Ball. Ball, very good, ooh. After the participant says ball, reinforce correct responding with access to the ball and verbal praise.

Next, hide the ball and tell the participant:You roll the ball, you roll the? When responding is stable, hide the ball and tell the participant:Say ball.Ball.Yay! Next, restrict access to the ball, and while showing to him, say:You roll the?

Reinforce responding with access to the ball and verbal praise. Fade prompting by restricting access to the ball and showing it to the participant without saying anything. Deliver the reinforcer, along with praise, when he mands access to it.

Once responding is stable, hide the ball, and then say:you roll the. Wait for the participant to ask for the ball. Finally, engage with the ball, then hide the ball.

Reinforce correct responding with access to the ball. These results show that echoics were found to have the greatest strength, and were emitted for half of all trials. Tacts show the next greatest strength, with responses for 1/3 of all trials.

Mands were emitted for 1/6 of all trials, while only one sequelic response was recorded. Further, after 13 weeks of referent-based instruction, a pre-test was compared to a post-test VOA. There was greater proportionality across each of the four operants.

The most important thing to remember when attempting these procedures is to isolate the control relations across mands, echoics, tacts, and sequelics. These procedures are also appropriate for individuals whose verbal behavior is selection-based, and may lead to developing more complex forms of augmentative and alternative communication. For children with a more advanced verbal repertoire, the derivational stimulus control ratio equation, or SCoRE-D, may be used to assess proportionality among reflexive, symmetrical, and transitive relations.

Participants with a defective mand repertoire often engage in challenging behavior. Care should be taken to place such behavior on extenture throughout the SCoRE assessment.