Why do you stop your car at a Red Light but go at a Green Light?

The light itself doesn't force your car to stop. It creates a "signal." You know that Green = Safe (Reinforcement) and Red = Crash (Punishment/No Reinforcement).

This is Discrimination Training. It is teaching a learner to tell the difference between two things (stimuli) so they know when reinforcement is available and when it is not.

Executive Summary

This video covers the foundational skill of Stimulus Control. We explore the two most important terms in ABA: SD (Discriminative Stimulus) and S-Delta (Stimulus Delta). We also break down how to teach these using "Matching to Sample" and "Errorless Learning" to prevent frustration.

⏱️ Video Timeline

00:00

SD vs. S-Delta
SD: Signals reinforcement is available (e.g., "Open" sign).
S-Delta: Signals reinforcement is NOT available (e.g., "Closed" sign).

03:12

Matching to Sample
A common DTT method. The learner must match a picture/item to a corresponding sample. This teaches "Same vs. Different."

05:23

Errorless Learning
Making the correct answer obvious (e.g., making it huge or closer) so the learner cannot fail. Then fading that prompt over time.

10:47

Real Life Examples
A dog coming to Owner's whistle (SD) but ignoring a Stranger's whistle (S-Delta).

🔑 Key Insights

Stimulus Control: When a behavior happens more often in the presence of an SD than it does in its absence.

Simple Discrimination: A vs. B (e.g., Red vs. Blue).

Conditional Discrimination: Context matters. (e.g., Identifying "Mom" in a picture requires knowing who Mom is, not just pointing to a woman).

Mastery: Usually 80-90% accuracy without prompts.

❓ Frequently Asked Questions

Q: What is the difference between a Prompt and an SD?

A: The SD is the natural instruction ("Touch Red"). The Prompt is the extra help you give (Pointing to Red).

Q: Why do we use Errorless Learning?

A: To prevent frustration. If a learner guesses wrong 10 times, they might quit. Errorless learning ensures they get high rates of reinforcement immediately.

1. SD vs. S-Delta (The Traffic Lights)

This is the most critical concept for "Discrimination."

Scenario

Behavior: Asking for a cookie.
SD: Mom is in the kitchen. (History of giving cookies).
S-Delta: Dad is in the kitchen. (History of saying "Go eat dinner").
The child learns to Discriminate between Mom (Ask) and Dad (Don't Ask).

2. Matching to Sample (MTS)

Identity Matching: Matching identical items. (Picture of Cat to Picture of Cat).

Symbolic Matching: Matching non-identical items. (Picture of Cat to the word "CAT").

📝 Knowledge Check

Can you tell the difference?

Q1: An S-Delta signals that...

Answer: Reinforcement is NOT available.
It is the "Closed" sign. The behavior will go unrewarded.

Q2: You hold up a Red card and say "Touch Red." The child touches the Red card. What is the Red card?

Answer: The SD (Discriminative Stimulus).
It is the stimulus that signals "If you touch this one, you get a reward."

▶

Acquisition Quiz

Mock Exam

Test your knowledge on SDs, S-Deltas, and Discrimination.

Start Practice Test

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