Poisoned Cues in Animal Training: What They Are and Why They Matter

By Abigail Greenwalt, R+ Trainer & Animal Science Educator

🌟 What Is a Poisoned Cue?

A poisoned cue is a signal that has been associated with both reinforcement and aversive consequences. While a cue should signify a chance to earn reinforcement, a poisoned cue leaves the learner unsureβ€”"Is this going to be good, or bad?"

Coined by Karen Pryor, a poisoned cue is a discriminative stimulus (SD) that predicts mixed outcomes. The result? Stress, hesitation, and degraded performance.

β€œA poisoned cue is one that has been used with both reinforcement and punishment, making the animal unsure of what’s coming next.” β€” Karen Pryor, 2002

🧠 The Research Behind Poisoned Cues

1. Murrey (2007) Thesis

A poodle trained with both R+ and leash corrections became avoidant. The cue, associated with punishment, failed to function as a reinforcer.

2. Ven vs. Punir Study (Rosales-Ruiz)

"Ven" (R+ only) led to fluent chains. "Punir" (with punishment) caused freezing.

3. Hearst & Sidman (1961)

In rats, a cue predicting both reward and shock became aversive.

4. Wassum et al. (2019)

Humans and animals respond emotionally to cues with uncertain outcomes.

🦀 Real-Life Horse Examples

Poisoned cues are common in crossover horses. Here are a few:

  • β€œCluck” or β€œKiss” β†’ Previously sometimes paired with whips or spurs.

  • Lead Rope Pressure β†’ Taught through Rβˆ’, now met with bracing.

  • Backing Up β†’ Previously involved correction; now causes anxiety.

  • Grooming/Touch β†’ History of forced desensitization.

  • Mounting Block β†’ Horse associates mounting with tension.

  • Voice Cues β†’ Linked with shouting or punishment.

Even environments can become poisoned: arenas, saddles, halters.

πŸ“ˆ What Are the Effects?

Signs of poisoned cues:

  • Inconsistent performance

  • Freezing before/after the cue

  • Avoidance or distractibility

  • Emotional shutdown or hyperactivity

βš–οΈ How to Fix a Poisoned Cue

βœ… Best Fix:

  • Replace the cue completely

  • Use only R+ to teach new behaviors

πŸ”§ Repairing a Cue:

  1. Isolate the cue

  2. Remove aversive associations

  3. Rebuild with R+ only

  4. Focus on emotional safety

Resources:

πŸŽ“ Learn More in the Greenwalt Equine Membership

I’m building a full Poisoned Cues course inside my membership. It includes:

  • Understanding poisoned cues

  • Identifying poisoned cues

  • Preventing poisoned cues

  • Cue repair strategies

πŸ”” Click here to join the waitlist and get notified when it’s live!



Poisoned cue repair:
https://tagteachblog.com/the-poisoned-cue-and-you/
https://clickertraining.com/poisoned-cues-the-case-of-the-stubborn-dog/ 

https://eileenanddogs.com/blog/2019/10/28/replace-retrain-poisoned-cue/
https://stalecheerios.com/training-concepts/thoughts-poisoned-cues/
https://behaviorexplorer.com/summer25/

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