Why Kong, balls, and food fail as first detection odors

Why Kong, balls, and food fail as first detection odors

Why starting detection training with Kong, tennis balls, or food creates more problems than solutions

Introduction (Link to NL version) 

Detection dog training has always balanced between tradition and science. Many trainers still rely on methods that “look good” or seem practical, such as starting with a Kong toy, a tennis ball, or food as the first target odor. These items are introduced because dogs love them, and trainers believe that pairing them later with operational odors, explosives, narcotics, wildlife, or electronics, will create a smooth transition. At first glance, this seems logical: the dog learns to search, the handler sees quick results, and motivation appears high. But when we dig deeper into the science, especially chemistry and learning theory, we see the cracks. These improvised methods rest on unstable foundations. They ignore one of the most crucial variables in odor detection: vapor pressure. Without understanding vapor pressure, trainers cannot control the difficulty of searches, the clarity of the odor, or the progression from training to operational environments.

This article will critically analyze the weaknesses of Kong, tennis ball, and food-based pairing methods. It will also explain the science of vapor pressure, using examples from explosives and narcotics to show why some odors are “loud” and others are “silent.” Finally, it will argue why standardized tools like NOTA are essential for professional detection work.

The illusion of success with Kong or tennis balls

Kong toys and tennis balls are popular in detection training because they are strong motivators. New rubber or felt releases powerful odors. When placed in a search area, dogs quickly locate them, and handlers reward with play. The session looks successful: the dog is eager, the search is fast, and the reinforcement is clear. But this success is deceptive.
  • Complex odor profile: Kong rubber is not one odor; it is a mixture of volatile organic compounds (VOCs), including sulfur residues, oils, and additives. Tennis balls add felt, glues, and synthetic materials to the mix.
  • Inconsistency: Old Kongs smell different than new ones. Different brands of tennis balls emit different chemicals. Surface area and temperature further change odor load.
  • Excessive strength: These odors are “loud,” flooding the air. Dogs learn to chase strong odor clouds instead of developing the skill to pinpoint faint, precise target odors.
What looks like training is often just the dog chasing the easiest scent in the room.

The problem with pairing

Pairing is one of the most common techniques in detection training. Trainers introduce a strong odor source (Kong, tennis ball, or food) together with the target odor (e.g., cocaine, TNT, wildlife scat). Over time, they remove the strong odor, leaving only the target. This sounds effective in theory, but in practice, pairing has major flaws:

1. Overshadowing

When two stimuli are presented together, the stronger one dominates. In our case, Kong odor (loud) overshadows cocaine odor (soft). The dog’s brain encodes Kong, not cocaine. Trainers think the dog learned the target odor, but in reality, the association is incomplete. The dog may never truly learn the operational odor, it just keeps looking for the strong one.

2. Contextual learning

If the dog always experiences narcotics in the presence of Kong, the odor is tied to that context. In the real world, when cocaine is hidden without Kong, the dog’s certainty drops. What was learned in training does not generalize to operations.

3. Vapor pressure mismatch

This is the most overlooked issue. Kong odor is uncontrolled and strong. Cocaine has a very low vapor pressure at room temperature. TNT (trinitrotoluene), an explosive, also has a low vapor pressure. When dogs are shifted from Kong (loud) to TNT or cocaine (silent), the gap is massive. Dogs appear unmotivated, but in truth, the chemistry makes detection far more difficult.

4. Pairing creates dogs that succeed in training rooms but fail in the field.

At first, pairing looks like an easy shortcut. You let the dog search for something it loves, like a Kong, tennis ball, or food, and then you introduce the real target odor alongside it. The idea is that the association transfers: the dog learns “Kong = fun, Kong + odor = fun, odor = fun.” The problem is that in the operational environment, things look very different:
In training, the odor always appeared with a Kong or food reward. Out in the field, those cues are gone. The dog’s certainty drops because the picture it learned doesn’t match reality. This is why many dogs trained with pairing shine in training rooms but stumble in real operations. The environment cannot be mimicked perfectly, and the dog’s foundation is built on the wrong associations.
Bottom line: Pairing creates unreliable detection dogs. If we want dogs that succeed in the real world, not just in training, we need to condition them directly on the true target odors, at controlled concentrations, without the interference of Kong, balls, or food.

Food searching and the dopamine box

Food is another improvised solution. Trainers hide food in the environment or use techniques like the dopamine box or odor pays. In these setups, the dog learns to place its head in a box, where the trainer delivers food. Later, odor is added to the box. Again, this looks effective, but science reveals problems:
  • Context dependency: The dog learns “odor in box = food,” not “odor in environment = find source.” The association is tied to the apparatus.
  • Overshadowing: Food odor and the act of receiving food overshadow the target odor. The dog may simply be repeating a trained behavior.
  • Lack of control: Trainers cannot calibrate odor intensity. Food is strong, narcotics and explosives are weak. The mismatch is baked into the method.
Ultimately, these methods produce behaviors tied to specific setups, not transferable operational skills.

The scientific gap

Why do so many trainers cling to these methods? Tradition, intuition, lack of skills and short-term success. They see enthusiastic dogs and believe the method works. What is missing is a foundation in chemistry and behavioral science.
Key scientific flaws:
  • Dogs detect the wrong odor (Kong, food) instead of the target.
  • Overshadowing blocks the independent learning of weak odors.
  • Contextual learning prevents generalization.
  • Vapor pressure mismatches create unrealistic expectations.
The result: dogs that perform in training but falter in real deployments.

Vapor pressure explained

Vapor pressure is the pressure exerted by molecules of a substance as they escape into the air. High vapor pressure means more molecules in the air, an odor that is “loud.” Low vapor pressure means fewer molecules, an odor that is “silent.”

Examples:
  • Cocaine: Very low volatility, faint odor.
  • Heroin: Even lower than cocaine, practically odorless under some conditions.
  • TNT: Also very low volatility.
  • RDX (explosive): Even lower vapor pressure, challenging to detect without stabilizers or taggants.
  • Ammonium nitrate: Low volatility, but hygroscopic, odor can change with humidity.
Contrast this with a Kong toy: it constantly releases VOCs at uncontrolled, much higher vapor pressures. The difference is not a small step; it is a chasm. Trainers who ignore vapor pressure are essentially training dogs in a fantasy environment, not the chemical reality they will face operationally. 

Influence of temperature

The environment in which the odor exists shapes how the dog experiences it, and two environmental factors are especially powerful: temperature and humidity.
Imagine working with an explosive such as TNT. At room temperature its vapor pressure is already extremely low, meaning only a tiny number of molecules escape into the air. Now place the same sample outside on a hot summer day. The molecules move faster, more of them escape, and the vapor pressure rises.
Schedule from Wikipedia 

To the dog, the odor suddenly seems louder. Finding TNT in the heat is far easier than on a cold winter morning, when the molecules slow down, fewer escape, and the odor becomes almost silent. Trainers who have only worked in a climate-controlled room may be shocked when their dogs suddenly struggle in a real deployment simply because the environment is cooler. See this short YouTube video about vapor pressure 

Narcotics follow the same pattern. Cocaine has a low vapor pressure at room temperature, making it faint even under good conditions. Raise the temperature and the odor becomes more available. Lower the temperature and the odor nearly disappears. Heroin is even more challenging, sometimes almost odorless at ambient conditions. A handler may mistake the dog’s hesitation for a lack of motivation, when in reality the chemistry has shifted against the dog.

Influence of humidity

Humidity adds another layer of complexity. It does not change the vapor pressure of the substance itself, that remains constant at a given temperature, but it changes how odor molecules behave once they leave the material. In humid air, water molecules can bind to or trap odor molecules, slowing their spread. Some substances even change physically in high humidity. Ammonium nitrate, used in improvised explosives, is hygroscopic; it absorbs water from the air. As it does so, the release of odor molecules drops, and the profile that reaches the dog may be different. In dry air, the opposite can happen: molecules may escape more easily, making the odor slightly stronger.

These shifts explain why a dog that works perfectly in training can stumble in operations. A narcotics dog conditioned in an indoor facility may find cocaine consistently when the temperature is stable. Move that dog to a cold airport cargo bay in winter, and the vapor pressure of the cocaine is much lower. The odor is faint, and the dog struggles. An explosives dog that easily detects ammonium nitrate in a dry desert environment may face difficulties when deployed to a humid coastal region, because the odor is absorbed and released differently.

Detection is also about the environment

For trainers, the lesson is clear: detection is not only about the odor source but about the environment in which it is encountered. Dogs must experience their target odors across a wide range of conditions. Heat, cold, wet air, dry air, each changes the availability and behavior of odor molecules. A dog trained only in one environment is not truly prepared for the real world.


Why NOTA is the professional alternative

Professional training requires acknowledging these scientific realities. This is where controlled tools, like NOTA, make the difference. With known vapor pressures and adjustable concentrations, trainers can design stepwise progressions that prepare dogs for the extremes of operational environments. By combining scientific odor control with varied environmental exposure, handlers can develop dogs that are not only enthusiastic in training but reliable in the field, no matter the weather. Professional detection requires controlled variables. This is where NOTA (Novel Odor Training Aid) enters the picture:
  • Defined target odors: NOTA uses pure, stable compounds relevant to explosives, narcotics, wildlife, and electronics.
  • Vapor pressure control: By diluting to precise concentrations (100% to 0.0001), trainers can set odor strength step by step.
  • Reproducibility: Every session can be calibrated, allowing training across dogs, units, and organizations to be consistent.
  • Direct conditioning: Dogs learn the true target odor, not a paired or overshadowing stimulus.
  • Calibration: NOTA doubles as a measurement tool, ensuring training progress can be tracked scientifically.
  • NOTA moves training from improvisation to science, from illusions of success to real-world readiness.

Conclusion

The widespread use of Kong toys, tennis balls, food searches, and dopamine box methods shows how tradition often overshadows science in detection training. These methods create dogs that succeed in controlled environments but are unreliable in the field. The reasons are clear: overshadowing, contextual dependence, and most critically failure to account for vapor pressure.
Explosives like TNT and RDX, narcotics like cocaine and heroin, wildlife samples, and electronic compounds have extremely low vapor pressures. They are faint, subtle odors. Training dogs with strong, uncontrolled, or irrelevant odors does not prepare them for this reality. Instead, it creates fragile training foundations.
To move forward, trainers must embrace the science. Vapor pressure must be treated as a variable to be controlled, not ignored. Improvised methods must give way to standardized, calibrated training aids. Only then can detection dogs meet the reliability and precision required in real operations.

NOTA provides that path

It empowers trainers to control odor strength, ensure reproducibility, and train dogs on the actual chemical realities they will encounter. For detection dogs in narcotics, explosives, wildlife, or electronics, this is not just an improvement, it is the professional standard.