Habituation is one of those terms habitually (see I did it again) used in training and experimental protocols. Trouble is, it is so overused and underdefined that its significance has been frayed at the edges, and is used by most as a term that means having gotten used to something.

Whether you are training horses, dogs or rats, or working with these in laboratory or field experiments, the importance of habituation is underestimated in most cases.

Some proponents define habituation as a waning of response to repeated presentations of a single stimulus, while others would argue that it would only be so if the stimulus was not followed by a second reinforcing or punishing stimulus.

It is almost as if depending on your worldview and the justification you need for your methods or protocols, habituation per se would acquire a distinct definition in almost every case. Having said that most definitions are simplistic and vague in that they do not provide enough information for anyone to differentiate habituation from other phenomenon in which a waning of response is sought.

Habituation is a widespread occurrence, observed across phyla, from single cell organisms capable of behaviour, to mammals. The strikingly different neural and biochemical circuitry of the animals in which habituation has been described, underlie an elemental and nearly ubiquitous form of biological plasticity , primal for survival and reproductive success in the majority of behaving organisms.

This same ubiquitousness however has led many to synonymously use the term instead of others whose underlying common denominator is a waning of response to repeated stimulus presentations such like acclimatization, accomodation, negative adaptation, desensitization, sensory or motor fatigue, extinction, or even inhibition, to name a few.

Even great trainers, that use scientifically backed knowledge are liable for mistakes in this sense. Let us take the example of this passage from the book; “Don’t Shoot the Dog” (Pryor, 2008), wherein habituation is used synonymously with the term extinguish, as follows:

“Habituation is a way to eliminate unconditioned responses. If a subject is exposed to an aversive stimulus that it cannot escape or avoid, and which nothing it does has any effect on, eventually its avoidance responses will extinguish.” (Pryor, 2008: p.121)

Going back to the passage from “Don’t Shoot the Dog” provided above, a closer look at the explanation of how habituation was apparently attained by exposure to aversive stimuli without possibility of escape, can equally refer to animals in a state of learned helplessness (Pryor, 2002: p.67)as explained in the very same book.

Furthermore according to Seligman (1992: p. 9) learned helplessness is “(…) a psychological state that frequently results when events are uncontrollable.” That is to say that if nothing the animal does can help it escape or avoid the aversive stimuli it plunges into learned helplessness.

All this is discussed in more detail in the Thesis I presented for the fullfilment of my obligations toward the Ethology Institute, and you can read the full thesis free online by following this link: