Animal Behavior for Shelter Veterinarians and Staff. Группа авторов
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Animals are learning all the time, meaning that their behavior is constantly changing, even if just a little bit. Knowing how easily and often behavior can change raises the question: How do animals learn? Answers to that question can help us effectively teach new behaviors or address behaviors that can be problematic.
Learning can be broken up into two categories: associative and non‐associative learning. Just like in its name, associative learning takes place when two or more events become associated with or related to each other. Events that can be paired may be two environmental stimuli, such as the sound of a can opener with the smell of food, or a behavior and a consequence, such as pawing a food bowl and the addition of more food. On the flip side, non‐associative learning does not involve a relationship between two events. This type of learning takes place with repeated exposure to a stimulus that occurs unrelated to any other stimulus. Depending upon the salience and timing of the stimulus, this exposure might cause the animal to pay less or more attention, exhibiting habituation and sensitization, respectively.
3.2 Non‐associative Learning
Habituation is a type of non‐associative learning in which an animal stops or reduces its response to a stimulus after repeated exposure to that stimulus. Consider Brutus, a terrier who barks at the sound of a lawn mower buzzing outside. As soon as the lawn mower turns on, Brutus barks wildly at the new sound. However, after a few minutes of the lawn mower continuously buzzing, Brutus calms down. In this example, the lawn mower buzz is the stimulus that elicits the response of barking. The response eventually stops even though the stimulus is still present in the animal’s environment. Brutus habituates to the buzzing. Essentially, he gets used to it. Habituation to the sound occurred without any other stimulus present in Brutus’s environment. The process of habituation is used widely to reduce animals’ fear response to harmless stimuli.
Sensitization is the opposite of habituation in that repeated exposure to a stimulus increases an animal’s response to the stimulus. As a new dog owner, Ruth had no idea that dogs can be so deathly terrified of fireworks. She naively took her Lhasa apso, Scruffy, to see fireworks to celebrate the New Year. When the fireworks started, Scruffy started to nervously pace around and pant heavily. Even though Ruth tried to calm her down by petting her and holding her close, it was no use. As the fireworks continued, she became increasingly nervous. After just a few minutes, Scruffy somehow got out of her collar and ran away into the crowd (Ruth found Scruffy shortly after, of course). Ruth expected Scruffy to habituate to the sound, but instead, she became sensitized to it. The presence of other stimuli was not relevant to Scruffy learning to become more and more sensitized to the noise. Her response to the stimulus became more intense as the stimulus continued to be present in her environment.
3.3 Associative Learning
3.3.1 Respondent Conditioning
One way that associative learning takes place is when a stimulus gets paired with another stimulus, a process called classical or respondent conditioning. Pavlov famously demonstrated this process in the early 1900s. While researching the physiology of digestion in dogs, Pavlov observed that dogs salivated in the presence of food. This was no surprise because Pavlov knew that salivation was a reflex elicited by the presence of food. However, Pavlov was puzzled when he noticed that the dogs began to salivate in the presence of the technician who normally fed the dogs. Pavlov began an experiment based on his serendipitous findings to uncover the process that he informally observed. In his experiment, he presented the sound of a metronome (commonly misreported as having been a “bell”) right before giving the dogs food. By itself, the metronome did not elicit salivation. However, after several pairings of the metronome followed by food, the metronome became associated with food and elicited salivation by itself!
The process of classical conditioning can be easily understood if we divide it into three phases: before conditioning, during conditioning, and after conditioning. Before conditioning, a stimulus automatically elicits an unlearned behavior (i.e., produces an involuntary response). This is the unconditioned stimulus because it automatically triggers a response. For similar reasons, the response that is naturally triggered by the stimulus is the unconditioned response. The food in Pavlov’s experiment served as the unconditioned stimulus and the salivation as the unconditioned response. Initially, the metronome was a neutral stimulus because it did not produce a response (yet!).
During conditioning, the neutral stimulus and the unconditioned stimulus are repeatedly presented together. The most effective method by which classical conditioning takes place is when the neutral stimulus precedes the unconditioned stimulus. The association occurs less effectively if the neutral stimulus occurs after or during the unconditioned stimulus, or if there is a long period of time between their presentations. During this phase, the metronome and food were repeatedly paired. This is the phase in which associative learning takes place; the metronome and food become related and the animal learns to salivate in the presence of the metronome.
After conditioning, the neutral stimulus becomes a conditioned stimulus and can reliably elicit the response by itself. When a conditioned stimulus elicits the response, the response is called a conditioned response. The conditioned response and unconditioned response are the same response; the difference is in what stimulus caused the response to happen. The associative learning is demonstrated in this phase when the metronome can produce salivation by itself. The metronome is now a conditioned stimulus and salivation produced by the metronome is the conditioned response. This example is a common one, but it can be hard to translate processes discovered in a laboratory to the real world. Instead, let’s look at an example you may have witnessed yourself.
When a caregiver enters the kennel area to feed, from a dog’s perspective the person makes a lot of noise, and these sounds are distinct. An animal that is naive to the shelter environment might not notice these sounds. Thus, the sound of the first run door opening is a neutral stimulus: one that elicits no response and thus has no meaning. Food is the unconditioned stimulus. It requires no conditioning to elicit a response (in this case, salivation). The animal’s salivation is the unconditioned response, because if caregivers present the animal with food, it will salivate automatically (without training). After multiple pairings of the first door opening with the daily feeding, the once‐neutral stimulus (the sound of the door opening) is now the conditioned stimulus and causes a conditioned response (salivating at the sound of the run door opening). See another example in Box 3.1 and try to label the neutral stimulus, unconditioned stimulus, unconditioned response, conditioned response, and the conditioned stimulus yourself.
Box 3.1 Understanding Respondent Conditioning
Can you identify the neutral stimulus, unconditioned stimulus, and unconditioned response in this example?
Nail trimming is essential to the well‐being of animals, but it could be an unpleasant experience if the owner is inexperienced at trimming nails. During a dog’s first experience with nail trimming, the dog might react calmly as his owner approaches him with the nail clippers. However, if the nail is trimmed too short, the dog could wince in pain. From then on, just the sight of the nail clippers can cause the dog to wince.
Do you think you labeled them correctly? Here is the answer:
The nail clippers are the neutral stimulus because it had no meaning to the dog prior to the trim. The unconditioned stimulus is getting the nails clipped. The unconditioned response is the pain the animal felt when the nail was trimmed too short because there is no conditioning required to make an animal react to pain. After pairing the nail clippers with the pain (conditioning), the once‐neutral stimulus becomes the conditioned stimulus and causes a conditioned response (just seeing the nail clippers can cause the animal to wince).
3.3.2 Operant Conditioning
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