Operant learning is all about consequences. Most trainers and behaviorists are well-versed in the uses of pleasant and aversive stimuli as dog training consequences. These can be constructed into a 2 x 2 matrix that includes the type of stimulus (desirable/pleasant or aversive/unpleasant) as one factor and the intended behavioral change (increase or decrease response frequency) as the second factor (1).
Learning occurs when one of these four consequences lead to a change in the dog’s behavior:
Positive reinforcement (+R): Delivery (acquisition) of a desirable stimulus (food treat, praise, petting, play) results in an increase in the response. Example: Dog increases “sit” response to acquire petting and a food treat.
- Negative Reinforcement (-R): Disappearance (avoidance) of an aversive stimulus (head collar pressure, collar jerk, harsh voice) results in an increase in the response that allows the dog to avoid the unpleasant stimulus. Example: Dog increases “sit” response to avoid pressure applied to head collar or collar jerk (or to avoid a horrible “ehhhh” sound emanating from the trainer. How do people produce that sound, anyway?)
- Positive Punishment (+P): Delivery of an aversive stimulus results in a decrease in response. Example: Dog decreases standing/lying down/moving away from a sit position to avoid pressure applied to head collar or collar jerk (or the horrible “ehhhh” sound).
- Negative Punishment (-P): Removal of a desirable stimulus results in a decrease in the response. Example: Dog decreases standing/lying down to avoid losing access to food treats, petting praise attained whilst sitting quietly.
The Hypothesis: There is a general (but certainly not universal) consensus among trainers and behaviorists that training methods that emphasize positive reinforcement are more effective and more humane than those that emphasize the use of aversive stimuli. To date, there is some evidence in the scientific literature that supports +R methods as more effective than -R (see Yogi Bear Dogs ). And now, there is a study that examines the effects of these two different training approaches upon dogs’ levels of stress and their relationships with their owners (2).
The Study: Stephanie Deldalle and Florence Gaunet of the University of Paris-Nord and the Laboratoire de Psychologie Cognitive conducted an exploratory study that observed two dog training schools and their students during a series of advanced training classes. One school used primarily +R methods in the form of food treats, praise and petting to increase desired behaviors in the dogs. The second school used primarily -R methods in the form of collar corrections (pressure/jerks) and physical manipulation (pushing the dog into a sit). Neither the schools’ instructors nor their students were aware of the study’s objectives or that their school had been selected because of the type of methods that were used.
Methods: A group of 24 owner-dog pairs training at the +R school (hereafter +RS) and a group of 26 owner-dog pairs at the -R school (hereafter -RS) were studied. The dogs represented a variety of breeds and ranged in age from 8 months to 7 years. One researcher attended two sessions of a one-hour advanced class at each school and collected data for 50 minutes during each visit. Data collected included the owner’s behavior and the dog’s response and body postures when walking on a loose lead and when responding to the “sit” command. Within each session the frequencies of +R and -R stimuli used by the observed owners were also recorded. Owners were asked to complete a questionnaire at the end of the session.
Results: No differences in owner demographics or dog characteristics were found between the +RS and the -RS groups. Training results were classified by activity:
- Response to sit command: Dogs trained using primarily -R showed significantly more mouth licking (38 % vs. 8 % of dogs), yawning (12 % vs. 0 % of dogs), and lowered body posture (46 % vs. 8 %) when compared with dogs trained with +R, behaviors that are all associated with stress. Altogether, 65 percent of dogs in the -RS group demonstrated at least one stress-related behavior, compared with only 8 percent of dogs in the +RS group. Conversely, significantly more dogs in the +RS group offered spontaneous gaze to their owners during the sit command when compared with dogs from the -RS group (88 % vs. 33 %), a behavior that is interpreted as an invitation to visually interact and a positive relationship.
- Walking on a loose lead: Although not statistically significant, more dogs in the -RS demonstrated a lowered body posture while walking when compared with dogs enrolled in the +RS (15 % vs. 4 %). However, reduced body posture while walking was relatively uncommon in both schools. Similar to their response during the sit command, significantly more dogs in the +RS group offered spontaneous gaze to their owner during heeling compared with dogs in the -RS group (63 % vs. 4 %).
Take away for dog folks: It is important to note this was a preliminary and exploratory study that compared students who were training their dogs at one of two possible schools. This methodology can allow comparison of the behavior of dogs trained using two sets of training instructions (which is exactly what the researchers did), but cannot be used to make general conclusions about training schools that use different methods because only one school of each type was studied. Although this may seem to be a minor point, it is an important one that cautions us to take care when interpreting the results of this study. (For a refresher on the need to study groups rather than single entities, see The Steve Series of this blog). The results of this study suggest that:
- The emphasis upon negative reinforcement when training dogs to perform basic manners exercises (sit, walk on lead) can cause stress, demonstrated as reduced body posture, tongue flicks, yawning, and avoiding eye contact.
- Conversely, the emphasis upon positive reinforcement may improve a dog’s confidence and relationship with her owner, as evidenced by offering voluntary eye contact (and by the absence of stress-related behaviors).
- Perhaps most importantly (and unique to this study design): All of the dogs in this study had been in training for at least several months and were enrolled in an advanced class. Those dogs who were trained using -R were most likely to respond with stress to the owner’s verbal command “sit”. The researchers suggested that the training itself and its attendant commands/cues had become a conditioned aversive stimulus for these dogs. In other words, there were consequences to the type of consequences that were used during training.
- Canine and Feline Behavior and Training: A Complete Guide to Understanding Our Two Best Friends, LP Case, page 89, Cengage, 2010.
- Deldalle S, Gaunet F. Effects of two training methods on stress-related behaviors of the dog (Canis familiaris) and on the dog-owner relationship. Journal of Veterinary Behavior: Clinical Applications and Research2014; In press. Abstract