Like many dog trainers, I use both verbal and gestural (hand) signals as cues with my dogs. With our students, we introduce both verbal and physical cues at the same time, but generally emphasize verbal signals because this is what most pet owners prefer to use with their dogs.
All of our classes include instructions for fading gestural cues in favor of verbal cues for owners who wish to use primarily verbal signals. Students are taught to “lead with the verbal cue and follow with the gesture“, thus establishing a classical relationship (verbal signal predicts gesture signal). This connection allows the trainer to gradually fade the hand signal and eventually to rely primarily on the verbal command.
On the other hand (literally), hand signals are a lot of fun to teach and come in handy in a wide variety of exercises. For these, we offer a dedicated “hand signals” class, for students who are interested in teaching their dog distance signals and hand cues for direction or jumping. This is great fun for dogs and their people and is also helpful for students who are interested in competing in dog sports.
However, like many dog training practices, the use of verbal versus hand signals with dogs has not been formally studied. Until recently, that is.
Enter Biagio D’Aniello and his team of scientists at the University of Naples (among others) in Italy. I have written about this group’s research on previous occasions. They work with retrievers who are trained for water rescue work and are reporting new information regarding the dog’s communication skills and ability to learn through observation (see “With a Little Help from My Friends” and “Doggie See, Doggie Do“).
This time around, the researchers asked whether dogs who are trained to respond equally to verbal and gestural cues show a preference for one type over the other.
The Study: A group of 25 certified water rescue dogs were enrolled. The group included 10 Golden Retrievers and 15 Labrador Retrievers, composed of 12 males and 13 females. Per training protocols for water rescue, all of the dogs had been trained to respond to both verbal and gestural cues. The dogs were tested in four behaviors; sit, down, stay and come. The study was conducted in three phases. Phase 1: The four basic commands were given using gestures only. Phase 2: Commands were delivered using a verbal cue only. Phase 3: (Here is where things get tricky). Both forms of a command were given, but incongruently (i.e. they conflicted with each other). For example, the verbal command for “sit” was paired with the gesture for “down”, the verbal command for “come” was paired with the gesture for “stay”, etc. The frequencies of correct responses were recorded in the first two phases, and a “preference index” that indicated the percent of correct gestural responses was calculated for the third phase.
- Just a sign, please: When gestures alone were used, all of the dogs responded correctly to all four commands, with the exception of a single error (one dog missed a “down” signal). In contrast, when verbal cues were used, the dogs made a total of 18 errors. The most common mistake was failing to lie down in response to the verbal command “down”. These results suggest that dogs who were trained using both verbal and hand signal cues (and when no attempt was made to emphasize one type of signal over the other), the dogs responded more consistently to gestures than to verbal cues.
- Location, location, location: While dogs showed an overall preference for gestures over verbal commands, this preference was not found when the verbal command to “come” was paired with the hand signal “stay” and the owner was located a distance away from the dog. In this case, the majority of dogs (56 %) responded to the verbal command. This difference suggests that although the dogs tended to pay more attention to hand signals than to verbal commands, this preference may be overridden by the preference to stay in close proximity to the owner.
- Girls may be more visual: An interesting result of this paper was the sex difference that was found. Female dogs showed a strong preference for responding to hand gesture cues, while males were more likely to respond equally to both types of cue. (Note: Although there is a bit of previous research suggesting that female dogs concentrate more on visual cues than do males, the small numbers in this trial coupled with the method of scoring lead the researchers to interpret this result with caution – in other words, this may be a “statistical hiccup”).
This pilot study suggests that when dogs are trained to both hand signals and verbal commands, they will respond most consistently to hand signals. The study also suggests that context is an important factor, in that having a preference to be close to the trainer may override a preference for gestural signals, leading a dog to choose the signal (verbal or gestural) that leads to proximity.
Take Away for Dog Folks
The finding that dogs (usually) respond better to hand signals than they do to verbal cues is probably not surprising to most trainers. This certainly supports our understanding of dogs as being highly responsive to body language and non-verbal cues. Still, it is always gratifying to find scientific data that supports one’s (previously unsupported) suppositions.
Do hand signals have enhanced saliency? However, is it possible that there is more to the differences found in this study than is explained by the dog’s proclivity for reading body language? This paper lead me to think more deeply about these two types of signals; specifically about the type of hand signals that we choose to use. The majority of hand signals that we use in dog training are far from being arbitrary signals. Rather they are structured in both form and function to direct the dog’s attention or body to part or all of the targeted behavior. For example, a commonly used hand signal for “down” is a sweeping motion from the dog’s “nose to his toes”. During training, this gesture easily doubles as both a lure when food is held in the hand and as a vehicle to deliver positive reinforcement when the hand delivers a food treat once the dog attains the down position. A reliable response to the hand signal alone is achieved by gradually removing the lure from the signaling hand and switching to +R from the opposite hand. We are then left with a hand signal that has, well, enhanced saliency for the dog, if you will. A second example is the use of body language and hand signals to inform a dog about the direction to run or jump in agility training. The physical signal itself has inherent meaning to the dog (we all get this). This signal is then enhanced by pairing it with food or an opportunity to tug. Contrast these gesture examples to the variety of verbal cues that we use with dogs (sit, down, come, etc). All of these, of course, are completely arbitrary from the dog’s point of view. We could just as easily use the word “down” to train a down command as the word “pumpkin” or “fluffy butt”. While we do enhance saliency by pairing these terms with reinforcers, they cannot be structured in the same way that gestures can to be naturally obvious (salient) to the dog.
So, in addition to dogs being highly attentive to body language (I think we all agree on that), it also seems that the hand signals that we select function to naturally attract our dog’s attention and direct behavior. The trainer “beefs up” this attraction by pairing the signal with positive reinforcement. Therefore, gestural cues may always have one step up over verbal cues when comparing the two (when the owner is in close proximity). Here is an idea – try training a sit using a down hand signal or teaching an agility dog to jump in the opposite direction from which you are pointing. In addition to this being a bit of a training challenge (more than a bit, I suspect), I would hypothesize that when arbitrary gestural signals are compared with verbal cues, we might see a leveling out of the preferences for gesture versus verbal signals. Just an idea……any researchers biting?
A role for individual preference and reinforcement history? I also pondered what the influence of an individual’s preference might be in this type of testing. All dogs tend to have certain exercises that they enjoy more than others. Some of these exercises may be inherently reinforcing for the dog while others may simply be preferred because they have a strong reinforcement history with the trainer (i.e. the exercise has been practiced and reinforced more frequently). In the case of this study, we might expect that dogs trained for water rescue work would be highly bonded to their owners and would also have a very strong reinforcement history for the “come” command. It would be interesting to explore verbal versus gesture preferences in dogs who are trained for different types of work, who may have different behavior preferences and reinforcement histories. Such a test would be analogous to the study that this same group did with dog’s looking back for help, in which they found some very interesting differences.
In practice: From a practical viewpoint, as a trainer, these results suggest to me that we should be doubly careful when fading hand signals in favor of verbal cues, especially when training a dog’s less preferred behaviors. While this research suggests that dogs are asking us to “just show me a sign”, it also seems that their responses will be influenced by a number of factors, including looking for the cue that tells them what they want to hear!
Cited Study: D’Aniello B, Scandurra A, Alterisio A, Valsecchi P, Prato-Previde E. The importance of gestural communication: A study of human-dog communication using incongruent information. Animal Cognition 2016; DOI: 10.1007/s10071-016-1010-5.