A new analysis suggests that, simply looking at the shape of the heads of various dog breeds, one can determine its intelligence and trainability.  The branch of science called “Physiognomy” is the estimation of the intelligence and personality of people by the shape of their heads and faces.  When referring to someone as “highbrow” or “lowbrow”, we’re not only talking about their cultural tastes and intellect we’re also inferring on measures published in books on physiognomy in the 19^th century.  Physiognomy ultimately fell out of favor because of parallels drawn between the shape of the head and face of people and those of various animals.  The thinking was that if an individual had the head shape and face similar to that of a particular animal, then he also must have the personality and intelligence of that animal.
In a study conducted at the University of Canterbury in New Zealand, research was done to see if intelligence and trainability were related to the shape of a dog’s head.  There is a wide variety in head shapes among the various breeds of dogs.  There are the “dolichocephalic” or long-headed dogs such as Greyhounds or Borzois, the “brachycephalic” which include wide-skulled dogs such as the Mastiff and Staffordshire bull terrier and the “mesocephalic” or “mesaticephalic” as in the Labrador retriever or Australian Cattle Dog.  In classifying a dog, the “Cephalic Index” is computed by measuring the width of the skull then dividing that by the skull length then multiplying the result by 100.
The rationale for the study is that brachycephalic dogs are specialized for fighting and guarding and dolichocephalic dogs are specialized for running but the mesocephalic dogs are not really specialized therefore might be associated more with cognitive flexibility resulting in more trainable and intelligent dogs.
Believing this reasoning a bit thin, research was conducted involving a number of dog obedience judges in the U. S. and Canada who were called upon to assess the dog’s performance in various learned activities.  Lower levels of competition asked the dogs to sit, lie down, come when called, etc.  Higher levels asked dogs to respond to signals, go over jumps, retrieve objects, and find items based on scent.  The judges used a long questionnaire to rank the dogs they had observed in competition.  The results showed that there are predictable differences of intelligence and trainability of various breeds of dogs.  Mesocephalic dogs ranked higher in intelligence than either the dolichocephalic or brachycephalic dogs with exceptions.
We must be careful in interpreting these results as the cephalic index is a continuous measure which moves gradually from brachycephalic to dolichocephalic.  But regardless of this fact, it’s interesting to think that by simply looking at the shape of the head of various breeds of dogs, we can make a rough guess as to which ones will be easiest to train and learn the best.