Results
Human scent identification by police dogs

As shown in figure 5 , the average number of trials required to reach the criterion in the different phases of initial training increases significantly with the level of difficulty of the task the dog has to acquire (one-way ANOVA on the "Phase" factor (F (4; 26) = 10.18; P < 0.001). The specificity scores achieved at the end of phase 5 show that the dogs have fully acquired the principle of deferred matching learning with human odors. These data suggest (1) that the...