In honor of national Adopt-A-Dog and Adopt-a-Shelter-Dog month, we will look at an interesting study on drug-dog evidence and mock-juror decision making, examining whether jurors would credit the alert of a drug-sniffing dog as a *sufficient condition* for guilt in a trafficking case.  The researchers in this study tested how much credit mock jurors would give to the alert of a drug-sniffing dog in a drug-trafficking case where no drugs were ever discovered and the only evidence of their presence was testimony that a drug-sniffing dog had alerted on the defendant’s automobile.  Lisa Lit et al., *Perceived infallibility of detection dog
evidence: implications for juror decision-making* (2019), *available at*  For just a word on the legal backdrop of this kind of evidence, the United States Supreme Court has approved of the admissibility of drug-dog alerts—though admissibility of that evidence is not without qualification.  *Florida v. Harris* 568
U.S. 237 (2013).

The researchers provided the subjects with a summary of testimony showing that a drug-sniffing dog alerted on the defendant’s car, though no drugs were ever found.  The dog’s alert was used to gain a warrant for defendant’s house where police found only a large sum of
stashed money.  Subjects were asked, among a host of other questions, whether the defendant was guilty of drug trafficking, how confident they were in their verdict, and how confident they were that a drug-dog alert indicated the presence of drugs.  Lit, et al, *supra *at 194.

Though a majority of the mock-jurors issued a not guilty verdict, 33.5% of the 554 participants voted to convict the defendant for drug trafficking even though no drugs were ever found in the defendant’s car or house.  *Id.  *Furthermore, “Participants assigning a guilty verdict
were more likely to indicate high levels of confidence in their verdict (70% or higher) than those assigning a verdict of not guilty [statistics omitted].”  *Id. *at 197.  80% of all participants either agreed or strongly agreed that a drug-dog’s alert at a location where no drugs were found simply meant that drugs were present at some point, even though such alerts could result from dog or handler errors.  *Id. *at 195, 197.  If the reader has pondered the so-called “halo effect” before—the human tendency to like or dislike, credit or discredit a person based on who they are or
how they are perceived—it is likely you have never considered any powers a dog’s halo might have.

You may or may not know that the origin of the famous phrase “a dog is a man’s best friend” is traced back to a rather rousing closing argument offered up by George Vest in a small Missouri courtroom in 1870.  Vest’s soaring oratory on the plaintiff’s deceased dog is worth a trial
lawyer’s read. Though Vest says that dogs are faithful, unselfish, and noble, we humans appear willing to also credit them with honesty, accuracy, and forensic reliability.