Experiment 3 data.

Working Dogs have shown an extraordinary ability to utilize olfaction for victim recovery efforts. Although instrumental analysis has chemically characterized odor volatiles from various human biospecimens, it remains unclear what perceptually constitutes human scent (HS) for dogs. This may be in part due to the lack of methodology and equipment to train and evaluate HS perception. The aims of this research were 1) to develop an automated human scent olfactometer (AHSO) to present HS to dogs in a controlled setting and 2) use the AHSO to evaluate dogs’ response to different scented articles and individual components of HS. A human volunteer was placed in a clear acrylic chamber and using a vacuum pump and computer-controlled valves, the headspace of this chamber was carried to one of three ports in a different room. Dogs were trained to search all three ports of the olfactometer and alert to the one containing HS. In Experiment 1 and 2, the AHSO was validated by testing two dogs naïve to HS (Experiment 1) and five certified Search and Rescue (SAR) teams naïve to the apparatus (Experiment 2). All dogs showed sensitivity and specificity to HS > 95% in the apparatus. In Experiment 3, we used a spontaneous generalization paradigm to evaluate generalization from the HS chamber to different scented articles exposed to the same volunteer and to a breath sample. Dogs’ response rate to the different scented articles was </div

False alerts during Phase 2.

Data points are the mean ± 95% confidence intervals. Introducing novel distractor odors increased the proportion of false alerts during the first two sessions. After the second session with novel distractors the proportion of false alerts reduced and by the end of the phase dogs did not show any false alerts to the distractors. The distribution of false alerts by distractor odor shows more responses to the person hygiene (PH) products of the volunteers and to the control chamber than to the other distractors.</p

Dogs (N = 6) average probability of alert and sniff time ± 95% confidence interval to the different testing odors.

Data points with different superscripts within a panel are statistically different from each other. A) shows dogs response rate to the different testing odors. B) Shows dogs sniff time (s) to the target and testing odors. Dashed line indicates the 3 s mark which was our alert criterion.</p

Schematic of the Automated Human Scent Olfactometer (AHSO).

Schematic of the Automated Human Scent Olfactometer (AHSO).</p

Experiment 2 data.

Working Dogs have shown an extraordinary ability to utilize olfaction for victim recovery efforts. Although instrumental analysis has chemically characterized odor volatiles from various human biospecimens, it remains unclear what perceptually constitutes human scent (HS) for dogs. This may be in part due to the lack of methodology and equipment to train and evaluate HS perception. The aims of this research were 1) to develop an automated human scent olfactometer (AHSO) to present HS to dogs in a controlled setting and 2) use the AHSO to evaluate dogs’ response to different scented articles and individual components of HS. A human volunteer was placed in a clear acrylic chamber and using a vacuum pump and computer-controlled valves, the headspace of this chamber was carried to one of three ports in a different room. Dogs were trained to search all three ports of the olfactometer and alert to the one containing HS. In Experiment 1 and 2, the AHSO was validated by testing two dogs naïve to HS (Experiment 1) and five certified Search and Rescue (SAR) teams naïve to the apparatus (Experiment 2). All dogs showed sensitivity and specificity to HS > 95% in the apparatus. In Experiment 3, we used a spontaneous generalization paradigm to evaluate generalization from the HS chamber to different scented articles exposed to the same volunteer and to a breath sample. Dogs’ response rate to the different scented articles was </div

Dogs (N = 5) averaged probability of alert and sniff time ± 95% confidence interval to the different testing odors and to whole human scent during training session in between testing sessions.

Data points with different superscripts within a panel are statistically different from each other. A. shows dogs’ probability of alert to the different testing odors. B) Shows dogs sniff time (s) to the testing odors. Dashed line indicates the 3 s mark which was our alert criterion. Sniff time above 3 seconds indicated that dogs sampled the ports multiple times.</p

Experiment 4 data.

Working Dogs have shown an extraordinary ability to utilize olfaction for victim recovery efforts. Although instrumental analysis has chemically characterized odor volatiles from various human biospecimens, it remains unclear what perceptually constitutes human scent (HS) for dogs. This may be in part due to the lack of methodology and equipment to train and evaluate HS perception. The aims of this research were 1) to develop an automated human scent olfactometer (AHSO) to present HS to dogs in a controlled setting and 2) use the AHSO to evaluate dogs’ response to different scented articles and individual components of HS. A human volunteer was placed in a clear acrylic chamber and using a vacuum pump and computer-controlled valves, the headspace of this chamber was carried to one of three ports in a different room. Dogs were trained to search all three ports of the olfactometer and alert to the one containing HS. In Experiment 1 and 2, the AHSO was validated by testing two dogs naïve to HS (Experiment 1) and five certified Search and Rescue (SAR) teams naïve to the apparatus (Experiment 2). All dogs showed sensitivity and specificity to HS > 95% in the apparatus. In Experiment 3, we used a spontaneous generalization paradigm to evaluate generalization from the HS chamber to different scented articles exposed to the same volunteer and to a breath sample. Dogs’ response rate to the different scented articles was </div

Search and Rescue (SAR) team information.

Teams with the same superscript share the same handler.</p

Averaged probability of alert to the different testing odors during a trial ± 95% confident interval.

Averaged probability of alert to the different testing odors during a trial ± 95% confident interval.</p

Schematic of the training and testing procedure.

During testing one of two volunteers were in the chamber and dogs were trained to whole human scent. The same two volunteers served as the source for the testing stimuli. During both positive controls dogs received 5 testing trials with the volunteer in the chamber as in training. During the Human No-Breath test the volunteer was in the chamber with a snorkel and a scuba mask. The breath of the volunteer was exhausted from the chamber through a PVC pipe attached to the side of the chamber during testing. A pump carried the headspace of the volunteer without breath to an olfactometer port. During the breath test a volunteer exhaled in a vial and a vacuum pump carried the breath to the olfactometer port. The distractor control consisted of presenting dogs with a novel random odor (Isobutyl propionate). Dogs received a training session in between testing sessions to ensure they still were responsive to the whole human scent target.</p