Development of a novel paradigm for the measurement of olfactory discrimination in dogs (Canis familiaris): A pilot study

Diagrammatic representation of testing apparatus from above. The position of the handler-dog combination, second experimenter and microphones are reversed when the odors are presented on the 2nd side. The camera is positioned on the ceiling above the center of the cage.

Odor card 6 cm × 3 cm perforated with 9, 3 mm diameter holes.

Diagrammatic representation of testing protocol using one of the randomized presentation sequences as an example. Sample odor ratios (novel: Master) are as follows: B = 100:0, C = 80:20, D = 60:40, E = 40:60, F = 20:80.

Significant habituation (P < 0.001) to Master odor by all dogs (N = 26). Standard error bars are shown for the 1st and 2nd presentaion.

Investigation time for the 2nd presentation of the Master odor as a proportion of the investigation time at the 1st presentation in three age groups: Young, < 5 years n = 9; Middle-aged, 5-8 years n = 9; and Aged, >8 years n = 6. Higher ratios indicate less habituation. Standard error bars are shown for all groups.

Discrimination between novel (B-F) odor mixtures and the familiar (Master) odor presented in the same trial for all dogs (N = 26). A positive value indicates a positive discrimination towards the novel odor mixture. A negative value indicates discrimination towards the familiar (Master) odor. 95% confidence intervals are given for each odor mixture. If the confidence interval crosses zero, the result is not significantly different from chance.

Discrimination between novel (B-F) odor mixtures and the familiar (Master) odor presented in the same trial for dogs (n = 15) which showed a positive discrimination towards the 100% novel (B) odor. 95% confidence intervals are given for each odor mixture. If the confidence interval crosses 0, the result is not significantly different from chance.