Use of a habituation-dishabituation test to determine canine olfactory sensitivity

Abstract

The habituation-dishabituation (H-D) paradigm is an established measure of sensory perception in animals. However, it has rarely been applied to canine olfaction. It proposes that animals will lose interest in, or habituate to, a stimulus after successive exposures but will regain interest in, or dishabituate to, a novel stimulus if they can perceive it. This study assessed an H-D test's practicability to determine dogs' olfactory detection thresholds (ODTs) for a neutral odorant. A random selection of mixed-breed pet dogs (n = 26) participated in two H-D tests in a repeated-measures crossover design. They were first habituated to a carrier odor and then presented with either ascending concentrations of n-amyl acetate in the known ODT range (experimental condition) or repeated carrier odor presentations (control condition). No single odor concentration elicited dishabituation in the majority of the dogs. However, individual dogs dishabituated at differing experimental concentrations significantly more often than in the control condition (p = .012). These findings provide some tentative support for using this method in studying canine olfaction. However, further assessment and refinement are needed before it can be a viable alternative to traditional ODT measurement.

Keywords: dishabituation; dogs; habituation; odor detection; thresholds.

Figure 1

A Flowchart Depicting the Odors Presented in Each of the Eight Trials in the Experimental Condition Note. The first three (E1‐E3) were habituation trials, and the following five (E4‐E8) were odor trials during which the experimental odor of amyl acetate was introduced in increasing concentrations in the liquid phase. Increasing color intensity reflects increasing odor intensity. nAA: n‐amyl acetate; MO: mineral oil; EVC: estimated vapor concentration.

Figure 2

The Front View of the Testing Pen

Figure 3

A Participant Dog Investigating the Odor Vial During a Trial

Figure 4

Boxplots Depicting the Medians and Ranges of Investigation Periods for Each Trial in the Control (Left) and Experimental (Right) Conditions

Figure 5

The Number of Individual Dogs Showing Dishabituations in Each Trial in the Control (Left) and Experimental (Right) Conditions Note. Different patterns represent the number of dogs from each breed category.