Table 1.

Brief discription of seven behavioral traits.

Items	Description	Examples of dog behaviors
Activity	Amount of activity typically observed	The dog moves around and runs a lot; Dog moves quickly and is hyperactive
Boldness	Low fearfulness displayed toward unfamiliar environments	The dog does not show fear signals (e.g. ears down or a tail curled between legs) in novel situations
Concentration	Attention span during training	The dog keeps sniffing in a search trial; The dog is not distracted by irrelevant stimuli in a training session
Friendliness to humans	Willingness to interact with humans	The dog approaches humans in a friendly and playful manner; The dog does not show fear signals toward strangers
Independence	Self-confidence or willingness to work without having to rely on humans	The dog spontaneously engages in a search task without human involvement; The dog does not need the handler's help
Interest in the target	Degree of interest in the rolled towel (i.e., reinforcer)	The dog gets excited by rolled towels; when the dog bites a rolled towel, it is not easily removed by humans
Tolerance to dogs	Low aggressiveness towards other dogs	The dog approaches other dogs in a friendly manner; The dog does not show aggressive signals (e.g., growl, bark) toward dogs

* Score 1 (lowest) to 5 (highest) for all traits.