Table 2.
Detailed descriptions of the exercises.
| Exercise | Description |
|---|---|
| Novel Object | |
| Puffed-up plastic bag | An empty plastic bin bag (40 × 25 cm) was inflated by mouth, turning it into a balloon-like object. Inside the puppy pen, the experimenter touched this object and slowly moved it around, as well as holding it still to allow the puppies to explore. |
| Umbrella | An umbrella was opened and closed several times next to the puppy pen. Subsequently, the open umbrella was placed into the puppy pen. |
| Cat toy | A cat toy (25 × 7 cm) was placed inside the puppy pen. The toy had a weighted lower half, an internal bell, and a feather on the top. It wobbled, without falling over, when the experimenter tapped it or when the puppies grabbed the feather. |
| Water bottle | A 1.5-L plastic bottle, filled with water, was moved around, shaken, and knocked over in the vicinity of the puppies. Then, the experimenter left the bottle standing or lying for the puppies to explore. |
| Paper bag | An empty paper carrier bag (32 × 17 × 44 cm) was placed inside the puppy pen and moved around by the experimenter. |
| Plastic cone | A red plastic cone (17.5 × 12 cm) was placed into the puppy pen. |
| Flamingo | An inflatable plastic flamingo (18 × 11 cm) was placed into the puppy pen and was moved around by the experimenter. Before the puppies could bite it, it was removed from the puppy pen. |
| Crumpled up paper | Several pieces of commercial white printer paper (A4) were crumpled up and thrown into the puppy pen, one after the other. |
| Roll-down blind | Inside the puppy pen, the experimenter repeatedly extended and retracted a roll-down blind (55 × 55 cm). |
| Plastic bag | A sturdy empty plastic carrier bag (40 × 20 × 45 cm) was placed inside the puppy pen and moved around by the experimenter. |
| Scooter | A scooter (HUDORA 14708 BigWheel 205) was placed in front of or into the puppy pen. The experimenter was either riding it or moved it by hand, depending on the available space. |
| Mirror | A mirror (40 × 80 cm) was either placed into the pen against a wall or on the floor. |
| Helmet | A bicycle helmet was presented to the puppies on the experimenter’s head. |
| Backpack | A backpack (29.2 × 18.3 × 39.6 cm) from Amazon Basics was placed inside the puppy pen. |
| Pump | A bicycle pump was placed into the puppy pen. |
| Trimmer | An electric trimmer was turned on and off by the experimenter (CAMRY CR-2821 Haarschneider für Haustiere). |
| Metal bowl | A metal food bowl weighing 260 g with a diameter of 20 cm placed inside the puppy pen. |
| Problem-Solving | |
| Book challenge | Puppy was placed onto a book (3 cm high; 17.5 × 25 cm) and had to step down on its own. |
| Plate challenge | Puppy was placed onto a cool ceramic dinner plate, 25 cm in diameter (approx. 2 cm off the floor), and had to step down. The plate had been kept in the fridge for approximately 10 min. |
| Wobble challenge | Puppy was placed onto an inflatable wobble cushion (34 cm in diameter; 4 cm high) and had to step down. |
| Tea towel challenge | A tea towel (approx. 40 × 30 cm) was placed over part of the puppy’s body, so that the puppy had to wriggle out. |
| Traversal challenge 1 | Puppy had to traverse an empty plastic carrier bag (40 × 20 × 45 cm), lying flat on the ground, to reach a human or their littermates. |
| Mirror challenge | Puppy had to traverse a mirror (40 × 80 cm) that was placed flat on the ground to reach a human or food. |
| Barrier challenge | Puppies had to climb over a metal grid barrier (10–16 cm high, depending on the size of the puppies) to reach littermates, human or food. To make the metal more comfortable for the puppies to climb over, it was covered by a towel. |
| Traversal challenge 2 | Puppy had to traverse an empty paper carrier bag (32 × 17 × 44 cm), lying flat on the ground, to reach food. |
| Detour challenge 1 | A bowl filled with food was placed behind a metal grid barrier. Puppies had to move around the grid in order to reach the food. The level of difficulty was adjusted to the litter and the individual. The food was placed 2–20 cm from the edge of the grid, and grid shape varied from a V-shape to a straight line. |
| Detour challenge 2 | Procedure as in detour challenge 1—with a small increase of difficulty by increasing the distance the puppy had to detour. |
| Shaping challenge 1 | A mat was placed on the ground. Each time the puppy touched the mat, the trainer marked the behaviour with a clicker and gave the puppy a food reward. All movements towards the ground—sitting, sniffing, lying down, etc., were clicked and reinforced. |
| Shaping challenge 2 | Shaping exercise part 2 (continuation of shaping the puppy to approach and lie down on the mat). |
| Find-food challenge | Small pieces of food were placed under a tea towel (approx. 40 × 30 cm), and the puppy had to find them. |
| Tea towel challenge 2 | A tea towel (approx. 40 × 30 cm) was placed over the puppy’s body, so that the puppy had to wriggle out, with increased difficulty (towel was covering the whole body). |
| Detour challenge 3 | Detour challenge 3 (procedure as in detour challenges 1 and 2—with a major increase of difficulty by increasing the distance the puppy had to detour). |
| Startle and recovery exercises | |
| Book dropped | A book, weighing 1.3 kg, was dropped onto a tiled floor. |
| Kitchen pod lid banged | A kitchen pot lid, weighing 314 g with a diameter of 22 cm, was banged against a metal kitchen pot, weighing 1080 g with a diameter of 22 cm and a height of 17 cm. |
| Kitchen pod lid dropped | A kitchen pot lid, weighing 314 g with a diameter of 22 cm, was dropped on a tiled floor. |
| Cutlery dropped | Several pieces of cutlery were dropped into a metal box (14 × 10 × 18 cm). |
| Wooden spoon drummed | The experimenter drummed a wooden spoon (30 cm) against a metal kitchen pot, weighing 1080 g, with a diameter of 22 and a height of 17 cm. |
| Plastic bottle dropped | A 1.5-L plastic bottle filled with water was dropped onto a tiled floor from a height of 33 cm. |
| Door slammed | A door was slammed next to the puppy pen. |
| Clapping hands | The experimenter clapped her hands several times. |
| Cake tin dropped | A cake tin, weighing 314 g with a diameter of 27 cm, was dropped onto a tiled floor. |
| Eyeglasses case dropped | An eyeglasses case was dropped onto the floor. |
| Bicycle horn tooted | A bicycle horn, made of metal with a rubber air bag, was tooted (18.5 × 5 cm). |
| Metal box with cutlery shaken | A metal box (14 × 10 × 18 cm) with several pieces of cutlery inside was shaken. |
| Gunshot recording | A gunshot recording from YouTube was presented to the puppies via a loudspeaker (Bose® SoundLink color II Bluetooth wireless speaker). https://www.youtube.com/watch?v=AGVz9zoWNrQ (accessed on 7 May 2018) |
| Hair dryer | A hair dryer was turned on and off several times. |
| Roll-down blind dropped | A roll-down blind was dropped onto a tiled floor. |
| Umbrella dropped | An umbrella was dropped onto a tiled floor. |
| Firework recording | A firework recording from YouTube was presented to the puppies via a loudspeaker (Bose® SoundLink color II Bluetooth wireless speaker). https://www.youtube.com/watch?v=H7FANXaanG4 (accessed on 10 May 2018) |
| Metal kitchen pod dropped | A metal kitchen pot, with a diameter of 22 and a height of 17 cm, weighing 1080 g, was dropped onto a tiled floor. |
| Metal food bowl dropped | A metal food bowl, weighing 260 g with a diameter of 20 cm, was dropped onto a tiled floor. |
| Metal clicker clicked | A metal clicker (sold as a dog training tool; 10.4 × 6 × 2.4 cm) was clicked several times. |
| Experimenter screamed | The experimenter screamed for about 2 s with a high voice. |
| Brush dropped | A brush, with a diameter of 15 cm, was dropped onto a tiled floor. |
| Plastic cone dropped | A plastic cone (17.5 × 12 cm) was dropped onto a tiled floor. |
| Plastic bowl dropped | A plastic bowl (26 × 17 × 33) was dropped onto a tiled floor. |