2.3.2. Apparatus in Experiments 1 and 2

The apparatus included a reaching room and an observation room [1]. Both compartments were 10 cm deep, 19 cm wide, and 20 cm tall and were made of transparent acrylic with a feeding table between the two sides. In the reaching room, a slit (10 mm) was created near the feeding table to allow the mice to reach for and grasp a piece of pasta. In the observation room, a slit (1 mm) was created towards the feeding table. The design of the reaching room was according to that described by Farr and Wishaw (2002) [3]. Using a stick that could hold pasta, the experimenter would bring the pasta in front of the slits. We placed two video cameras, one above and another in front of the apparatus, and recorded the animals’ behaviors (60 fps).