1. Department of Psychology, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji, Tokyo 192-0397, Japan
2. NTT Communication Science Laboratories, 3-1 Morinosato Wakamiya, Atsugi 243-0198, Japan
3. Faculty of Education, Iwate University, 3-18-8 Ueda, Morioka, Iwate, Japan