W.C. Dement (Eds.). Principles and practice of sleep medicine, 2 nd ed. (pp. 3-15). Philadelphia: 
Saunders. 
Domjan, M., and Purdy, J.E. (1995). Animal research in psychology: More than meets the eye 
of the psychology student. American Psychologist , 50, 496-503. 
Dunlop, J.C. (1999). Molecular basis for circadian clocks. Cell, 96, 271-290. 
Diamond, M.C, and Connor, J.R., Jr. (1982). Plasticity of the aging cerebral cortex. 
Experimental Brain Research, Suppl 5, 36-44. 
Dollard, J., and Miller, N.E. (1950). Personality and psychotherapy. New York: McGraw-Hill. 
Duke, A. (1989). How a chewing device affects calculus build-up in dogs. Veterinary Medicine 
84, 1110-1114. 
Escorihuela, R.M., Tobena, A., and Fernandez-Teruel, A. 1995. Environmental enrichment 
and postnatal handling prevent spatial learning deficits in aged hypoemotional (Roman High- 
avoidance) and hyperemotional (Roman Low-avoidance) rats. Learning & Memory, 2, 40-48. 
Fordyce, W.E., Fowler, R.S., Jr., Lehmann, J.F., Delateur, B.J., Sand, P.L., and Trieschmann 
R.B. (1973). Operant conditioning in the treatment of chronic pain. Archives of Physical 
Medicine and Rehabilitation, 54, 399-408. 
Gilloux, L, Gumell, J., and Shepherdson, D.J. (1992). An enrichment device for great apes. 
Animal Welfare, 1, 279-289. 
Heim, C., Newport, D.J., Heit, S., Graham, Y.P., Wilcox, M., Bonsall, R., Miller, A.H., and 
Nemeroff, C.B. (2000). Pituitary-adrenal and autonomic responses to stress in women after 
sexual and physical abuse in childhood, journal of the American Medical Association, 284, 
592-597. 
Hunt, J. McV. (1961). Intelligence and experience. New York: Ronald Press. 
Johnson, C.H., and Golden, S.S. (1999). Circadian programming in cyanobacteria: 
Adaptiveness and mechanism. Annual Review of Microbiology , 53, 389-409. 
Kamiya, J. (1969). Operant control of the EEG alpha rhythm and some of its reported effects 
on consciousness. In C. Tart (Ed.), Altered states of consciousness (pp. 489-501). New York: 
Wiley. 
29 
