School of Psychology, Birkbeck College

Course PSYC044U (Psychobiology II.) WEEK 3
February 8 2007

gifThis is just 6 of the pages of the much longer paper handout. Web versions of the other pages in the paper handout are accessible from the side index. If you need to print all the pages, you could try the 'pdf' file, but this is quite large and may be difficult to download over a telephone modem.



Lecture 1: Habituation, sensitization and stimulus learning


  1. Habituation is measured as the decline in an already-present response to the repetition of a single stimulus.

  2. The methodology for habituation experiments is very straightforward - a single stimulus is repeatedly presented, and the strength of an initally present response is measured.
  3. Sometimes the repitition of a single stimulus leads to increases in responsiveness to it - the phenomena is called “Sensitization”.
  4. More often, with stimuli which are not very strong or which have little motivational significance, repitition leads to a decline in any response to them. This waning of responsiveness is know an habituation.
  5. [middle of page 1 of handout]
  6. Habituation can be regarded as a “global principle of adaptation” (Davey, 1989) since it can be observed in a very wide range of species.
  7. It is possible to obtain the basic result in relatively simple neural systems (e.g. Aplysia, the mammalian spinal cord) and it is therefore necessary to distinguish habituation as a form of learning from forms of sensory and response fatigue.
  8. Even when this can be done habituation in simple neural systems is clearly likely to be explicable in terms of basic neuronal processes and the properties of individual neurons (e.g. Carew and Kandel, 1973; Castellucci and Kandel, 1976; Bristol and Carew, 2005; Shafer, 2005; Hawkins et al., 2006.
  9. However, the methodology of habituation can also be applied to perception in normal human subjects, and is particularly useful in studies of perceptual development in human preverbal infants (Sokolov, 1963; Maurer and Maurer, 1988, Olson, 1976; Kellman and Spelke, 1983; Csibra, 2003; Phillips & Wellman, 2005; O'Connell and Dunbar, 2005; Temple et al., 2006).
  10. In these cases explanations of the phenomena of habituation may involve more complex processes relating to stimulus categorization and representation, and interactions with the attentional and motivational processes which are associated with the dimension of stimulus novelty and familiarity.
  11. (See also the notes on habituation later on in the handout).


Sample essay


To what extent should habituation be regarded as a simple form of learning?




Main Sources and Further Reading (HABITUATION)

Gleitman, H. (1995/99/2004) Psychology. 4/5/6th Edition. Norton, London. pp 106-7/118/124-5 and pp 512- 3/554/479-80

Green, S. (1987) An Introduction to Physiological Psychology. Routledge & Kegan Paul: London. Chapter 7

Lieberman, D. (1993/2000) Learning: Behavior and Cognition. Belmont: Wadsworth.( pp 33-35/ pp. 39-40)

Walker, S.F. (1987) Animal Learning: An Introduction. Routledge & Kegan Paul: London. Chapter 2

Other references (Habituation: Not normally needed for further reading).

Albright, T. D., Kandel, E. R., & Posner, M. I. (2000). Cognitive neuroscience. Current Opinion in Neurobiology, 10(5), 612- 624.

Bornstein, M. H., & Suess, P. E. (2000). Physiological self-regulation and information processing in infancy: Cardiac vagal tone and habituation. Child Development, 71(2), 273-287.

Bristol, A. S., & Carew, T. J. (2005). Differential role of inhibition in habituation of two independent afferent pathways to a common motor output. Learning & Memory, 12(1), 52-60.

Broster, BS and Rankin, CH (1994) Effects of changing interstimulus-interval during habituation in Caenorhabditis-elegans. Behavioral Neuroscience, Vol.108, No.6, Pp.1019-1029

Bundy, R., Columbo, J. and Singer, J. (1982) Pitch perception in young infants. Developmental Psychology, 18, 10-14.

Carew, T. J., & Kandel, E. R. (1973). Acquisition and Retention of Long-Term Habituation in Aplysia - Correlation of Behavioral and Cellular Processes. Science, 182(4117), 1158-1161.

Carew, T. J., Pinsker, H. M., & Kandel, E. R. (1972). Long-Term Habituation of a Defensive Withdrawal Reflex in Aplysia. Science, 175(4020), 451-&.

Castellucci, V. and Kandel, E. (1976) An invertebrate system for the cellular study of habituation. In Tighe, T.J. and Leaton, R.N. (eds.) Habituation. Lawrence Erlbaum Associates: Hillsdale, N.J., 1-47.

Cohen, TE, Kaplan, SW, Kandel, ER, Hawkins, RD (1997) A simplified preparation for relating cellular events to behavior: mechanisms contributing to habituation, dishabituation, and sensitization of the aplysia gillwithdrawal reflex. Journal of Neuroscience, Vol.17, No.8, Pp.2886-2899.

Cornell, E.H. (1974) Infants' discrimination of photographs of faces following redundant presentations. Journal of Experimental Child Psychology, 18, 98-106.

Csibra, G. (2001) Illusory contour figures are perceived as occluding surfaces by 8-month-old infants. Developmental Science, Volume 4 (2001) pp F7-F11

Csibra, G. (2003). Teleological and referential understanding of action in infancy. Philosophical Transactions of the Royal Society, London B, 358, 447-458.

Davis, M. and Wagner, A.R. (1969) Habituation of startle response under incremental sequence of stimulus intensities. Journal of Comparative and Physiological Psychology, 67, 486-92.

del Rosal, E., Alonso, L., Moreno, R., Vazquez, M., & Santacreu, J. (2006). Simulation of habituation to simple and multiple stimuli. Behavioural Processes, 73(3), 272-277.

Dethier, V.G. (1963) The Physiology of Insect Senses. Methuen: London.

Eisenstein, E. M., & Eisenstein, D. (2006). A behavioral homeostasis theory of habituation and sensitization: II. Further developments and predictions. Reviews in the Neurosciences, 17(5), 533-557.

Ezzeddine, Y., & Glanzman, D. L. (2003). Prolonged habituation of the gill-withdrawal reflex in Aplysia depends on protein synthesis, protein phosphatase activity, and postsynaptic glutamate receptors. Journal of Neuroscience, 23(29), 9585-9594.

Frings, M., Awad, N., Jentzen, W., Dimitrova, A., Kolb, F. P., Diener, H. C., et al. (2006). Involvement of the human cerebellum in short-term and long-term habituation of the acoustic startle response: A serial PET study. Clinical Neurophysiology, 117(6), 1290-1300.

Gray, J.A. (1975) Elements of a Two-Process Theory of Learning. Academic Press: London.

Groves, P.M. and Thompson, R.F. (1970) Habituation: A dual-process theory. Psychological Review, 77, 419-50.

Haupt, S. S., & Klemt, W. (2005). Habituation and dishabituation of exploratory and appetitive responses in the honey bee (Apis mellifera L.). Behavioural Brain Research, 165(1), 12-17.

Hawkins, R. D., Cohen, T. E., & Kandel, E. R. (2006). Dishabituation in Aplysia can involve either reversal of habituation or superimposed sensitization. Learning & Memory, 13(3), 397-403.

Heisz, J. J., Watter, S., & Shedden, J. M. (2006). Progressive N170 habituation to unattended repeated faces. Vision Research, 46(1-2), 47-56.

Hinde, R.A. (1970) Animal Behaviour: A Synthesis of Ethology and Comparative Psychology. McGraw-Hill: London.

Hodgkin, J., Horwitz, H.R., Jasny, B.R. and Kimble, J. (1998) C. elegans: Sequence to biology. Science, 282 (Dec 11), p. 2022.

Humphrey, G. (1933) The Nature of Learning in Relation to Living Systems. Kegan Paul, Trench, Trubner: London.

Johnson, M.C. and Wuensch, KL (1994) An investigation of habituation in the jellyfish Aurelia aurita. Behavioral and Neural Biology 61, pp.54-59

Kandel, E. R. (2001). Neuroscience - The molecular biology of memory storage: A dialogue between genes and synapses. Science, 294(5544), 1030-1038.

Kandel, E. R., & Pittenger, C. (1999). The past, the future and the biology of memory storage. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences, 354(1392), 2027-2052.

Kellman, P. J., & Spelke, E. S. (1983). Perception of partly occluded objects in infancy. Cognitive Psychology, 15(4), 483-524.

Leussis, M. P., & Bolivar, V. J. (2006). Habituation in rodents: A review of behavior, neurobiology, and genetics. Neuroscience and Biobehavioral Reviews, 30(7), 1045-1064.

Maurer, D. and Maurer, C (1988) The World Of The Newborn. New York: Basic Books (IVID [Mau]).

McNamara, F., Wulbrand, H., & Thach, B. T. (1999). Habituation of the infant arousal response. Sleep, 22(3), 320-326.

McSweeney, F. K., & Swindell, S. (1999). General-process theories of motivation revisited: The role of habituation. Psychological Bulletin, 125(4), 437-457.

O'Connell, S., & Dunbar, R. I. M. (2005). The perception of causality in chimpanzees (Pan spp.). Animal Cognition, 8(1), 60-66.

Olson, G.M. (1976) An information-processing analysis of visual memory and habituation in infants. In Tighe, T.J. and Leaton, R.N. (eds.) Habituation. Lawrence Erlbaum Associates: Hillsdale, N.J., 239-77.

Peeke, H.V.S. and Petrinovich, L. (1984) Habituation, Sensitization, and Behaviour. Academic Press: London.

Peeke, HVS (1995) Habituation of a predatory response in the stickleback (Gasterosteus-aculeatus). Behaviour, Vol.132, No.Pt15-16, Pp.1255-1266.

Phillips, A. T., & Wellman, H. M. (2005). Infants' understanding of object-directed action. Cognition, 98(2), 137-155.

Phillips, A. T., & Wellman, H. M. (2005). Infants' understanding of object-directed action. Cognition, 98(2), 137-155.

Pinsker, H. M., Hening, W. A., Carew, T. J., & Kandel, E. R. (1973). Long-Term Sensitization of a Defensive Withdrawal Reflex in Aplysia. Science, 182(4116), 1039-1042.

Pinsker, H., Kupfermann, I., Castellucci, V. and Kandel, E. (1970) Habituation and dishabituation of the gill withdrawal reflex in Aplysia. Science, 167, 1740-2.

Rankin, C. H. (2000). Context conditioning in habituation in the nematode Caenorhabditis elegans. Behavioral Neuroscience, 114(3), 496-505.

Rankin, C. H. (2002). From gene to identified neuron to behaviour in Caenorhabditis elegans. Nature Reviews Genetics, 3(8), 622-630.

Rankin, C. H. (2004). Invertebrate learning: What can't a worm learn? Current Biology, 14(15), R617-R618.

Rose, J. K., & Rankin, C. H. (2006). Blocking memory reconsolidation reverses memory-associated changes in glutamate receptor expression. Journal of Neuroscience, 26(45), 11582-11587.

Schafer, W. R. (2005). Deciphering the neural and molecular mechanisms of C-elegans behavior. Current Biology, 15(17), R723-R729.

Scheiner, R. (2004). Responsiveness to sucrose and habituation of the proboscis extension response in honey bees. Journal of Comparative Physiology a-Neuroethology Sensory Neural and Behavioral Physiology, 190(9), 727-733.

Schicatano, EJ and Blumenthal, TD (1994) Caffeine delays habituation of the human acoustic startle reflex. Psychobiology, 22. pp.117-122.

Schicatano, EJ, Blumenthal, TD (1998) The effects of caffeine and directed attention on acoustic startle habituation. Pharmacology Biochemistry and Behavior, Vol.59, No.1, Pp.145150.

Sirois, S., & Mareschal, D. (2004). An interacting systems model of infant habituation. Journal of Cognitive Neuroscience, 16(8), 1352-1362.

Slater, A. and Morison, V. (1985) Shape constancy and slant perception at birth. Perception, 14, 337-344.

Sokolov, E.N. (1963) Perception and the Conditioned Reflex. Permagon Press: Oxford.

Sokolov, E.N. (1975) The neuronal mechanisms of the orienting reflex. In Sokolov, E.N. and Vinogradova, O.S. (eds.) Neuronal Mechanisms of the Orienting Reflex. Lawrence Erlbaum: Hillsdale, N.J., 217-35.

Staddon, JER, Higa, JJ (1996) Multiple time scales in simple habituation. Psychological Review, Vol.103, No.4, Pp.720-733 Is: 0033-295x.

Temple, J. L., Kent, K. M., Giacomelli, A. M., Paluch, R. A., Roemmich, J. N., & Epstein, L. H. (2006). Habituation and recovery of salivation and motivated responding for food in children. Appetite, 46(3), 280-284.

Thompson, R.F. and Glanzman, D.L. (1976) Neural and behavioural mechanisms of habituation and senstization. In Tighe, T.J. and Leaton, R.N. (eds.) Habituation. Lawrence Erlbaum Associates: Hillsdale, N.J., 49-93.

Thompson, R.F. and Spencer, W.A. (1966) Habituation: A model phenomenon for the study of the neuronal substrates of behaviour. Psychological Review, 73, 16-43.

Thorpe, W.H. (1963) Learning and Instinct in Animals. 2nd edition. Methuen: London.

Timmann, D, Musso, C, Kolb, FP, Rijntjes, M, Juptner, M, Muller, SP, Diener, HC, Weiller, C (1998) Involvement of the human cerebellum during habituation of the acoustic startle response: a pet study. Journal of Neurology Neurosurgery and Psychiatry, Vol.65, No.5, Pp.771-773.

Tipton, MJ, Eglin, CM, Golden, FSC (1998) Habituation of the initial responses to cold water immersion in humans: a central or peripheral mechanism?. Journal of Physiology-London, Vol.512, No.2, Pp.621-628 Is: 0022-3751.

Vogel, E. H., & Wagner, A. R. (2005). Stimulus specificity in the habituation of the startle response in the rat. Physiology & Behavior, 86(4), 516-525.

Wicks, SR, Rankin, CH (1997) Effects of tap withdrawal response habituation on other withdrawal behaviors: the localization of habituation in the nematode Caenorhabditis elegans. Behavioral Neuroscience, Vol.111, No.2, Pp.342-353.

Wilson, D. A. (2000). Odor specificity of habituation in the rat anterior piriform cortex. Journal of Neurophysiology, 83(1), 139-145.

Wood, ER, Wiel, DE, Weeks, JC (1997) Neural correlates of habituation of the proleg withdrawal reflex in larvae of the hawk moth, manduca sexta. Journal of Comparative Physiology A-Sensory Neural and Behavioral Physiology, Vol.180, No.6, Pp.639-657.




Lecture 2: Pavlovian (Classical) Conditioning (sheet 11 of handout)



The most basic procedure of Pavlovian conditioning is the pairing of two stimuli, with the expected outcome being that responses originally only elicited by one of them will be also elicited by the other. Usually the conditioned stimulus (CS), which only elicits the response after training, can be said to operate as a signal for the other (the Unconditioned Stimulus, — US or UCS). Important variations on the simplest procedure include Discrimination, where one stimulus (CS+) is paired with the UCS, and another (CS–) isn’t.

In Pavlov’s experiments dogs salivated to signals for food, but classical conditioning is studied in many other contexts.

Theoretical questions include the nature of the associations responsible for conditioning, and the critical conditions for producing associations.


The main possibilities are associations between the conditioned stimulus and the measured unconditioned response, and associations between the two stimuli. The general conclusion is that it is associations between the stimuli which are important, the main theory being that of stimulus-substitution.


The obvious first assumption would be that associations are caused by the stimulus-pairings, that is by contiguity. This principle is sometimes known as the “Hebb rule” after Hebb (1949) who proposed that this operated at the level of associations between neurons. However, at the behavioural level the contiguity explanation is rejected in favour of contingency: it can be shown that the strength of an association between two stimuli depends on the conditional probability of their conjunction, rather than on the absolute number of pairings (Rescorla, 1967, 1988). Thus “conditioning is now described as the learning of relations among events.” (Rescorla, 1988; see also Pearce & Bouton, 2001).

There are two other empirical findings which argue against the exclusive importance of stimulus pairings.

(i) Blocking (Kamin, 1969). Loosely, it appears that if animals are already expecting food, then a new signal which is paired with it is not noticed: “A useful shorthand is that organisms adjust their Pavlovian associations only when they are ‘surprised’.” (Rescorla, 1988, p.153; Lieberman, 1990 or 2000, Chap 3).

(ii) Qualitative relations between stimuli. Stimuli may become associated even though they are never paired. This can happen in “Taste-aversion learning” (Garcia and Koelling, 1966; Garcia, 1981) or the “cue to consequence effect”: animals appear to associate the taste of something they have eaten previously with becoming ill some time later. Similarity between stimuli is an additional variable when they are paired. (Rescorla, 1988, p. 154)


Classical conditioning phenomena are observed in a wide variety of contexts (e.g. Bouton et al., 2001; Cardinal et al., 2002; Lorenzetti et al., 2006; Mineka and Ohman, 2002; Qi et al., 2006; Stockhurst et al., 2006) which are likely to differ greatly in the involvement of motivational systems and in the level of perceptual representation of the stimuli. Exactly what gets associated with what depends on the context, and in particular on the stimuli used (see Walker, 1987; pp. 100-104 and 65-91).


Sample Essay.



To what extent is classical conditioning explicable in terms of the principle of contiguity (stimulus pairings)?  



Main Sources (CLASSICAL CONDITIONING: alternatives)

Davey. G. (1989) Ecological Learning Theory. London: Routledge. CHAPTER 2

Gleitman, H. (1995/99/2004) Psychology. 4/5/6th Edition. Norton, London. pp 106-7/118/124-5 and pp 512-3/554/479-80

Lieberman, D. (1990/93/2000) Learning: Behavior and Cognition. Belmont: Wadsworth. CHAPTERS 2 & 3.(2000 and 1990 – NB : In the 1993 edition, CHAPTERS 3 & 4)

Walker, S.F. (1987) Animal Learning: An Introduction. Routledge & Kegan Paul: London. pp 56-65 and pp. 97-116.



Pearce, J. M., & Bouton, M. E. (2001). Theories of associative learning in animals. Annual Review of Psychology, 52, 111-139.

Rescorla, R.A. (1988) Pavlovian conditioning: It's not what you think it is. American Psychologist, 43, 151-160.

Walker, S.F. (1984) Learning Theory and Behaviour Modification. Methuen: London. CHAPTER 3.

Walker, S.F. (1985) Animal Thought. Routledge & Kegan Paul: London. pp. 65-73.


Other references (Not normally needed for further reading)

Ader, R. and Cohen, N. (1993) Psychoneuroimmunology. Annual Review of Psychology, 44, 53-85.

Arcediano, F., Escobar, M., & Matute, H. (2001). Reversal from blocking in humans as a result of posttraining extinction of the blocking stimulus. Animal Learning & Behavior, 29(4), 354-366.

Baxter, D. A., & Byrne, J. H. (2006). Feeding behavior of Aplysia: A model system for comparing cellular mechanisms of classical and operant conditioning. Learning & Memory, 13(6), 669-680.

Berman, D. E., & Dudai, Y. (2001). Memory extinction, learning anew, and learning the new: Dissociations in the molecular machinery of learning in cortex. Science, 291(5512), 2417-2419.

Bouton, M. E., & Moody, E. W. (2004). Memory processes in classical conditioning. Neuroscience and Biobehavioral Reviews, 28(7), 663-674.

Bouton, M. E., Mineka, S., & Barlow, D. H. (2001). A modern learning theory perspective on the etiology of panic disorder. Psychological Review, 108(1), 4-32.

Buchel, C., & Dolan, R. J. (2000). Classical fear conditioning in functional neuroimaging. Current Opinion in Neurobiology, 10(2), 219-223.

Buchel, C., Dolan, R. J., Armony, J. L., & Friston, K. J. (1999). Amygdala-hippocampal involvement in human aversive trace conditioning revealed through event-related functional magnetic resonance imaging. Journal of Neuroscience, 19(24), 10869-10876.

Cardinal, R. N., Parkinson, J. A., Hall, J., & Everitt, B. J. (2002). Emotion and motivation: the role of the amygdala, ventral striatum, and prefrontal cortex. Neuroscience and Biobehavioral Reviews, 26(3), 321-352.

Carter, R. M., Hofstotter, C., Tsuchiya, N., & Koch, C. (2003). Working memory and fear conditioning. Proceedings of the National Academy of Sciences of the United States of America, 100(3), 1399-1404.

Clark, R. E., Manns, J. R., & Squire, L. R. (2002). Classical conditioning, awareness, and brain systems. Trends in Cognitive Sciences, 6(12), 524-531.

Colwill, RM, Goodrum, K, Martin, A (1997) Pavlovian appetitive discriminative conditioning in aplysia californica. Animal Learning & Behavior, Vol.25, No.3, Pp.268-276.

de Bono, M., & Maricq, A. V. (2005). Neuronal substrates of complex behaviors in C-elegans. Annual Review of Neuroscience, 28, 451-501.

De Houwer, J., Thomas, S., & Baeyens, F. (2001). Associative learning of likes and dislikes: A review of 25 years of research on human evaluative conditioning. Psychological Bulletin, 127(6), 853-869.

Delamater, A. R. (2004). Experimental extinction in Pavlovian conditioning: Behavioural and neuroscience perspectives. Quarterly Journal of Experimental Psychology Section B- Comparative and Physiological Psychology, 57(2), 97-132.

Dickinson, A. (2001). Causal learning: Association versus computation. Current Directions in Psychological Science, 10(4), 127-132.

Dickinson, A. (2001). The 28th Bartlett Memorial Lecture Causal learning: An associative analysis. Quarterly Journal of Experimental Psychology Section B- Comparative and Physiological Psychology, 54(1), 3-25.

Donahoe, J. W., & Vegas, R. (2004). Pavlovian conditioning: The CS-UR relation. Journal of Experimental Psychology-Animal Behavior Processes, 30(1), 17-33.

Exton, M. S., von Auer, A. K., Buske-Kirschbaum, A., Stockhorst, U., Gobel, U., & Schedlowski, M. (2000). Pavlovian conditioning of immune function: animal investigation and the challenge of human application. Behavioural Brain Research, 110(1-2), 129-141.

Gabrieli, JDE, Carrillo, MC, Cermak, LS, McGlincheyberroth, R, Gluck, Ma, Disterhoft, JF (1995) Intact delay-eyeblink classical-conditioning in amnesia. Behavioral Neuroscience, Vol.109, No.5, Pp.819-827

Garcia, J. (1981) Tilting at the paper mills of academe. American Psychologist, 36, 149-58.

Garcia, J. and Koelling, R.A. (1966) Relation of cue to consequence in avoidance learning. Psychonomic Science, 4, 123-4.

Gerber, B., & Ullrich, J. (1999). No evidence for olfactory blocking in honeybee classical conditioning. Journal of Experimental Biology, 202(13), 1839-1854.

Gray, J.A. (1979) Pavlov. Fontana: London.

Green, J. T., & Woodruff-Pak, D. S. (2000). Eyeblink classical conditioning: Hippocampal formation is for neutral stimulus associations as cerebellum is for association- response. Psychological Bulletin, 126(1), 138-158.

Hebb, D.O. (1949) The Organization of Behaviour. Chapman & Hall: London.

Ivkovich, D., Collins, K. L., Eckerman, C. O., Krasnegor, N. A., & Stanton, M. E. (1999). Classical delay eyeblink conditioning in 4- and 5-month-old human infants. Psychological Science, 10(1), 4-8.

Kamin, L.J. (1969) Predictability, surprise, attention and conditioning. In Campbell, B.A. and Church, R.M. (eds.) Punishment and Aversive Behaviour. Appleton-Century-Crofts: New York, 279-96.

Levy, M., & Susswein, A. J. (1999). Separate effects of a classical conditioning procedure on respiratory pumping, swimming, and inking in Aplysia fasciata. Learning and Memory, 6(1), 21-36.

Lorenzetti, F. D., Mozzachiodi, R., Baxter, D. A., & Byrne, J. H. (2006). Classical and operant conditioning differentially modify the intrinsic properties of an identified neuron. Nature Neuroscience, 9(1), 17-19.

Marenco, S., Weinberger, D. R., & Schreurs, B. G. (2003). Single-cue delay and trace classical conditioning in schizophrenia. Biological Psychiatry, 53(5), 390-402.

Masini, C. V., Sauer, S., White, J., Day, H. E. W., & Campeau, S. (2006). Non-associative defensive responses of rats to ferret odor. Physiology & Behavior, 87(1), 72-81.

Mineka, S., & Ohman, A. (2002). Phobias and preparedness: The selective, automatic, and encapsulated nature of fear. Biological Psychiatry, 52(10), 927-937.

Mozzachiodi, R., Lechner, H. A., Baxter, D. A., & Byrne, J. H. (2003). In vitro analog of classical conditioning of feeding behavior in Aplysia. Learning & Memory, 10(6), 478-494.

Murphy, R. A., & Baker, A. G. (2004). A role for CS-US contingency in Pavlovian conditioning. Journal of Experimental Psychology-Animal Behavior Processes, 30(3), 229-239.

Neumann, D. L., & Waters, A. M. (2006). The use of an unpleasant sound as an unconditional stimulus in a human aversive Pavlovian conditioning procedure. Biological Psychology, 73(2), 175-185.

Pavlov, I.P. (1927) Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex. Dover: New York.

Pearce, J. M., & Bouton, M. E. (2001). Theories of associative learning in animals. Annual Review of Psychology, 52, 111-139.

Qi, H. J., Saunders, J. A., Stone, R. W., & Backus, B. T. (2006). Demonstration of cue recruitment: Change in visual appearance by means of Pavlovian conditioning. Proceedings of the National Academy of Sciences of the United States of America, 103(2), 483-488.

Redondo, J., & Marcos, J. L. (2003). Effects of CS-US interval on unconditioned response diminution in human heart rate classical conditioning. Journal of Psychophysiology, 17(1), 30-38.

Reed, P., McCarthy, J., Latif, N., & DeJongh, J. (2002). The role of stimuli in a virtual shopping environment: A test of predictions derived from conditioning models of marketing firms. Journal of Economic Psychology, 23(4), 449-467.

Rescorla, R.A. (1967) Pavlovian conditioning and its proper control procedures. Psychological Review, 74, 71-80.

Rescorla, R.A. and Wagner, A.R. (1972) A theory of Pavlovian conditioning: variations in the effectiveness of reinforcement and nonreinforcement. In Black, A.H. and Prokasy, W.F. (eds.), Classical Conditioning II: current research and theory. Appleton-Century-Crofts: New York, 64-9.

Stockhorst, U., Steingrueber, H. J., Enck, P., & Klosterhalfen, S. (2006). Pavlovian conditioning of nausea and vomiting. Autonomic Neuroscience-Basic & Clinical, 129(1-2), 50-57.

Turkkan, J.S. (1989) Classical conditioning: The new hegemony. Behavioural and Brain Sciences, 12, 121-179

Vansteenwegen, D., Francken, G., Vervliet, B., De Clercq, A., & Eelen, P. (2006). Resistance to extinction in evaluative conditioning. Journal of Experimental Psychology-Animal Behavior Processes, 32(1), 71-79.

Watanabe, H., & Mizunami, M. (2006). Classical conditioning of activities of salivary neurones in the cockroach. Journal of Experimental Biology, 209(4), 766-779.

Welzl, H., D'Adamo, P., & Lipp, H. P. (2001). Conditioned taste aversion as a learning and memory paradigm. Behavioural Brain Research, 125(1-2), 205-213.

Wilensky, A. E., Schafe, G. E., Kristensen, M. P., & LeDoux, J. E. (2006). Rethinking the fear circuit: The central nucleus of the amygdala is required for the acquisition, consolidation, and expression of pavlovian fear conditioning. Journal of Neuroscience, 26(48), 12387-12396.