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Unconscious cerebral initiative and the role of conscious will in voluntary action

Published online by Cambridge University Press:  04 February 2010

Benjamin Libet
Affiliation:
Department of Physiology, School of Medicine, University of California, San Francisco, Calif. 94143

Abstract

Voluntary acts are preceded by electrophysiological “readiness potentials” (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about—550 ms. Such RPs were used to indicate the minimum onset times for the cerebral activity that precedes a fully endogenous voluntary act. The time of conscious intention to act was obtained from the subject's recall of the spatial clock position of a revolving spot at the time of his initial awareness of intending or wanting to move (W). W occurred at about—200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event.

For spontaneous voluntary acts, RP onset preceded the uncorrected Ws by about 350 ms and the Ws corrected for S by about 400 ms. The direction of this difference was consistent and significant throughout, regardless of which of several measures of RP onset or W were used. It was concluded that cerebral initiation of a spontaneous voluntary act begins unconsciously. However, it was found that the final decision to act could still be consciously controlled during the 150 ms or so remaining after the specific conscious intention appears. Subjects can in fact “veto” motor performance during a 100–200-ms period before a prearranged time to act.

The role of conscious will would be not to initiate a specific voluntary act but rather to select and control volitional outcome. It is proposed that conscious will can function in a permissive fashion, either to permit or to prevent the motor implementation of the intention to act that arises unconsciously. Alternatively, there may be the need for a conscious activation or triggering, without which the final motor output would not follow the unconscious cerebral initiating and preparatory processes.

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Target article
Copyright
Copyright © Cambridge University Press 1985

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References

Ach, N. (1935) Analyse des Willens. Urban & Sehwarzenberg. [ES]Google Scholar
Akert, K., Peper, K. & Sandri, C. (1975) Structural organization of motor end plate and central synapses. In: Cholinergic mechanisms, ed. Waser, P. G.. Raven Press. [JCE]Google Scholar
Allan, L. G. (1978) The attention switching model: Implications for research in schizophrenia. Journal of Psychiatric Research 14:195202. [taBL]CrossRefGoogle ScholarPubMed
Arezzo, J. & Vaughan, H. G. Jr (1975) Cortical potentials associated with voluntary movements in the monkey. Brain Research 88:99104. [CCW]CrossRefGoogle ScholarPubMed
Bauer, H. & Nirnberger, G. (1981) Concept identification as a function of preceding negative or positive spontaneous shifts in slow brain potentials. Psychophysiology 18:466–69. [JSS]CrossRefGoogle ScholarPubMed
Beloff, J. (1962) The existence of mind. MacGibbon and Kee. [taBL]Google Scholar
Bolanowski, S. J. Jr & Doty, R. W. (1982) Monocular loss, binocular maintenance of perception in Ganzfeld. Abstracts, Society for Neuroscience 8:675. [RWD]Google Scholar
Boring, E. G. (1957) A history of experimental psychology. Applcton-Century-Crbfts. [taBL]Google Scholar
Born, J., Whipple, S. C. & Stamm, J. (1982) Spontaneous cortical slow-potential shifts and choice reaction time performance. Electroencephalography and Clinical Neurophysiology 54:668–76. [taBL, JSS]CrossRefGoogle ScholarPubMed
Breitmeyer, B. & Ganz, L. (1976) Implications of sustained and transient channels for theories of visual pattern masking, saccadic suppression, and information processing. Psychological Review 87:5269 [BB]CrossRefGoogle Scholar
Bridgeman, B. (1971) Metacontrast and lateral inhibition. Psychological Review 78:528–39. [BB]CrossRefGoogle ScholarPubMed
Bridgeman, B. (1978) Distributed sensory coding applied to simulations of iconic storage and metaconstrast. Bulletin of Mathematical Biology 40: 605–23. [BB]CrossRefGoogle Scholar
Brinkman, C. & Porter, R. (1979) Supplementary motor area in the monkey: Activity of neurons during performance of a learned motor task. Journal of Neurophysiology 42:681709. [JCE]CrossRefGoogle ScholarPubMed
Broadbent, D. E. (1971) Decision and stress. Academic Press. [GU]Google Scholar
Campion, J. & Latto, R. (1985) What is a blindsight? Behavioral and Brain Sciences 8:755757. [RL]CrossRefGoogle Scholar
Campion, J., Latto, R. & Smith, Y. M. (1983) Is blindsight an effect of scattered light, spared cortex, and near-threshold vision? Behavioral and Brain Sciences 6:423–86. [RWD, RL]CrossRefGoogle Scholar
Cheesman, J. & Merikle, P. M. (1984) Priming with and without awareness. Perception & Psychophysics 36:387–95. [PMM]CrossRefGoogle ScholarPubMed
Cheesman, J. & Merikle, P. M. (in press) Word recognition and consciousness. In: Reading research: Advances in theory and practice, vol. 5, ed. Besner, D., Waller, T. G. & MacKinnon, G. E.. Academic Press. [PMM]Google Scholar
Churchland, P. S. (1981a) The timing of sensations: Reply to Libct. Philosophy of Science 48:492–97. [CCW]CrossRefGoogle Scholar
Churchland, P. S. (1981b) On the alleged backwards referral of experiences and its relevance to the mind-body problem. Philosophy of Science 48:165–81. [CCW]CrossRefGoogle Scholar
Creutzfeldt, O. D. & Rager, G. (1978) In: Cerebral correlates of conscious experience, ed. Buser, P. A. & Rougeul-Buser, A.. Elsevier/North Holland. [taBL]Google Scholar
Deecke, L., Bashore, T., Brunia, C. H. M., Grüncwald-Zuberbier, E., Griinewald, G. & Kristeva, R. (1984) Movement-associated potentials and motor control. Annals of the New York Academy of Sciences 425:398428. [CCW]CrossRefGoogle ScholarPubMed
Deecke, L., Grözinger, B. & Kornhuber, H. H. (1976) Voluntary finger movement in man: Cerebral potentials and theory. Biological Cybernetics 23:99119. [taBL, CCW]CrossRefGoogle ScholarPubMed
Deecke, L. & Kornhuber, H. H. (1978) An electrical sign of participation of the mesial “supplementary” motor cortex in human voluntary finger movement. Brain Research 159: 473–76. [taBL]CrossRefGoogle ScholarPubMed
Dennett, D. C. (1978) Brainstorms: Philosophical essays on mind and psychology. Bradford Books. [CCW]Google Scholar
Dennett, D. C. (1984) Elbow room: The varieties of free will worth wanting. Bradford/MIT Press. [CCW]Google Scholar
Doty, R. W. (1975) consciousness from neurons. Acta Neurobiologiae Experimentalis 35:791804. [RWD]Google ScholarPubMed
Eccles, J. C. (1980) The human psyche. Springer. [taBL]CrossRefGoogle Scholar
Eccles, J. C. (1982a) The initiation of voluntary movements by the supplementary motor areas. Archiv für Psychiatric und Nervenkrankheiten 231:423–41. [taBL]CrossRefGoogle Scholar
Eccles, J. C. (1982b) How the self acts on the brain. Psychoneuroendocrinology 7:271–83. [JCE]CrossRefGoogle ScholarPubMed
Efron, R. (1973) An invariant characteristic of perceptual systems in the time domain. In: Attention and performance, vol. 4, ed. Kornblum, S.. Academic Press. [taBL]Google Scholar
Fitts, P. M. & Deininger, R. L. (1954) S-R compatibility and information reduction. Journal of Experimental Psychology 48:483–92. [CBR]CrossRefGoogle Scholar
Flachsbart-Kraft, F. (1930) Messung von Hemmungszeiten. Zeitschrift für Psychology 117:73145. [ES]Google Scholar
Fodor, J. (1983) The modularity of mind. Bradford/MIT Press. [CCW]CrossRefGoogle Scholar
Freud, S. (1925) Collected papers. Hogarth Press. [CCW]Google Scholar
Freud, S. (1915/1955) The unconscious. Standard Edition. Hogarth Press. [taBL]Google Scholar
Gemba, H., Sasaki, S. & Hashimoto, S. (1980) Distribution of premovement slow cortical potentials associated with self-paced hand movements in monkeys. Neuroscience Letters 20:159–63. [CCW]CrossRefGoogle ScholarPubMed
Gilden, L., Vaughan, H. C. Jr. & Costa, L. D. (1966) Summated human EEC potentials with voluntary movement. Electroencephalography and Clinical Neurophysiology 20:433–38. [taBL]CrossRefGoogle Scholar
Goldberg, G., Kwan, H. C., Borrett, D. & Murphy, J. T. (1984) Differential topography of the movement-associated scalp potential with internal vs. external dependence of movement timing. Archives of Physical Medicine and Rehabilitation 65:630. [rBL]Google Scholar
Green, D. M. & Swets, J. (1966) Signal detection theory and psychophysics. Wiley. [LEM]Google Scholar
Grey Walter, W., Cooper, R., Aldridge, V. J., McCallum, W. C. & Winter, A. L. (1964) Contingent negative variation: An electric sign of sensorimotor association and expectancy in the human brain. Nature 203:380–84. [RL]CrossRefGoogle Scholar
Grözinger, B., Kornhuber, H. H. & Kriebel, J. (1977) Human cerebral potentials preceding speech production, phonation and movements of the mouth and tongue with reference to respiratory and extracerebral potentials. In: Progress in clinical neurophysiology, vol. 3, Language and hemispheric specialization in man: Cerebral event-related potentials, ed. Desmedt, J. E.. Karger. [rBL]Google Scholar
Grünewald-Zuberbier, E., Graünewald, G. & Jung, R. (1978) Slow potentials of the human precentral and parietal cortex during goal-directed movements (Zielbewegungspotentiale). Journal of Physiology (London) 284:181–82P. [RJ]Google ScholarPubMed
Haber, R. N. & Hershenson, M. (1980) The psychology of visual perception, 2d ed.Holt, Rinehart & Winston. [RL]Google Scholar
Hammer, A. (1914) Untersuchung der Hemmung einer vorbereiteten Willenshandlung. Psychologische Studien 9:321–65. [ES]Google Scholar
Harnad, S. (1982) Consciousness: An afterthought. Cognition and Brain Theory 5:2947. [BGB, tarBL]Google Scholar
Harnad, S. (unpublished) Conscious events cannot be localized in real time. [taBL]Google Scholar
Hashimoto, S., Gemba, H. & Sasaki, K. (1980) Premovement slow cortical potentials and required muscle force in self-paced hand movements in the monkey. Brain Research 197:415–23. [CCW]CrossRefGoogle ScholarPubMed
Hebb, D. O. (1980) Essay on mind. Erlbaum. [CHV]Google Scholar
Hillyard, S. A., Simpson, G. V., Woods, D. L., Van Voorhis, S. & Munte, T. F. (1984) Event-related brain potentials and selective attention to different modalities. In: Cortical integration, ed. Reinoso-Suarez, F. & Ajmone-Marsan, C.. Raven Press. [RL]Google Scholar
Hofstadler, D. R. (1979) Gödel, Escher, Bach: An eternal golden braid. Basic Books. [CCW]Google Scholar
Holender, D. (1986) Semantic activation without conscious identification in dichotic listening, parafoveal vision, and visual masking: A survey and appraisal. Behavioral and Brain Sciences, in press. [RL]CrossRefGoogle Scholar
Hook, S., ed. (1960). Dimensions of mind. New York University Press. [taBL]Google Scholar
Hunzelmann, N. & Spillmann, L. (1984) Movement adaptation in the peripheral retina. Vision Research 24:1765–69. [RWD]CrossRefGoogle ScholarPubMed
Jack, J. J. B., Redman, S. J. & Wong, K. (1981) The components of synaptic potentials evoked in cat spinal motoneurones by impulses in single group la afferents. Journal of Physiology 321:6596. [JCE]CrossRefGoogle Scholar
Jacobson, E. (1930a) Electrical measurements of neuromuscular states during mental activities. 1. Imagination of movement involving skeletal muscle. American Journal of Physiology 91:567608. [CHV]CrossRefGoogle Scholar
Jacobson, E. (1930b) Electrical measurements of neuromuscular states during mental activities. 2. Imagination and recollection of various muscular acts. American Journal of Physiology 94:2234. [CHV]CrossRefGoogle Scholar
James, W. (1890) The principles of psijchology. Holt. Dover repr., 1950. [BGB, ES]Google Scholar
Jonides, J. (1981) Voluntary versus automatic control over the mind's eye's movement. In: Attention and performance, vol. 9, ed. Long, J. B. & Baddeley, A. D.. Erlbaum [BGB]Google Scholar
Jung, R. (1981) Perception and action. In: Advances in physiological sciences. Regulatory functions of the CNS: Motion and organization principles, ed. Szentágothai, J., Palkovits, M., & Hámori, J.. Pergamon Press; Adadémiai Kiadó. [RJ]Google Scholar
Jung, R. (1982) Postural support of goal-directed movements: The preparation and guidance of voluntary action in man. Acta Biologica Academiae Scientiarvm Hungaricae 33:201–13. [RJ]Google ScholarPubMed
Jung, R. (1984) Electrophysiological cues of the language dominant hemisphere in man: Slow brain potentials during language processing and writing. Experimental Brain Research Suppl. 9:430–50. [RJ]Google Scholar
Jung, R., Altenmüller, E. & Natseh, B. (1984) Zur Hemisphärendominanz für Sprache and Rechnen: Elektrophysiologische Korrelate einer Linksdominanz bei Linkshändem. Neuropsychologia 22:755–75. [RJ]CrossRefGoogle Scholar
Jung, R., Hufschmidt, A. & Moschallski, W. (1982) Langsame Hirnpotentiale beim Schreiben: Die Wechselwirking von Schreibhand und Sprachdominanz bei Rechtshandem. Archiv für Psychiatric und Nervenkrankheiten 232:305–24. [RJ]CrossRefGoogle Scholar
Kaufmann, W. (1961) The faith of a heretic. Doubleday. [taBL]Google Scholar
Korn, H. & Faber, D. S. (1985) Regulation and significance of probabilistic release mechanisms at central synapses. In: New insights into synaptic function, ed. Edelman, G. M., Gall, W. E. & Cowan, W. M., Neurosciences Research Foundation. Wiley. In press. [JCE]Google Scholar
Kornhuber, H. H. & Deecke, L. (1965) Hirnpotentialänderungen bei Willkürbewegungen und passiven Bewegungen des Menschen: Bereitschaftspotential und reafferente Potentiale. Pflügers Archiv für Gesamte Physiologic 284:117. [RWD, RJ, taBL, RN]CrossRefGoogle Scholar
Krech, D. (1969) Does behavior really need a brain? In: William James: Unfinished business, ed. MeLeod, R. B.. American Psychological Association. [rBL]Google Scholar
Küpfmüller, K. (1971) Grundlagen der Informationstheorie und der Kybernetik. In: Physiologic des Menschen, vol. 10, Allgemeine Neurophysiologie, ed. Gauer, O. H., Kramer, K., & Jung, R.. Urban & Schwarzenberg. [RJ]Google Scholar
Laszlo, J. (1966) The performance of a simple motor task with kinaesthetic sense loss. Quarterly Journal of Experimental Psychology 18:18. [rBL, CHV]CrossRefGoogle Scholar
Latto, R. & Campion, J. (1986) Approaches to consciousness: Psychophysics or philosophy? Behavioral and Brain Sciences, in press. [RL]CrossRefGoogle Scholar
Leibniz, G. W. F. von (1704/1916). New essays concerning human understanding. Macmillan. [LEM]Google Scholar
Libet, B. (1965) Cortical activation in conscious and unconscious experience. Perspectives in Biology and Medicine 9:7786. [tarBL]CrossRefGoogle ScholarPubMed
Libet, B. (1966) Brain stimulation and the threshold of conscious experience. In: Brain and conscious experience, ed. Eccles, J. C.. Springer. [tarBL, CCW]Google Scholar
Libet, B. (1973) Electrical stimulation of cortex in human subjects, and conscious sensory aspects. In: Handbook of sensory physiology, ed. Iggo, A.. Springer. [JCE, tarBL, CCW]Google Scholar
Libet, B. (1978) Neuronal vs. subjective timing for a conscious sensory experience. In: Cerebral correlates of conscious experience, ed. Buser, P. A. & Rougeul-Buser, A.. Elsevier/North Holland Biomedical Press. [rBL]Google Scholar
Libet, B. (1979) Can a theory based on some cell properties define the timing of mental activities? Behavioral and Brain Sciences 2:270–71. [rBL]CrossRefGoogle Scholar
Libet, B. (1981a) The experimental evidence for subjective referral of a sensory experience backwards in time. Philosophy of Science 48:182–97. [tarBL, CCW]CrossRefGoogle Scholar
Libet, B. (1981b) ERPs and conscious awareness; neurons and glia as generators. In: Electrophysiological approaches to human cognitive processing. NRP Bulletin, vol. 20, ed. Galambos, R. & Hillyard, S. A., MIT Press. [tarBL]Google Scholar
Libet, B. (1982) Brain stimulation in the study of neuronal functions for conscious sensory experiences. Human Neurobiology 1:235–42. [tarBL]Google Scholar
Libet, B., Gleason, C. A., Wright, E. W. & Pearl, D. K. (1983) Time of conscious intention to act in relation to onset of cerebral activities (readiness-potential); the unconscious initiation of a freely voluntary act. Brain 106:623–42. [BGB, tarBL, GU, CCW]CrossRefGoogle ScholarPubMed
Libet, B., Wright, E. W. Jr, Feinstein, B. & Pearl, D. K. (1979) Subjective referral of the timing for a conscious sensory experience. A functional role for the somatosensory specific projection system in man. Brain 102:193224. [RL, tarBL, CCW]CrossRefGoogle ScholarPubMed
Libet, B., Wright, E. W. Jr & Gleason, C. A. (1982) Readiness-potentials preceding unrestricted “spontaneous” vs. pre-planned voluntary acts. Electroencephalography and Clinical Neurophysiology 54:322–35. [tarBL, JSS]CrossRefGoogle ScholarPubMed
Libet, B., Wright, E. W. Jr & Gleason, C. A. (1983) Preparation- or intention-to-act, in relation to pre-event potentials recorded at the vertex. Electroencephalography and Clinical Neurophysiology 56:367–72. [RL, tarBL]CrossRefGoogle ScholarPubMed
McCloskey, D. I., Colebatch, J. G., Potter, E. K. & Burke, D. (1983) Judgements about onset of rapid voluntary movements in man. Journal of Neurophysiology 49:851–63. [taBL, CCW]CrossRefGoogle ScholarPubMed
MacKay, D. M. (1951) Mindlike behavioin- in artefacts. British Journal for the Philosophy of Science 2:105121. [DMM]CrossRefGoogle Scholar
MacKay, D. M. (1965) From mechanism to mind. In: Brain and mind, ed. Smythies, J. R.. Routledge and Kegan Paul. [DMM]Google Scholar
MacKay, D. M. (1966) Cerebral organizaton and the conscious control of action. In: Brain and conscious experience, ed. Eccles, J. C.. Springer. [DMM]Google Scholar
MacKay, D. M. (1980) The interdependence of mind and brain. Neuroscience 5:1389–91. [DMM]CrossRefGoogle ScholarPubMed
MacKay, D. M. (1982) Ourselves and our brains: Duality without dualism. Psychoneuroendocrinology 7:285–94. [DMM]CrossRefGoogle ScholarPubMed
Margenau, H. (1984) The miracle of existence. Ox Bow Press. [JCE, taBL, RJN]Google Scholar
Melzack, R. & Bromage, P. R. (1973) Experimental phantom limbs. Experimental Neurology 39:261–69. [rBL, CHV]CrossRefGoogle ScholarPubMed
Milgram, S. (1974) Obedience to authority: An experimental view. Harper & Row. [RL]Google Scholar
Nagel, T. (1979). Mortal questions. Cambridge University Press. [taBL]Google Scholar
Näätänen, R. (1971) Non-aging fore-periods and simple reaction time. Acta Psychologica 35:316–27. [RN]CrossRefGoogle Scholar
Näätänen, R. (in press) Selective attention and stimulus processing: Reflections in evoked potentials, magnetoencephalograms, and regional cerebral blood flow. In: Attention and performance, vol. 11, ed. Posner, M. I. & Marin, O. S.. Erlbaum. [RN]Google Scholar
Näätänen, R., Gaillard, A. W. K. & Mäntysalo, S. (1978) Early selective-attention effect on evoked potential reinterpreted. Acta Psychologies 42:313–29. [RN]CrossRefGoogle ScholarPubMed
Näätänen, R., Gaillard, A. W. K. & Mäntysalo, S. (1980) Brain potential correlates of voluntary and involuntary attention. In: Motivation, motor and sensory processes of the brain: Electrical potentials, behaviour and clinical use, ed. Kornhuber, H. H. & Deecke, L.. Elsevier. [RN]Google Scholar
Näätänen, R. & Koskinen, P. (1975) Simple reaction times with very small imperative-stimulus probabilities. Acta Psychologica 39:4350. [RN]CrossRefGoogle Scholar
Näätänen, R. & Merisalo, A. (1977) Expectancy and preparation in simple reaction time. In: Attention and performance, vol. 6, ed. Domic, S.. Erlbaum. [RN]Google Scholar
Nääntänen, R., Sams, M. & Alho, K. (in press) The mismatch negativity: The ERP sign of a cerebral mismatch process. Electroencephalography and Clinical Neurophysiology, Supplement. [RN]Google Scholar
Näätänen, R., Simpson, M. & Loveless, N. E. (1982) Stimulus deviance and evoked potentials. Biological Psychology 14:5398. [RN]CrossRefGoogle ScholarPubMed
Nisbett, R. E. & Wilson, R. E. (1977) Telling more than we can know: Verbal reports on mental processes. Psychological Review 84:231–59. [CHV]CrossRefGoogle Scholar
Norman, D. A. & Shallice, R. (1980) Attention to action: Willed and automatic control of behavior. Technical report, Center for Human Information Processing, University of California, San Diego. [BB]Google Scholar
Oshima, T. (1983) Intracortical organization of arousal as a model of dynamic neuronal processes that may involve a set for movements. In: Motor control mechanisms in health and disease, ed. Desmedt, J. E.. Raven Press. [JCE]Google Scholar
Papakostopoulos, D. & Cooper, R. (1973) The contingent negative variation and the excitability of the spinal monosynaptic reflex. Journal of Neurology, Neurosurgery and Psychiatry 36:1003–10. [CHV]CrossRefGoogle ScholarPubMed
Penfield, W. (1958) The excitable cortex in conscious man. Liverpool University Press. [RL, taBL]Google Scholar
Popper, K. R. & Eccles, J. C. (1977) The self and its brain. Springer [taBL, RJN, CCW]CrossRefGoogle Scholar
Posner, M. I. (1980) The orienting of attention. Quarterly Journal of Experimental Psychology 32:325. [MDR]CrossRefGoogle ScholarPubMed
Pylyshyn, Z. (1973) What the mind's eye tells the mind's brain: A critique of mental imagery. Psychological Bulletin 80:124. [CHV]CrossRefGoogle Scholar
Reason, J. (1979) Actions not as planned: The effects of automatisation. In: Aspects of consciousness, vol. 1, ed. Underwood, G. & Stevens, R.. Academic Press. [GU]Google Scholar
Remington, R. (1980) Attention and saccadic eye movements. Journal of Expericntal Psychology: Human Perception and Performance 6:726–44. [BGB]Google ScholarPubMed
Roland, P. E. (1978) Sensory feedback to the cerebral cortex during voluntary movement in man. Behavioral and Brain Sciences 1:129–71. [RWD]CrossRefGoogle Scholar
Rollman, G. B. (1974) Electrocutaneous stimulation. In: Cutaneous communication systents and devices, ed. Geldard, F. A.. Psychonomic Society. [GBR]Google Scholar
Rozhkova, G. I., Nickolayev, P. P. & Shchadrin, V. E. (1982) Perception of stabilized retinal stimuli in dichoptic viewing conditions. Vision Research 22:293302. [RWD]CrossRefGoogle ScholarPubMed
Schreiber, H., Lang, M., Lang, W., Kornhuber, A., Heise, B., Kcidel, M., Deecke, L. & Kornhuber, H. H. (1983) Frontal hemispheric differences of the Bereitschaftspotential associated with writing and drawing. Human Neurobiology 2:197202. [RJ]Google ScholarPubMed
Shibasaki, H., Barrett, G., Halliday, E. & Halliday, A. M. (1980) Components of the movement-related cortical potential and their scalp topography. Electroencephalography and Clinical Neurophysiology 49:213–26. [taBL]CrossRefGoogle ScholarPubMed
Skinner, B. F. (1974) About behaviorism. Alfred A. Knopf. [CHV]Google Scholar
Sperry, R. W. (1980) Mind-brain interaction: Mentalism, yes; dualism, no. Neuroscience 5:195206. [tarBL]CrossRefGoogle Scholar
Stamm, J. S. & Gillespie, O. (1980) Task acquisition with feedback of steady potential shifts from monkeys prefrontal cortex. In: Motivation, motor and sensory processes of the brain: Electrical potentials, behavior and clinical use, ed. Kornhuber, H. H. & Deecke, L.. Elsevier. [JSS]Google Scholar
Sternberg, S. & Knoll, R. L. (1973) The perception of temporal order: Fundamental issues and a general model. In: Attention and performance, vol. 4, ed. Kornblum, S.. Academic Press. [taBL, CCW]Google Scholar
Swets, J. A., Tanner, W. P. & Birdsall, T. G. (1961). Decision processes in perception. Psychological Review 68:301–40. [LEM]CrossRefGoogle ScholarPubMed
Thorpe, W. H. (1974) Animal nature and human nature. Methuen. [taBL]Google Scholar
Underwood, G. (1982) Attention and awareness in cognitive and motor skills. In: Aspects of consciousness, vol. 3, ed. Underwood, G.. Academic Press. [GU]Google Scholar
Uttal, W. R. (1971) The psychobiological silly season, or what happens when neurophysiological data become psychological theories. Journal of General Psychology 84:151–66. [BB]Google Scholar
Vanderwolf, C. H. (1983a) The influence of psychological concepts on brain-behavior research. In: Behavioral approaches to brain research, ed. Robinson, T. E.. Oxford University Press. [CHV]Google Scholar
Vanderwolf, C. H. (1983b) The role of the cerebral cortex and ascending activating systems in the control of behavior. In: Handbook of behavioral neurobiology, vol. 6, Motivation, ed. Satinoff, E. & Teitelbaum, P.. Plenum Press. [CHV]Google Scholar
Vanderwolf, C. H. & Robinson, T. E. (1981) Reticulo-cortical activity and behavior: A critique of the arousal theory and a new synthesis. Behavioral and Brain Sciences 4:459514. [CHV]CrossRefGoogle Scholar
Vaughan, H. G. Jr (1982) The neural origins of human event-related potentials. Annals of the New York Academy of Sciences 388:125–38. [CCW]CrossRefGoogle ScholarPubMed
Vaughan, H. C. Jr, Costa, L. D. & Ritter, W. (1968) Topography of the human motor potential. Electroencephalography and Clinical Neurophysiology 25:110. [taBL]CrossRefGoogle ScholarPubMed
Wagstaff, G. F. (1981). Hypnosis, compliance and belief. St. Martin's Press. [RL]Google Scholar
Wasserman, G. S. (1978) Limulus psychophysics: Temporal summation in the ventral eye. Journal of Experimental Psychology: Ceneral 107:276–86. [CSW]CrossRefGoogle ScholarPubMed
Wasserman, G. S. & Kong, K.-L. (1979) Absolute timing of mental activities. Behavioral and Brain Sciences 2:243304. [GSW]CrossRefGoogle Scholar
Weisstein, N. (1972) Metacontrast. In: Handbook of sensory physiology, vol. 7(4). Visual Psychophysics, ed. Jameson, D. & Hurvich, L.. Springer. [BB]Google Scholar
Whyte, L. L. (1960) The unconscious before Freud. Basic Books. [taBL]Google Scholar
Wood, C. C. & Allison, T. (1981) Interpretation of evoked potentials: A neurophysiological perspective. Canadian Journal of Psychology 35: 113–35. [CCW]CrossRefGoogle ScholarPubMed
Woodworth, R. S. (1938) Experimental psychology. Holt. [ES]Google Scholar
Wundt, W. (1874/1904). Principles of physiological psychology, vol. 2. Macmillan. [BGB]Google Scholar