Skip to main content
    • Aa
    • Aa

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

  • Benjamin Libet (a1)

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.

Hide All
Ach N. (1935) Analyse des Willens. Urban & Sehwarzenberg. [ES]
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]
Allan L. G. (1978) The attention switching model: Implications for research in schizophrenia. Journal of Psychiatric Research 14:195202. [taBL]
Arezzo J. & Vaughan H. G. Jr (1975) Cortical potentials associated with voluntary movements in the monkey. Brain Research 88:99104. [CCW]
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]
Beloff J. (1962) The existence of mind. MacGibbon and Kee. [taBL]
Bolanowski S. J. Jr & Doty R. W. (1982) Monocular loss, binocular maintenance of perception in Ganzfeld. Abstracts, Society for Neuroscience 8:675. [RWD]
Boring E. G. (1957) A history of experimental psychology. Applcton-Century-Crbfts. [taBL]
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]
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]
Bridgeman B. (1971) Metacontrast and lateral inhibition. Psychological Review 78:528–39. [BB]
Bridgeman B. (1978) Distributed sensory coding applied to simulations of iconic storage and metaconstrast. Bulletin of Mathematical Biology 40: 605–23. [BB]
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]
Broadbent D. E. (1971) Decision and stress. Academic Press. [GU]
Campion J. & Latto R. (1985) What is a blindsight? Behavioral and Brain Sciences 8:755757. [RL]
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]
Cheesman J. & Merikle P. M. (1984) Priming with and without awareness. Perception & Psychophysics 36:387–95. [PMM]
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]
Churchland P. S. (1981a) The timing of sensations: Reply to Libct. Philosophy of Science 48:492–97. [CCW]
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]
Creutzfeldt O. D. & Rager G. (1978) In: Cerebral correlates of conscious experience, ed. Buser P. A. & Rougeul-Buser A.. Elsevier/North Holland. [taBL]
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]
Deecke L., Grözinger B. & Kornhuber H. H. (1976) Voluntary finger movement in man: Cerebral potentials and theory. Biological Cybernetics 23:99119. [taBL, CCW]
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]
Dennett D. C. (1978) Brainstorms: Philosophical essays on mind and psychology. Bradford Books. [CCW]
Dennett D. C. (1984) Elbow room: The varieties of free will worth wanting. Bradford/MIT Press. [CCW]
Doty R. W. (1975) consciousness from neurons. Acta Neurobiologiae Experimentalis 35:791804. [RWD]
Eccles J. C. (1980) The human psyche. Springer. [taBL]
Eccles J. C. (1982a) The initiation of voluntary movements by the supplementary motor areas. Archiv für Psychiatric und Nervenkrankheiten 231:423–41. [taBL]
Eccles J. C. (1982b) How the self acts on the brain. Psychoneuroendocrinology 7:271–83. [JCE]
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]
Fitts P. M. & Deininger R. L. (1954) S-R compatibility and information reduction. Journal of Experimental Psychology 48:483–92. [CBR]
Flachsbart-Kraft F. (1930) Messung von Hemmungszeiten. Zeitschrift für Psychology 117:73145. [ES]
Fodor J. (1983) The modularity of mind. Bradford/MIT Press. [CCW]
Freud S. (1925) Collected papers. Hogarth Press. [CCW]
Freud S. (1915/1955) The unconscious. Standard Edition. Hogarth Press. [taBL]
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]
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]
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]
Green D. M. & Swets J. (1966) Signal detection theory and psychophysics. Wiley. [LEM]
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]
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]
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]
Haber R. N. & Hershenson M. (1980) The psychology of visual perception, 2d ed.Holt, Rinehart & Winston. [RL]
Hammer A. (1914) Untersuchung der Hemmung einer vorbereiteten Willenshandlung. Psychologische Studien 9:321–65. [ES]
Harnad S. (1982) Consciousness: An afterthought. Cognition and Brain Theory 5:2947. [BGB, tarBL]
Harnad S. (unpublished) Conscious events cannot be localized in real time. [taBL]
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]
Hebb D. O. (1980) Essay on mind. Erlbaum. [CHV]
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]
Hofstadler D. R. (1979) Gödel, Escher, Bach: An eternal golden braid. Basic Books. [CCW]
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]
Hook S., ed. (1960). Dimensions of mind. New York University Press. [taBL]
Hunzelmann N. & Spillmann L. (1984) Movement adaptation in the peripheral retina. Vision Research 24:1765–69. [RWD]
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]
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]
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]
James W. (1890) The principles of psijchology. Holt. Dover repr., 1950. [BGB, ES]
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]
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]
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]
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]
Jung R., Altenmüller E. & Natseh B. (1984) Zur Hemisphärendominanz für Sprache and Rechnen: Elektrophysiologische Korrelate einer Linksdominanz bei Linkshändem. Neuropsychologia 22:755–75. [RJ]
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]
Kaufmann W. (1961) The faith of a heretic. Doubleday. [taBL]
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]
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]
Krech D. (1969) Does behavior really need a brain? In: William James: Unfinished business, ed. MeLeod R. B.. American Psychological Association. [rBL]
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]
Laszlo J. (1966) The performance of a simple motor task with kinaesthetic sense loss. Quarterly Journal of Experimental Psychology 18:18. [rBL, CHV]
Latto R. & Campion J. (1986) Approaches to consciousness: Psychophysics or philosophy? Behavioral and Brain Sciences, in press. [RL]
Leibniz G. W. F. von (1704/1916). New essays concerning human understanding. Macmillan. [LEM]
Libet B. (1965) Cortical activation in conscious and unconscious experience. Perspectives in Biology and Medicine 9:7786. [tarBL]
Libet B. (1966) Brain stimulation and the threshold of conscious experience. In: Brain and conscious experience, ed. Eccles J. C.. Springer. [tarBL, CCW]
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]
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]
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]
Libet B. (1981a) The experimental evidence for subjective referral of a sensory experience backwards in time. Philosophy of Science 48:182–97. [tarBL, CCW]
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]
Libet B. (1982) Brain stimulation in the study of neuronal functions for conscious sensory experiences. Human Neurobiology 1:235–42. [tarBL]
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]
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]
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]
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]
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]
MacKay D. M. (1951) Mindlike behavioin- in artefacts. British Journal for the Philosophy of Science 2:105121. [DMM]
MacKay D. M. (1965) From mechanism to mind. In: Brain and mind, ed. Smythies J. R.. Routledge and Kegan Paul. [DMM]
MacKay D. M. (1966) Cerebral organizaton and the conscious control of action. In: Brain and conscious experience, ed. Eccles J. C.. Springer. [DMM]
MacKay D. M. (1980) The interdependence of mind and brain. Neuroscience 5:1389–91. [DMM]
MacKay D. M. (1982) Ourselves and our brains: Duality without dualism. Psychoneuroendocrinology 7:285–94. [DMM]
Margenau H. (1984) The miracle of existence. Ox Bow Press. [JCE, taBL, RJN]
Melzack R. & Bromage P. R. (1973) Experimental phantom limbs. Experimental Neurology 39:261–69. [rBL, CHV]
Milgram S. (1974) Obedience to authority: An experimental view. Harper & Row. [RL]
Nagel T. (1979). Mortal questions. Cambridge University Press. [taBL]
Näätänen R. (1971) Non-aging fore-periods and simple reaction time. Acta Psychologica 35:316–27. [RN]
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]
Näätänen R., Gaillard A. W. K. & Mäntysalo S. (1978) Early selective-attention effect on evoked potential reinterpreted. Acta Psychologies 42:313–29. [RN]
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]
Näätänen R. & Koskinen P. (1975) Simple reaction times with very small imperative-stimulus probabilities. Acta Psychologica 39:4350. [RN]
Näätänen R. & Merisalo A. (1977) Expectancy and preparation in simple reaction time. In: Attention and performance, vol. 6, ed. Domic S.. Erlbaum. [RN]
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]
Näätänen R., Simpson M. & Loveless N. E. (1982) Stimulus deviance and evoked potentials. Biological Psychology 14:5398. [RN]
Nisbett R. E. & Wilson R. E. (1977) Telling more than we can know: Verbal reports on mental processes. Psychological Review 84:231–59. [CHV]
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]
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]
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]
Penfield W. (1958) The excitable cortex in conscious man. Liverpool University Press. [RL, taBL]
Popper K. R. & Eccles J. C. (1977) The self and its brain. Springer [taBL, RJN, CCW]
Posner M. I. (1980) The orienting of attention. Quarterly Journal of Experimental Psychology 32:325. [MDR]
Pylyshyn Z. (1973) What the mind's eye tells the mind's brain: A critique of mental imagery. Psychological Bulletin 80:124. [CHV]
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]
Remington R. (1980) Attention and saccadic eye movements. Journal of Expericntal Psychology: Human Perception and Performance 6:726–44. [BGB]
Roland P. E. (1978) Sensory feedback to the cerebral cortex during voluntary movement in man. Behavioral and Brain Sciences 1:129–71. [RWD]
Rollman G. B. (1974) Electrocutaneous stimulation. In: Cutaneous communication systents and devices, ed. Geldard F. A.. Psychonomic Society. [GBR]
Rozhkova G. I., Nickolayev P. P. & Shchadrin V. E. (1982) Perception of stabilized retinal stimuli in dichoptic viewing conditions. Vision Research 22:293302. [RWD]
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]
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]
Skinner B. F. (1974) About behaviorism. Alfred A. Knopf. [CHV]
Sperry R. W. (1980) Mind-brain interaction: Mentalism, yes; dualism, no. Neuroscience 5:195206. [tarBL]
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]
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]
Swets J. A., Tanner W. P. & Birdsall T. G. (1961). Decision processes in perception. Psychological Review 68:301–40. [LEM]
Thorpe W. H. (1974) Animal nature and human nature. Methuen. [taBL]
Underwood G. (1982) Attention and awareness in cognitive and motor skills. In: Aspects of consciousness, vol. 3, ed. Underwood G.. Academic Press. [GU]
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]
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]
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]
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]
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]
Vaughan H. C. Jr, Costa L. D. & Ritter W. (1968) Topography of the human motor potential. Electroencephalography and Clinical Neurophysiology 25:110. [taBL]
Wagstaff G. F. (1981). Hypnosis, compliance and belief. St. Martin's Press. [RL]
Wasserman G. S. (1978) Limulus psychophysics: Temporal summation in the ventral eye. Journal of Experimental Psychology: Ceneral 107:276–86. [CSW]
Wasserman G. S. & Kong K.-L. (1979) Absolute timing of mental activities. Behavioral and Brain Sciences 2:243304. [GSW]
Weisstein N. (1972) Metacontrast. In: Handbook of sensory physiology, vol. 7(4). Visual Psychophysics, ed. Jameson D. & Hurvich L.. Springer. [BB]
Whyte L. L. (1960) The unconscious before Freud. Basic Books. [taBL]
Wood C. C. & Allison T. (1981) Interpretation of evoked potentials: A neurophysiological perspective. Canadian Journal of Psychology 35: 113–35. [CCW]
Woodworth R. S. (1938) Experimental psychology. Holt. [ES]
Wundt W. (1874/1904). Principles of physiological psychology, vol. 2. Macmillan. [BGB]
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Behavioral and Brain Sciences
  • ISSN: 0140-525X
  • EISSN: 1469-1825
  • URL: /core/journals/behavioral-and-brain-sciences
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 307 *
Loading metrics...

Abstract views

Total abstract views: 2513 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 20th October 2017. This data will be updated every 24 hours.