Psychology Unconscious Processes
John F. Kihlstrom
  • LAST REVIEWED: 26 May 2023
  • LAST MODIFIED: 26 May 2023
  • DOI: 10.1093/obo/9780199828340-0228


Consciousness has to do with two aspects of mental life: monitoring ourselves, our phenomenal awareness of our experiences, thoughts, and actions; and controlling ourselves, engaging in voluntary behavior that goes beyond reflex, instinct, and conditioned response. The unconscious mind—whether it exists at all, and if so what its scope and limits are—has been an important theoretical issue since the beginning of scientific psychology. There are of course many physical and biological processes that, in some sense, proceed unconsciously: the orbiting of planets around the sun and photosynthesis are two examples. Changes in blood pressure are not accessible to phenomenal awareness; and the brain activity which gives rise to consciousness itself goes on unconsciously (neurosurgeons assure us that there is no afference in the brain). But there is little point in talking about something being unconscious if that same thing cannot also be conscious, in the sense of being accessible to phenomenal awareness and voluntary control. Therefore, the adjective unconscious only makes sense when applied to mental states and mental activity, as an adjectival contrast to conscious. Mental states come in various forms—namely cognition (percepts, memories, thoughts, and knowledge acquired through learning), emotion (positive and negative feelings), and motivation (desires and goals of approach and avoidance). Usually, these mental states are accessible to consciousness, in that people are generally aware of what they are thinking, what they want and feel. “The unconscious” is shorthand for mental states and processes that are inaccessible to introspective phenomenal awareness and voluntary control. The question is whether, and to what extent, mental states can exist (and mental activities transpire) outside the scope of phenomenal awareness and voluntary control. Objection: If these mental states and activities are unconscious, how are we to know them? Answer: We know them indirectly by virtue of their effects on our ongoing conscious experience, thought, and action. Question: If there are two kinds of mental states and processes, conscious and unconscious, how do they compare and contrast? Answer: In principle, unconscious processes differ from conscious processes because they operate outside phenomenal awareness. And because conscious awareness is the logical prerequisite for conscious control; unconscious processes are not susceptible to voluntary self-regulation. Other differences between conscious and unconscious processes are empirical questions. This revision adds items that appeared through 2022.

Textbooks and Monographs

There is only one textbook specifically devoted to unconscious mental life: Weinberger and Stoycheva 2020. However, there are several textbooks and monographs that discuss various aspects of the unconscious in the context of the more general philosophical, psychological, and neuroscientific literature on consciousness. The best of these is Farthing 1992—now out of print, but well worth finding on the used book market. Revonsuo 2018; Wallace, et al. 2011; and Zeman 2002 provide more up-to-date coverage. Although none are as comprehensive as Farthing, they are good alternatives for classroom use. Blackmore and Troscianko 2018 focuses mostly on the mind-body problem. Schechter 2018 examines the implications of neurological patients with cerebral commissurotomies. There have been many philosophical monographs dealing with the mind-body problem and other aspects of consciousness, some of which also discuss the problem of the unconscious. Seager 2016 provides a comprehensive textbook treatment of the philosophical debates, but some flavor of the current scene can be gleaned from Searle 1997 and Natsoulas 2018. There is also Blackmore 2005, which is a contribution to Oxford’s Very Short Introduction series, and even a graphic treatment of the topic in Papineau and Selina 2000. Schechter 2018 reviews the implications for consciousness of neurological patients with disconnected hemispheres.

  • Blackmore, S. 2005. Consciousness: A very short introduction. Oxford: Oxford Univ. Press.

    DOI: 10.1093/actrade/9780192805850.001.0001

    Too short to serve as a standalone text for a course in consciousness but an excellent ancillary text for courses on philosophy of mind, cognitive psychology, and cognitive neuroscience—and, as intended, as an introduction for the general public.

  • Blackmore, S., and E. D. Troscianko. 2018. Consciousness: An introduction. 3d ed. Abingdon, UK: Routledge.

    DOI: 10.4324/9781315755021

    Expressly intended as an undergraduate text, like most books on consciousness it focuses mostly on the mind-body problem but also covers the evolution of consciousness, consciousness in artificial intelligence, and altered states of consciousness.

  • Farthing, G. W. 1992. The psychology of consciousness. Englewood Cliffs, NJ: Prentice-Hall.

    Some twenty-five years after its original publication, this remains the best and most comprehensive textbook for a course on consciousness: the model for any who would aspire to replace it. Covers, sometimes in multiple chapters, introspection, the mind-body problem, explicit-implicit dissociations, daydreaming, hypnosis, sleep and dreams, meditation, and psychedelic drugs.

  • Natsoulas, T. 2018. States of consciousness: The pulses of experience. New York: Cambridge Univ. Press.

    DOI: 10.1017/9781316017791

    Comprehensive treatment of classical and modern discussions of consciousness by one of the pioneers of the “consciousness revolution” in psychology, making connections between the philosophical and psychological literature.

  • Papineau, D., and H. Selina. 2000. Introducing consciousness: A graphic guide. London: Icon Books.

    Comprehensive illustrated inquiry into the mind-body problem, “the last frontier of science”; not just for young people and other reluctant readers.

  • Revonsuo, A. 2018. Foundations of consciousness. Oxford: Routledge.

    In the absence of a new edition of Farthing, this volume can serve as the core textbook in an undergraduate course on consciousness. Excellent coverage of the neural correlates of consciousness and other aspects of the mind-body problem. Compared to Farthing 1992, there is less extensive coverage of altered states of consciousness.

  • Schechter, E. 2018. Self-consciousness and “split” brains: The minds’ I. New York: Oxford Univ. Press.

    DOI: 10.1093/oso/9780198809654.001.0001

    Reviews the psychological consequences of cerebral commissurotomy and argues that in such cases, the left and right hemispheres support separate streams of consciousness.

  • Seager, W. 2016. Theories of consciousness; An introduction and assessment. 2d ed. New York: Routledge.

    DOI: 10.4324/9780203485583

    Comprehensive coverage of contemporary philosophical analyses of consciousness. A genuine textbook for courses in philosophy.

  • Searle, J. R. 1997. The mystery of consciousness. 1st ed. New York: New York Review of Books.

    Reprints Searle’s reviews of major monographs on consciousness by Daniel Dennett, David Chalmers, and others, as well as responses from the authors and rejoinders to them. An excellent resource.

  • Wallace, B., B. B. Oswald, and L. E. Fisher. 2011. Consciousness and behavior. 5th ed. Dubuque, IA: KendallHunt.

    Also a good choice as the text for an undergraduate course, with much the same coverage as Farthing 1992, and the addition of chapters on parapsychology and sensory deprivation.

  • Weinberger, J., and V. Stoycheva. 2020. The unconscious: Theory, research, and clinical implications. New York: Guilford.

    One of the few textbook-length treatments of unconscious mental life; covers clinical as well as experimental research, including classical and modern psychoanalytic theory.

  • Zeman, A. 2002. Consciousness: A user’s guide. New Haven, CT: Yale Univ. Press.

    Written by a practicing neurologist, this is also an excellent choice for a core text. Contains lots of material on the neural bases of consciousness but less on altered states and unconscious processes.

back to top

Users without a subscription are not able to see the full content on this page. Please subscribe or login.

How to Subscribe

Oxford Bibliographies Online is available by subscription and perpetual access to institutions. For more information or to contact an Oxford Sales Representative click here.