Abstract
In recent decades, Chinese scholars have introduced and modified several experimental paradigms for studying consciousness. With the advent of new fields, the paradigms used by Chinese scholars are essentially at the level of those used abroad. More importantly, they have proposed theories of consciousness including the concrete-and-steel model; the model of the interrelationship between consciousness, attention, and stimulus quality; the station monitoring room model; and the emergence theory. These theories have similarities as well as differences with classical theories of consciousness and unconsciousness, and have enriched the theoretical thinking in this field. However, there is still room for considerable theoretical and experimental development of the novel consciousness and unconsciousness research emerging from China; theories must be further developed and additional experimental research conducted in China.
The relationship between consciousness and unconsciousness is complex, and has perplexed scholars and philosophers for a long time. It remains an important topic in psychology (Zelazo et al., 2007). In this review, “consciousness” refers to cognitions one is aware of and “unconsciousness” to cognitions that cannot be perceived—mental processes “operating outside phenomenal awareness, [which] nevertheless influence conscious experience, thought, and action” (Kihlstrom, 1987, p. 1445). Influenced by Western psychology, consciousness and unconsciousness have been largely considered philosophical rather than scientific problems in China (Huo, 2006; Z.-M. Wang, 1993; W. D. Yang & Ye, 2014). However, some theoretical psychology scholars began exploring the topic of consciousness in the 1930s and 1940s. In the 1980s, Shu Pan, a psychologist well known for his contributions in establishing Chinese theoretical psychology, led a group of experts to systematically explore this issue and made numerous academic achievements as a result, arguably the most important being the book, Consciousness: A Research of Psychology (Pan, 1998). In this book, Pan emphasized the importance of consciousness in psychology, discussed the definition and nature of consciousness in depth, and pointed out that “consciousness is a fundamental question of psychology. Only if we study the issue of consciousness, can the other problems of psychology be learned and the scientific system of psychology be built” (1998, p. 9). In 1987, Wenbo Che, another scholar in Chinese theoretical psychology, proposed five conditions for reciprocal transformation between consciousness and unconsciousness. Their works confirmed that consciousness is a subject for psychological research and provided direction for further research in China.
More recently, there has been an upsurge of academic interest in consciousness that has drawn on modern scientific practices rather than on purely philosophical thinking. In this same vein, Chinese scholars have introduced, modified, and improved numerous experimental paradigms for consciousness and unconsciousness from Western psychology, yielding some new knowledge. They have also designed and elaborated theoretical models related to the topic of consciousness, which have enabled scholars to make some progress in our understanding of this topic.
However, their accomplishments have not received recognition from international peers owing to language barriers. This article attempts to address this gap by introducing Chinese achievements in consciousness studies, focusing on theoretical formulations and theory-building, and contrasting them with classical theories from Western psychology. Thereafter, we summarize and analyze the similarities and gaps between Chinese and Western research, in the hope of informing the international community of theoretical and empirical work on consciousness being conducted in China, and promoting further international communication and collaboration in the field.
Theoretical accomplishments on the consciousness–unconsciousness relationship
With advancements in experimental paradigms, computer technology, and cognitive neuroscience, effective theories of consciousness and unconsciousness have been enabled in research globally. In China, several innovative theoretical models of consciousness have emerged.
The concrete-and-steel model of consciousness
Z. L. Yang and colleagues (Z. L. Yang et al., 1998; Z. L. Yang et al., 1997) proposed the concrete-and-steel model to explain the relationship between conscious and unconscious processing. The model stated that cognition has two subsystems: conscious and unconscious cognition. While independent, the two subsystems interact and have some degree of interdependence. The inner world of the human is metaphorized as a mansion comprised of unconsciousness, which functions like steel in construction, and consciousness, which functions like concrete. A mansion cannot be built using steel or concrete alone, and similarly, for humans, the interdependence of consciousness and unconsciousness enables their inner world to function properly.
Subsequently, Z. L. Yang and colleagues proposed a model that was a trade-off view of the development of consciousness and unconsciousness. Guo, Yang, and Zhou (2003) used the process dissociation procedure (PDP; Jacoby, 1991) to explore the development of implicit and explicit memory for nonlinguistic recognition. The results supported the concrete-and-steel model, meaning that participants of any age employ simultaneous implicit (unconscious) and explicit (conscious) memory for nonlinguistic recognition. Based on the results, they suggested that the contributions of conscious processing decrease with age while the contributions of unconscious processing increase; however, both could decrease or increase simultaneously. This suggests that consciousness and unconsciousness may have a more complex relationship than merely taking turns, which Guo et al. called “trade-off.” The trade-off view focuses on the dynamic proportions of shifts in conscious and unconscious processing throughout the cognitive system, supplementing the concrete-and-steel model with further details. Furthermore, Z. L. Yang and Li (2003) list four general characteristics that can describe the trade-off relationship between consciousness and unconsciousness: dependence, interaction, inequality, and interdependence. Dependence refers to conscious and unconscious processing belonging to two different cognitive subsystems, which follow different processing patterns and have specific neural mechanisms. Interaction is the dynamic interaction between the two kinds of processing, which may promote or inhibit each other. Inequality means that the relative contributions of consciousness and unconsciousness in processing vary and shift. Finally, interdependence is the inability to separate consciousness and unconsciousness from each other, even using advanced paradigms and techniques.
The concrete-and-steel model was the earliest attempt to explain the relationship between consciousness and unconsciousness via experimental methods in China and guided subsequent Chinese consciousness researchers; however, its present-day practical value is relatively small (see below). While this model has received some experimental support (Yu & Wang, 2013; Zheng & Cen, 2009) and some scholars still regard it with high esteem (Guo & Li, 2006; Xie, 2005), it is not sufficiently systematic or complete, especially compared to the more integrated theories of Western psychology, which are detailed below.
The interrelationship between consciousness, attention, and stimulus quality
Geng and colleagues (Geng & Li, 2002; Geng & Zhu, 2001a, 2001b; Geng et al., 2001) conducted studies on memory using Stroop, exclusion, and false recognition tasks, finding that perception of a stimulus as conscious or unconscious depends on the systematic trade-off between attention and stimulus quality. When the “activation level” of a stimulus reaches a certain threshold, it can be perceived consciously. Greater stimulus quality (e.g., the duration of stimulus presentation) and attention can increase the activation level, and these contributions are cumulative; thus, when the duration of stimulus presentation is too short for the stimulus to be detected consciously but sufficient for unconscious detection, increasing attention can raise perception of that stimulus to the level of consciousness and vice versa. In this way, the transition between conscious and unconscious perception depends on attention level and stimulus quality. The model also states that the activation level for a mental representation might mediate its processing, so attention level or stimulus quality directly influences the activation level for the mental representation, which, in turn, determines the transition between conscious and unconscious perception.
Later, Geng, Zhu, and Li (2001) presented three probable models of the interrelationship between consciousness, attention, and stimulus quality: (a) attention and stimulus quality influence consciousness independently, (b) attention mediates the influence of stimulus quality on consciousness, or (c) all three interact. However, their experimental techniques could not clearly distinguish stimulus quality and attention, so they were unable to explain the relationship between the variables. These results demonstrate that conscious and unconscious perception might influence participants’ behaviors differently and that conscious and unconscious perceptions are separate, potentially originating from different cognitive systems. Thereafter, Geng shifted her attention to aspects of visual awareness, such as eye contact, gaze cueing effect, and self-face processing (e.g., Geng et al., 2012; Xu et al., 2018). Although Geng garnered valuable behavioral and electrophysiological evidence on visual cognition, the evidence was unsystematic and did not directly explore the relationship between consciousness, attention, and stimulus quality.
Around the same time, Dehaene and colleagues (Dehaene et al., 2006; Dehaene & Naccache, 2001) proposed the global neuronal workspace theory (GNWT) of consciousness, which resembles Geng and colleagues’ model (Geng & Li, 2002; Geng & Zhu, 2001a; Geng et al., 2001). GNWT was developed out of the influential global workspace theory (GWT; Baars, 1997, 2002), which sees the brain as a collection of sub-networks processing specific inputs which consciousness makes available to a wide range of networks. GNWT extends GWT by explaining consciousness via computational modeling and neuroimaging studies (Dehaene & Changeux, 2011). Like Geng et al.’s model (Geng & Li, 2002; Geng & Zhu, 2001a; Geng et al., 2001), GNWT states that whether stimuli can be perceived consciously depends on two key elements: bottom-up stimulus strength and top-down attention. When a sensory target has sufficient bottom-up strength (e.g., when a word is shown for sufficient duration), and attention is directed at that target, it will be consciously visible. However, GNWT has greater empirical support than Geng et al.’s model (Dehaene & Changeux, 2011) and is supported by research on the physiological structure of the brain and cognitive neuroscience, whereas Geng et al.’s model is based primarily on behavioral studies and lacks support from cognitive neuroscience.
Another influential Western theory of consciousness and unconsciousness is the radical plasticity thesis (RPT; Cleeremans, 2011), which has similarities to Geng et al.’s model (Geng & Li, 2002; Geng & Zhu, 2001a; Geng et al., 2001). The RPT states that whether a stimulus is consciously perceived depends on its quality of representation (reminiscent of Geng et al.’s stimulus quality). Quality of representation has three dimensions: stability in time, strength, and distinctiveness. Depending on the representation quality, related cognitions are classified as implicit (characterized by weak, poor-quality representations that cannot be identified by the brain), explicit (wherein representations are deeper, wider, and more distinctive), and automatic (when representations become so strong that their influence on behavior can no longer be controlled). Both the RPT and Geng et al.’s model underline that the quality of stimuli or their representation are important indicators of a conscious state; however, the RPT relies on physiological mechanisms of the brain and is sophisticated enough to provide detailed explanations for conscious processing.
Although Geng et al.’s model (Geng & Li, 2002; Geng & Zhu, 2001a; Geng et al., 2001) had an impact on consciousness research in China (Cao & Tang, 2005; Huo, 2006) and received some support from behavioral experiments (Geng & Li, 2002), it is less complete than alternative models (e.g., GNWT) and lacks cognitive-neuroscientific evidence. Future research should utilize neuroscientific methods to confirm whether an increase in stimuli quality and attention levels can similarly influence the neural correlates of consciousness and further stimulate conscious processing, which was the focus of Geng et al.’s theory.
The station monitoring room model
Y. J. Wang and colleagues (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003) proposed the station monitoring room model and a conceptual equation to measure consciousness from a computational neuroscience perspective. This model states that besides integration and complexity, consciousness has another important characteristic—moderation. Although previously mentioned (e.g., Kandel et al., 1991), the importance of moderation in neural activity has been underestimated (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003). Nerve cells are the signaling units of the nervous system, which, when activated, convey electrochemical signals to other neurons, in order to interact and communicate with them. These action potentials are initiated by various events affecting the human body, and the brain uses them to receive, analyze, and convey information (Kandel et al., 2013). Y. J. Wang and Yang (2003) supposed that when the nervous system is moderately active—that is, neural activities related to conscious processing are neither too low nor too high in energy expenditure and electric activity—individuals are “fully conscious.” In contrast, when in a coma, brain activity is extremely low, leading to unconsciousness; while in an epileptic seizure, brain activity is extremely high—also leading to unconsciousness. Therefore, from the perspective of neurophysiology or biophysics, normal consciousness could be viewed as an emergent property of a moderately excited neural system, in terms of both energy expenditure and electrical activity. This is the basis of the station monitoring room model.
Y. J. Wang and colleagues (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003) have stated that the function of consciousness is not to be a “control center,” but rather a “monitoring center” that learns instantly from the internal and external environments of the body. Thus, the monitoring room of consciousness does not determine anything through information processing itself but helps with the exchange of signals and messages. The neural correlate of consciousness is linked to and exchanges signals with sensory systems, visceral receptors, proprioceptors, motor areas, the speech system, and other response systems, to respond to the environment.
If so, the neural correlate of consciousness might be in a brain area near the frontal lobe, sensory area, and motor area. According to Y. J. Wang et al.’s (2001; Y. J. Wang & Yang, 2003) hypothesis, the “monitoring room of consciousness” is a group of neurons forming a layer of neural networks. Sensory systems send signals in real time to this monitoring room, where each sensory system has its own active projection area. Signals from the thalamus adjust the threshold parameters of each neuron. The frontal lobe also submits copies of active states to the monitoring room, and active projection areas within the neural networks change information via synchronous neural oscillation of 40 Hz. In a conscious state, neural networks appear as moderately variable neural information waves. The normal state of “being conscious” relies on excitation waves from the frontal lobe, which engage in synchronous oscillations with excitation waves from the sensory and reaction systems. An unconscious state, in contrast, reflects unique patterns of excitation waves within the neural networks. When unconsciousness (where neural network activity is too low or too high) shifts to consciousness, the excitability of neural electrical activity is enhanced (or reduced) and neural network energy expenditure increases (or decreases) to a moderate level (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003, pp. 271–273).
In addition, Y. J. Wang and colleagues (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003) proposed theoretical measures of consciousness in two ways, using either energy expenditure on conscious activities or a neurophysiological approach (i.e., synchronous neural oscillation of 40 Hz). They provided a formula to measure brain state (physiological electrical activity during conscious or unconscious states) using positron emission tomography (PET) and functional magnetic resonance imagery (fMRI) data, representing the activity level of the neural correlates of consciousness. They successfully estimated states of consciousness, including brain death, epileptic seizure, slow wave sleep, and rapid eye movement sleep.
Compared to Western-developed theories, the station monitoring room model is somewhat incomplete and lacks empirical support. It is a scientific metaphor, much like GWT (Baars, 1997, 2002), in which the content of conscious experience is an actor in the spotlight of attention on the stage of working memory. However, where GWT is an elaborated, well-supported theory (Baars, 1997, 2002; Windey & Cleeremans, 2015), the station monitoring room model remains a collection of “hypotheses” on consciousness. It is also similar to the recently proposed integrated information theory (IIT; Oizumi et al., 2014; Tononi, 2004, 2008; Tononi & Koch, 2015), which states that consciousness is a fundamental property of physical systems with specific causal properties corresponding to the system’s capacity to integrate information (Tononi & Koch, 2015). A system’s quantity of consciousness at a given time is measured as the Φ value of a complex of elements (Tononi, 2004), in which “Φ is the amount of causally effective information that can be integrated across the informational weakest link of a subset of elements” and “a complex is a subset of elements with Φ > 0 that is not part of a subset of higher Φ” (Tononi, 2004, Abstract, para. 2). Comparing these two theories, first, both theories propose that consciousness states have the characteristic of integration—as IIT puts it, that consciousness is unified, and each conscious experience is irreducible to independent subsets of phenomenal distinctions (Tononi & Koch, 2015), while the station monitoring room model states that integration is an acknowledged characteristic of consciousness. Second, both contend that consciousness is graded and measurable; however, the station monitoring room model only provides a conceptual method of quantifying consciousness, while IIT offers a more practical applied measure of a particular physical system. The two theories also differ: IIT, for instance, discusses consciousness across organisms, and the station monitoring room model mostly among humans; IIT states that neuron activation is unnecessary for conscious experience, while the station monitoring room model posits moderate nervous system activation as an essential condition of consciousness. In summary, while the station monitoring room model offers a theoretical framework and conceptual measure of consciousness, and suggests a potential role of the thalamus, it does not yet have sufficient empirical support (particularly from fMRI and PET studies) compared to GWT or IIT.
The emergence theory of consciousness
As Chalmers (1995a) says, “the easy problems of consciousness are those that seem directly susceptible to the standard methods of cognitive science, whereby a phenomenon is explained in terms of computational or neural mechanisms. The hard problems are those that seem to resist those methods” (p. 200). Chalmers further points out that the hard problem . . . is the question of how physical processes in the brain give rise to subjective experience. This puzzle involves the inner aspect of thought and perception: the way things feel for the subject. When we see, for example, we experience visual sensations, such as that of vivid blue. (1995b, p. 81)
To answer that “hard” question, Tang proposed (e.g., 2004a, 2004b) and developed (2017a, 2017b) the emergence theory of consciousness, suggesting the emergence of consciousness involves the dynamic transformation of information processing in areas of the cerebral cortex in synergy with other brain areas (to be discussed further below). In this theory, a “brain area” is any area of the cerebral cortex with a specific function, “activation” of these brain areas means neural activities, and the “energy state” of the brain area is its activation level. Energy states can be classified into a ground state, or inactivation of the brain area, and various excited states corresponding to different levels of activation. Consciousness and unconsciousness are then the result of different energy states throughout the brain, making them similar (Tang, 2004a).
Consciousness arises from the transfer of activation within brain networks, as interactions between brain areas lead to a transition in energy states. When a brain area’s excited state does not reach the consciousness threshold, the brain remains in an unconscious state. When it does reach that threshold, a phase transition occurs, and the brain shifts from unconsciousness to consciousness, with conscious perception arising in line with the activated brain area. In this way, the emergence of consciousness is the result of constant competition and selection between the transition and activation of various brain areas. Information is then processed in active brain areas, both conscious and unconscious (Tang, 2004a), and differences in information processing relate to the energy state of the brain area. Each of the many brain areas has a specific function and stores specific information. When a brain area enters an excited energy state, information unique to this area will be expressed (consciously or unconsciously; Tang, 2004a).
Tang (2003) proposed this internal structure of consciousness based on experimental evidence and argued that consciousness consists of four ingredients and their interactions: awareness of consciousness, content of consciousness, intentionality of consciousness, and affection of consciousness (i.e., the subjective experience in terms of emotion and affection). These ingredients interact with each other and integrate into consciousness. However, the emergence of consciousness requires the support and modulation of numerous brain areas, not only one. Tang (2004a, 2004b, 2017a) proposed that conscious experience is the result of the interaction and correlated activities of four functional systems in the brain: the three systems proposed by Luria (1973)—arousal system, information processing system, monitoring system, and a fourth—the evaluation-emotion system of Tang and Huang (2003), which relates to information evaluation and the subjective experiences that accompany the information evaluation. How do these four systems influence consciousness? Since information processing in each brain area is unique, the content of consciousness is unique to each brain area. The arousal system and monitoring system modulate the activation of attention, while the evaluation-emotion system modulates the entire process.
Tang (2017a, 2017b) further developed this model, integrating a quantitative, neurobiological perspective recognizing four elements of consciousness in the brain: arousal activity of consciousness, information processing, enhancement of attention, and global broadcasting (reminiscent of global access in GWT; Baars, 1997, 2002). Arousal activity of consciousness mainly depends on the brainstem and intralaminar nuclei, while information processing is based on specific functional brain areas (differing by the nature of the processed information). Enhancement of attention is also a necessary element of consciousness. In addition, information processed in specific brain areas must be disseminated to the brain globally, requiring coordination and feedback from many brain structures, such as the cerebral ganglion, prefrontal lobe, and parietal lobe. In essence, Tang proposed two essential conditions for the emergence of consciousness. First, the brain area’s excitation reaches the consciousness threshold, and then, the four neurobiological elements of consciousness are present.
Tang (2017a, 2017b) also discussed possible means of quantitatively studying consciousness, proposing a mind–brain equation based on the four ingredients of consciousness. Unlike GWT (Baars, 1997, 2002) and GNWT (Dehaene et al., 2006; Dehaene & Naccache, 2001), Tang’s theory suggests that consciousness is a graded and quantifiable phenomenon. The basic elements of consciousness (e.g., sensation, emotion) have different ranges of intensity in subjective experience, and are directly, positively related to the activation level (or energy state) of brain areas in specific conscious experiences. In Tang’s proposed mind–brain equation, specific letters represent the respective strength of different ingredients of consciousness: “A” refers to the activation level of information processing in a specific functional brain area; “α” denotes the perception of the brain’s arousal activity; “β” denotes the perception of global broadcasting in the brain; “γ” is a coefficient explaining that the degree of attention amplifies the activation level of certain brain areas; “C” denotes the intensity of subjective experience; and “Ac” denotes the consciousness threshold. When α>0, β>0, and γ>1 (γA>Ac), consciousness emerges in a given brain area. The quantitative relationship between intensity of subjective experience for certain information (“i”) and activation level of certain brain areas is:
Here, “ν” refers to the dimension between subjective experience and the activation level of the brain area, “a” refers to the dimensional transformation, and “Ai” refers to the activation level of target information processing (“i”) for the specific functional brain area.
The emergence theory of consciousness has similarities and differences with GWT (and thus, GNWT). Regarding differences, unlike GWT, emergence theory conceives of consciousness as a graded, quantifiable phenomenon. While GWT (and GNWT) do not mention the processing of in-brain stimuli, explaining only the processing of external stimuli, emergence theory tries to explain internal processing as well. As for similarities, both theories consider global broadcasting in information processing to be an essential element of the emergence of consciousness, and both are supported by experimental and neuroimaging evidence (Dehaene & Changeux, 2011; Dehaene et al., 2006). Emergence theory also has similarities with RPT (Cleeremans, 2011), as both propose that a threshold in certain dimensions is an essential standard for consciousness, considering consciousness from a graded, dynamic perspective.
Emergence theory also bears similarities to IIT (Tononi & Koch, 2015). Both IIT and emergence theory take an interdisciplinary perspective on the consciousness–unconsciousness relationship, rooted in neuroscience, computing science, psychophysics, and other empirical sciences and both offer a quantitative measure to evaluate consciousness. However, there are also differences between the two theories. For example, IIT posits that consciousness is not unique to humans, but is common among other organisms (e.g., octopuses, as demonstrated by Godfrey-Smith, 2016) and can even occur in some very simple systems (e.g., circuits; Tononi & Koch, 2015). Emergence theory, on the other hand, discusses consciousness mostly in terms of humans. In addition, unlike emergence theory, which emphasizes the activation (or excited energy state) of brain areas in the emergence of consciousness, IIT has predicted that a system such as the cerebral cortex may generate conscious experience even if most of its neurons are nearly silent (i.e., not activated; Sullivan, 1995; Tononi & Koch, 2015); in other words, the activation of neurons is not a necessary condition for consciousness.
Emergence theory correlates consciousness with changes in physical phases of brain activity and proposes a mind–brain equation to enable the quantitative study of consciousness. It also provides a new perspective on the transition from unconsciousness to consciousness and a framework explaining both the subjective experience and the neurobiological structure of consciousness. Despite the lack of sufficient experimental evidence on consciousness, this theory represents a good attempt to understand consciousness in a multidisciplinary way.
It is important to note that the concept of “emergence” has a long history as a central concept in Western philosophy of mind, particularly from the early 20th century (e.g., Lloyd, 1927; Patrick, 1922) onward (e.g., El-Hani & Pihlström, 2002; Kim, 1999). As Patrick (1922) stated, “mind is something which the body achieves, or which nature achieves by means of the body” (p. 702). Emergence has been used to describe the relationship between mind and body and represents the view that the mind emerges at a new level from the interaction of bodily processes. Therefore, it cannot be wholly reduced to physiological structures (El-Hani & Pihlström, 2002). This notion was inherited by Tang as the emergence theory of consciousness. Tang (2017b, pp. 36–37) stated that mind or consciousness is hierarchical, and different levels of mind possess different neural correlates of consciousness. Novel features that do not exert any influence at the lower levels may emerge with the integration of higher-level mental processes, and more complex and advanced levels of consciousness emerge from all pre-existing levels of consciousness.
Summary
There have been four noteworthy theories of consciousness and unconsciousness in China in recent decades, but they are not equally valuable for understanding the elements and mechanism of consciousness. Both the concrete-and-steel model (Z. L. Yang et al., 1998) and Geng et al.’s model (Geng & Zhu, 2001a, 2001b; Geng et al., 2001) are relatively incomplete and lack experimental support. Of the four theories, the emergence theory (Tang, 2004a, 2004b, 2017a, 2017b) may be the most widely supported and valuable. Based on neuroscience research, emergence theory appears to be a substantive attempt to resolve the hard problem of consciousness and offers a feasible measurement of consciousness. However, further verification and supplementation are needed. The station monitoring room model (Y. J. Wang et al., 2001; Y. J. Wang & Yang, 2003) is less complete and more superficial than the emergence theory, and its conceptual measurement of consciousness needs further empirical validation. In general, Chinese theories of consciousness are relatively incomplete and unsystematic compared to some integrated Western theories but have provided valuable insight on the nature of consciousness and unconsciousness.
Similarities between Chinese and Western research
Before the 1980s, Chinese scholars mostly perceived consciousness as a philosophical issue or a problem in philosophical psychology and did not study it using scientific paradigms (Huo, 2006). Thereafter, in modern psychology, Chinese scholars started to adopt a scientific ontological position of consciousness and used paradigms based on natural science to clarify how unconsciousness functions as a means by which humans experience the world. Research on consciousness in contemporary psychology has had three phases in China, beginning with investigation of experiential phenomena, then moving to the application of a miniature theory (as compared to a more well-developed theory) and thereafter several well-articulated theoretical models. Research on consciousness in China has changed considerably compared to even a decade ago; researchers like Shu Pan did not expect that we would make such progress in our understanding of consciousness in only a few years.
After a period of following Western research on the relationship between consciousness and unconsciousness, Chinese scholars have begun to employ unique paradigms that are essentially at the same level as those used abroad, and have made some developments in methodology. Furthermore, the complicated relationship between consciousness and unconsciousness has been demonstrated to some extent. Nevertheless, the direction of research development on this topic in China and elsewhere have some similarities.
Pursuit of the scientific nature of consciousness
Research on consciousness has a long and often tortuous history, both in China and elsewhere, and has primarily dealt with complex issues, such as the relationship between finiteness and infiniteness, the relationship between consciousness and unconsciousness, the question of intentionality, and the relationship of consciousness with attention, memory, and morality. However, a basic theme throughout the past 100 years of psychological research on consciousness is the unremitting pursuit of its scientific nature, and whether consciousness can be studied in scientific research.
In the history of Western psychology, research on consciousness has had a rather convoluted development, in line with psychologists’ pursuit of the scientific nature of consciousness. Since the beginning of psychological study, psychological theories have insisted that consciousness should be an object of scientific study and emphasized the importance of research on its properties. The use of introspection in this endeavor was criticized by behavioral and psychoanalytic schools of thought due to its subjectivity and lack of scientific basis. Later, the schools of humanistic and transpersonal psychology conducted research on some advanced problems of consciousness (e.g., the spectrum of consciousness in transpersonal psychology), leading to a renewed interest in the topic. However, some of their concepts—such as “transcendence” or the notion of “transforming the state of consciousness”—were flawed due to a lack of empirical evidence. Contemporary advances in cognitive and neurophysiological psychology have brought the study of consciousness back into the realm of experimental psychology, and, compared to research in the 1980s, current research on consciousness has produced numerous empirical techniques (e.g., experimental paradigms such as PDP, and neuroimaging technology such as fMRI) that allowed for the experimental study of consciousness, thereby making this research area more scientific.
In contrast to this pursuit of the scientific nature of consciousness in Western psychology, most Chinese scholars have historically perceived consciousness to be a philosophical issue or a problem of philosophical psychology (Huo, 2006, p. 26). Before the mid-1990s, there were few or no specific chapters on consciousness in general or experimental psychology textbooks (Huo, 2006, p. 32). Since the rapid development of Western cognitive psychology, neuroscience, and experimental psychology in the mid-1990s, researchers in China have had increased interest in the interaction between conscious and unconscious processing during cognitive activity. Indeed, developments in the field of cognitive neuroscience confirm that issues related to consciousness can be empirically studied and analyzed. Moreover, the accumulation of experimental results, especially those revealing contradictions in the understanding of consciousness, could lead to new conceptions of consciousness.
Chinese researchers’ international standards of the experimental paradigms
Chinese researchers have provided considerable experimental results to contribute to our understanding of consciousness. They have introduced, conducted, and modified experimental paradigms from Western psychology, and their paradigms are essentially consistent with international standards, while still providing new perspectives. Although these studies were relatively unsystematic, they still held value in terms of understanding this topic.
In the field of implicit memory, implicit learning, and implicit social cognition, Chinese researchers have made some progress. Li and Guo (2007) combined sequences (namely, letter sequences) and rhythm (temporal sequences) to expand the serial reaction time paradigm (SRT; Nissen & Bullemer, 1987), creating the “double-dimensional SRT paradigm.” They concluded that, compared to letter sequences, people implicitly learn rhythms more holistically, suggesting that different dimensions of implicit learning have different characteristics and that the double-dimensional SRT paradigm could be a creative, effective way to study this topic. Chang and Du (2007) explored implicit self-esteem using the implicit association test (IAT; Greenwald et al., 1998) and confirmed that implicit self-esteem was distinct from explicit self-esteem, and was automatic and unconscious. These results implied that the attitude toward the self might have two different systems—conscious and unconscious processing. All the adapted paradigms have been widely used in empirical research in social psychology, including the study of aggressive behavior, stereotypes, implicit attitudes, and the treatment of anxiety.
Since 2000, false memory, implicit representations of time, and inattentional blindness have become hot topics in China, and research on them has become increasingly systematic (e.g., Ge & Jin, 2015; Zhang et al., 2010). Zhou et al. (2007) used the Deese–Roediger–McDermott paradigm (DRM; Roediger & McDermott, 1995) to confirm that conscious processing is unnecessary for the generation of false memories, whereas unconscious processing is sufficient for the production of such memories, implying that unconscious processing might influence cognition and behavior alone. Huang and Liang (2002) adopted the representation momentum paradigm to show that, like the cognition of physical time, implicit representations of time have the characteristics of orientation, succession, and continuity. Some researchers are also conducting comparative studies of conscious and unconscious processing by combining the paradigms of emotional processing, implicit learning, inattentional blindness, memory capture, and attentional blink to provide novel approaches to the relationship between these forms of processing (e.g., Jia et al., 2016; S. M. Wang & Ji, 2014).
Unconscious thought and emotion have recently become the focus of consciousness–unconsciousness research in China (e.g., Su et al., 2017; Zhong et al., 2013). Chinese researchers have furthered our understanding of these topics. For example, Liu et al. (2012) conducted two experiments on knowledge transfer addressing the weaknesses of the paradigm of Bos et al. (2008), who ignored the effect of internal factors on unconscious thought. The results suggested that when there was a task goal, participants who had learned via unconscious thought theory performed better than participants who did not learn; unconscious thought is both knowledge-dependent and external-goal-dependent. Consciousness–unconsciousness scholars in China also have provided results using the techniques of cognitive neuroscience which we will discuss below (e.g., Jia et al., 2016; Meng & Guo, 2006; Sun, 2013).
Shifting from dialectical phenomenon analysis to controlled empirical research
From the perspective of research techniques, Chinese and Western research on consciousness and unconsciousness have both shifted away from dialectical analysis of phenomena towards empirical research in controlled settings. “Dialectical phenomenon analysis” here means that scholars abstractly studied the topic or discussed it in terms of the phenomena of everyday life, rather than scientifically. “Controlled empirical analysis” refers to experimental paradigms and other forms of rigorous scientific inquiry. The empirical transformation of this research field in China has occurred under the influence of Western psychology.
Although philosophers, both in China and abroad, have discussed the problem of consciousness and unconsciousness for centuries, psychologists and neuroscientists only began to consider consciousness to be a legitimate area of inquiry in the 1960s. Before that, psychologists ignored consciousness for a variety of reasons, both subjective and objective. The subjective reasons included the long-dominant role of behaviorism in psychology and the lack of appropriate scientific techniques to conduct research on consciousness. The objective reasons included the complexity of the question of consciousness and unconsciousness and the need for cooperation among many disciplines.
Influenced by psychology in the Soviet Union, theoretical psychology in China has traditionally adopted a dialectical analysis of consciousness. At the end of the 1950s and in the early 1960s, Chinese scholars were embroiled in a heated discussion regarding research objects, tasks, and methods in which consciousness was a prominent topic. The beginning of the “reform and opening-up” period in the 1980s involved a second peak in research on consciousness in China; in December 1982, for instance, the theme of the Academic Annual Meeting of Psychology Basic Theory of China was the “problem of consciousness.” Moreover, there was a section on consciousness in one of the most authoritative publications on psychology in China, Psychological Science Communication (Journal of Psychological Science). Throughout the 1980s, psychologists in China mainly focused on the nature of consciousness and unconsciousness, and conducted reviews of consciousness–unconsciousness theories and problems (Che, 1987; Pan, 1981). The research results of these efforts helped to close the gap between China and the West in this area of research. Since the 1990s, with greater international academic exchange, Chinese research techniques have been further influenced by Western psychology, and the empirical orientation of psychology research toward consciousness has been further strengthened.
Shifting from purely academic discussion to practical application
Even as consciousness has been regarded as a field of purely academic research, Chinese and Western scholars have attached importance to not only strictly academic discussion but also its practical applications. Western psychology has applied the results of consciousness research to several settings, including organization, management, education, ethics, health, and medicine. Influenced by Western researchers, Chinese scholars have begun discussing similar applications in China. For example, after underlining the independent and interdependent nature of the relationship between consciousness and unconsciousness in humans, Guo and Yang (2002) tried to apply this view to the teaching process at school. They noted that implicit learning, which primarily involves unconscious processing, is a relatively common phenomenon which needs to be noticed by teachers. They also mentioned the need to create more favorable conditions for students’ implicit learning in their daily classes.
Remaining gaps between Chinese and Western research
Although Chinese scholars have made several advances toward understanding the relationship between consciousness and unconsciousness, there is still room for considerable development in Chinese research. The paradigms used by Chinese scholars are essentially at the same level as those used internationally, but further multidisciplinary, systematized research must be done, and theories on this relationship must be further developed.
Trend toward shallow description
While Chinese scholars have expanded the research on consciousness, their work has shown an overall trend toward shallow description that lacks explanatory power. Most empirical consciousness–unconsciousness studies in China have been superficial and focused on describing data, rather than attempting to uncover the nature of the relationship between consciousness and unconsciousness, and theoretical accomplishments have been limited to description of the phenomena rather than developing testable predictions (e.g., the IIT; Tononi, 2004, 2008; Tononi & Koch, 2015). Future research must be extended in terms of both strength and depth. Chinese researchers must provide not only more in-depth theoretical interpretations of existing results but also create testable predictions based on those theories. Without this shift, Chinese researchers cannot extend current rationale and methodological bases for the available theories and build new ones.
Lack of integrated theories
Chinese theories of consciousness do not go into much depth, and lack sufficient integration within them. As noted before, although the concrete-and-steel model (Z. L. Yang et al., 1998) and the model of the interrelationship between consciousness, attention, and stimulus quality (Geng & Li, 2002; Geng & Zhu, 2001a, 2001b; Geng et al., 2001) are good attempts at explaining the relationship between consciousness and unconsciousness using experimental methods, neither theory is sufficiently integrated or complete due to the lack of systematic empirical support using advanced techniques.
In Western psychology, there are more integrated theories on this topic, such as GWT (Baars, 1997, 2002), which frames consciousness as a “theater.” In devising this theory, Baars (1997) integrated a diverse set of achievements in comparative neurology, neuropsychology, psychiatry, and neuroimaging, with elements of ecological development and contrastive analysis; he also analyzed the brain mechanisms of conscious and unconscious processing at multiple levels and hypothesized four kinds of spatial dimension of brain structure and four simulation systems for brain functioning. Thereafter, he developed a dynamic model explaining the brain mechanisms of consciousness. Although the concrete-and-steel model (Z. L. Yang et al., 1998) is similar to GWT (Baars, 1997, 2002) to some extent—both, for example, are scientific metaphors—the GWT offers a more precise explanation of the relationship between consciousness, unconsciousness, attention, and working memory, and has received increasing support from neurobiological evidence. The GWT is a keystone achievement of consciousness science (Huo, 2006; Windey & Cleeremans, 2015), while the concrete-and-steel model is less systematic and less complete, as it relies primarily on results from behavioral experiments.
Although some have criticized the IIT for being too radical (Horgan, 2015), it remains a relatively complete and integrated theory that starts from experience itself via five phenomenological axioms (on intrinsic existence, composition, information, integration, and exclusion, respectively), and derives five postulates about the properties required by physical mechanisms that might be able to support consciousness (Tononi & Koch, 2015). Based on these axioms and properties, the IIT can explain a range of clinical and laboratory findings (Casali et al., 2013; Massimini et al., 2005) and make several testable predictions (Tononi & Koch, 2015). The emergence theory of consciousness (Tang, 2004a, 2004b, 2017a, 2017b) is somewhat similar to IIT, but its lack of testable predictions makes it less complete.
Need for interdisciplinary perspective research
Addressing the problem of consciousness that considers how physical processes in the brain lead to subjective experience is the essential goal of consciousness research. Reaching this goal requires the integration of research at multiple levels (gene, neuron, and brain) across disciplines (e.g., psychology, neuroscience, computer science, and physics). Western researchers have made considerable achievements in this area largely because they adopted an interdisciplinary perspective. More specifically, these researchers have tended to integrate advanced theoretical achievements from cognitive science with the notion of implicit and explicit mental processes and dissociation experimental procedures from psychology. They have also adopted multi-level research methods from neuroscience (e.g., for GWT, RPT, and IIT). Moreover, in theoretical consciousness–unconsciousness studies in Western psychology, researchers have integrated findings from disciplines beyond psychology and neuroscience. For example, Godfrey-Smith (2016) did his research on octopuses from the perspective of applied philosophy and ethology, and put forward an evolutionary point of view on consciousness. He stated that conscious experience in the human brain is not the only form of consciousness, and there are other kinds of intelligence in nature (e.g., the octopus) with radically different neurophysiological structures from humans, and that experience gradually develops from the selection of more basic forms of subjective experiences to more complex and conscious ones. This evolutionary view of consciousness provided us a new way of understanding the relationship between the conscious experience of humans and animals and the relationship between consciousness and unconsciousness by focusing on not only humans but also other creatures in the world. With these interdisciplinary theoretical and experimental techniques, researchers outside China have established consciousness as an area of focus at the frontier of scientific study and have made numerous breakthroughs as a result.
In contrast, in China, empirical research on consciousness is only beginning to shift from behavioral research to the use of cognitive neuroscience methodologies; theoretical discussions on this topic are mostly aimed at individuals (unlike the IIT and the evolutionary view of Godfrey-Smith, 2016). Although there have been attempts at integrated studies (e.g., the station monitoring room model and emergence theory), they have not achieved sufficient integration between disciplines. If we wish to leap forward in this area in China, it will be necessary to increase integration and communication between disciplines and to pursue more interdisciplinary studies on this topic, both experimentally and theoretically. We also need to find more opportunities to cooperate with international peers in the field. We must acknowledge, however, that there is likely a long way to go.
Future research on neural mechanisms
Compared to Western psychology, few studies in China have examined the neural mechanisms of the relationship between consciousness and unconsciousness (e.g., Jia et al., 2016; Meng & Guo, 2006; Sun, 2013). Through brain imaging technology such as event-related potentials (ERPs), electroencephalograms (EEG), and fMRI, researchers can now directly observe brain activity while participants perform perceptual or cognitive tasks. By combining functional brain imaging with sophisticated experimental designs and data analysis methods, the functions of brain regions and their various interactions can be examined. Some studies have already provided neural evidence of unconscious perception (e.g., Duan et al., 2010; Eimer et al., 2002; Silverstein et al., 2015), thus indicating that stimuli that are not consciously processed can be represented at numerous levels of the neural system.
Studies examining neural mechanisms are also known as studies of the neural correlates of consciousness (NCCs). Some scholars have argued that a given kind of experience correlates to a specific region of the brain, and cling to the proposition that NCCs are reducible to a certain anatomical structure in the brain (e.g., Crick & Koch, 2003, contended that a special and restricted population of neurons—perhaps only a few thousand cells—are responsible for selective attention in visual perception). Other scholars have posited the converse—that consciousness is a global property of the brain involving vast numbers of nerve cells and a complex system of reentrant circuits. Based on neurophysiology and neuropsychology studies at the molecular and cellular levels, Edelman (1987, 1989, 2001) posited the theory of neuronal group selection (or “Neural Darwinism”), and an immunological-evolutionary view of the mind–body relationship. He stated that as a result of evolution, consciousness could be categorized into primary consciousness (awareness of things in the world) and higher-order consciousness (the recognition by a thinking subject of his or her own actions or feelings, unique to humans; Edelman & Tononi, 2000). The neural substrate of consciousness is not related to specific brain areas alone but also relies on the interaction of multiple, reciprocally connected brain regions (mainly the thalamocortical system) through the process of reentry. Crucially, he argued that the higher functions of the brain (higher-order consciousness) also rely on the interactions between the brain and the external environment. In recent years, this kind of hypothesis on NCC has come to be called modular processing: All cognitive abilities result from the interaction of many processing mechanisms distributed in several regions of the brain. Specific brain regions are not responsible for specific mental faculties but instead are elementary processing units. Perception, movement, language, thought, and memory are all made possible by the interlinkage of serial and parallel processing in discrete brain regions, each with specific functions. (Kandel et al., 2013, p. 18)
Regarding NCCs, this evokes the philosophical mind–body problem. In fact, Edelman (2001) held a non-reductive view on the mind–body relationship, and emphasized the notion of emergence in the appearance of consciousness, for example, “it is the evolutionary development of the ability to create a scene that led to the emergence of primary consciousness” (p. 118). This reminds us of Tang’s emergence theory of consciousness. Tang (2017b, pp. 36–37) also pointed out that reductive research into mind or consciousness per se is not sufficient for us to understand the reality of the mind–body problem; research incorporating concepts of integration and emergence should be conducted as well.
Although it has received some critical scrutiny (Crick, 1989), Edelman’s theory (as well as Tang’s) offers us a different perspective from which to understand the mind–body relationship, and has encouraged new research directions in further studies of consciousness, particularly in the exploration of the neural mechanisms of higher-level mental processes, including memory, thinking, and emotions.
Conclusions
In recent decades, Chinese scholars have made substantial efforts to understand the consciousness–unconsciousness relationship. In addition to the introduction of some experimental paradigms in the study of consciousness to research in China and their modification, noteworthy theories have been proposed on the topic. However, these efforts have been largely unknown by international peers owing to language barriers. We summarized these achievements to fill in this gap. By conducting a careful comparison between some Chinese- and Western-developed theories, we attempted to evaluate the meanings and values underlying Chinese theories and to help international peers recognize and better understand the state of practice in consciousness studies in China. These works in China have promoted our understanding of consciousness. However, there is still room for considerable development of the novel consciousness and unconsciousness research emerging from China; existing theories must be further developed and additional empirical research conducted.
In summary, being one of the most complicated but also attractive problems in the world, the question of consciousness and unconsciousness still needs to be further explored by scholars from multiple disciplines globally. We hope this article will provide readers with a comprehensive portrayal of consciousness studies in China (particularly theoretical developments), help Chinese researchers improve and increase communication with international scholars in this field, and allow Chinese research the opportunity to be evaluated by international peers. This should enable better collaboration between Chinese and international scholars in this field.
Footnotes
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
