Monthly Archives: September 2014

Conscious content

I have been thinking about some information in a not too recent paper. (see citation below) Panagiotaropoulos and others looked at the location of the content of consciousness in primates. They used binocular flash suppression (BFS) to give two different visual stimulation that compete for a place in the content of consciousness. Here is their figure and description of the method:

We recorded simultaneously neuronal discharges and LFPs (local field potentials) in the LPFC (lateral prefrontal cortex) of two alert macaques during a passive fixation task that included randomly interleaved trials of physical alternation and BFS. BFS constitutes a highly controlled variant of BR (binocular rivalry) that has been extensively used to dissociate subjective visual perception from purely sensory stimulation. The BFS (‘‘perceptual’’) trials, as well as the physical (‘‘sensory’’) alternation of the visual stimuli that was used as a control condition, are depicted in Figure 1. Every trial starts with the presentation of a fixation spot in both eyes that is binocularly fused and remains on until the end of the trial. In both sensory (Figure 1A, upper panel, ‘‘Physical alternation’’) and perceptual (Figure 1A, lower panel, ‘‘Flash suppression’’) trials, a fixation spot was presented for 300 ms followed by monocular stimulation with the same visual pattern (a polar checkerboard in the paradigm presented in the figure). In perceptual trials, 1 s after stimulus onset, a disparate visual pattern (here, a monkey face) is suddenly flashed to the corresponding part of the contralateral eye. It has been repeatedly shown that, in both humans and monkeys, the flashed stimulus remains dominant for at least 1,000 ms, robustly suppressing the perception of the contralaterally presented visual pattern that is still physically present. … Thus, in perceptual trials, a visual competition period dissociating sensory stimulation from perception is externally induced for at least 1,000 ms. During this period, the newly presented image is perceptually dominant while the initially presented visual pattern is perceptually suppressed despite its physical presence in the retina (Figure 1A, middle panel). In sensory trials, the same visual patterns physically alternate between the two eyes, resulting in a visual percept identical to the perceptual condition but this time without any concurrent visual competition (Figure 1A, upper panel). Specifically, after 1 s of visual stimulation, the initially presented pattern is removed and immediately followed by the presentation of the disparate pattern in the contralateral eye.

Under this methodology it is possible to tell whether the neurons are registering the information that is actually on the retina or the information that is actually in consciousness, when they differ. Previous research has established that conscious content is not necessarily found in the visual system up to the completion of perception. The temporal lobe is the first place where the content of consciousness alone is registered in an area with a two-way communication with the lateral prefrontal cortex and that is why the researchers looked for the conscious signal in the LPFC (and we indeed found it). These two areas, as well as their direct connections, are each connected to a particular part of the thalamus, the pulvinar nucleus. This traffic seems to carry the mark of consciousness in the high frequency of the brain waves.

It is very interesting to see that the visual perception is complete and the ambiguities resolved for both the image that is conscious and the one that is unconscious before the temporal – prefrontal – thalamus signals show the content that is destined for awareness. There does not appear to be a difference between the processing of conscious and unconscious input up to the point of entering the consciousness loops. There are not two minds creating two perceptions, but one mind producing both perceptions, only one of which becomes conscious. The process of perception completes without, it appears, being affected by the mechanism of conscious awareness in any substantial way.

Here is the abstract:

Neuronal discharges in the primate temporal lobe, but not in the striate and extrastriate cortex, reliably reflect stimulus awareness. However, it is not clear whether visual consciousness should be uniquely localized in the temporal association cortex. Here we used binocular flash suppression to investigate whether visual awareness is also explicitly reflected in feature-selective neural activity of the macaque lateral prefrontal cortex (LPFC), a cortical area reciprocally connected to the temporal lobe. We show that neuronal discharges in the majority of single units and recording sites in the LPFC follow the phenomenal perception of a preferred stimulus. Furthermore, visual awareness is reliably reflected in the power modulation of high-frequency (>50Hz) local field potentials in sites where spiking activity is found to be perceptually modulated. Our results suggest that the activity of neuronal populations in at least two association cortical areas represents the content of conscious visual perception.

Panagiotaropoulos, T., Deco, G., Kapoor, V., & Logothetis, N. (2012). Neuronal Discharges and Gamma Oscillations Explicitly Reflect Visual Consciousness in the Lateral Prefrontal Cortex Neuron, 74 (5), 924-935 DOI: 10.1016/j.neuron.2012.04.013

Sometimes choices are not thought out

In some competitive situations animals can produce random behavior rather than behavior based on prior experience. The anterior cingulate cortex is where strategies based on models of reality and history are generated; switching to random behavior is done by inputs to this part of the brain from the locus coeruleus. This was reported in a recent paper (citation below).

We generally assume that deciding what to do is based on the best guess of what will be the successful thing to do. Why would random behavior ever be better? It would be if the world seemed to change from what it had been and a new model needed to be constructed. Random exploration would be helpful. Or, there is the case of an opponent that is better at the fight. “We find that when faced with a competitor that they cannot defeat by counterprediction, animals switch to a distinct mode of action selection consistent with stochastic choice. In this mode, characterized by highly variable choice sequences, behavior becomes dramatically less dependent on the history of outcomes associated with different actions and becomes independent from the ACC. ” Primates appear to always try counterprediction before using random choice.

The random behaviour is not the product of the ACC system but is generated elsewhere. A mixture of modelling in the ACC and a random overlay seems the normal state with the amount of randomness depending on the confidence in the modelling. It is like a balance between exploitation and exploration set by the performance of the ACC model. “We note that complete abandonment of an internal model and adoption of a fully stochastic behavioral mode is normally maladaptive because of the associated insensitivity to new information. In rats, such a mode appears to be triggered when repeated modeling efforts prove to be ineffective and thus bears a similarity to the condition of learned helplessness thought to follow the sustained experience of the futility of one’s actions. Intriguingly, functional imaging studies in humans have suggested that a chronic reduction in ACC activity might play a role in this disorder .

This arrangement also seems to fit with the ‘deliberate’ errors that happen in well-learned sequences in sports, bird song, and children’s speech. Confidence in the model is occasionally tested.

Here is the abstract:

Behavioral choices that ignore prior experience promote exploration and unpredictability but are seemingly at odds with the brain’s tendency to use experience to optimize behavioral choice. Indeed, when faced with virtual competitors, primates resort to strategic counterprediction rather than to stochastic choice. Here, we show that rats also use history- and model-based strategies when faced with similar competitors but can switch to a “stochastic” mode when challenged with a competitor that they cannot defeat by counterprediction. In this mode, outcomes associated with an animal’s actions are ignored, and normal engagement of anterior cingulate cortex (ACC) is suppressed. Using circuit perturbations in transgenic rats, we demonstrate that switching between strategic and stochastic behavioral modes is controlled by locus coeruleus input into ACC. Our findings suggest that, under conditions of uncertainty about environmental rules, changes in noradrenergic input alter ACC output and prevent erroneous beliefs from guiding decisions, thus enabling behavioral variation.

Tervo, D., Proskurin, M., Manakov, M., Kabra, M., Vollmer, A., Branson, K., & Karpova, A. (2014). Behavioral Variability through Stochastic Choice and Its Gating by Anterior Cingulate Cortex Cell, 159 (1), 21-32 DOI: 10.1016/j.cell.2014.08.037

Doing a task while asleep

A recent paper (citation below) describes subjects working away at a task, categorizing words, while asleep. Here is the abstract:

Falling asleep leads to a loss of sensory awareness and to the inability to interact with the environment. While this was traditionally thought as a consequence of the brain shutting down to external inputs, it is now acknowledged that incoming stimuli can still be processed, at least to some extent, during sleep. For instance, sleeping participants can create novel sensory associations between tones and odors or reactivate existing semantic associations, as evidenced by event-related potentials. Yet, the extent to which the brain continues to process external stimuli remains largely unknown. In particular, it remains unclear whether sensory information can be processed in a flexible and task-dependent manner by the sleeping brain, all the way up to the preparation of relevant actions. Here, using semantic categorization and lexical decision tasks, we studied task-relevant responses triggered by spoken stimuli in the sleeping brain. Awake participants classified words as either animals or objects (experiment 1) or as either words or pseudowords (experiment 2) by pressing a button with their right or left hand, while transitioning toward sleep. The lateralized readiness potential (LRP), an electrophysiological index of response preparation, revealed that task-specific preparatory responses are preserved during sleep. These findings demonstrate that despite the absence of awareness and behavioral responsiveness, sleepers can still extract task- relevant information from external stimuli and covertly prepare for appropriate motor responses.

This study does not address whether a task can be initiated while asleep because the subjects fell asleep while engaged in the task. And, of course, as movement is blocked during REM sleep, the initiation of movement while unconscious was also not tested. What was tested was the processing required to carry on the task and prepare for movement.

Some previous postings have looked at unconscious processes. Some experiments used unconscious priming to test whether such priming can result in particular processes. In (does control of cognition have to be conscious?) it was indicated that control of cognition (conflict adaption) can be unconscious and in (unconscious effects) it was shown that unconscious priming could be responsible for perceiving, doing semantic operations and making decisions. Other experiments have used control over the use of consciousness by forcing its content. In (discovering rules unconsciously) blocking the use of consciousness for a particular problem showed that unconscious processing was superior to conscious processing for discovering ‘grammatical’ rules. Now we have a third method, the comparison between awake and asleep states showing that task-related processing can proceed unconsciously, starting from perception, through processing and decision making to preparation of motor responses.

It is not news any more that most of the processes in the brain can be done unconsciously. We are not aware of these processes, naturally, because they are unconscious, but that does not mean they do not happen. The bulk of the brain’s activity is unconscious. We should not be surprised at unconscious thought. The exceptions that, to date, appear to require consciousness are the formation of explicit memories, the use of working memory, and the particular form of awareness that we associate with consciousness. Perhaps consciousness has more to due with a particular use of memory rather than a particular type of thought process.

Kouider, S., Andrillon, T., Barbosa, L., Goupil, L., & Bekinschtein, T. (2014). Inducing Task-Relevant Responses to Speech in the Sleeping Brain Current Biology, 24 (18), 2208-2214 DOI: 10.1016/j.cub.2014.08.016

Unconscious effects

There is an interesting item in ScienceDaily (here) on the effect of perceptions that we are not conscious of. We can perceive an object, understand its meaning, and have that meaning affect our behavior, without any conscious awareness of the object. The paper’s lead author, Cacciamani, says, “Every day our visual systems are bombarded with more information than we can consciously be aware of. We’re showing that your brain might still be accessing information without your conscious awareness, and that could influence your behavior.

The researchers use the way we perceive the figure and ground of a silhouette. We perceive the figure before we perceive the ground and we perceive the semantic meaning of the figure before the ground - in many cases we do not seem to be concerned at all about the meaning of the ground. They showed a silhouette for 50 milliseconds before a test, and did not tell the subjects to do anything with the image. The subjects were not aware that the ground suggested a particular meaning. As in the image, where the figure is meaningless and the ground suggests leaves, the leaves do not reach awareness in the short exposure.

The test was that subjects were shown an object and had to indicate whether it was natural or man-made. Before each test object, the short exposure to the silhouette was shown. “We found that participants performed better on the natural/artificial word task when that word followed a silhouette whose ground contained an object of the same rather than a different category.”

So although the subjects had no consciousness of meaningful objects in the ground, they were affected by the meanings. The perceptions of the ground-objects were complete and they were assigned meanings without conscious awareness. The meanings affected the choice of actions without conscious awareness. To me this indicates that perception, meaning, and decision are not necessarily always exclusively bound to consciousness.

Here is the citation and abstract:

Laura Cacciamani, Andrew J. Mojica, Joseph L. Sanguinetti, Mary A. Peterson. Semantic access occurs outside of awareness for the ground side of a figure. Attention, Perception, & Psychophysics, 2014.

Traditional theories of vision assume that figures and grounds are assigned early in processing, with semantics being accessed later and only by figures, not by grounds. We tested this assumption by showing observers novel silhouettes with borders that suggested familiar objects on their ground side. The ground appeared shapeless near the figure’s borders; the familiar objects suggested there were not consciously perceived. Participants’ task was to categorize words shown immediately after the silhouettes as naming natural versus artificial objects. The words named objects from the same or from a different superordinate category as the familiar objects suggested in the silhouette ground. In Experiment 1, participants categorized words faster when they followed silhouettes suggesting upright familiar objects from the same rather than a different category on their ground sides, whereas no category differences were observed for inverted silhouettes. This is the first study to show unequivocally that, contrary to traditional assumptions, semantics are accessed for objects that might be perceived on the side of a border that will ultimately be perceived as a shapeless ground. Moreover, although the competition for figural status results in suppression of the shape of the losing contender, its semantics are not suppressed. In Experiment 2, we used longer silhouette-to-word stimulus onset asynchronies to test whether semantics would be suppressed later in time, as might occur if semantics were accessed later than shape memories. No evidence of semantic suppression was observed; indeed, semantic activation of the objects suggested on the ground side of a border appeared to be short-lived. Implications for feedforward versus dynamical interactive theories of object perception are discussed.

Underestimating dolphin’s brains

I have been reading in the social media an essay by Captain Paul Watson, and as I know nothing about his scientific credentials, I have been fact checking. Watson was associated over the years with a number of conservation groups, especially Sea Shepherd Conservation Society.

From other sites I find that his description of the dolphin brain is a good one. The cetacean brain has been large for a long time compared to humans and it is indeed very large. It is unusual in having four rather than three cerebral lobes. Its cerebrum is differently organized with an unusually large association cortex and a very close ‘cortical adjacency’ of the senses and motor areas.

The human brain, like most mammals, has a cerebrum divided into a rhinic lobe, limbic lobe and supralimbic lobe (divided into sub-lobes occipital, parietal, temporal, frontal). In the dolphin there are four lobes. The rhinic is somewhat different. The limbic lobe is large but similar to ours. Between the limbic and the supralimbic another lobe is inserted, the paralimbic. The supralimbic is not divided into sub-lobes and appears to be totally associative, like our frontal lobe. The sensory and motor areas occur in the paralimbic lobe, but they are organized differently: much more integrated and in close contact. Some believe that this gives a more unified perception without separate senses but with a single sort of perception. The cetaceans use an acoustic (sonar) sense that seems to be at one with their vision. The contact between sensory and motor areas may give the animals great speed of perception and action.

Watson’s essay (here) points out: Interspecies (intelligence) comparisons focus on the extent of lamination, the total cortical area, and the number and depth of neocortex convolutions. In addition, primary sensory processing relative to problem solving is a significant indicator; this can be described as associative ability. The association or connecting of ideas is a measurable skill: a rat’s associative skill is measured at nine to one. This means that 90 percent of the brain is devoted to primary sensory projection, leaving only 10 percent for associative skills. A cat is one to one, meaning that half the brain is available for associative ability. A chimpanzee is one to three, and a human being is one to nine. We humans need only utilize 10 percent of our brains to operate our sensory organs. Thus the associative abilities of a cat are measurably greater than a rat but less than a chimp, and humans are the highest of all. Not exactly. The cetacean brain averages one to twenty-five and can range upward to one to forty. The reason for this is that the much larger supralimbic lobe is primarily association cortex. (and not basic sensory and motor cortex)

In humans, the projection areas for different senses are widely separated from one another, and the motor area is adjacent to the touch area. For us to make an integrated perception from sight, sound, and touch, impulses must travel by long fiber tracts with a great loss of time and information. The cetacean’s paralimbic system makes possible the very rapid formation of integrated perceptions with a richness of information unimaginable to us. He gives an example: A dolphin can see a tumor inside the body of another dolphin. If an animal is drowning, this becomes instantly recognizable from being able to “see” the water filling the lungs.

…Based upon comparisons of cortical structure alone, a sperm whale would score 2,000 (in IQ). The truth of the matter is that we know absolutely nothing about what goes on in the brain of a whale or a dolphin. In our ignorance, we resort to the arrogance of denial and dismissal. We deny the physiological evidence and in general we have denied that other animals can think or even feel.

Sight in humans is a space-oriented distance sense which gives us complex simultaneous information in the form of analog pictures with poor time discrimination. By contrast, our auditory sense has poor space perception but good time discrimination. This results in human languages being comprised of fairly simple sounds arranged in elaborate temporal sequences. The cetacean auditory system is primarily spatial, more like human eyesight, with great diversity of simultaneous information and poor time discrimination. For this reason, dolphin language consists of very complex sounds perceived as a unit. What humans may need hundreds of sounds strung together to communicate, the dolphin may do in one sound. To understand us, they would have to slow down their perception of sounds to an incredibly boring degree. It is for this reason that dolphins respond readily to music. Human music is more in tune with dolphin speech.

While I was looking at Watson and some authorities on cetacean anatomy, there was a blog on Babel’s Dawn about dolphin names. (here) The message was that using names does not in itself make a language; language talks about some topic. It seems to me that looking for something that we would call a language in whales and dolphins is probably not a reasonable search. What we really want to know is how cetaceans communicate. We know that they have sophisticated ways of communicating from their behavior. We have no idea whether their communication is analogous to our language, with matching points of reference or structural relationships or whether it has a completely different sort of structure. We have no idea whether their communication is in any way superior or inferior to ours. We also have little idea of their knowledge and culture; they could be all the way from impoverished to rich.


A recent article in The Psychologist by Carhart, Kaelen and Nutt (here) reviews what is known about the action of chemicals that cause hallucinations: LSD from ergot fungi, dimethyltryptamine from ayahuasca and psilocybin from magic mushrooms.

The molecular action of the hallucinogens is to excite particular pyramidal neurons by mimicking the action of the transmitter serotonin. These layer 5 pyramidal neurons are important for projecting to lower centers outside the cortex and within it. They mostly project to neurons that are inhibitory. The net effect is that the exciting of the pyramid cells creates an inhibitory signal from other neurons. It tends to generally shut things down. The oscillations in the cortex, so important to the workings of the brain, are decreased in strength and also desynchronized. The disruption of brain waves seems to stem from the interference with the pyramidal cells - inhibitory cell chains.

This decrease in activity is especially evident in some very important hubs in the brain: the thalamus, posterior cingulate cortex and the medial prefrontal cortex, all integrating and executive control hubs. This may be the source of the lack of integration and constraint seen in hallucinations. There is a lack of distinctness in the network structure of the brain and networks seem to melt into one another. One of the effects of this is increased cognitive flexibility and ability to learn. This may be very useful to therapists in controlled doses. The inhibition of some centers allows areas they control to escape that control. When the cat is away, the mice with play.

It is interesting that the hallucinogens “profoundly alter the quality of consciousness whilst leaving arousal or wakefulness intact.” How does the hallucinogen create the complex vivid visual hallucinations or the loss of ego? During periods of hallucination there are ‘phasic discharges’ from the hippocampus, amygdala and septal nuclei (medial temporal lobe sites) in contrast to the general disorder of brain waves. This resembles the activity of the medial temporal lobe in REM sleep and dreaming. Stimulation of the MTL experimentally can produce hallucinations and distortions of vision.

One of the most common yet abstract experiences described in relation to the hallucinogenic drug state is a disintegration or dissolution of the self or ego. Such an experience is difficult to fathom from the vantage of normal waking consciousness, where an integrated sense of self is felt as pervasive and permanent. It is perhaps not surprising therefore that the experience of ego-disintegration is described as profoundly disconcerting and unusual …Classic accounts of so-called ‘mystical’ or ‘spiritual’ experiences have placed emphasis on the necessity for self or ego disintegration for their occurrence. Thus, in order to investigate the neurobiological basis of ego-disintegration and mystical-type experiences, it is useful to first examine the neural correlates of self-awareness.” The strength of alpha waves in the posterior cingulate cortex, a major hub in the default mode network is correlated with the strength of the self. In hallucinogen sessions, the activity of the PCC decreases in correlation with ego-disintegration. The self is also weak during dreaming.

Astrocyte role in gamma waves

The study of the brain has been very neuron centered. Glial cells outnumber neuron by about 10 to 1 in the cortex and are known to be important to brain function but it is not clear just what they do other than some housekeeping tasks and shepherding neurons to their final locations during development. Astrocyte roles appear to be important but unknown.

Now Lee et al, (see citation below) have published an excellent paper showing one role connected with gamma oscillations. The work was very impressive, but too specialized to describe here - it is summarized in the abstract below. The paper really ‘nailed down’ one role of the astrocytes.

In hippocampus slices they showed that astrocyte intercellular calcium rises before the start of gamma oscillations . This rise does not trigger the gamma but is required for the waves to have duration. They were able to block glutamate release of astrocytes without affecting neuron activity and showed that this glutamate release was the mechanism for maintaining gamma duration. They developed a strain of mouse where astrocyte glutamate release could be switched on and off, and again they showed that neuron behavior was not affected. When the glutamate release from astrocytes was blocked, the gamma power spectrum decreased in the 20 to 40 Hz range. The power spectrum decrease happened only during waking and not in REM or non-REM sleep. The behavior of the mice was examined. There was no difference in maze navigation or in fear conditioning, but novel object recognition was defective when the mice were turned ‘off’ and normal when they were ‘on’. So gamma oscillation in the hippocampus is required for novel object recognition and this ability depends on glutamate release from astrocytes.

They explain in their discussion why there would be a difference in the three behavior tests. “Although both the Y-maze task and the NOR test rely on the rodent’s innate exploratory behavior in the absence of externally applied positive or negative reinforcement, defects were selectively observed in the case of the NOR test. This is particularly relevant because the Y-maze task evaluates a simpler form of memory processing, i.e., short-term spatial working memory, whereas NOR involves a higher memory load engaging long-term storage, retrieval, and restorage of memory processing. During the test phase of the NOR test, a novel object needs to be detected and encoded, whereas the memory trace of a familiar object needs to be updated and reconsolidated after long delays. In contrast, fear conditioning might constitute a strong and highly specific form of learning involving a sympathetic reflex reaction with suppression of voluntary movements (freezing), in which subtle changes in memory content might not be detectable. Moreover, there is strong evidence that suggests fear-conditioned learning encodes a long-term memory process involving the amygdala and the hippocampus, whereas the NOR paradigm engages different structures: the hippocampus and adjacent cortical areas including entorhinal, perirhinal, and parahippocampal cortex.”

Here is the abstract:

Glial cells are an integral part of functional communication in the brain. Here we show that astrocytes contribute to the fast dynamics of neural circuits that underlie normal cognitive behaviors. In particular, we found that the selective expression of tetanus neurotoxin (TeNT) in astrocytes significantly reduced the duration of carbachol-induced gamma oscillations in hippocampal slices. These data prompted us to develop a novel transgenic mouse model, specifically with inducible tetanus toxin expression in astrocytes. In this in vivo model, we found evidence of a marked decrease in electroencephalographic (EEG) power in the gamma frequency range in awake-behaving mice, whereas neuronal synaptic activity remained intact. The reduction in cortical gamma oscillations was accompanied by impaired behavioral performance in the novel object recognition test, whereas other forms of memory, including working memory and fear conditioning, remained unchanged. These results support a key role for gamma oscillations in recognition memory. Both EEG alterations and behavioral deficits in novel object recognition were reversed by suppression of tetanus toxin expression. These data reveal an unexpected role for astrocytes as essential contributors to information processing and cognitive behavior.

Perhaps astrocytes are involved in the production of other brain waves in other locations too.

Lee, H., Ghetti, A., Pinto-Duarte, A., Wang, X., Dziewczapolski, G., Galimi, F., Huitron-Resendiz, S., Pina-Crespo, J., Roberts, A., Verma, I., Sejnowski, T., & Heinemann, S. (2014). Astrocytes contribute to gamma oscillations and recognition memory Proceedings of the National Academy of Sciences, 111 (32) DOI: 10.1073/pnas.1410893111

Discovering rules unconsciously

Dijksterhuis and Nordgren put forward a theory of unconscious thought. They propose that there are two types of thought process: conscious and unconscious. “CT (conscious thought) refers to object-relevant or task-relevant cognitive or affective thought processes that occur while the object or task is the focus of one’s conscious attention, whereas UT (unconscious thought) refers to object-relevant or task-relevant cognitive or affective thought processes that occur while conscious attention is directed elsewhere.’’

Like Kahneman’s System 1 and System 2 thought there is no implication here that there is purely conscious thought with no unconscious components but only that conscious awareness is part of the process. I prefer the System name as it avoids the possible interpretation that there might be purely conscious thought. System 1 is like UT and is characterized as: autonomous, fast, effortless, hidden/unconscious, simultaneous/parallel/complex. System 2 is like CT: deliberate, slow, effortful, conscious, serial/logical/simple. The most telling difference is whether working memory is used; working memory restricts the number of items that can be manipulated in thought to about 7 or less at a time and introduces the conscious awareness of the working memory. It is often viewed as a difference between calculation and estimation, or between explicit and implicit knowledge.

The way these two processes are compared is to set out a problem and then compare the results after one of three activities: the subjects can consciously think about the problem for a certain length of time; the subjects can spend the same amount of time doing something that completely engages their consciousness; or they can be giving no time at all and asked for the answer immediately after the problem is presented. It has been found that with complex problems with many ingredients, that System 1/UT gives more quality results then System 2/CT and both are better than immediate answers.

A recent paper by Li, Zhu and Yang looks at another comparison of the two ways of thinking. (citation below)


According to unconscious thought theory (UTT), unconscious thought is more adept at complex decision-making than is conscious thought. Related research has mainly focused on the complexity of decision-making tasks as determined by the amount of information provided. However, the complexity of the rules generating this information also influences decision making. Therefore, we examined whether unconscious thought facilitates the detection of rules during a complex decision-making task. Participants were presented with two types of letter strings. One type matched a grammatical rule, while the other did not. Participants were then divided into three groups according to whether they made decisions using conscious thought, unconscious thought, or immediate decision. The results demonstrated that the unconscious thought group was more accurate in identifying letter strings that conformed to the grammatical rule than were the conscious thought and immediate decision groups. Moreover, performance of the conscious thought and immediate decision groups was similar. We conclude that unconscious thought facilitates the detection of complex rules, which is consistent with UTT.

It is a characteristic of System 2/CT that it is used to rigorously follow rules to calculate a result. However there is a difference between following a rule and discovering one. This rule discovery activity may be the same as implicit learning. “Mealor and Dienes (2012) combined UT and implicit learning research paradigms to investigate the impact of UT on artificial grammar learning. A classic implicit learning paradigm consists of two stages: training and testing. ” The UT group had better results but they categorized the process as random selection. The current paper shows that the UT group can find the grammatical rules illustrated in the training and then identify grammatical as opposed to ungrammatical strings. System 1/UT is better at uncovering rules and of identifying examples that break the rules. This does not seem to be a rigorous following of rules as in System 2 but more a statistical tendency or a stereotypical categorization of the nature of implicit learning.

It is important to be clear that System 2 or CT is thought that has a conscious component and it does not imply that the thought is conducted ‘in’ consciousness. We are aware of the steps in a train of thought, but not aware of the process, they are hidden.

Li, J., Zhu, Y., & Yang, Y. (2014). The Merits of Unconscious Thought in Rule Detection PLoS ONE, 9 (8) DOI: 10.1371/journal.pone.0106557

Mind to mind transfer


I read the abstract of a new paper (see citation below) about brain-to-brain communication. I had been thinking while I read the title that we already do brain-to-brain communication – it’s called language. And sure enough the first sentence of the abstract said, “Human sensory and motor systems provide the natural means for the exchange of information between individuals, and, hence, the basis for human civilization.” What Grau and others were aiming for and succeeded in doing was to bypass language, motor output or peripheral sensory input without invading the skulls – from conscious thought-to-conscious thought via computer based hardware. “The main differences of this work relative to previous brain-to brain research are a) the use of human emitter and receiver subjects, b) the use of fully non-invasive technology and c) the conscious nature of the communicated content. Indeed, we may use the term mind-to-mind transmission here as opposed to brain-to-brain, because both the origin and the destination of the communication involved the conscious activity of the subjects.”Their abstract is below.

But lets look at how we do mind-to-mind now. We have to share a language, and to a large extent that means we also have to share a good deal of a culture. For normal human communication, it takes a fairly rich language and culture. It the case of the paper’s experiment, the language was patterns of ls and 0s. The sender and his equipment output the pattern and the receiver with his equipment input it. And to understand that the patterns were meaningful required a cultural agreement on their meaning.

It is the language/culture part that is important to the communication. It is as if I utter a phrase which has meaning to me, you hear the phrase, and with it I seem to reach into your brain to pick out that meaning and put it into your stream of consciousness. Without the shared language and culture this trick would not be possible. If anyone thinks that his thoughts can be loaded into a computer and delivered to someone else’s brain by some means that avoids a shared language/culture of some type – he will be disappointed.


Human sensory and motor systems provide the natural means for the exchange of information between individuals, and, hence, the basis for human civilization. The recent development of brain-computer interfaces (BCI) has provided an important element for the creation of brain-to-brain communication systems, and precise brain stimulation techniques are now available for the realization of non-invasive computer-brain interfaces (CBI). These technologies, BCI and CBI, can be combined to realize the vision of non-invasive, computer-mediated brain-to-brain (B2B) communication between subjects (hyperinteraction). Here we demonstrate the conscious transmission of information between human brains through the intact scalp and without intervention of motor or peripheral sensory systems. Pseudo-random binary streams encoding words were transmitted between the minds of emitter and receiver subjects separated by great distances, representing the realization of the first human brain-to-brain interface. In a series of experiments, we established internet-mediated B2B communication by combining a BCI based on voluntary motor imagery-controlled electroencephalographic (EEG) changes with a CBI inducing the conscious perception of phosphenes (light flashes) through neuronavigated, robotized transcranial magnetic stimulation (TMS), with special care taken to block sensory (tactile, visual or auditory) cues. Our results provide a critical proof-of-principle demonstration for the development of conscious B2B communication technologies. More fully developed, related implementations will open new research venues in cognitive, social and clinical neuroscience and the scientific study of consciousness. We envision that hyperinteraction technologies will eventually have a profound impact on the social structure of our civilization and raise important ethical issues.

Note: Some in the press have been calling this transfer telepathy. It is not telepathy!!

Grau C, Ginhoux R, Riera A, Nguyen TL, Chauvat H, Berg M, Amengual JL, Pascual-Leone A, & Ruffini G (2014). Conscious Brain-to-Brain Communication in Humans Using Non-Invasive Technologies. PloS one, 9 (8) PMID: 25137064