Science Literature Is Full of Misleading Claims About Brain Waves

Many neuroscientists mislead with colors, and some other neuroscientists mislead us with lines. I give a detailed explanation of how neuroscientists so often mislead us with colors in my post here.  I can summarize that post in a single paragraph. What goes on is that neuroscientists do brain imaging studies attempting to show what are called neural correlates of particular mental activities. The neuroscientists are hoping to find evidence that some particular part of the brain will become much more active during some mental activity. With the exception of activity in the occipital part of the brain (which is more active when people are seeing things), no such evidence of much greater activity is found. Typically the brain imaging will only show some brain region being only about 1 part in 200 more active, a half of one percent more active, no more than we would expect to see by chance fluctuations.  But what goes on is that such very tiny "half of one percent" variations will be depicted with brain imaging visuals showing the tiny fluctuations appearing in bright red against a black-and-white background. Such visuals deceive us by giving the idea that a large variation has occurred. If the visuals were to be honestly done, they would show variations in color so small you never would be able to notice them. Human brains don't look or act significantly different when you think or imagine or remember, contrary to claims that such things are neural activities. 

Now let me explain how so many neuroscientists mislead us with lines and mislead us about lines. This goes on when neuroscientists give us misleading visuals regarding brain waves, and make misleading statements about brain waves. Below is a type of chart that we see very often in the literature of neuroscience, mostly in popular accounts. As I note at the bottom, this type of diagram is misleading, because all five of these types of brains waves show up in all of the different states listed.

Claims matching the claims above are made in popular literature and also in some very misleading papers written by neuroscientists. This is just another example of neuroscientists making claims in their papers that are not justified by observations, something that occurs massively. An example of such a misleading paper is the paper "Changes of the brain’s bioelectrical activity in cognition, consciousness, and some mental disorders." The authors make generalizations about brain waves and cognitive activity that are not justified by any research they cite. The misleading generalizations the authors make in Table 1 of their paper (and the paragraph preceding it) are repeated word-for-word in the wikipedia.org article on Electroencephalography.

Below are some reports from the neuroscience literature, reports that conflict with diagrams like the one above, and conflict with the paper cited above, by showing that all the main types of brain waves occur during the main types of neural activity:

Delta Waves (1-4 Hz)

• "This wave is recorded during very low activities of the brain and deep sleep (link)."
• "Delta waves (DW) are present both during sleep and in wakefulness (link)."
• "Our recordings reveal rhythmic delta during wakefulness at 10% of all recording sites" in 18 humans (link). 
• "Recently, however, many studies have reported the presence of prominent delta activity during conscious states, which casts doubt on the hypothesis that high amplitude delta oscillations are an indicator of unconsciousness (link)." 
• The diagram here shows many delta waves (1-4 Hz) occurring abundantly in animal brains while animals "waited to see a new image." 
• The paper here has a graph showing delta waves (1-4 Hz) occurring abundantly while humans meditated. 
• A paper on epileptic seizures says, "Slow waves (≤4 Hz) can be found in seizures with impairment of consciousness and also occur in focal seizures without impairment of consciousness but with inhibited access to memory functions."
• The paper "Brain Activation and Cognitive Load during EEG Measured Creativity Tasks Accompanied by Relaxation Music" has circular "power spectral analysis" charts for six subjects, showing mostly delta and theta waves (about 5 Hz) for subjects while they were doing three things: resting, doing creative work, and speaking.  
• The paper "IDENTIFICATION OF DOMINANT WAVE DURING THE RECITATION OF AL-MULK VERSE WITH (WITHOUT) UNDERSTANDING USING EEG SIGNAL" reports "During Al-Quran recitation (without understanding), the highest amplitude of the power spectrum distribution was observed in Delta at the Frontal area (F1, F2, F4, F7 and F8), and Beta2 and Gamma on EEG, predominantly in the T3, T4 and T5 area." This is an example of what occurs very frequently: which brain wave is dominant will vary depending on which brain region is read from. 

Theta Waves (4-8 Hz)

• "In anxious individuals for example, research suggests that there is a significantly higher degree of frontal-midline theta activity compared to non-anxious individuals, and that could be associated with more reactive control modes of behavior in the moment rather than proactive behaviors such as planning and preparation (link)."
• "This rhythm is recorded during low brain activities, sleep, or drowsiness (link)."
• "Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals (link)."
• The diagram here shows many theta waves (4-8 Hz) occurring in animal brains while animals "waited to see a new image."
• The paper here has a graph showing theta waves (4-8 Hz) occurring abundantly while humans meditated.
• A scientific paper states that "REM sleep is characterized by frequencies in the theta (4–8 Hz), beta (16–32 Hz), and gamma (>32 Hz) ranges."
• The paper here has a graph (Figure 8) showing theta waves (4-8 Hz) occurring abundantly in people playing a throwing game.
• The paper "Brain Activation and Cognitive Load during EEG Measured Creativity Tasks Accompanied by Relaxation Music" has circular "power spectral analysis" charts for six subjects, showing mostly delta and theta waves (about 5 Hz) for subjects while they were doing three things: resting, doing creative work, and speaking.
• The paper here found quite a bit of alpha, theta and gamma waves during a memorization test.

Alpha Waves (8-13 Hz)

• The paper here has a graph showing alpha waves occurring abundantly while humans meditated.
• The diagram here shows many alpha waves (8-13 Hz) occurring abundantly in animal brains while animals "waited to see a new image."
• The paper here has a graph (Figure 8) showing alpha waves (8-13 Hz) occurring abundantly in people playing a throwing game.
• In Figure 1 of the paper here, we are shown  multitaper EEG spectrograms that are called representative of sleep, and those diagrams seem to depict theta, alpha and beta waves occurring almost as frequently as delta waves.
• The paper here refers to alpha waves occurring during anesthesia, when a patient is in deep unconsciousness. We read, "All four spectrograms for these data show the well-known alpha-beta oscillations (8–17 Hz) and slow-delta oscillations (0.1–4 Hz) that are characteristic of general anesthesia maintained by sevoflurane." 
• The paper here found quite a bit of alpha, theta and gamma waves during a memorization test.
• While the page here claims that alpha waves "disappear during sleep," the page here states that "stage 1 sleep is associated with both alpha and theta waves," and shows an EEG of alpha waves recorded during sleep.  The page here states that alpha waves of between 8 to 14 Hz occur in "bursts of activity" in stage 2 sleep (light sleep). 
• A paper studying brain waves during hypnosis in 8 subjects found little change in brain waves, with alpha waves being the main type of wave before, during and after hypnosis. Conversely, another paper tells us "a number of studies have not found an increase in alpha activity with hypnosis (Kihlstrom, 2013; Ray, 1997; Sabourin, Cutcomb, Crawford, & Pribram, 1990)," and it also tells us "findings linking hypnosis to theta oscillations, however, are more common."

Beta Waves (13-30 Hz)

• The first graph below show gamma waves while animals "waited to see a new image."
• The paper here has a graph showing beta waves occurring abundantly while humans meditated.
• An article in an encyclopedia of neuroscience states, "Beta and gamma waves (20–80 Hz) occur spontaneously during REM sleep and waking and are evoked by intense attention, conditioned responses, tasks requiring fine movements, or sensory stimuli."
• In Figure 1 of the paper here, we are shown  multitaper EEG spectrograms that are called representative of sleep, and those diagrams seem to depict theta, alpha and beta waves occurring almost as frequently as delta waves.
• The paper here has a graph showing beta waves occurring in significant amounts during anesthesia.
• The paper here has a graph (Figure 8) showing beta waves (13-30 Hz) occurring abundantly in people playing a throwing game.

Gamma Waves (30-100 Hz)

• The first graph below show gamma waves while animals "waited to see a new image."
• The paper here has a graph showing gamma waves occurring abundantly while humans meditated. Despite some claims of gamma wave activity being associated with concentration, a study of brain-injured veterans found they have much higher levels of gamma waves in a certain brain region. 
• A paper found that "gamma oscillations in low (30–50 Hz) and high (60–120 Hz) frequency bands recurrently emerged in all investigated regions" in the brains of 20 humans during "slow wave sleep."
• A paper on sleeping monkeys says, "Gamma oscillations around 50 Hz or higher were most prominently observed during REM sleep."
• An article in an encyclopedia of neuroscience states, "Beta and gamma waves (20–80 Hz) occur spontaneously during REM sleep and waking and are evoked by intense attention, conditioned responses, tasks requiring fine movements, or sensory stimuli."
• A scientific paper states that "REM sleep is characterized by frequencies in the theta (4–8 Hz), beta (16–32 Hz), and gamma (>32 Hz) ranges. "
• Another paper found gamma wave activity (in the range of 30-40 Hz) in hypnotized subjects.
• A paper states that "gamma oscillations (30-50 Hz) recorded in the local field potentials (LFP) of the hippocampus are a marker of temporal lobe seizure propagation," and that "78.2% of seizures involving both the hippocampus and amygdala showed hippocampal gamma oscillations," conflicting with claims that such gamma waves (gamma oscillations) are characteristic of problem solving or concentration. 
• The paper here found quite a bit of alpha, theta and gamma waves during a memorization test. 
• The source here states that "some researchers contest the validity or meaningfulness of gamma wave activity detected by scalp EEG, because the frequency band of gamma waves overlaps with the electromyographic frequency band," so  "gamma signal recordings could be contaminated by muscle activity."

Graphs Plotting Multiple Brain Wave Types During a Single Activity

One way to get a clearer idea about such matters is to look for papers that plot multiple brain wave types during a single type of mental activity. You can find some papers of this type by doing a Google search for "brain wave power frequency." For example, the link here takes to a press release for a study with a line graph that plots all types of brain waves seen while animals "waited to see a new image."  We see the diagram below:

The graph shows brain waves from three different parts of the brain. The graph shows plenty of all five of the main types of brain waves: delta waves, theta waves, alpha waves, beta waves and gamma waves. The graph does not match the depiction in the typical brain wave chart, suggesting delta waves only occur during sleep. 

The paper here shows a similar graph of brain waves arising when humans meditated. Delta waves, theta waves, alpha waves, beta waves and gamma waves all occur in pretty much equal abundance. The paper here shows a similar graph arising with three subjects in a resting state (awake but eyes closed) and one subject looking at a blue "O" in front of him. All had delta, theta, alpha and beta waves in roughly equal amounts. 

The paper here shows (1) a circular graph of brain waves arising when six humans were in a resting awake state; (2) a circular graph of brain waves arising when six humans were doing creative activity  (3)  a circular graph of brain waves arising when six humans were speaking. There is little different in the three graphs. They all show theta waves of about 5 Hz as being by far the most common brain wave during all of these mental states, with beta waves and gamma waves occurring much less frequently. 

There is a type of graph called a multitaper EEG spectrogram. Someone unfamiliar with it will have to take a few minutes studying how the graph works before he can understand it. The graph can show up to 8 hours of brain activity. Each column of pixels shows the activity for a particular short time unit such as a minute. The higher rows on the graph represent the higher-frequency brain waves. A red color represents a high intensity; a yellow or green color represents a medium intensity; and a blue color represents a lower intensity. 

We are sometimes shown versions of this graph which will suggest that lower-frequency brain waves are much more common during sleep. However, in Figure 1 of the paper here, we are shown  multitaper EEG spectrograms that are called representative of sleep, and those diagrams seem to depict theta, alpha and beta waves occurring almost as frequently as delta waves. 

In a Dream Catcher study described here and the 2020 scientific paper here, EEG recordings were made of subjects while they were sleeping. The subjects were awakened at random times, and asked to tell whether or not they were dreaming.  Then some scientists ("blind" to which EEG readings were from the dreamers) were asked to guess whether particular subjects were dreaming. The result was a null result. There was no evidence that by studying EEG recordings you can tell whether a person is dreaming.  

Scientists apparently delayed the release of these results for years. A 2015 paper describes results just like those of the Dream Catcher study, but results that had apparently not yet been published:

"When data from serial awakenings of 9 subjects had been collected, these data were divided. Introspective reports and electroencephalographic recordings were analysed by different judges who were ignorant of which EEG sequences had led to dream reports and which ones had not. An external EEG research group used a number of statistical methods to identify the signature of the recordings that were followed by dream reports. But the accuracy of their predictions turned out to be no better than chance. A doctoral researcher presenting these findings at a conference explained that there were 4 different explanations for this failure: ‘Subjective experience is a) not in the brain, b) is in the brain, but not in the EEG, c) is in the EEG, but not in our data, or d) is in the data, but needs more complex and novel methods of analysis.’" 

The paper then quotes someone from 2008 saying this:

"We still haven’t found any objective sign indicating the presence or absence of consciousness in the dreaming brain. Maybe that’s something that Descartes would have predicted: that you cannot objectively capture consciousness because it is this immaterial, non-spatial, and imperceptible thing ... We haven’t been able to disprove the Cartesian position ... The dream catcher experiment is a test of the whole emergent materialist position ... We will continue our analysis, but if we can’t find anything then we have a real problem where to go."

Brain Waves During Hypnosis

A paper studying brain waves during hypnosis in 8 subjects found little change in brain waves, with alpha waves being the main type of wave before, during and after hypnosis. A study with a much larger study group size (32 subjects) found little change in brain wave activity during hypnosis. The paper ("An Investigation of Changes in Brain

Wave Energy during Hypnosis with Respect to Normal EEG") states this:

"We have found significant changes in the delta and beta band relative energy in channel C3. But the results of the statistical analysis show that the changes of the energy in the other frequency bands and also in the other channels are not significant."

Hypnosis involves dramatic changes in human consciousness.  The topic of changes in human pain perception, mental abilities and suggestibility during hypnosis is itself a huge topic with a very large literature.  The fact that something (hypnosis) involving so large a change in mental states seems to involve so little a change in brain waves is one that helps to undermine claims that minds come from brains. 

Trying to Predict Personality From Brain Waves

An interesting paper with a sample size much larger than in most neuroscience papers is the paper "Personality cannot be predicted from the power of resting state EEG." We read this:

"EEG was recorded from a large sample of subjects (n = 289) who had answered questionnaires measuring personality trait scores of the five dimensions as well as the 10 subordinate aspects of the Big Five. Machine learning algorithms were used to build a classifier to predict each personality trait from power spectra of the resting state EEG data. The results indicate that the five dimensions as well as their subordinate aspects could not be predicted from the resting state EEG data."

Conclusion

Neuroscience literature very often makes untrue simplistic generalizations about brain waves, statements suggesting incorrectly that particular types of brain waves only occur during particular types of activities. In general, with a few scattered exceptions, there is no close correspondence between brain waves and particular types of mental activities and mental states. Scientific studies and popular articles on this topic make extensive use of cherry-picking, in which signal dominance will be reported with some activity, based on readings from only one part of the brain. Typically a reading of brain waves from all parts of the brain will show a mix of most types of brain waves occurring during most types of mental activities. In general, brain waves are not signatures of some particular type of mental activity. 

Frequent claims that brain waves play a role in memory or learning are without foundation, and the evidence is consistent with such waves being merely an epiphenomenon of neural activity (like the scent arising from cooking soup). Brain waves show no sign of the signal modulation that characterizes information signals (like the signal modulation we see in man-made radio waves).