Archive for 'Memory'

Subconscious Security – Storing Passwords in Memory with Implicit Learning

A team of neuroscientists and cryptographers have developed a prototype system which uses the concept of implicit learning to store a 30 character password in subconscious memory.

I wish I was reporting that this technology will soon be widely available, eliminating the annoyance of forgotten passwords for good. But if anything, the methods described here are more likely to be put into use at the highest levels of government/military operations. Even so, the concept, and the research pushing the boundaries of what we can knowingly do with our subconscious memory, is highly intriguing:

The system was designed by Hristo Bojinov and Dan Boneh of Stanford University, in partnership with neuroscientists and cryptographers from Northwestern University and SRI International. Their design for subconscious password storage involves the use of a specially crafted computer game (shown in the screenshot above). Before running, the game creates a random sequence of 30 letters chosen from S, D, F, J, K, and L, with no repeating characters. In the training game, the user has to hit the corresponding key for each of those letters when a circle reaches the bottom of the screen. As others have noted, the training game isn’t so different from “Guitar Hero” at a glance. Results of the research so far suggest that it takes about 45 minutes of playing this game to deeply lodge a 30-character password in your subconscious.

To log back into a machine, the user simply plays a quick round of the game, in which some segments are their actual password, but others are randomly created strings of characters. The research team observed that users were consistently able to perform better on the portions of the game containing their password, as those patterns were stored subconsciously. Reliably performing the password sections better than the random sections is what authenticates the user, and allows them to log in.

Because the system is based on performance and speed, rather that rote memorization, it cannot be written down or given away, even to legal authorities or under threat. It is “thousands/millions of times more secure than your average, memorable password,” reports Extreme Tech.

As mentioned earlier, this system isn’t being developed with everyday security needs in mind. Lead designer Hristo Bojinov believes it’s ideal for monitoring access to “highly secure, sensitive physical areas. We see our scheme as complementary to other authentication methods, not as a replacement for them,” he writes.

In the team’s published paper describing their study, they describe goals for future research that would further illuminate the possibilities for making use of implicit learning/subconscious memory in this way. The team hopes to better analyze the rate at which passwords are forgotten after this training, and to more accurately determine when individual users have reliably learned the password. They also plan to test whether sequences as long as 80 items could be subconsciously stored, and whether even more complex structures can be learned implicitly.


Extreme Tech

Neuroscience Meets Cryptography: Designing Crypto Primitives Secure Against Rubber Hose Attacks (Original research article)

Theta Wave Activity Linked to Improved Memory Recall

If you think about it, you probably feel as though you have both good and bad memory days- maybe even hours. I like to think that my memory is pretty strong as a general rule, but there are periods of time where I’m just drawing blanks. There’s a whole host of reasons for these variations. After all, it’s not as though every person is born with a “memory score” that permenantly determines their ability to recall information. Like everything related to our minds, it’s far more intricate than that.

New findings from a prestigious center of neuroscience are demonstrating the significant relationship between levels of theta brain wave activity and our ability to remember at that moment in time. A paper describing this work, from scientists at UC Davis, was recently published in the journal Proceedings of the National Academy of Sciences.

To prove their case, professors and graduate students measured theta wave oscillations in the brains of volunteers during a memory test. Volunteers were asked to memorize a series of words. They later had to recall whether they had seen the word previously, and the context in which the word was seen. Volunteers who were experiencing higher levels of theta wave activity right before they were asked to remember an item were more likely to remember correctly.

Memory recall improved only when volunteers had high theta activity before they heard the cues. If it had been the case that theta activity had increased only after the cues were given, this study would instead suggest that theta waves were stimulated by the cues themselves—perhaps an indicator that the brain was processing a new challenge. But that was not the outcome here. Subjects whose brains were in a high-theta state were essentially “primed” to do better on the memory test once it started.

Of course, this should not be taken to mean that high levels of theta activity are the only factor behind successful memory recollection, but the study does lend support to the idea that everyday memory ability is just as much as a reflection of what’s going on inside the mind as the context outside of it.

“The work goes against the assumption that the brain is waiting to react to the external world. In fact, most of the brain is busy with internal activity that is not related to the outside world — and when external stimuli come in, they interact with these spontaneous patterns of activity.”

– Charan Ranganath, Professor, UC Davis Center for Neuroscience

In this study, the researchers did not actually attempt to stimulate theta activity- they were merely measuring it and recording results. Their hope is that research could lead to treatments for memory loss. Ideally, audio visual stimulation methods to increase theta activity will be part of the dialogue as this research moves forward.

Source: University of California

New study on Brainwave Entrainment (By Dr. Huang)

I’m pleased to announce the publication of “A Comprehensive Review of the Psychological Effects of Brainwave Entrainment” in Alternative Therapies in Health and Medicine this month. This paper is the most comprehensive review of peer reviewed research in the subject, and was written in order to inform those within and the beyond the field of brainwave entrainment (BWE), and to provide sufficient background for future research.

Most of the research known to date has been summarized by David Siever in two unpublished manuscripts that he sells and distributes. They contain much valuable information about the history of BWE, both published and unpublished studies and proposed mechanisms of action. However, despite their length, they do not provide a complete listing of the peer reviewed literature, nor have his manuscripts faced the scientific scrutiny that comes with publishing in a peer reviewed journal. In fact, in our comprehensive search, we found articles that have never before been mentioned by those in the brainwave entrainment development and scientific community. Why? Believe it or not, the problem is in the inconsistency in terminology used to describe BWE. The term, BWE, until today, cannot be found in the scientific literature. Instead it is referred to as audiovisual stimulation, photic stimulation, photic driving, auditory entrainment, etc, etc. In all I did a search using 31 different terms to look for articles on brainwave entrainment, which returned 27,830 articles using Ovid (1 out of the 4 databases I used to do the search). Only a very small handful of these turned out to be articles on BWE. Thus much of the credit needs to go to my bosses at Transparent Corporation, who gave me the time to do this exhaustive, time consuming, and yet important work.

I looked for papers with psychological terms that described outcomes that I’d seen associated with BWE on the web, in conferences and in the published and unpublished literature. After combining the two searches, and screening for those that were indeed articles addressing psychological outcomes of BWE, and those that passed some basic scientific criteria, we ended up with just 20 articles.

The psychological effects that had been examined in relation to BWE included cognitive functioning (we divided it into verbal, non-verbal, memory, attention and overall intelligence), stress (long and short-term), pain, headache/migraines, mood, behavior and pre-menstrual syndrome (PMS). When two or more studies had examined similar outcomes, we placed them into tables for greater comparability. Thus we had five tables divided by cognitive functioning, stress, pain, headaches/migraines and mood. Studies used a variety of different frequency protocols and stimulation methods which are outlined in the tables.

Out of the 20 studies, 17 were actually developed to support or confirm a hypothesis, and of these, all found a positive effect in at least one outcome. And in each outcome mentioned, at least one study had a positive finding. What was remarkable was that for some outcomes, only one of several protocols had a positive effect, while others were improved by a variety of different protocols. The most consistent positive findings were found in attention (4/4 studies), pain (3/3 studies) and headache/migraines (3/3). While positive effects were found in all other outcomes examined except for mood, either fewer studies had been conducted or a smaller percentage of the protocols examined were effective. Mood was examined in the 3 studies where the effects of theta were examined on a variety of outcomes. So we believe that the ability of brainwave entrainment to positively effect mood has not been properly tested in the peer reviewed literature.

Overall, we conclude that brainwave entrainment shows real potential to positively affect psychological outcomes. However, more and bigger studies need to be done, using additional outcomes and outcomes already examined. We hope that we’ve provided the necessary background to inspire future research and collaboration, so that the field of brainwave entrainment can gain recognition and momentum in the scientific literature.

To view a copy of this article, visit:

Tina L. Huang, Ph.D.
Director of Research
Transparent Corporation

The effect of belief on intelligence

A unique and fascinating new study was released this year by Carol Dweck, a psychologist at Stanford University, researching the effects of belief on cognitive performance.

The results: children who believed that intelligence was malleable and could be improved were much more likely to perform well in school. Children who believed intelligence was something set in stone – a genetic gift from birth that never changes – did not perform as well.

To test this, Dweck separated one hundred 7th grade students into 2 equal groups. All students had suffering math scores. One group was taught good studying habits, the other was taught about the plasticity of the brain, and how the brain can change; new neural connections can be formed and intelligence can actually be increased.

At the end of the semester, the children who had the crash course in neuroscience ended up performing better than those who were taught study skills! This is because their beliefs about intelligence had changed.

Here’s some excerpts from an article on this:

“Some students start thinking of their intelligence as something fixed, as carved in stone,” Dweck says. “They worry about, ‘Do I have enough? Don’t I have enough?'”

Dweck calls this a “fixed mindset” of intelligence.

“Other children think intelligence is something you can develop your whole life,” she says. “You can learn. You can stretch. You can keep mastering new things.”

She calls this a “growth mindset” of intelligence.  

“When they studied, they thought about those neurons forming new connections,” Dweck says. “When they worked hard in school, they actually visualized how their brain was growing.”

“We saw among those with the growth mindset steadily increasing math grades over the two years,” she says. But that wasn’t the case for those with the so-called “fixed mindset.” They showed a decrease in their math grades.

“If you think about a child who’s coping with an especially challenging task, I don’t think there’s anything better in the world than that child hearing from a parent or from a teacher the words, ‘You’ll get there.’ And that, I think, is the spirit of what this is about.”

In the articles on our website, we’ve been talking for years about how beliefs can work for or against your cognitive performance. Many people who approach us with cognitive issues want to focus only on the neurological or physiological aspect of that. Often, after a few months of work, it becomes apparent that a psychological approach is needed – the physiology is right for peak performance, but the belief system keeps the brain stuck in first gear. Negative beliefs about one’s intelligence can often be very hard to counteract. This study is useful in that it shows that merely learning more about the brain can help give your brain the boost it needs to make real progress.

NPR has a nice broadcast of this new research online:

Using gamma waves to distinguish false memories from real ones

New research from the University of Pennsylvania has unveiled distinct gamma brainwave patterns associated with memory formation and recall:

Patients volunteered to study lists of words which they were then asked to recall at a later time.  When asked to recall the studied words, participants recalled some number of correct items and also made a small number of errors, recalling words that had not appeared on the target list.  

While patients performed the memory game, scientists observed electrical activity in their brains to determine whether specific brain waves were associated with successfully storing and retrieving memories. Researchers found that a fast brain wave, known as the gamma rhythm, increased when participants studied a word that they would later recall. The same gamma waves, whose voltage rises and fall between 50 and 100 times per second, also increased in the half-second prior to participants correctly recalling an item.  

These analyses revealed that the same pattern of gamma band oscillatory activity in the hippocampus, prefrontal cortex and left temporal lobe that predicts successful memory formation also re-emerged at retrieval, distinguishing correct from incorrect responses, said Per B. Sederberg, lead author and former Penn neuroscientist now performing post-doctoral research at Princeton University.  The timing of these oscillatory effects suggests that self-cued memory retrieval initiates in the hippocampus and then spreads to the cortex.  Thus, retrieval of true as compared with false memories induces a distinct pattern of gamma oscillations, possibly reflecting recollection of contextual information associated with past experience.

Full article: 

These kinds of advancements in our understanding of memory will be incredibly useful in diagnosing and alleviating neurological problems from epilepsy to schizophrenia.

Here is the full paper:

For more on recent work on gamma waves, check out this lecture by Robert Knight: 

Thanks to Tyler on the forums for finding this.

Sleep learning in the 1920’s

Here is an interesting news blurb from a 1923 Time Magazine about radio operators who accidentally stumbled upon the idea of sleep learning:

The accidental falling asleep, with the phones on his head, of a student in training for a job as radio operator in the U. S. Navy led to a discovery which will vastly shorten the process of manufacturing experts in wireless telegraphy. While the code and its translation were coming through the ether, the brain cells of the sleeping man, in a state of plastic receptivity, were absorbing the meaning of the dots and dashes and forming new associations. On waking, he was able to repeat accurately everything he had received in sleep. Psychologists say that such results are feasible because of the automatic, repetitive nature of the material conveyed to the dormant brain.

Navy officials immediately instituted tests of the method at Pensacola, Fla. Twelve students who were making unsatisfactory progress were tried out. After two nights, during which the code was sent to those students in sleep, ten had learned the lesson, and the other two had left the class before completion of the experiment. The instructors now report that ” the experimental stage is past, and the method may now be termed a standard one.”

Today the concept of sleep learning actually focuses less on unconscious sleep and more on the “twilight state” between alpha and theta. This highly receptive state is useful not only for memorizing rote facts, but for conceptualizing them, and forming new ideas. This is the state we focus on in one of the learning tools in NP2

Thanks to Mind Hacks for this.

Weekly Brain Video: Memory techniques

Andi Bell isn’t an autistic savant. He wasn’t born with photographic memory. Yet, he is currently the reigning champion in the speed category of the World Memory Championships.

This is possible because of a memory technique Andi uses, which is explained in the following videos:


Part 2:


This technique reminds me a lot of Memory Pegs, which many of you may have already heard of.

The basic idea of these memory techniques is to associate a story or image with what you want to remember. The more humorous and outlandish the story, the better. For example, if I wanted to remember to buy turkey and paper towels at the store, I might picture a live turkey comically trying to escape from a wrap of paper towels.

I use this technique when I play Brain Age, which lists words much like the experiment in the above videos. I associate 2 words with something comical, and move to the next pair. Usually, I can remember all of them, and I certainly don’t have prodigious memory.

To me, the interesting and unique part about Andi Bell’s technique is the use of a familiar route to further reinforce the memory pathways. Start at the door of your house, associate a memory with it, walk into the foyer, associate a memory with that, walk through the living room, a new memory, and so on. This is brilliant.

Theta’s involvement in choices and learning

Monitoring brainwaves simultaneously in different areas of the brain can yield some intriguing insights into how various parts of the brain cooperate and “talk” to each other.

In a recent study from St. Lawrence University, Theta rhythms in the striatum and the hippocampus were monitored in rats as they went through a maze and made decisions about how to reach the goal. Although these two brain structures are both involved in memory and learning, they are involved in different ways and generally work independently of each other. The striatum is involved in planning and procedures, while the hippocampus is involved in forming memories of experiences or events.

While monitoring these two brain structures, researchers noticed that as choices were made about which way to turn in the maze, theta rhythms in both the striatum and the hippocampus became highly coherent, indicating a link between them, and a link to theta rhythms as an important component in learning and decision making.

“Rhythmic activity in the theta range (7–14 Hz in the rodent) has been proposed to be crucial for mnemonic coding in the hippocampus and related limbic structures. Pathways interconnecting the hippocampus and neocortex are thought to use these rhythms for transferring and coordinating neural representations in cortico-hippocampal circuits in relation to sequential spatial behavior.”

“Simultaneously recorded striatal and hippocampal theta rhythms are modulated differently as the rats learned to perform the T-maze task but nevertheless become highly coherent during the choice period of the maze runs in rats that successfully learned the task.”

“For the rats that learned the task, the magnitude of coherence between the striatal and the CA1 theta rhythms rose to a peak as they reached the instruction tone part of the task, and the coherence remained high or fell only slightly as the rats made a decision about a turning direction and turned.”

“Oscillatory modulation of neuronal activity has been implicated in a wide range of functions, including sensory processing, network coordination, expectancy coding, sequence learning, episodic memory, and interval timing. We demonstrate here that during goal-directed behavior, striatal theta-band oscillations have structured, task-dependent, and learning-dependent coherence relationships with the theta rhythms”

I’ve uploaded a PDF version of the report for our readers: Learning-related coordination of striatal and hippocampal theta rhythms during acquisition of a procedural maze task

Eye exercises provide 10% memory boost

A new study led by Dr. Andrew Parker of the Manchester Metropolitan University found that moving your eyes from side to side for 30 seconds every morning can enhance your memory by, on average, 10%.

He presented 102 university students with recordings of a male voice reading 20 lists of 15 words. The subjects were then handed a list of words and asked to pick out those that they had just heard. On average, the students who had moved their eyes from side to side performed 10 per cent better than the rest. Up and down eye movement was of no use at all to recall.

According to Parker, it can also improve the accuracy of your memory, or reduce “false” memories.

Contained within the lists were “lure” words that were not in the spoken list but were similar to some of those that were. Students who had moved eyes sideways were 15 per cent better at ignoring the misleading words.

Why would eye exercises improve memory? Dr. Parker explains: 

“One reason for this is that bilateral eye movements may improve our ability to monitor the source of our memories.” He said that people are often confused over whether a memory is real or imagined, such as whether a bill was paid or a door locked.

“The problem is to determine the source of one’s memory — real or imagined. Bilateral eye movements may help us to determine accurately the source of our memory”.

Horizontal eye movements are also theorized to enhance communication between the left and right brain hemispheres.

This reminds me of the controversial EMDR (Eye Movement Desensitization and Reprocessing) technique for PTSD, which I admittedly don’t know a whole lot about.

It also reminds me of NLP eye-accessing cues, which also deals with memory.

I have been experimenting with this the last few days since reading the article. I can’t say I have found a major improvement in memory (but then, it is probably hard to consciously notice a 10% improvement in anything). I do, however, enjoy the feeling I get after 30 seconds of uninterrupted side-to-side eye movement. A meditation instructor I had years ago would use eye movement techniques to quickly enter an alpha state.

Here’s the full article:

Alpha’s involvement in memory, and how 10 hz flicker can improve it

It is well known that episodic memory – the ability to recall events, times and places – degrades as we get older. What is interesting is that the strength of Alpha rhythms in the brain also decreases with age, and falls sharply with diseases such as Alzheimer’s.

This is important because alpha is theorized to be intimately involved in the encoding of certain types of memories. It has been well known for some time that drugs used to modulate slow rhythmic EEG activity can actually enhance memory. More recently, brain stimulation in the form of a flicker is showing even greater promise in this area, and is offering the incredible possibility of a completely drug-free solution to age-related memory problems.

In March of 2006, a paper was published in BMC Neuroscience which outlined the effects a 10 hz flicker had on a difficult memory task, showing very promising results. The performance of older participants on memory tasks was as low as would be expected given their advancing years. However, once the Alpha stimulation was introduced, their memory performance shot up to that of typical young adults!


The Method 

Unlike many of the effects produced by audio-visual stimulation, this one seems to be extremely frequency specific. A mere .5 hz difference between flicker rates made the difference between a positive effect and no effect at all. 10 hz and 10.2 hz seem to be the “magic” frequencies studied in this paper.

Also interesting is the duration of the flicker: only 1 second! Participants were asked to memorize words as they appeared on the screen. Before each item was presented, a 1 second burst of 10 hz alpha stimulation was administered using LED lights, set up in their peripheral vision.


Why would such a brief stimulation period have any effect?

The study mentions that this could be because alpha’s involvement in memory formation is exceptionally brief. For a rapid moment as memories form, Alpha synchronizes. The theory is that short bursts of alpha stimulation increases this synchronizing effect, leading to enhanced memory. The hippocampus, which is involved in memory formation, may be the brain structure that makes this possible. There is evidence that slow-wave activity of this type seen in the hippocampus facilitates memory formation.

On the other hand, the study also notes that the duration between flickers was also very brief, so the alpha-inducing effects could have carried over from item to item. The effects of longer durations, and any long-term effects of this stimulation, have yet to be studied. Still, this is all very promising, especially since we know from other research that long-term, permanent alpha enhancement is very possible.


Other interesting tidbits about this research:

· The flicker’s effect does not appear to be retroactive. In other words, it was only AFTER the flicker that memory appeared to be enhanced. Memories encoded before the flicker were unaffected.

· The brightness of the LEDs correlated with greater effects. The brighter the LEDs, the more enhanced memory became. 

· The memory-enhancing effects seemed more pronounced in the elderly, but the study did mention previous work that indicated alpha also enhanced memory in young adults!

· Other previous studies have indicated that theta stimulation could improve memory consolidation after learning has already taken place.


Here is the paper, if you are interested in taking a look for yourself:


The best part about this study is that the LED lights were positioned around the eyes, not in their direct line of sight. In fact, some participants didn’t even notice them!

This has encouraged me to start using the new open-eye glasses more: