Sunday, September 25, 2016

High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk


Background
This study focused on the affect binaural beats had on the brain's ability to multitask. Theories stated that the use of binaural beats for cognitive control had two methods, persistent and flexible. The persistent beats allowed a listener to focus on a single task whereas the flexible beats allowed the listener to be able to focus on several tasks equally. This study looked at the affect the second selection of beats had on crosstalk, which is, in this case, two tasks affects on each other. Previous studies had suggested that there is some connection between certain types of frequencies and this crosstalk phenomenon.
Method
The study used forty students (32 female, eight male; aged 18–27 years old) from Leiden University. At the end of the experiment, they received a fiver and were debriefed. A test group was exposed to "gamma" frequencies (40 Hz binaural beats) and a control group listened to a 340 Hz standard frequency. The participants were asked questions about their overall mood and state of arousal. They then, while listening to their respective noises, performed a series of simple key press tasks which were recorded and analyzed.
Results
The study found there were statically significant events in the study to the respondent's reaction times. These increases in reaction times show that the use of binaural beats for cognitive flexibility shows verifiable gains. Furthermore, the questions on mood show that there was no change to mood from pretest to posttest, which the researchers used to rule out the theory's concerning the injection of dopamine into the central nervous system as the reason for previous test's success. Essentially, the test showed that there was increased crosstalk within the task as potentially brought on by the use of binaural beats.
Critique
The whole report was written several leagues of smart above my station. While that itself is not a point against it, it tells me that this concept is still rather new. The hard science, with its top tier terminology, is still working on the topic to understand the effect of binaural beats on the cognitive functions of humans. What this says is the field is still very new and there is still some serious research that needs to be done before any definitive statement for or against binaural beats can be made. Furthermore, it may be some time before much of it is flushed out. Finally, I listened to so called binaural beats while reading the report and writing this synopsis. I found there to be no difference in my ability to focus on the task while listening to binaural beats versus white noise. However, the reports states: "On the positive side, our findings suggest that binaural beats provide the opportunity for cognitive enhancement by providing people with tools to tailor their cognitive-control states to situational demands." This means that the researchers feel that their test shows that binaural beats can be used to alter the cognitive abilities of a listener. While I am hesitant to argue with experts, the concept of binaural beats must lay in the ears of the listener. 

Source
Hommel, B., Sellaro, R., Fischer, R., Borg, S., & Colzato, L. S. (2016). High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk. Cognition, 1287. http://doi.org/10.3389/fpsyg.2016.01287
 

Friday, September 23, 2016

The Impact of Binaural Beats on Creativity

Background
  
This study aimed to analyze the effect that binaural beats have on human creativity. The study defined binaural beats as an auditory illusion and form of cognitive entertainment that operates by stimulating neuronal phase locking. This auditory illusion occurs when a tone of a certain frequency is played in one ear, while another tone of a slightly different frequency is played in the person's other ear. Instead of hearing two separate tones, the person will hear one fluctuating tone, or a beat. For example, if a tone of 335 HZ is played in the right ear and a tone of 345 HZ is played in the left ear, then this results in perceived binaural beat of 10 Hz. In this study, binaural beats with an alpha condition and a gamma condition are used.

Past research has linked dopamine, a neurotransmitter, to human creativity. In addition, binaural beats are thought to affect dopamine-driven processes. Therefore, this study hypothesized that binaural beats can influence human creativity, and uses the variables of divergent thinking and convergent thinking to test this hypothesis. This is due to findings that both divergent and convergent thinking are two main processes in human creativity

Method 

The participants in this study consisted of 24 first-year students at Leiden University. Each participant took part in three separate sessions. The three sessions consisted of the participants listening to an alpha condition of 10 HZ binaural beats, a gamma condition of 40 HZ binaural beats, and a control condition of a constant tone of 340 HZ. Before and during each session, the participants' dopamine levels were tested through their eye-blink rate (EBR). During each session, the participants completed tasks involving divergent thinking and convergent thinking. 

For the divergent thinking task, participants completed an Alternate Uses Task (AUT). The AUT presented participants with six items: a brick, shoe, paper, pen, bottle, and towel. The purpose of the AUT was for participants to then list alternate uses for each item. The answers were scored on four components, originality, fluency, flexibility, and elaboration, in order to determine creativity. Participants were given 10 minutes to solve two items per session.

The convergent thinking task was a Remote Associations Task (RAT). The RAT presented participants with three unrelated words for which they had to find a single compound word that could be associated with each word. For example, the words "market", "star", and "hero" are all associated with the compound word "super", as in "supermarket", "superstar", and "superhero". Participants were given 4 minutes to solve 10 items per session.

Finally, the participants' moods were assessed before and after each session using a Positive and Negative Affect Schedule Mood State Questionnaire (PANAS-S). This is because the study assumed that positive mood influences divergent and convergent thinking.

Results

A repeated measure analysis of variance (ANOVA) was used to measure the differences in EBR during each session, and found that there were no differences. In other words, the alpha, gamma, and control conditions did not have different effects on the participant's EBRs. Additionally, the study found that the effects of binaural beats on both divergent and convergent thinking were not statistically significant. However, the study found that participants with lower baseline EBRs (20 blinks per minute or lower) revealed beat-induced benefits in divergent thinking. The enhancements in divergent thinking especially related to the task's flexibility component. On the other hand, binaural beats impaired divergent thinking in participants with higher baseline EBRs (20 blinks per minute or higher). The study determined that mood did not affect the difference in divergent thinking performances for participants with lower baseline EBRs. 

The study concluded that binaural beats trigger dopamine, but instead support neuronal phase locking in general. The study also stated that binaural beats do not represent a comprehensive tool for cognitive enhancement, such as creativity, as it relies on the individual's dopamine levels (indicated by the individual's baseline EBR).

Critiques

The sample for this study was not very diverse as the participants consisted of 24 college students between the ages of 17 and 25 years-old who were mostly female (22 females; 2 males). It would be interesting to see if the results of the study would differentiate with a larger and more diverse group of participants. There were also many components in the study that were being analyzed, making it difficult to determine the significance of the study's findings. For example, it is confusing that the study found that binaural beats did not cause any differences in the EBRs between each session, and yet binaural beats influenced the divergent thinking performances for participants with lower baseline EBRs.



Source

Reedijk, S. A, Bolders, A., & Hommel, B. (2013). The impact of binaural beats on creativity. Frontiers in Human Neuroscience, 7(786). doi:10.3389/fnhum.2013.00786. Retrieved from http://journal.frontiersin.org/article/10.3389/fnhum.2013.00786/full 

 

The Effect of Binaural Beats on Working Memory Capacity


Background

It has been suggested that cognitive and executive functioning is accompanied by specific brain wave oscillations. Overall, the brain activity within alpha rhythm (7.5 – 12.5 Hz in adults) has been associated with vigilance, inhibitory processes, attention, working memory, perceptual abilities, and information processing speed. Some authors have concluded that oscillations in alpha rhythm indirectly enhance performance in such a way that they filter out irrelevant information and prevent disruptions caused by conflicting stimuli (Klimesch et al., 2007; Rihs et al., 2007; Tuladhar et al., 2007).

One way of ensuring induction of electrical activity in the brain is through binaural beats (BB). BB are subjective auditory sensations caused by presenting tones of slightly different frequencies separately to each ear. As a result, the listener perceives sound with an amplitude that changes with a frequency equal to the difference of frequency in the presented tones, and these two frequencies are integrated at the cortical level into the above-mentioned binaural beat. If the difference in frequencies corresponds to the alpha range (7.5 – 12.5 Hz), then the electrical activity of both hemispheres should merge into one synchronized activity.

Method

In this study, consisting of 50 university/college students, each participant was randomly assigned to either an experimental or control group. The subjects took a computer-administered test consisting of a training period and actual test. During the task, a person is asked to retain randomly presented series of 3 to 7 defined letters. The letters were presented one at a time for 800 milliseconds. After the presentation of each letter, a simple mathematical equation appears on the screen (ex. (2*3) + 7 = ?)

The participant has to assess whether the proposed solution is correct. The mathematical operation is presented to each participant for a specific amount of seconds calculated from his/her individual tempo as measured during his/her individual rehearsal task + 2 SDs. Afterwards, a letter comes up for 800 ms. This process is presented anywhere between 3 and 7 times. Afterwards, a set of letters (a table of all possible letters) is presented to the participant. The participant has to choose the letters that were presented in that trial. The whole task consists of 3 series of each set size. The set sizes range from 3 to 7 letters plus the mathematical operations. In total, 75 letters and 75 mathematical operations are administered to the participant. After completing the AOSPAN task, two scores related to the assessment of working memory capacity were computed. The first score, the Ospan score, has an absolute scoring method, and it represents the sum of all correctly recalled sets of letters in the correct order. The second additional score reflects the total number of errors made solving the mathematical operations.

The baseline measure of the AOSPAN was obtained at the beginning of the experiment. After the first completion of the AOSPAN, participants were randomly assigned to either music with a BB or music without a BB. All participants then listened to a 12 minute long recording of one of the recordings. After those 12 minutes they were asked to retake
the AOSPAN. Both the experimental and control group were exposed to the same procedure with the exception of the inclusion of BB in the music in the experimental condition. Completing the experiment took approximately 50 minutes.

Findings

The results of the study illustrate that BB frequencies corresponding to alpha range of brain activity had a temporary positive effect on the capacity of working memory. Participants undergoing a 12-minute BB stimulation of 9.55 Hz frequency achieved a significant increase in the capacity of their working memory in comparison to a control group, which was not exposed to BB stimulation. Participants exposed to BB just for 12 minutes showed an improvement in their working memory capacity on average by 4.6 points in their score. In terms of the control group, this group either remained unchanged by means of measured performance, or deteriorated by the maximum of one set on average (deterioration of 2.45 points). Thus, the ultimate difference between the experimental and control group represents the difference of 1-2 correctly recalled sets, roughly a range of 7 – 13 %. While the experimental group improved by an average of slightly more than one remembered letter, the control group deteriorated by almost 3 letters in total. The overall mean difference between the two groups was, on average, 4 correctly recalled letters.

Critique

Although this study presents findings that confirm the authors’ hypothesis and further validates previous studies, the sample was composed of young, healthy students. It would be interesting to see results achieved by individuals with memory or other cognitive deficits, older individuals, or people without university/college experience. Additionally, it would be appropriate to extend the time between the solving of the two AOSPAN tasks to reduce the potential effect of fatigue on the test subjects. 

Source

Kraus, J., & Porubanova, M. (2015). The effect of binaural beats on working memory capcity. Studia Psychologica 38 (2), 135-145. 

Tuesday, September 20, 2016

Effect of Binaural Stimulation on Attention and EEG



Background
The focus of this study was on identifying the effects of binaural beat (BB) stimulation on participants’ cognitive abilities and electroencephalogram (EEG) brainwave activity. Anecdotal reports in the existing field of literature on BB’s ability to increase EEG activity and arousal levels were the motivators for this study and the topics the authors wanted to test. The authors cited multiple sources of previously conducted BB experiments and criticized their lack of a rigidly organized double blind study to ensure the validity of their findings. Many self-reported cases were identified where participants expressed their opinions that they felt more alert or were able to concentrate better after exposure to various BBs. However these opinions could be susceptible to the placebo effect of participants knowing they are being exposed to BBs. Additionally, marketing companies spread the idea that BB producing products are effective at increasing concentration and are capable of helping users fall asleep faster and more restfully without showing evidence to prove such claims. This prior programming may have also influenced the participants in previous studies skewing their results.
Methods
This experiment consisted of a double blind study that was split into two groups. Group A consisted of 60 volunteers (28 females, 32 males) from Madrid with an average age of 28.9 and a standard deviation of 4.3 years who were to be evaluated on their cognitive abilities following 20 minutes of BB exposure. The groups were randomly split into three subsections of 20 each who would experience different sounds: 1) Commercially available binaural audio beat within a pink noise background; 2) a placebo group with just a pink noise background; 3) and a self-made collection of four BBs overlapping at once within a pink noise background.  The exclusion criteria for involvement in this group was that participants had to have no neurological diseases and could not be left-handed. Each participant also had to pass a hearing test. The participants were instructed to sit comfortably in a room with their eyes closed and listen to the audio for 20 minutes before conducting a series of three tests designed to test their perception, process speed, and attention control.
Group B consisted of 18 volunteers (5 females, 13 males) from Madrid with an average age of 26.6 and a standard deviation of 7.5 years who were to have their brainwave activity monitored by an EEG following twenty minutes of exposure to BBs. This group was similarly divided into the three subcategories listed above, each with six participants. The exclusion criteria for this group was that participants had to have no neurological diseases and could not be right-handed. Each participant also had to pass a hearing test. The participants’ EEGs were monitored three minutes before the audio began to establish a baseline. Then they listened to the audio for 20 minutes in a comfortable position with their eyes closed as they were monitored by the EEG.
Findings
The results of the testing were that no scientifically significant improvements in cognitive abilities or EEG activity were recorded. In group A there were no significant differences within any of the three subgroups at either of the three tests. A non-parametric Kruskal-Wallis analysis of variance was performed. p < 0.05 was considered significant. See table two below.


In group B the EEG revealed no significant changes between the three subgroups. A non-parametric
Kruskal-Wallis analysis of variance was performed but could not find any significant differences between the three groups for any electrode, band, or moment of stimulation.
Criticism
The authors admitted that their sample sizes may have been too small to accurately generate enough data to substantiate findings. Additionally, they acknowledged that the exposure to BBs may have been too short to allow the participants time to acclimate. Finally, they speculated on the use of pink noise alongside the BBs within the experiment as a potential variable that could have disrupted the results. I agree that any of the three criticisms could have been a factor in the findings. I was also curious about the exclusionary criteria between the two groups. I’m unsure as to how being right or left handed impacts an EEG reading and why the authors decided to limit one group to left handers and one to right. Finally, I found the participant pool to be too varied for my taste. If I were to conduct a neurological experiment I would want my focus groups to be as similar as possible in age to limit the impact time has on brain function. The participants history of participation in contact sports along with medical records of any previous head trauma would also be valuable knowledge to possess. As would knowledge of the participants history with drugs and alcohol. 
This study is easily re-producible and with a few altercations as suggested above could prove to be a valuable addition to the field of study. As it is currently, I’m not sure the findings which suggest BBs do not improve concentration or alertness are backed by enough data to hold any significant weight in the current field of study. More research is necessary before binaural beats can be efficiently categorized in terms of their effectiveness.  
Source:
Crespo, A., Recuero, M., Galvez, G., & BegoƱa, A. (2013). Effect of binaural stimulation on attention and EEG. Archives of Acoustics, 38(4), 517-528.

Monday, September 19, 2016

Summary of Findings: Trend Analysis (4 out of 5 Stars)

Note: This post represents the synthesis of the thoughts, procedures and experiences of others as represented in the articles read in advance (see previous posts) and the discussion among the students and instructor during the Advanced Analytic Techniques class at Mercyhurst University in September 2016 regarding Trend Analysis as an Analytic Technique specifically. This technique was evaluated based on its overall validity, simplicity, flexibility and its ability to effectively use on structured data.

Description:

Trend analysis is an analytical method that takes historical data and measures geographical and temporal changes among others. Based on these changes, a forecast can be made about potential future changes. Additionally, trend analysis can be used to isolate past events for further interpretation.

Strengths:

  • Increases forecasting accuracy
  • Data is flexible to use and manipulate pending the size of a given source’s data set
  • Supported by hard data but can also be adapted to forecast unstructured data to a degree
  • Presents visual perspectives that are easy to interpret
  • Simple to conduct analysis

Weaknesses:

  • Does not work as well with unstructured data
  • Susceptible to data tampering (cherry picking)
  • Dependent on the reliability of a data sources method of reporting
  • Does not always capture variability in data, and may propose a consistent forecast
  • Usually requires software to complete effectively

How-To:

  1. Collect measurable data that can be aggregated and utilized for analysis
  2. Input that data into a database tool that can be imported to other analytical programs
  3. Clean data so that it is correctly categorized and labeled to minimize potential errors
  4. Import data into analytical tool to oversee long-term and short-term changes
  5. Review data and set appropriate boundaries (time, location, etc.) to limit data for concise analysis
  6. Use forecasting analysis tools to predict future based on trend found within boundaries

Application of Technique:

Members of the class led a demonstration on how to create a trend analysis in the software Tableau. Data used consisted of Apple stock prices (open, close, adjusted close, high, and low) from the time period 1981-2016, and also pulled crime data from Chicago’s crime data portal on assaults in the Austin community area from 2002-2016. A trend of Apple’s stock price over time was created and a forecast was made to estimate future stock price changes over time. For the law enforcement data, observations were geocoded and used to create a heat map of incidents and how they changed in different areas over time.

For Further Information:

Investopedia Trend Analysis Definition: http://www.investopedia.com/terms/t/trendanalysis.asp

Trend Analysis Cliff Notes:

Trend Analysis for forecasting (+Tableau):

Google Trends:

Google Ngrams:

IACA - Types of Crime Analysis (Trend Analysis):

Historical Stock Data:
http://www.stockhistoricaldata.com/download