Markdown lines 1264–1456 · Part 5 of 6
definition list. At the end of five minutes the researcher again stated “stop,” and collected the recalled
list from the subject.
The Digit Span and Digit Symbol Tests
The experimenter presented the Digit Span and Digit Symbol subtests in accordance with standard
test administration procedures for the Wechsler Adult Intelligence Scale, as outlined in the WAIS-R
manual.
Scoring of Tests
The Word List Recall and the German vocabulary recognition/recall tests were scored with one point
being assigned for each correct answer. These were 25 item tests yielding a possible score of 0 to 25
points for each subject.
The Digit Symbol and Digit Span subtests of the WAIS-R were scored and scaled before being
analyzed, in accordance with the procedures outlined in the WAIS-R manual.
Limitations
In an attempt eliminate confounding variables a simple posttest-only design was employed. Each
subject was seen in a single interview to be assigned to a group, be exposed to one of the two levels
of the independent variable, and finally to have the effect of the independent variable measured.
While this design maximized the isolation of the independent variable it did not provide the
independent variable an opportunity to exert a cumulative effect upon the dependent variable.
This is an important limitation in this study because of the noted cumulative effect of brain-wave
training. Russell and Carter observed “that the degree of significant improvement in functioning is
related to the number of treatment sessions” (Hutchinson, 1994, p. 362). Peniston and Kulkosky also
note “Time course analysis of the EEG effects of brain-wave training revealed that increases in alpha
and theta rhythms occurred gradually across the 15 treatment sessions” (Peniston, & Kulkosky, 1989
p. 276).
The studies which evaluated student performance over a period of weeks or months have had the
benefit of the cumulative effect of brain-wave training. The cumulative effect of the binaural-beat
audio signals is a part of the brain-wave training process which was not included in the design of this
study and may have a significant impact on the strength of the response as measured by the
dependent variable.
This study did not provide for repeated exposures to the dependent variable due to limitations in
resources. A logical next step might be to conduct this study again with a longitudinal dimension to
observe any increase of performance across repeated sessions, and to observe the effect of binaural
audio signals on learning as well as memory.
Placebo and suggestion effects were deliberately filtered out with a double-blind design, in order to
gain clarity on what role the layered binaural-beat audio signals play in the positive results obtained
with binaural-beat audio signals. Some of the positive results of previous studies may have been the
result of just such effects, thus the positive results of this study may not be as profound as in previous
research.
RESULTS
There were four hypothesis used in this research, each postulating that in a study controlling for
confounding variables the experimental group would display a statistically significant improvement in
mean scores over the control group at a .05 or less significance level.
Hypothesis one (H1) postulated a statistically significant higher mean score for the experimental
group as measured by a 25 item word list recall test. Hypothesis two (H2) postulated a statistically
significant higher mean score for the experimental group as measured by a 25 item word list
recall/recognition test. Hypothesis three (H3) postulated a statistically significant higher mean score
for the experimental group as measured by the WAIS-R digit symbol subtest. Hypothesis four (H4)
postulated a statistically significant higher mean score for the experimental group as measured by the
WAIS-R digit span subtest.
In reviewing the data the experimental group does display statistically significant higher mean scores
on three of the four dependent measures, allowing for the rejection of the null hypothesis for H1, H3,
and H4. The obtained data does not allow for the rejection of the null hypothesis with H2. Figures one
through four display the mean scores with histograms and significance level.
Word List Free Recall Results
On the Word List Recall subtest, the control group displayed a mean score of 14 correct responses,
and the experimental group displayed a mean score of 15.93 correct responses out of a possible 25.
When evaluated with a t-test for the statistical significance of the result, the value of t(2.5) is found to
fall between a probability of .02 and .01 (df=48). Since this is less than the minimum significance level
of .05, the result is considered statistically significant.
Word List Recognition Results
On the Word List Recognition subtest, the control group had a mean score of 12.61 correct
responses, and the experimental group had a mean score of 15.04 correct responses out of a
possible 25. When evaluated with a t-test for the statistical significance of the result, the value of
t(1.76) is found to fall between a probability of .10 and .05 (df=48). Since this is greater than the
minimum significance level of .05 the result is not considered statistically significant.
Digit Symbol Results
The scaled Digit Symbol subtest displayed a mean score of 9.46 for the control group, and a mean
score of 11.44 for the experimental group. When evaluated with a t-test for the statistical significance
of the result, the value of t(2.83) was found to be greater than the critical value for a probability of .01
(df=48). Since this is less than the minimum significance level of .05, the result is considered
statistically significant.
Digit Span Results
The scaled Digit Span subtest displayed a mean score of 7.69 for the control group and 9.85 for the
experimental group. When evaluated with a t-test for the statistical significance of the result, the value
of t(2.4) was found to fall between a probability of .02 and .01(df=48). Since this is less than the
minimum significance level of .05, the result is considered statistically significant.
DISCUSSION
For H1 the Word List Recall test, H3 the Digit Symbol test, and H4 the Digit Span tests, the data does
permit the rejection of the null hypothesis in favor of the research hypothesis. For H2 the Word List
Recognition test, the data does not allow for the rejection of the null hypothesis.
The data does support binaural-beat audio signals facilitating memory as measured by the word list
recall test. The results of the digit span and digit symbol tests support the reports of Edrington, who
found a decrease in student hyperactivity and an increased ability to pay attention in class while using
BBS’s.
It is reasonable to infer, given the current data, that beta-frequency BBS’s are helpful for those
individuals seeking help in free recall memory, attention and completion of routine tasks.
The Four Dependent Variables
The Word List Recall is a simple free recall test, and thus was considered by the experimenter to be
the core dependent variable for examining any facilitation of memory with binaural-beat audio signals.
The facilitation of memory as measured by higher mean scores on this test in the experimental group
demonstrate that binaural-beat audio signal beta brain-wave training did facilitate memory.
The German vocabulary recognition list is more of a combined free recall and cued recall task and
was also expected to be facilitated by the beta-frequency BBS’s. Surprisingly the results for this
subtest did not show a statistically significant increase in memory as the other three subtests did.
Since a Latin Squares rotation of the tests was used, this data is not the result of the order of
presentation.
The results may mean that the associative memory mechanisms behind remembering the meanings
for a novel set of words were not reinforced as strongly as the mechanisms behind the pure recall of
a word list.
These results are not expected to be a reflection of previous knowledge of German by some of the
subjects. All subjects stated that they did not know German, and the words used were not similar in
sound to the English equivalent.
Given that previous work in the comparable task of second language acquisition has reported
success with BBS improving performance (Pawelek, & Larson, 1985), the lack of statistically
significant mean scores may be an artifact of the single session limitations of this study. As noted in
the limitations section, brain-wave training has been shown to increase in effectiveness with repeated
sessions.
It would be interesting to see if the data from administering a foreign language vocabulary test would
have statistically significant outcomes in a longitudinal study, which would provide for a repeated
exposures to beta-frequency BBS brain-wave training.
The Digit Span subtest is not only an indication of an ability to recall and repeat back a series of rote
numerical digits, but also of an individuals ability to attend. The increase in Digit Span should be of
interest for assisting those populations, such as ADHD, with an impaired ability to maintain their
attention on rote memory tasks.
This data supports the anecdotal reports of teachers and other professionals who have reported an
increased ability to attend (or a decrease in student distractibility) among their students when using
binaural-beat audio signals (Edrington, 1985). The binaural-beat audio signals should, as reported by
Edrington, reported, be of use in the classroom to increase the students’ ability to attend to the lesson
and instructor at hand.
The Digit Symbol test is timed, and the more the subject must look up the meaning of a symbol, the
less time he has for filling out the meanings. Heightened memory should facilitate higher scores on
this test due to less time spent going back to the list of symbols and their numerical equivalents.
However, the Digit Symbol subtest is not characterized in psychological assessment as a memory
test, but as a performance subtest, measuring the subject’s ability to persevere at routine tasks.
The increase in performance of the experimental group over the control group at this task may be
significant in its implications for assisting those populations who have academic difficulty due to an
impaired ability to persevere at routine motor tasks, such as an ADHD child.
Relation of Obtained Results with Previous Research
The results support the ability of BBS’s to function as an effective stand alone form of brain-wave
training. The research does provide support for the observations of teachers who have reported
increased grades and fewer behavioral problems with their students while utilizing binaural-beat audio
in the classroom.
The data is able to support the conclusions of previous research that binaural-beat audio signals
increase a subject’s ability to perform free recall tasks, attend (reduced student distractibility) and
persevere at routine tasks (as measured by the Digit Span and Digit Symbol subtests); three
important dimensions for success in the classroom.
The beta-frequency BBS brain-wave training did have a positive impact on dimensions of mental
performance known to be impaired in ADHD. This opens the possibility that beta frequency BBS’s
may yield comparable results to the beta frequency brain-wave training conducted with EEG
biofeedback and light and sound machines.
The results for the German vocabulary recognition/recall list are not able to support the data on a
similar task as reported by Pawelek and Larson in the BBS facilitation of second language
acquisition. This may be an artifact of the number of brain-wave training sessions used. It would be
interesting to see if the data from administering a foreign language vocabulary test would have
statistically significant outcomes in a longitudinal study.