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Weight Discrimination Research Study
Citation preview
Weight
Discrimination
Alyssa Figueroa
Marissa Jacob
Kinesiology 4573
Hypotheses
The dominant hand group will have less number of
errors in their final mean score compared to the non-
dominant hand group
The non-dominant hand group will show a greater
improvement between their initial mean error score
and their final mean error score compared to the
dominant hand group
There will be no significant difference between the
final mean times for dominant hand group and non-
dominant hand group
What does the literature say? Field-dependence-independence as “sensitivity” of the nervous
system: supportive evidence with color and weight discrimination
Hypothesized that field-independent participants would perform significantly better than the field-dependent participants on a weight discrimination task
56 participants (soldiers)
- Either in field-independent or field-dependent group based on nervous system level of sensitivity
10 black discs varied in weight from 50-86 g
Participants were asked to arrange disks in order from lightest to heaviest
- 2 trials with dominant hand and 2 trials with non-dominant hand
Hypothesis was supported
*Both groups performed better with their dominant hand compared to their non-dominant hand
(Fine, 1973)
What does the literature say? Aberrant judgmental pattern of schizophrenic patients in weight
discrimination
32 participants (right handed)
- 16 chronic schizophrenics (11 female and 5 male)
- 16 normal controls (9 female and 7 male)
Weight discrimination task
Categorical conditions
- Heavier/lighter
- Heavier/lighter/equal
- Heavier/lighter/doubtful
Hand conditions
- Left, right, and bimanual
Standard weight placed in palm 2 s; comparison weight immediately placed in palm 2 s
- Cylindrical plastic weights ranging from 29-71 g for comparison weight and standard weight was 50 g
-Screen board prevented participants from seeing their palms and weights
Schizophrenics made more reversal errors than normal group in heavier/lighter condition
- Indicated sensory deficits of proprioceptive acuity in schizophrenics
No significant difference in the heavier/lighter/doubtful condition
Increased occurrence of equal judgments in schizophrenic group
-Might indicate deficit at the judgmental level and partly from a deficit at the sensory level
(Tanno, Shiihara, & Machiyama, 1999)
What does the literature say? Jiggling a lifted weight does aid discrimination
Fact:
- Ability to discriminate between weights is affected by the manner of obtaining
the stimuli
- Active lifting results in better discrimination than passive pressure
- Discrimination improves with the frequency of the lift and the stimulus
intensity and number of limb joints involved in the lift
Therefore, hypothesized that jiggling objects when estimating their weight
should aid discrimination
30 undergraduate students (17 male and 13 female)
Cylinders weighing from 50-64 g
Blind folded
Participants were asks to state whether the weight was heavier or lighter than the
standard 50 g weight
Hypothesis was correct; there was a significant difference
(Brodie & Ross, 1985)
Subjects Where did we get them:
- Friends and family
Characteristics:
- Must be female
- Must be 18-80 years of age
How many?
- 10 subjects in the Dominant Hand Group
- 10 subjects in the Non-Dominant Hand Group
- Total of 20 participants
How did you get them?
- We asked each participant if they would like to volunteer in our activity and once they gave consent we continued on to completing the task.
Research Personnel How many?
- Two (2)
Characteristics?
- Female
- College students
What do they have to do?
- Explain purpose and procedures of the test to the
participant.
- Shuffle the labeled containers before each trial
- Record the time and number of errors for each trial
Before the Experiment Research Personnel must:
o Location of Test:
- Brought study to the participant’s household since equipment is easily
transportable
o Equipment
- 20 identical containers (colored outside)
- 110 pennies
- Stop watch
- Paper and pen
- Marker (number containers on bottom)
Subjects Requirements:
- Must meet participant requirements as previously mentioned before
- Must give consent to participate in activity/test
During the Experiment
Subjects will be asked to:
- Without turning object over, arrange 10 containers in
order according to weight while being timed
o Dominant hand group
- Only the participants dominant hand will be used
for all trials
o Non-Dominant hand group
- Dominant hand will be used for trials 1, 2, 5, and 6
- Non-Dominant hand will be used for trials 3 and 4
During the Experiment Cont.
Why do it this way?
- To see overall improvement between participants
with their non-dominant and dominant hand
- To identify a difference between dominant and
non-dominant hand final mean error score
- To identify a faster final response time in dominant
hand group versus non-dominant hand group
During the Experiment Cont.
When?
- Whenever it was convenient for the participant
How many trials and why?
- The participants will complete a total of 6 trials
- In order to get an average value for the initial,
practice, and final to get more accurate data
Consent Form Permission to Participate in Study
- I agree to volunteer in Alyssa Figueroa and Marissa
Jacob’s research study.
- I know I can quit at any time.
- I will not hold TWU responsible if I am injured in
the study.
Signature Date
Statistical Hypotheses
Hypothesis: The dominant hand group will have less number of
errors in their final mean score compared to the non-dominant
hand group.
Dominant Hand vs Non-Dominant Hand Group In Final Mean Error Score
t-Test: Two-Sample Assuming Equal Variances
Non-dominant Dominant
Mean 2.40 1.05
Standard Deviation 0.57 0.76
Variance 0.32 0.58
Observations 10.00 10.00
Pooled Variance 0.45
Hypothesized Mean Difference 0.00
df 18.00
t Stat 4.49
P(T<=t) one-tail 0.00
t Critical one-tail 1.73
P(T<=t) two-tail 0.00
t Critical two-tail 2.10
t(18)=4.49, p<.05
Accept Hypothesis, because the dominant hand group had
the least amount of errors in their final mean score
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
Non-dominant Dominant
# o
f errors
Group
Dominant Hand vs Non-Dominant Hand
Group In Final Mean Error Score (Mean + SD)
Hypothesis: The non-dominant hand group will show a greater
improvement between their initial mean error score and their
final mean error score compared to the dominant hand group.
Dominant Hand vs Non-Dominant Hand Group In Error Improvement Between Intial and
Final Trials
t-Test: Two-Sample Assuming Equal Variances
Non-dominant Dominant
Mean -0.30 0.30
Standard Deviation 0.59 0.59
Variance 0.34 0.34
Observations 10.00 10.00
Pooled Variance 0.34
Hypothesized Mean Difference 0.00
df 18.00
t Stat -2.29
P(T<=t) one-tail 0.02
t Critical one-tail 1.73
P(T<=t) two-tail 0.03
t Critical two-tail 2.10
t(18)=2.29, p<.05
Reject Hypothesis, because the dominant hand group showed the greatest
improvement. The non-dominant hand group actually performed worse in
their final trial than their initial trial.
-1.00
-0.80
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
1.00
Non-dominant Dominant
# o
f errors
Group
Dominant Hand vs Non-Dominant Hand
Group In Improvement Between Initial and Final Trials (Mean + SD)
Hypothesis: There will be no significant difference
between the final mean times for dominant hand group
and non-dominant hand group.
Dominant Hand vs Non-Dominant Hand Group In Final Mean Time
t-Test: Two-Sample Assuming Equal Variances
Non-dominant Dominant
Mean 50.25 36.40
Standard Deviation 23.51 8.32
Variance 552.74 69.27
Observations 10.00 10.00
Pooled Variance 311.00
Hypothesized Mean Difference 0.00
df 18.00
t Stat 1.76
P(T<=t) one-tail 0.05
t Critical one-tail 1.73
P(T<=t) two-tail 0.10
t Critical two-tail 2.10
t(18)=1.76, p>.05
Accept Hypothesis, because p value was greater than .05 and the
computed t value was less than the critical t value. Therefore there
is no significant difference in final mean times.
0.00
10.00
20.00
30.00
40.00
50.00
60.00
70.00
80.00
Non-dominant Dominant
Tim
e (
sec)
Group
Dominant Hand vs. Non-Dominant Hand
Group In Final Mean Time (Mean + SD)
Our Findings
We believe the dominant hand group improved more in our research study because, the participants are use to constantly using that particular hand on a daily basis. Which, allowed their time to improve and number of errors to decrease as they progressed over several trials of practice.
We believe the second group didn’t improve as much as the first group because research personnel involved trials that used both dominant and non-dominant hands. Which, potentially lead to their overall time and number of scores to be slightly effected.
Research Design Evaluation
Yes, we strongly believe that the weight
discrimination test design was best used to accurately
test our research hypotheses and identify the variables
used throughout the study.
Problems
Did not distinguish 6 and 9 labels on the bottom of
containers sufficiently
- Added a line under the 9 so participants and
research personnel could better understand the
difference.
Questions or Comments?
References
Brodie, E. E. & Ross, H. E. (1985). Jiggling a lifted weight does aid discrimination. The American Journal of Psychology 98(3), 469-471.
Fine, B. J. (1973). Field-dependence-independence as “sensitivity” of the nervous system: supportive evidence with color and weight discrimination. Perceptual and Motor Skills 37, 287-295.
Tanno, Y., Shiihara, Y., & Machiyama, Y. (1999). Aberrant judgmental pattern of schizophrenic patients in weight discrimination. Psychiatry and Clinical Neurosciences 53, 477-483.