Brain Teasers

Brought to you by:

Yifat TamirDavid AndersonKaylie DieneltMirelle Phillips

Are Dartmouth students this anxious under time

pressure?

Introduction

• Getting admitted to Dartmouth College requires the combination of high SAT scores, strong grades, and involvement in extra-curricular activities.

• Performing well on a test such as the SAT correlates with an ability to maintain high performance under time pressure.

• But does time pressure help or hinder cognitive performance?

The Test: Nervous yet?• Choosing the Brain Teaser Task:

– Somewhat cerebral, but still fairly simple

– Short and sweet– Lack of associated prior sense

of anxiety

• Two groups: one low-pressure (untimed) and one high-pressure (time limit)

• HP group was told the mean time needed to complete brain teaser task for participants in LP scenario.

• Does this foster a sense of competition or anxiety?

Selection of Participants:

– Two experimenters assigned to each subject group

– 30 LP, 30 HP subjects

– Random selection of participants across a number of campus locations (collis, hop, baker, novack)

– Each participant tested individually so as not to increase any group-oriented competitiveness

– Results would be analyzed both for time and response accuracy

The Test: Exposed

123safety456

0________________  Ph.D. B.Sc. B.A.

Hypotheses: Will they freak out?? Null Hypothesis:

There will be no difference in the mean amount of time it takes for each group to complete the task.

Alternate Hypothesis: There will actually be a difference in the mean amount of time it takes for each group to complete the task.

Our Beautiful Thoughts: Can they handle the PRESSURE?

We hypothesized two possibilities for the effects of pressure: Subjects may take more time

to complete the task due to anxiety induced by time-pressure

Subjects may take less time to complete the task because they are already motivated to perform well in high-pressure, competitive situations (by virtue of being Dartmouth students).

These effects could have confounded each other, confusing the difference between our means and increasing variance.

Holy Platypus! What Brilliance! Holy Platypus! What Brilliance! But are there any significant But are there any significant

effects?effects?Results:Results:

• The average time for the LP The average time for the LP group was 198 seconds (3 group was 198 seconds (3 min. 18 sec.) with a min. 18 sec.) with a standard deviation of 89 standard deviation of 89 seconds.seconds.

• Average time for HP group Average time for HP group (once told the average for (once told the average for LP) was 221 seconds (3 min. LP) was 221 seconds (3 min. 41 sec.) with a standard dev. 41 sec.) with a standard dev. of 144 seconds.of 144 seconds.

• But what about accuracy?! But what about accuracy?!

Mathematical Shizzy: Mathematical Shizzy: Graphical Graphical Comparison of Performance across Subject GroupsComparison of Performance across Subject Groups

Times for the Low-Pressure Trial

0

100

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1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Subjects

Times (seconds)

Times for High-Pressure Trial

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1 3 5 7 9 11 13 15 17 19 21 23 25 27

Subjects

Time (seconds)

Shooting in the Dark: Accuracy Shooting in the Dark: Accuracy across experimental situationsacross experimental situations

Correct Answers in Low-Pressure Trial

0

1

2

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5

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7

8

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29

Subjects

Number of Correct Answers

Correct Answers in High-Pressure Trial

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1 3 5 7 9 11 13 15 17 19 21 23 25 27

Subjects

Number of Correct Answers

Accuracy Issues: Accuracy Issues: Did some punks like to Did some punks like to hit it and quit it, or did they like to stay and play?hit it and quit it, or did they like to stay and play?

Average number of Average number of correct answers in the correct answers in the low-pressure group was low-pressure group was 5.13 (out of 7) with a 5.13 (out of 7) with a standard deviation of 1.5. standard deviation of 1.5.

Average number of Average number of correct answers in the correct answers in the high pressure group was high pressure group was 5 with a standard 5 with a standard deviation of 1.5.deviation of 1.5.

No real statistically No real statistically significant difference significant difference between group accuracybetween group accuracy

Our friend

Sir Mix-a-Lot

**************************************************************•Had to remove one subject from LP Had to remove one subject from LP group: only answered two teasersgroup: only answered two teasers

•Removed three subjects from HP Removed three subjects from HP group: two only answered a limited group: two only answered a limited number of teasers, and one was a number of teasers, and one was a huge outlier (4 standard deviations huge outlier (4 standard deviations away from mean)away from mean)

•Subject pool became 29 for LP and Subject pool became 29 for LP and 27 for HP. 27 for HP.

Significance: means and sd’s- F-Significance: means and sd’s- F-test and t-testtest and t-test

To calculate the t-score for the difference To calculate the t-score for the difference between two means, we used between two means, we used t = (xt = (x11 – x – x22)/ (s)/ (s11

22/n /n

11 + s + s2.52.522/ n/ n2.52.5))

Our critical region required that t ≤ +1.671 or t ≥ -1.671Our critical region required that t ≤ +1.671 or t ≥ -1.671 t = 0 = No significancet = 0 = No significance To calculate the difference in variance between the two To calculate the difference in variance between the two

samples, we used F = ssamples, we used F = s1122/ s/ s22

22

To be significant at a 5% level, F would have to be in To be significant at a 5% level, F would have to be in the range of 1.87-1.91the range of 1.87-1.91

F = 1.27 = No significanceF = 1.27 = No significance

Discussion: Robbed of rightful results with the rebus

The problem with the “3 degrees below zero” rebus.

How the rebus might have skewed the data in two directions:

– students who spent too much time on one rebus (more time)

– students who just gave up (less time)

Perhaps we need a cognitive measure that would make time much more of a salient factor than accuracy.

0________________ 

Ph.D. B.Sc. B.A.

Ridiculous Rebus

Discussion Part Deux: Discussion Part Deux: Faster, Hotter, and More All-EncompassingFaster, Hotter, and More All-Encompassing

Sampling ProblemsSampling Problems

Self-Selection:Self-Selection: After seeing the task, people could choose not to After seeing the task, people could choose not to

participate and it is likely that people who are not participate and it is likely that people who are not familiar with or do not like brain teasers would opt familiar with or do not like brain teasers would opt not to participatenot to participate

Location: Location: Public area, Presence of other students: increased Public area, Presence of other students: increased

sense of anxiety or competition (respectively)sense of anxiety or competition (respectively) Ideally, subjects would be isolated in a small room Ideally, subjects would be isolated in a small room

Conclusion: Overly verbose suggestions for further, equally-awesome projects

The results of the study indicate that applying pressure in the form of an implied time constraint does not significantly affect cognitive performance.

• Potential mplications for the SAT and other high-stakes testing, suggesting that there is not much truth to the claim that cognitive performance is negatively affected by time constraints. On the other hand, no one was really invested in our little task, so who really knows what would happen under real pressure.

• However, certain common characteristics of our participants should be noted. As we might be able to assume at Dartmouth, the participants in such an elite academic environment tend to have been trained to perform well under timed conditions.

• Therefore, we would recommend that future projects be performed on a large population of students from many different grade-levels and institutions, that a more time-oriented cognitive task be chosen, and that the subjects be truly isolated in the testing situation.