按键盘上方向键 ← 或 → 可快速上下翻页，按键盘上的 Enter 键可回到本书目录页，按键盘上方向键 ↑ 可回到本页顶部！
————未阅读完？加入书签已便下次继续阅读！
association norms； reaction time table； and verdict slips。
Having several stopwatches and calculators would be helpful。
Subjects
Three （or four） for pretesting； two to participate； rest of class to be given research tasks。
Time required for Research
25…30 minutes for data collection； 10…20 minutes for analysis and verdict。
Time Required for Discussion
10 minutes before demonstration； 10…30 minutes after。 （This section could be extended over two class periods。）
Method
1。 Before class； prepare two envelopes。 One should contain the instructions designed to introduce
413
guilt； the other contains innocuous instructions （see letters at the end of this section）。 The envelopes
should be identical。 In the guilty letter； you must indicate a safe place where the subject must go in
order to perform the guilty act； you must also make the necessary preparations of having at that
place： （a） Three matches； （b） a “blood…stained” （red inked） envelope containing the victim’s photo
（any photo of a woman will do）； （c） a metal pan in which the envelope can be burned。 （Find a
relatively secluded spot for the guilty suspect to burn the note and picture。 One of our section
leaders found to his dismay that a janitor had thrown the envelope away shortly before the section
meeting； another suspect was interrupted by the sound of the fire alarm； set off by a very sensitive
smoke detector。 These problems can be avoided by careful planning。）
3。 Bring a stopwatch to class。
4。 Select two male subjects at the beginning of the class （it is possible to use two women as suspects；
you might then want to make some changes in the content of the letter the guilty one gets）。
Premeasure the RTs of three early…arriving students on each of five premeasured words （see Word
List）。 Select the two with most similar Reaction Times （RTs） in order to minimize individual
differences in speed of reaction to neutral words。 If all three vary considerably； test a fourth and use
the two who are most parable。 It is crucial that the suspect try to conceal his guilt； pick students
you believe will play the part well and remind them to carefully follow all the directions they will
receive。 Give one unmarked envelope to each of them and send them out of the room in opposite
directions。 Do not inform the “suspects” about what will happen when they return to the class； this
would give the guilty person time to prepare himself； nor should they talk to each other at any time。
They are to knock on the door when ready to return。
5。 While the suspects are out of the room； tell the class the circumstances of the crime。 Explain their
task and the scoring procedure they will use。 You will need to assign to students three roles：
。 One or more students to note the suspect’s verbal response。
。 One or more students to note the suspect’s reaction time。
。 Two or more students to note significant signs of expressive behavior acpanying each
verbal response （see Expressive Behavior Encoding Guide and tally table）。 Does the suspect
stutter； answer in an especially low or loud voice； clear throat； cough； sigh； etc。？ Jot down
any such behaviors and code them as “S” for a speech disturbance。 Does the suspect shift
in his seat； cross his legs； twist； wring his hands or put them in his pockets； fidget with
cigarettes； paper clips； etc。？ Note these behaviors and code them as “P”； for a physical
movement。 Finally； focusing on the suspect’s face； does he smile； frown； wet his lips； close
his eyes； etc？ These behaviors can be noted and coded in a general facial expression
category as “F”。 Code behaviors not fitting these categories as “O”。 If time allows； give
students a chance to practice their scoring； using a volunteer “suspect” from the class。
Have your reaction…timer write the times on the data sheet。
6。 When the first suspect returns and knocks on the door； bring him in and seat him in front of the
class with his back to the timekeeper （on a high； backless stool if you have one） and have a student
experimenter give him the following instructions： “I will call out a word and you are to reply
quickly with the first word that es to mind。 We will repeat this for each of 30 words。 That is all
there is to it。 Is that clear？” （Minimize questions。）
7。 If time is a problem； 20 of the 30 words should suffice； but pick half neutral and half critical ones。
Have your timekeeper erase the times before the second suspect es in。
8。 If the first subject is allowed to remain in class while the second is being tested； he should sit
behind the class so as not to give any telling reactions。
9。 An excellent extension of this demonstration； proposed by Mikkel Hansen of Stanford University； is
to have students （or associates） film the two suspects pleting their tasks。 At the end of the class；
after votes have been cast； the videos can be played to the section to dramatically reveal who is
414
innocent and who is guilty。
PITFALLS TO AVOID
Do not get too involved in the initial discussion； this demonstration requires a lot of time； so hold all but the
necessary setting of the context for afterward。 Pick a safe place for the burning to take place。 Do not select
subjects who are very expressive–the guilty one might give it all away with the first blush。
DATA ANALYSIS AND INTERPRETATION
1。 Half of the stimulus words are neutral； in the sense that they are not associated with any aspect of
the crime； whereas half are emotionally loaded； in that they relate to some details of the crime of
which you and the “criminal；” but not the innocent suspect； are aware。 Have the class discuss
which words should be counted as “critical”； based on their knowledge of the crime。 To help them
with this； you may want to read a description of the crime （the instructions given to the suspect）。
Then have them calculate mean reaction times separately for both types of words for each suspect。
2。 Mention the use of premeasured RTs for neutral words and its function。
3。 Was there a difference in the reaction time of the two suspects to the critical words they had in
mon？ Repeat this analysis for the other measures。 How would you explain the differences you
observed？
4。 There may be two plex effects of guilt or emotion on RT： a perseverance effect that carries over to
the next word in the sequence； and a heightened variability effect of giving either much faster or
slower RTs to the critical words。 This would yield a mean parable to the innocent victim； so
different statistical methods might have to be used to assess the significance of this bimodal
reaction tendency （should it occur）。
5。 Ask students to suggest other ways of analyzing the data to detect guilt。 Have them discuss which
measures seem to be doing the best job of predicting guilt。 Using the measures they agree on； have
the students predict which of the two suspects is guilty。 Each student should make a private verdict
and give an estimate of his or her confidence in the verdict。 These data should be tallied and
presented to the class。 （Once the verdicts are in； have the two susp