恒常刺激法测音高阈限

1、 Experiment Report Name: 曾翘楚 Zoe Major: Psychology No: 2012213970 Report time: 2013/12/25 The method of constant stimuli 1 Introduction1.1 Experiment objective Have a good grasp of the method of constant stimuli and measure the difference threshold of pitch.1.2 Experiment contentLearn the method of

2、constant stimuli. Do the experiment of measuring difference threshold of pitch and collect data then analysis it. Difference threshold of three kinds of reaction:Up difference threshold (Dlu) = up- equalLower difference threshold (Dli) =equal- lowerDifference threshold= (Dlu+Dli)/2 1.3 Experiment me

3、aningMethod of constant stimuli is one of the important ways in classical psychological physics. The characteristic of the method of constant stimuli is a few stimulates, including 5 to 10, which is unchangeable in the whole procedure of measure. Every time a paired of stimulates are displayed, part

4、icipants are required to compare the two stimuli and make a decision.When using the method of constant stimuli to measure the difference threshold, participants are recommended to respond that whether the second stimulus is same to the first one, stronger or weaker than the first stimuli. In this wa

5、y, we can get two turning points of feelings. Further then, we can get up-threshold and lower-threshold.2 Method2.1 Subject 4 college students of CCNU. They are all females whose ages are range 18 to 20.2.2 Equipment or materialPsykey experiment system and computers. A series of pitch including 7 pi

6、tch materials in different rate (691694697700703706709 or 688692698700704708712). A keyboard contains a red bottom, a green bottom and a yellow bottom.2.3 procedureBefore the formal experiment, we should do a prepare experiment in the method of minimal difference to measure a general threshold. Acco

7、rding to the results of prepare experiment, we should choose different series of pitch. In prepare test, the initial difference rate of pitch is 3Hz. Firstly, participants are required to compare a standard stimuli and the minimal or biggest stimuli. Each group contains ten times comparison for a pa

8、ir of stimuli. If both of two groups accuracies are high than 90%, we will choose the group whose interval is 2Hz; and if the accuracy is less than 70%, the group of 2Hz interval should be chosen. Or else, we will use 3Hz interval.The specific method of operation is below:After two pitch displayed i

9、n order, if participants think the second pitch is same to the first one, he or she should press yellow bottom. And if they think the second one is higher than the first one, they should press the red bottom or else pressing green bottom is correct reaction. After them making a decision, another pai

10、r of pitch would be displayed.After prepare experiment, we will enter into main experiment.In formal experiment, the operation is same to the prepare experiment. There are 7 changeable stimuli including one standard stimulate. Each pair of stimulate should be displayed randomly and compared for ten

11、times and 70 times in total. When finished experiment, computers would record the date. Finally, we should collect data and analysis it.3 Results I picked up 4 participants data to analysis. The specific results are below:Participant 1:Changeable stimuliThe number of judgment( - )( = )( + )( + ) + (

12、 = )69190.00%10.00%0.00%10.00%69470.00%30.00%0.00%30.00%69730.00%70.00%0.00%70.00%7000.00%90.00%10.00%100.00%7030.00%60.00%40.00%100.00%7060.00%60.00%40.00%100.00%7090.00%20.00%80.00%100.00%This is the first participants result. According to de graph, we can inform that both of her Dlu and Dli is ne

13、arly 0, we can reasonable predict that her difference threshold is nearly 0. She is very sensible to the difference of pitch.Participant 2:Changeable stimuliThe number of judgment( - )( = )( + )( + ) + ( = )68870.00%20.00%10.00%30.00%69250.00%30.00%20.00%50.00%6960.00%80.00%20.00%100.00%70020.00%60.

14、00%20.00%80.00%70430.00%50.00%20.00%70.00%7080.00%20.00%80.00%100.00%7120.00%0.00%100.00%100.00% Her data and picture reveal that her Dlu=2 and her Dli=3, in that case, her difference threshold is 2.5.Participant 3:Changeable stimuliThe number of judgment( - )( = )( + )( + ) + ( = )68870.00%30.00%0.

15、00%30.00%69240.00%60.00%0.00%60.00%69610.00%90.00%0.00%90.00%7000.00%100.00%0.00%100.00%7040.00%90.00%10.00%100.00%7080.00%50.00%50.00%100.00%7120.00%20.00%80.00%100.00%The data and graph acknowledge us that both of her Dlu and Dli is nearly 0, we can reasonable predict that her difference threshold

16、 is nearly 0. She is very sensible to the difference of pitch.Participant 4:Changeable stimuliThe number of judgment( - )( = )( + )( + ) + ( = )68860.00%20.00%20.00%40.00%69280.00%10.00%10.00%20.00%69640.00%40.00%20.00%60.00%70020.00%70.00%10.00%80.00%70440.00%30.00%30.00%60.00%70810.00%20.00%70.00%

17、90.00%71210.00%0.00%90.00%90.00% Her data and graph suggest that her Dlu is approximately equal to 2.5 and her Dli is approximately equal to 4.5, in that case, her difference threshold is nearly 3.5.4 Discussion4.1 Difference threshold of 75% When using method of constant stimuli, we usually ask par

18、ticipant to response stronger/weaker or equal. In that case, we can gain two turn points of feeling in a series of reaction, and according to these we can know the up threshold and lower threshold. While some times, participants are only required to response whether the changeable stimuli is stronge

19、r or weaker than the standard stimuli. This method can overcome the flaws of difference error influenced by degree of confidence in three kinds of reaction. In two kinds of reaction, the compared stimuli which can be differed from the standard stimuli actually cant be distinguished to the standard s

20、timuli. Under this kind of situation, we define the 75% times judged as stronger than the standard stimuli as the up threshold of equal district and 25% times judged as stronger than the standard stimuli as the lower threshold of equal district. The half of the equal district is difference threshold

21、. However, the difference threshold we got in this way is not conforming to the definition. So we call it 75% difference threshold.4.2 Space error When measuring the difference threshold of pitch in the method of constant stimuli, we should take care of space error. Space error here means the error

22、caused by left ear of right ear. Right ear is considered controlled by left side of brain and the left ear is controlled by right side of brain. While different sides of brain are in charge of different ability. It means that different side of ear may have different degree of sensibility of differen

23、ce of pitch. In that case, we need counterbalance the space error. We can arrange the same amount of stimuli displayed to both sides of ears or we can display stimuli to both sides of ears at the same time. 4.3 Time error Besides the space error, time error also makes a difference in this experiment

24、. Time error represents the error caused by the time order of displaying stimuli. Difference threshold measured when the changeable stimuli is displayed first may different from the situation of the standard stimuli is displayed first. These kinds of error that up or lower threshold are higher of lo

25、wer than the real value is defined as time error. To counterbalance the time error, we should make sure that the number of situation where the changeable stimuli is displayed first is equal to the other situation and randomly assignment. 5 Conclusion By using method of constant difference, we can me

26、asure the difference threshold of pitch. Different people have different difference threshold of pitch. Method of constant stimuli is one of the important ways in classical psychological physics. When measuring the difference threshold in this method, we should pay attention to counterbalance the ti

27、me error and the space error. We also need to distinct the 75% difference threshold and the normal difference threshold.6 ReferenceBoming Yang心理实验纲要Ying Zhu,2000,实验心理学7 Appendix序号 变异刺激频率 标准刺激位置 反应 1 697 后 = 2 700 前 = 3 691 后 - 4 700 前 + 5 709 后 + 6 691 后 - 7 694 前 = 8 694 前 = 9 709 后 = 10 703 前 = 11

28、 709 前 + 12 706 后 = 13 697 后 - 14 694 后 - 15 694 后 - 16 703 后 + 17 706 后 = 18 691 前 - 19 694 后 - 20 694 前 = 21 706 前 + 22 697 前 = 23 691 前 - 24 697 前 = 25 706 前 + 26 700 后 = 27 700 前 = 28 709 后 + 29 694 前 - 30 709 后 = 31 703 前 + 32 709 前 + 33 697 后 - 34 706 前 + 35 703 后 = 36 709 后 + 37 703 前 = 38 70

29、0 前 = 39 694 后 - 40 697 后 = 41 709 前 + 42 709 前 + 43 700 后 = 44 697 前 = 45 706 后 = 46 706 前 = 47 691 前 = 48 697 前 = 49 691 前 - 50 709 前 + 51 700 后 = 52 700 后 = 53 703 后 = 54 703 后 = 55 697 前 = 56 691 后 - 57 706 后 = 58 706 前 + 59 700 后 = 60 691 后 - 61 706 后 = 62 700 前 = 63 703 前 + 64 691 前 - 65 697 后

30、 - 66 703 前 + 67 694 前 - 68 691 后 - 69 694 后 - 70 703 后 =序号 变异刺激频率 标准刺激位置 反应 1 708 前 + 2 692 前 - 3 688 后 = 4 712 前 + 5 700 前 - 6 712 前 + 7 700 前 + 8 692 后 = 9 696 前 = 10 712 后 + 11 704 后 = 12 692 后 = 13 688 前 + 14 708 后 = 15 704 前 = 16 708 后 + 17 696 前 = 18 704 后 = 19 704 后 - 20 696 前 = 21 692 前 + 2

31、2 708 后 = 23 696 前 = 24 712 后 + 25 712 后 + 26 692 后 + 27 700 后 + 28 692 后 - 29 696 后 = 30 708 前 + 31 696 前 + 32 708 前 + 33 688 前 - 34 688 前 - 35 688 前 - 36 688 后 - 37 700 前 - 38 712 后 + 39 700 前 = 40 712 前 + 41 712 后 + 42 704 后 = 43 708 前 + 44 704 前 + 45 692 前 - 46 712 前 + 47 700 前 = 48 688 后 = 49 7

32、00 后 = 50 692 前 = 51 704 前 - 52 700 后 = 53 688 前 - 54 688 后 - 55 712 前 + 56 688 后 - 57 700 后 = 58 692 前 - 59 692 后 - 60 704 前 = 61 696 后 = 62 708 前 + 63 704 前 + 64 708 后 + 65 696 后 + 66 708 后 + 67 704 后 - 68 696 后 = 69 700 后 = 70 696 后 =序号 变异刺激频率 标准刺激位置 反应 1 712 前 + 2 688 后 = 3 696 后 = 4 696 后 - 5 6

33、96 后 = 6 700 前 = 7 708 后 = 8 700 前 = 9 708 前 + 10 692 前 = 11 708 前 + 12 688 前 - 13 712 前 + 14 692 后 = 15 692 后 = 16 708 前 + 17 692 前 - 18 708 后 = 19 688 前 - 20 712 后 = 21 692 后 - 22 708 后 = 23 712 后 + 24 696 前 = 25 692 后 = 26 688 前 - 27 700 前 = 28 700 后 = 29 704 前 = 30 700 前 = 31 704 前 = 32 712 前 +

34、33 696 前 = 34 708 后 = 35 708 后 + 36 712 前 + 37 688 后 = 38 692 前 = 39 688 后 - 40 688 后 - 41 712 后 = 42 692 前 - 43 696 前 = 44 696 后 = 45 696 前 = 46 688 前 - 47 692 前 - 48 700 后 = 49 696 后 = 50 704 前 = 51 696 前 = 52 712 后 + 53 708 前 = 54 704 后 = 55 704 后 = 56 692 后 = 57 704 后 = 58 688 后 = 59 700 后 = 60

35、700 后 = 61 712 后 + 62 700 后 = 63 704 前 + 64 704 后 = 65 700 前 = 66 704 前 = 67 712 前 + 68 704 后 = 69 688 前 - 70 708 前 +序号 变异刺激频率 标准刺激位置 反应 1 704 后 - 2 696 前 + 3 692 前 - 4 688 前 + 5 704 前 = 6 688 前 - 7 704 后 = 8 696 后 = 9 696 后 = 10 712 前 - 11 700 前 = 12 688 后 + 13 712 后 + 14 688 后 - 15 688 后 = 16 696 后 - 17 704 后 + 18 696 前 + 19 708 前 + 20 708 后 + 21 688 后 = 22 704 后 = 23 700 后 - 24 704 前 - 25 700 前 + 26 692 前 - 27 692 后 - 28 7