Perceptual Matching Worksheet AS PDF

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Perceptual Matching Worksheet

This experiment is a replication of Posner’s (1960) Experiment 1. Participants were shown two letters presented on a screen, and were asked to decide as quickly as possible whether the two letters were the same letter or different letters. Letter combinations could either be a physical match (e.g., A/A), a name match (e.g. A/a) or no match (A/b, A/B). On some trials, letters were presented at the same time (simultaneously), whereas on other trials there was either a 1 second or 2 second delay between the appearance of the first letter and the appearance of the second (inter-stimulus interval, or ISI). Reaction time data was recorded to measure how quickly subjects could identify whether the two letters were the same or different. - Middle of the screen 1. Based on Posner’s (1960) Experiment 1 results, what were the expected results of our experiment? State the two hypotheses that follow from Posner’s results. a. Reaction Time will be faster when the letters are a physical match b. The benefit of the physical match will disappear at 2 second 2. What was the dependent variable? 3. List all independent variables and include all of their levels. 2x3 Match type: - Physical - Name - Different Interstimulus interval: - Simultaneous - One second - Two seconds 4. In excel, create a table of means for all IV combinations. Physical Name None 649 649 706 0 575 581 637 1 580 600 669 2

5. Using the table you created, create a line graph displaying the data. Graph shows opposite of what Posner (1969) found. At 0 its all constant and at 1 there is a 4 second difference, and at 2 second ISI you have the benefits of 20ms difference. Posner found the opposite that at 2ms didn’t matter Opposite of what Posner said because he said there would be an interaction and at 2 sec there would be no effect (interaction of match type and ISI)

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0 0

1 Physical

Name

2 None

6. Run a repeated measures ANOVA in SPSS. Were there any statistically significant main effects or interactions? Report the results as accurately as possible. 7. Did our results confirm our hypotheses stated in question 1? A two way repeated measures ANOVA was conducted to examine the effects of ISI (0 seconds, 1 second, and two seconds) and match type (physical, name, none) on reaction time (ms). The analysis revealed that there was a significant main effect of ISI on reaction time F(2,34)= 8.208,p...