Motion aftereffect Prelab

Travis Hallenbeck

March 4, 2004

1. The materials used in this lab are a watch with a second hand, a ruler, the Exploring Perception CD ROM, a print out of the score sheet, and an index card.

2. If motion aftereffect is due to fatigue, the longer trials will create a longer aftereffect in only the eye exposed to the stimulus. If the aftereffect is due to a neural adaptation, an aftereffect primed in one eye will show an aftereffect in the other unstimulated eye.

3. If peripheral mechanisms are involved in motion aftereffects, I would predict to get an equal aftereffect after both interocular and monocular viewing.

4. If central mechanisms are involved in motion aftereffects, the interocular trials would produce a longer aftereffect than monocular trials.

5. The type of design used for this experiment is 3x2 within-subjects design.

6. The adaptation durations used are a minute, 3 minutes, and 6 minutes.

7. Monocular conditions consist of adapting and testing the same eye and then alternating between eyes for each duration trial.

8. Interocular conditions consist of adapting one eye, testing the other, then alternating the order for each duration trial.

9. I will sit 30 inches from the screen if I am the participant.

10. I will set the interframe interval to 90.

11. The complete order of how I will run the experiment, if I were the first participant is:

O1T1, O2T1, O1T2, O2t2, O1T3, O2T3, O1T4, O2T4, O1T5, O2T5, O1T6, O2T6.

Order #1

Trial Adapt Duration Test

_____ _____ ________ _____

1 Right 6 min Right

2 Left 3 min Left

3 Right 1 min Right

4 Left 6 min Right

5 Right 3 min Left

6 Left 1 min Right

Order #2

Trial Adapt Duration Test

_____ _____ ________ _____

1 Right 1 min Left

2 Left 3 min Right

3 Right 6 min Left

4 Left 1 min Left

5 Right 3 min Right

6 Left 6 min Left

12. I will fixate on the red cross if I am the participant.

13. On each trial, the experimenter sets up the adaptation stimulus and records in the motion aftereffect in seconds on the appropriate place on the data sheet.

14. On each trial, the participant will fixate on the red cross with whatever configuration of viewing (duration, viewing condition) that the trial calls for.

15. The measurement taken on each trial is how long the participant observes the motion aftereffect in seconds.

16. We counterbalance the order to examine duration as a seperate variable from viewing condition.

17. Each partner will act as participant for three trials and experimenter for three trials.

18. The data sheet is in the same order as the order each participant will run in.

19. After finishing, we will give the data sheet to Hope, the lab instructor.

20. If there is a significant main effect of duration, the afterimage durations will be longer than the adaptation durations and will increase as the adaptation durations increases.

21. If there is a significant main effect of viewing condition (monocular vs. interocular), the afterimage durations will be longer for one of the viewing conditions, and this will give insight to what level of sense and/or perception the motion aftereffect is occuring.

22. A significant interaction would be indicated by the ANOVA performed on the compiled data.

23. A trial is a period in which the experiment is conducted with one of the conditions purposely varied. The condition is a measurable quantity that can be changed to figure out the condition is affecting the system.