An example stimulus displaying three eccentricities (e.g., 10, 20, and 30) with distractors used.
Below you will find an explanation of how each setting can change the stimulus.
| Setting | Description | Example Image |
|---|---|---|
| Num Of Blocks | Determines how many blocks the experiment will have. | |
| Target Visual Angle | The size of the target stimulus in the number of degrees in visual angle. |  |
| Distractor Visual Angle | The size of the distractor stimuli in the number of degrees in visual angle. |  |
| Eccentricities | The number of locations in each direction that a target will appear in. Expand this list to set the individual eccentricity values to control exactly where the stimuli will appear in the number of degrees in visual angle. Example values include 10, 20, and 30. These values would represent 10, 20, and 30 degrees of visual angle. |  |
| Exposure Times | The number of different display times that each target will appear for. Expand this list to set the individual exposure time values to control exactly how long the target stimulus will be visible for in each trial in seconds. Example values include .04, .06, .10. These values would represent 40, 60, and 100 ms, respectively. | |
| Trial Repetitions | Determines how many times each unique trial will be presented in each block. A unique trial is comprised of an eccentricity, an exposure time, and a direction within the visual field. Stimuli will appear in 8 different directions in any iteration of this experiment as it is based on the computer AVF task. In this example image, there would be 72 unique trials (8 directions x 3 eccentricities x 3 exposure times) per block. 2 trial repetitions would lead to there being 144 total trials in the experiment. | |
| Mask Display Time | The length of time in seconds that the masking image will be displayed after the target stimulus is presented. The value of .2 shown in the image represents 200 ms. | |
| Response Window | The length of time in seconds that participants will have to respond after the target stimulus is presented. The value of 2 shown in the image represents 2 seconds. | |
| Break Time | The length of time in seconds that participants will have between the presentation of each trial. The value of 2 shown in the image represents 2 seconds. | |
| Practice Trial Num | The number of randomly selected trials (based on the criteria entered in each setting) that participants will have the chance to respond to in the practice session that occurs before the experiment starts. | |
| Use Distractors | Determines if distractor images will be used during the stimulus presentation. |  |
| Target Color | Determines what color the target stimulus will appear as. |  |
| Distractor Color | Determines what color the distractor stimuli will appear as. |  |
| Target Img | Determines what image the target stimulus is. Note: if an alternate target image is desired, ensure that it is equal in height and length and approximately 66 x 66 pixels. |  |
| Distractor Img | Determines what image the distractor stimuli are. Note: if an alternate distractor image is desired, ensure that it is equal in height and length and approximately 66 x 66 pixels. |  |