Millisecond Forums

Priming Tasks with Inquisit Web

https://forums.millisecond.com/Topic30809.aspx

By jmbeadle - 2/12/2021

Hello, 
I am exploring options for an online priming experiment (either evaluative priming or the Affective Misattribution Task).Is it possible to ensure consistent stimulus presentation times (i.e., 100ms) for the prime and target using inquisit web? That is, when online participants are using different computers,  is it possible to control for consistency in stimulus presentation?

Thanks,
Julie
By Dave - 2/12/2021

jmbeadle - 2/13/2021
Hello, 
I am exploring options for an online priming experiment (either evaluative priming or the Affective Misattribution Task).Is it possible to ensure consistent stimulus presentation times (i.e., 100ms) for the prime and target using inquisit web? That is, when online participants are using different computers,  is it possible to control for consistency in stimulus presentation?

Thanks,
Julie

Different computers have different display refresh rates. The most common refresh rates you'll encounter in the wild are 50Hz (=20ms display frame duration), 60Hz (=16.67ms display frame duration), 75Hz (13.33ms frame duration), and 100Hz (10ms frame duration). Displays running at higher rates (120Hz, 150Hz, 200Hz, etc.) exist, but are relatively rare still.

When you have stimulus timings in /stimulustimes such as

/stimulustimes = [0=prime; 100=target]

Inquisit will automatically determine the closest frame available given a system's refresh rate. I.e., for a display running at 50Hz, 100ms amount to 5 display frames (5 x 20 = 100); at 60Hz, the closest frame is the 6th (6 x 16.67 = 100.02); at 75Hz, it's the 8th (8 x 13.33 = 106.64), and at 100Hz, it would be the 10th (10 x 10 = 100).

That is stimulus durations of approximately, though not necessarily exactly 100ms are achievable on practically all systems you'll encounter.
By jmbeadle - 2/12/2021

Dave - 2/13/2021
jmbeadle - 2/13/2021
Hello, 
I am exploring options for an online priming experiment (either evaluative priming or the Affective Misattribution Task).Is it possible to ensure consistent stimulus presentation times (i.e., 100ms) for the prime and target using inquisit web? That is, when online participants are using different computers,  is it possible to control for consistency in stimulus presentation?

Thanks,
Julie

Different computers have different display refresh rates. The most common refresh rates you'll encounter in the wild are 50Hz (=20ms display frame duration), 60Hz (=16.67ms display frame duration), 75Hz (13.33ms frame duration), and 100Hz (10ms frame duration). Displays running at higher rates (120Hz, 150Hz, 200Hz, etc.) exist, but are relatively rare still.

When you have stimulus timings in /stimulustimes such as

/stimulustimes = [0=prime; 100=target]

Inquisit will automatically determine the closest frame available given a system's refresh rate. I.e., for a display running at 50Hz, 100ms amount to 5 display frames (5 x 20 = 100); at 60Hz, the closes frame is the 6th (6 x 16.67 = 100.02); at 75Hz, it's the 8th (8 x 13.33 = 106.64), and at 100Hz, it would be the 10th (10 x 10 = 100).

That is stimulus durations of approximately, though not necessarily exactly 100ms are achievable on practically all systems you'll encounter.

Thank you, Dave! This is very helpful.