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Priming Tasks with Inquisit Web

jmbeadle — Sat, 13 Feb 2021 01:16:32 GMT

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

RE: Priming Tasks with Inquisit Web

jmbeadle — Sat, 13 Feb 2021 01:16:32 GMT

+x[quote]

[b]Dave - 2/13/2021[/b]
+x[quote]

[b]jmbeadle - 2/13/2021[/b]
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
[/quote]

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.
[/quote]

Thank you, Dave! This is very helpful.

RE: Priming Tasks with Inquisit Web

Dave — Sat, 13 Feb 2021 01:12:46 GMT

+x[quote]

[b]jmbeadle - 2/13/2021[/b]
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
[/quote]

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.