Brief Psychomotor Vigilance Test (PVT-B)

Sleep researchers have known for decades that a loss of sleep reduces vigilance. What is now widely known as the Psychomotor Vigilance Test is based on the work by Wilkinson and Houghton (1982). These authors had developed a test called the Unprepared Simple Reaction Time Test (USRT) which was run on something looking like a portable casette recorder. David Dinges elaborated this task and called it first simply Visual Reaction Time in a much cited paper (Dinges & Powell, 1985). It seems the term "PVT" was first used around 1990 (Graeber et al., 1990).

In this task, the participant sees a red box. Every so often, a yellow running number is presented within this box. The participant needs to respond as quickly as possible to the running number. When responded, the running number disappears and participant waits for next number.

In the regular version, this task lasts exactly 10 minutes, but there are shorter versions, including the PVT-B (B for "brief"), which is a 3 minute version of this which has even been tested in by astronauts in the International Space Station (Tu et al., 2022).

There are different ways to extract scores from the data from a participant. The PVT scores include 3 measures:

Sleep deprivation can be measured in three ways in the PVT:

Advantages of the PVT-B (compared to standard PVT) are that it is considerably shorted and thus easier to integrate in a larger study. According to the authors, "PVT-B may be a useful tool for assessing behavioral alertness in settings where the duration of the 10-min PVT is considered impractical, although further validation in applied settings is needed." (Bassner, Mollicone, & Dinges, 2011).

You can calculate an overall performance score, as was for example done by Tu and colleagues (2022):

Overall Performance Score = 1 - ( Number of False starts + Number of lapses ) / ( All trials )

This score, however, ignores the response speed.

Timing is a key issue in this task and varies between different PVT versions. In this 3-minutes PVT-B version, the timing of one trials is as follows. You can of course change these variables as you please.

In the normal PVT setup, participants are told to respond as quickly as possible. They do not get feedback when they respond to early or too late (i.e., after 500 ms).

Participants do not get feedback about their mistakes. If people try to be really fast, they will by definition make more early starts. They are not told they do this so there is no learning. Also, when people are too slow this no feedback is given.

The PVT-B article (Basner et al, 2011) is sometimes somewhat ambiguous, but this seems due to wrong use of the term Inter Stimulus Interval (ISI).

On the one hand the paper states: "The inter-stimulus intervals varied randomly from 1 to 4 s (including a 1 s RT feedback interval)."

On the other hand, it says (but not necessarily explicitly states) that the response window is up to 30 seconds:

"Both versions gave a signal after a 30 s period without response, which was counted as a lapse (see below) with 30 s response time."

The latter means that the inter-stimulus interval cannot possible be 1 to 4 seconds, it means that the response-stimulus interval is 1 to 4 seconds.

It seems that they actually mean Inter Response Interval instead of Inter Stimulus Interval.

So how to people perform on this task? The original Basner (2011) paper focuses mostly on validating the task in relation to the longer PVT task and the best estimate of RTs are in the figures, especially Figure 1. Of course, you could use the PVT 10 (10 minutes) for which there are more published data.

A good paper to get average data in the regular 10 minute PVT are in the paper by Thomann and colleagues (2014). Their Table 2 shows among other things the following for 67 healthy control participants. We added the corresponding regular RTs.

Notes about the table (these are direct quotes from Table 2 of the Thoman paper:

The use of reciprocal RTs is common in the PVT literature. For example, a reciprocal RT of 4.51 is 1/4.41 seconds or 222 ms.

The task is relatively simple to implement, as it simply involves responding to a running timer in a box. People are only allowed to respond if a counter is shown. Response times shorter than 100 ms are also considered false starts, in line with the paper (Basner, 2011).

Meaning of the columns in the output datafile. You need this information for your data analysis.

The PsyToolkit code

The PsyToolkit code zip file of the 3 minute PVT-B version

If you want to upload the zipfile into your PsyToolkit account, make sure the file is not automatically uncompressed (some browsers, especially Mac Safari, by default uncompress zip files). Read here how to easily deal with this.