How To: Participant Tokens


Welcome to the Participant Token 'how to'


Explore the list of questions in the menu to the left to find out more about Participant Tokens.

If you can't find an answer to your question here, please get in touch with us. We are always happy to help you.

What is Pay per Participant?
As of August 2017 we have introduced the Pay per Participant Tier which replaces the standard sign-up account. All new users will automatically start on this account type. Any exisiting Gorilla users who do not already have a licence will be automatically upgraded to this tier. Pay per Participant means exactly that - you can pay for just the participants you want to recruit for your study, without needing to buy a yearly licence subscription.

What does this mean for me?
This is exciting news, as we can now offer all users many features which were originally only available by purchasing a full licence such as:

  • Task Builder Script feature
  • All Code Editor tools
  • Full access to all Recruitment options

I already have a Gorilla licence subscription
For those on existing licences you can continue to use Gorilla as you always have done - unlimited participants with no additional fees and no need to purchase tokens. Your licence subscription also allows you full access to Gorilla's support services.


I don't know if my department has a subscription
If your department has a subscription, you will not need to pay per participant. A list of institutions with subscriptions is available here. You can find your subscription status through 'My Account'. If you think you should be on a subscription, please contact your department's subscription manager.

What are Tokens?


In order to recruit participants for your experiment you need participant tokens.

For each participant that you wish to collect data from you need one token. Current Pay-As-You-Go prices are shown here.

You can limit the number of participants recruited for an experiment - and therefore the total number of tokens you wish to use - by setting the Recruitment Target for your experiment. Giving you complete control of when Tokens are consumed.

When are Tokens Consumed?


When a participant starts your experiment the Start Node reserves a token for them. When that same participant enters the Finish Node that token is then consumed.The token this participant consumed is then permanently removed from your accounts token total.

If the participant does not enter the Finish Node, and does not pass through a Reject Node, the participant's token will remain reserved until they are included or rejected (either manually or via a timelimit). Both reserved tokens and fulfilled (consumed) tokens count towards your experiment Recruitment Progress.

Including participants permanently consumes tokens. Once a token is consumed it cannot be reused or reclaimed.

Sometimes recruited participants will not meet your experimental requirements and for these participants you may not wish to consume a token. Gorilla allows you to 'reject' participants in these cases. Rejecting participants returns their reserved tokens (unless you have previously included them). Rejected participants can later be included, as long as you have sufficient remaining tokens in your recruitment target. Find out more about 'rejecting participants' here.

The total number of participant tokens that can be consumed during an experiment is set using the Recruitment Target giving you complete control of how many tokens you use for an experiment.

How do I reject participants?


Sometimes participants will not meet your experimental requirements and for these participants you may not want to consume a token. For these cases Gorilla allows you to 'reject' participants.

There are three ways to reject participants and stop them from consuming a token.

  1. Using a Reject Node - in your experiment tree design.
  2. Time Limit - on your experiment recruitment page.
  3. Manual Rejection - on your experiment participants page.

Rejected participants are:

  • Marked as 'Rejected' on your participants Page.
  • Not counted towards your Recruitment Progress.
  • Not included in your downloadable data.

Rejected participants can still be manually included in your downloadable data if you wish, find out how here.

Consumed tokens cannot be reclaimed by later rejecting them.


  1. Reject Nodes

The classic use-case for a Reject Node is 'Screening Out'.

If your experiment has specific participant-requirements, you may wish to screen participants out early on in your experiment (for example, based on demographic questions or perfomance in a task) and not include them in your downloadable data. This can be achieved by directing participants into a Reject-Node (instead of a Finish Node).

Any participant who ends your experiment at a Reject Node will be given the status 'rejected' on your Participant Page. Their reserved token will be returned and they will not count towards your recruitment progress. They will not be included in your downloadable data.

You can find out more about the Reject Node in the Tooling Reference Guide

  1. Time Limit

The classic use-case for Manual Rejection is preventing participants with 'Live' Status.

You may wish to set a Time Limit on your Experiment. This means that participants who take more than the allowed time will be automatically rejected. This will prevent you having to manually reject participants who are still marked as 'Live' because they left the experiment part-way through.

Participants who reach the Time Limit will be automatically rejected, but will be allowed to finish their current task, before being redirected to the Finish Node.

  1. Manual Rejection

The classic use-case for Manual Rejection is participants with 'Live' Status.

Sometimes participants will leave your experiment part-way through. On your experiments 'Participants' page, the status of these participants will remain as 'Live'.

While a participant has 'Live' status you can choose to manually 'reject' the participant from your experiment if you wish. You do this on the participants page by choosing the action 'Reject' in the dropdown menu for that participant. Manually Rejecting a participant in this way will set the participant's status to 'Rejected' with the tag 'Manual'. This will reclaim the reserved token back into your experiment, so it can then be reserved and then consumed by another participant. Once a token has been consumed however, it cannot be reclaimed in this way.

To make educated decisions about whether or not to reject a 'Live' participant, we strongly recommend you make use of Checkpoint Nodes in order to know how far through your experiment your participant progressed.

How do I Manually Include a Participant?


To manually include a participant in your downloadable data, select the 'Include' Action for that participant, on your experiment 'Participants' page.

Choosing to Manually Include a Participant in this way will:

  • Mark the participant as Included on your 'Participants' page.
  • Include this participant in your downloadable data.
  • Count the participant towards your Recruitment Progress as 'Fulfilled'.
  • For Pay-per-Participant accounts, manually including a participant will consume a Token from your experiments allocation.

Including a participant is a permanent action; once a participant has been included in your downloadable data, and a token consumed, the decision cannot be reversed. Be sure to only include participants whos data you wish to download and use.

There are two classic cases where you may wish to Manually Include a participant:

  1. Manually including previously rejected participants
  2. Manually including 'Live' Participants

To make educated decisions about whether or not to manually include a participant, we strongly recommend you make use of Checkpoint Nodes in order to know how far through your experiment your participant progressed.

Note: If your recruitment progress is at 100%, you must first increase your Recruitment Target before you can continue to manually Include participants. For Pay-per-Participant accounts this allows you to keep tight control of how many tokens you spend on an experiment.

  1. Manually Including Previously 'Rejected' Participants

Sometimes you may wish to include 'rejected' participants in your data collection even though they did not complete your experiment, or else ended your experiment at a 'Reject Node'. Even though you have marked these participants as 'rejected' you always retain the option to Manually Include these participants in your downloadable data.

For Pay-per-Participant accounts this will consume one token for each participant manually included in this way.

  1. Manually Including 'Live' Participants

You may also choose to include participants who have the 'Live' status at any time. This will allow you to download their data and view it while they are still progressing through your experiment. This can be a useful in Teaching situations or Supervised trials using the 'Supervised' Recruitment Policy.

For Pay-per-Participant accounts this will consume one token for each participant manually included in this way.

Assigning Tokens


In order to recruit participants for your experiment you will need to set a Recruitment Target on your experiments 'Recruitment' page. This will assign tokens to your experiment from your accounts total.

Note: You will only be able to change the recruitment target if you are the project owner (you created the project). Collaborators are not able to assign tokens.

You cannot assign more tokens to an individual experiment than the total number of tokens you have left on your account. If you wish to recruit more participants than you have available tokens you must first buy more tokens.

You can change your recruitment target at any point during your experiment.

  • Increasing the Recruitment Target total will assign additional tokens from your account.
  • Decreasing the Recruitment Target total will un-assign tokens from your experiment and return them to your account, where you can then freely assign them to other experiments.

However, consumed tokens cannot be reclaimed or reassigned. Therefore, you cannot change the Recruitment Target to be lower than the number of tokens already consumed plus the number currently reserved.

You can view which experiments you have assigned tokens to on your My Account page.

Buying Tokens


You can purchase more tokens at any time by clicking a 'Buy More Tokens' button which will take you to the 'Buy Tokens' menu.

There are two main places where you can Buy More Tokens:

  • Your main account page: My Account
  • The 'Recruitment' page of any experiment.

When you purchase more tokens, they are immediately added to your account. You can then assign tokens from your account to your experiments as you see fit.

You can find out about the different Pay per Participant pricing tiers here.

Earning Free tokens


You can earn free 'Match Funding Tokens' via our referral system. You can find out more about Match Funding here.

In the future we will look to implement more ways to earn free tokens.

Subscription Tokens


If your department is on a metered subscription, you will need to request tokens. Your department will set a limit on the number of tokens that can be granted to each user automatically upon request, and any further requests will have to be approved by your subscription administrator. The workflow for this is built into Gorilla so that it is as easy and efficient as possible.

You can request tokens either:

  • Through your account page


  • Through the 'Change Recruitment Target' settings in your experiment



After you click the 'Request Tokens from Subscription' button, you will need to fill in the Token Request form. See your subscription administrator for the details you need to include on this.



If your request is below your individual limit, the request will be granted automatically. If it is above this limit, you will be notified by email whether your request has been approved or denied.

Accessing a Subscription


You can find your subscription status through 'My Account'.

If your department has a subscription, you will not need to pay per participant. If you think your department may have a subscription, check our list of institutions with subscriptions here.

If you think you should be on a subscription, please contact your department's subscription administrator, whose details can also be found on this page. If your subscription administrator is not listed, please contact us to be added to the subscription.

Do I qualify for Academic Pricing?


To qualify for the Academic pricing tier you must use your academic email address in Gorilla.

You can find out more about the different Pay per Participant pricing tiers here.

I didn't use my academic address to sign up to Gorilla, what can I do?
If you have set up your Gorilla account with a non-academic address you can change your email address at any time on the My Account page.

I signed up with my academic address but I'm still on commercial pricing, what can I do?
If you are from an academic institution but your academic email is not being recognised by Gorilla, please get in touch with us with proof of your academic affiliation.