CNP DRL

From Pheno Wiki
Revision as of 17:04, 26 May 2011 by Stigge (Talk | contribs)

Jump to: navigation, search

Basic Task Description

The deterministic reversal learning task (DRLT) is a computerized measure of reversal learning, a form of behavioral/cognitive flexibility that has been widely investigated in both animal and human studies (Robbins et al., 2000). This particular task version was modeled after a paradigm originally used to examine genetic associations with reversal learning in BXD strains of mice (Laughlin et al., 2011). Participants are presented with two doors and instructed that they will receive monetary rewards based on which door they choose. The initial side of reinforcement (right or left) is randomly selected by the computer. If participants select the door associated with the reward, they immediately see two quarters appear in place of the door and hear a rewarding sound (cash register noise). Rewarded selections also present a running total of earnings on the bottom of the screen. If participants select the door that is not associated with the reward, they immediate see an empty white box in place of the door and hear a negative sound (buzzing noise). Once participants have consistently selected the reinforced door, the reward contingencies for the doors are reversed. After this reversal, participants need to consistently select the newly reinforced door in order to complete the task. The primary dependent variable is the number of errors that are made after reversal.

Task Procedure

This DRLT was programmed in E-Prime 2.0. Participant responses are made on computer keyboard, with three keys marked for use in this task: A (left), H (middle), and '(right). At the beginning of the task, instructions are presented on the screen in yellow, size 20 Arial font, with a black screen background. The instructions are as follows:

"In this game, you have an opportunity to win money by

looking behind doors. Do your best to find as much money as possible.

You will actually be given the money that you earn in this task.

You may only use the index finger of your dominant hand to respond,

and you must respond as quickly as you can.

You may NOT use two hands on this task.

On the keyboard, you'll see three marked keys: left, middle, and right.

To start each play of the game,

PRESS AND HOLD THE MIDDLE KEY DOWN,

and release the key only when you see doors appear to the left and right.

Then choose one of the doors to open by pressing either the left or right keys.

You will get money based on which door you choose.

Before we start the game, let's take a moment to practice the key presses..."

Participants are then shown another instruction slide that prepares them for the practice trials:

"In the following trials you will practice making quick key presses.

You'll hear a sound to let you know if your responses are fast enough.

Please tell your experimenter when you are ready to begin the practice trials."

Practice trials provide a basic orientation to the trial format and response keys in order to shape prompt responding during the task. Practice trials begin with a box in the center of the screen with the word "Press" and the words "Press and hold the middle button" at the top of the screen. Once the participant presses the middle key, the word "Hold" appears in the center box and the words "Wait until you see the doors!" appears at the top of the screen. The "Hold" cue remains on the screen for either 2000 ms or 2500 ms, during which time participants must keep the middle key pressed down. If they release the middle key prematurely during this time, they receive the following feedback and the trial restarts: "Oops! Make sure to wait for the doors. Let's try again." Following the "Hold" delay, two doors appear on the left and right sides of the screen. The doors remain on the screen for up to 4000 ms or until the participant presses the left or right key. While the doors are present, the "Hold" cue is then replaced by "Left or Right?" which prompts the participants to press either the left or right key. If a left or right keypress is made within 2000 ms, then participants are given feedback of "Good Job!" in the center box, along with a positive noise (fanfare). If participants take too long to respond (more than 2000 ms), they receive the following feedback in the center of the screen: "Oops! Please respond more quickly. Let's try again." Feedback slides are all presented for a total of 2000 ms. After three consecutive responses within the 2000 ms time limit, the practice trials end and the following instructions are presented on the screen:

"Now that you are familiar with pressing the keys, we can start the game.

In this game, you'll need to choose either the left or the right door to win money.

Please tell your experimenter when you are ready to begin."

Experimental trials follow general parameters similar to the practice trials, and begin with a box in the center of the screen with the word "Press." If participants do not press the middle button within 5000 ms, they receive the following feedback in the center of the screen: "Please press the middle key to begin the next trial." After pressing the middle key, the word "Hold" appears in the center box and remains on the screen for either 1000 ms, 1500 ms, 2000 ms, or 2500 ms. These 4 durations for the "Hold" cue are randomized across all trials. If they release the middle key prematurely during this time, they receive the following feedback and the trial restarts: "Oops! Make sure to wait for the doors. Let's try again." Following the "Hold" delay, two doors appear on the left and right sides of the screen. The doors remain on the screen for up to 2000 ms or until the participant presses the left or right key. While the doors are present, the "Hold" cue is then replaced by "Left or Right?" which prompts the participants to press either the left or right key.

For each experimental block of trials, the computer randomly selects either the left or right door to be associated with reward initially. Participants receive $0.50 each time they select the rewarded. As soon as the participant presses the key corresponding to the side of the rewarded door, then they immediately see two quarters appear in place of the door and hear a rewarding sound (cash register noise). Rewarded selections also present a running total of earnings on the bottom of the screen. If participants select the door that is not associated with the reward, they immediate see an empty white box in place of the door and hear a negative sound (buzzing noise).