Game of Chicken

Technical Manual

Script Author: Katja Borchert, Ph.D. (katjab@millisecond.com), Millisecond

Last Modified: January 07, 2025 by K. Borchert (katjab@millisecond.com), Millisecond

Script Copyright © Millisecond Software, LLC

Background

This script runs an experiment designed for kids based on the dove-hawk paradigm (aka Game of Chicken)*. The basic premise of the dove-hawk paradigm is that two people compete for the same resources and have to decide to (a) take the resources fast or (b) wait for the opponent's decision. If they decide to take the resource they can either win the resource (=> the other person waited) or experience a devastating loss (=>the other person also went for the resource). If they wait they either don't get the resource (=> the other person went for the resource) or are able to share it (=> the other person also waited).

References

•Reference for Dove-Hawk Paradigm (aka Game of Chicken): https://en.wikipedia.org/wiki/Chicken_(game)

Duration

12 minutes

Description

In this experiment, kids are asked to collect as many bananas as they can for a hungry monkey named "Charly" while competing with a (computer-generated) "second player", e.g. "Alex"*. In order to decide if they want to a) wait to see what the opponent is doing (=dove behavior) or b) take the bananas right away (=hawk behavior) they have to consider the following rules that determine the outcome of their decisions:

1) If the participant takes the bananas and the opponent waits, the participant gets the full amount of the offered bananas 2) If the opponent takes the bananas and the participant waits, the participant neither wins nor loses any bananas 3) If the opponent and the participant wait, they equally share the bananas (each gets half) 4) If both take the bananas, they each lose double the amount of bananas offered

Procedure

The experiment offers 3 basic blocks that vary the probability with which the computer-generated opponent decides to take bananas
(=hawk) or wait (=dove):
1) Mixed Block: p(hawk) = 0.5
2) Hawk: p(hawk) = 0.8
3) Dove: p(hawk) = 0.2

In each of these blocks, participants are presented with 15 trials in which they have to make a dove-hawk decision.
The name of the opponent for each block is randomly pulled from a pool of 3 gender-neutral names
if trial sequence needs a build-in delay, there are several editable parameter that can be set to accomplish a delay.

A second round of the three basic blocks continuously increases the amount of bananas that can be won by 2
(max amount of bananas that can be won = 30, max of bananas that can be lost = 60).

Stimuli

provided by Millisecond - check under section EDITABLE STIMULI

Instructions

provided by Millisecond - check under section EDITABLE INSTRUCTIONS

Summary Data

File Name: dovehawk_summary*.iqdat

Data Fields

NameDescription
inquisit.version Inquisit version number
computer.platform Device platform: win | mac |ios | android
startDate Date the session was run
startTime Time the session was run
subjectId Participant ID
groupId Group number
sessionId Session number
elapsedTime Session duration in ms
completed 0 = Test was not completed
1 = Test was completed
pTotal The total sum of bananas won

Raw Data

File Name: dovehawk_raw*.iqdat

Data Fields

NameDescription
build Inquisit version number
computer.platform Device platform: win | mac |ios | android
date Date the session was run
time Time the session was run
subject Participant ID
group Group number
session Session number
blockCode Name of the current block
blockNum Number of the current block
trialCode Name of the current trial
trialNum Number of the current trial
opponentName Name of the current opponent
pHawk Probability of hawk-strategy (likelihood that opponent "takes" the bananas)
winAmount Current amount of bananas that can be won
compStrategy Opponent's decision: 1 = hawk (=take), 0 = dove (=wait)
response The response box that participant clicked
pResponse Participant's choice: 1 = hawk (take), 0 = dove (=wait) (interpretation of selected response box)
latency Time it took participant to make a choice in ms (once the response boxes were presented)
outcome The outcome of the "fight": 1 = opponent wins, 2 = participant wins, 3 = both lose, 4 = compromise
pTotal The total sum of bananas won at this time

Parameters

The procedure can be adjusted by setting the following parameters.

NameDescriptionDefault
skipDelay False = delay trials are run
true = delay trials are not run
true
responseBoxDelay Delay of the response boxes in ms0
posttrialPauseChoice Default = 0 ms0
delayDuration The duration of the delay trial in ms - runs only if skipdelay = false5000
posttrialPauseFeedback Default = 0 ms0
nextDelay Delay of the 'continue/next' buttons after feedback was given0
prMixed Sets the probability of hawk strategy in the mixed condition0.5
prHawk Sets the probability of hawk strategy in the hawk condition0.8
prDove Sets the probability of hawk strategy in the dove condition0.2