Specs for SetTran1

This is a simple experiment which should be written in VB. It does not exactly have either Trialtypes of Blocktypes (well, it sort of has a blocktype variable called MAPPING, but otherwise everything is selected randomly and independently on each trial).

First, Experimenter is asked what order condition to use for the subject (1 or 2) as well as the usual questions.

At the beginning of the experiment, subject should get these instructions:

Thank you for participating in this experiment. This experiment will be divided into twelve blocks of trials, each lasting just a few minutes. The task is very simple. On each trial, one of two stimuli will be presented. One stimulus looks like a Stop Sign, the other looks like a Green Light.

One stimulus means RESPOND, and the other means DON'T RESPOND. When the stimulus to RESPOND is presented, you should press the N key with the index finger of your dominant hand, responding as rapidly as possible. When the stimulus is the DON'T RESPOND stimulus, you should do nothing.

The computer will tell you at the beginning of each trial which is the RESPOND stimulus, and which is the DON'T RESPOND stimulus. Sometimes you will need to RESPOND to the Green Light but not the Stop Sign; other times you will need to RESPOND to the Stop Sign but not the Green Light.

One stimulus means RESPOND, and the other means DON'T RESPOND. When the stimulus to RESPOND is presented, you should press the N key with the index finger of your dominant hand, responding as rapidly as possible. When the stimulus is the DON'T RESPOND stimulus, you should do nothing. The computer will tell you at the beginning of each trial which is the RESPOND stimulus, and which is the DON'T RESPOND stimulus. Sometimes you will need to RESPOND to the Green Light but not the Stop Sign; other times you will need to RESPOND to the Stop Sign but not the Green Light.

Task:

12 blocks X 50 trials/block

On each trial, pick one of the 2 stimuli random and independently. Stimulus is either RESPOND or DON'T RESPOND (50% chance of each). If it is RESPOND, the

correct response is to press the N key. If it is DON'T RESPOND, the correct response is no response at all. What varies between blocks (not between trials) is what stimulus you present for a Go, and what you present for a Nogo.

For subjects in order condition 1, use mapping 1 on blocks 1-6 and mapping 2 on blocks 7-12. For subjects in order condition 2, use mapping 2 on blocks 1-6 and mapping 1 on blocks 7-12.

At the beginning of each block, show the subject which stimulus is for RESPOND, and which is for DON'T RESPOND. Show them the actual stimuli with the appropriate labels right below them, and keep that up there for 5 seconds (10 seconds on the blocks 1 and 7, where they are just getting used to it).

Mapping 1:

Stop Sign Go

Green Light Nogo

Mapping 2:

Stop Sign Nogo

Green Light Nogo

When you present the stimulus, it should stay up until the subject responds (or 750 msec when the proper response is no response). Save what response they make, if any, and what the response time is (measured from stimulus onset).

Code responses as 0=no response to Go stimulus; 1 = correct response to Go stimulus; 2= correct nonresponse to nogo stimulus; and 3 = incorrect occurence of response (false alarm) to nogo stimulus.

The interval between one response and the next stimulus should be 1.5 seconds.

I am attaching jpeg images for the stopsign and the greenlight.

Test out the program by making a miniversion with just 5 trials per block instead of 50, and running yourself right through.

Please let me know if you have any questions.

DATA STORAGE

Raw Data File

For each trial, there should be the following columns

block #

trial #

mapping (which mapping is used in this block? 1 or 2 as defined above in specs)

stimulus (Stopsign or Greenlight)

correct response (0=no resp; N = n key)

actual response made (0=no response; otherwise code what key was struck)

RT (call it -1 if there was no response within 750 msec window)