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DRM Experiment

Jaap Murre

So called DRM paradigm experiment. A critical lure 'sleep' is used as a base. Several associated words are derived from that, called targets. These are shown to the subject. Then these are mixed with words not seen before and with the critical lure. For each of these, the subject has to indicate whether were presented before or not. A typical finding is that many people mistakingly believe that have seen the critical lure earlier, when in fact it was not presented before.

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var critical_lure = getwords('critical_lure.txt');
var targets = getwords('targets.txt');
var lures = getwords('lures.txt');
var i;
var e;
lured = false;
var correct = 0;
var false_alarm = 0;

text("Look at the following words");
await(4000);
clear();
await(1500);

for (i = 0; i < targets.length; i++) {
    text(targets[i]);
    await(1500);
    text('');
    await(1000);
}

var all = targets.concat(lures);
all.push(critical_lure);
all = shuffle(all);

input("Add the following numbers: 47, 39, 23, 85, 17","addition"); // short distractor task

text("For each word, type the S-key for 'Seen' (Old), the L-key for 'Later Added' (New)");
await(4000);
clear();

var b = addblock(0,90,100,10);
b.style("font-size","70%");
b.text("Type S for 'Seen (Old)', L for 'Later Added (New)'");
await(4000)

for (i = 0; i < all.length; i++) {
    text(all[i]);
    e = awaitkey('s,l');
    if (e.key === 's') {
        if (targets.includes(all[i])) {
            log(1,all[i]); // Correct trial
            ++correct;
        } else {
            ++false_alarm;
            log(0,all[i]); // Incorrect trial
        }
        
        if (all[i] === critical_lure) {
            lured = true;
            log(1,"lured")
        }
    }
}

log(correct,"correct_trials");
log(false_alarm,"false_alarms");

clear();
await(2000);

if (lured) {
    text('You fell for the illusion: sleep was not shown earlier, only related words');
} else {
    text('You did not fall for the illusion');
}

await(4000);
await(1000);
text("Thank you for participating!");