Discovery Lab: Illusory Truth (Alternative)

Illusory Truth

Both explicit and implicit processing can influence judgment and decision making as is shown in this lab activity based on the illusory truth effect.

True and False Statements

In this lab activity, you will be presented with a series of sentences. Read each sentence out loud if possible. If the sentence is written in BLUE, then assume it is a TRUE statement. If the sentence is written in ORANGE, then assume it is a FALSE statement. When you have finished reading each statement, press the spacebar. You will then be presented with another statement. You will read a total of 40 statements. Throughout this activity, keep in mind the instruction that blue statements are true and that orange statements are false.

Explicit vs. Implicit Processing

After reading the 40 statements, you will assess the truthfulness of a set of statements presented one at a time. In some cases, you had seen the statements earlier and you were led to believe they were true (i.e., familiar/true). In other cases, you had seen the statements earlier and you were led to believe they were false (i.e., familiar/false). In some other cases, you were presented with statements that you had not read previously (i.e., unfamiliar/new). The experiment tested the extent to which explicit recollection and familiarity each influenced your evaluation of the truthfulness of statements you have seen before. Importantly, the statements were based on facts that most people would not be familiar with already. About half of the statements in each condition were actually true and half of the statements in each condition were actually false. Explicit recollection occurred when you recalled whether a statement had previously been coded (i.e., colored) as true or false. Explicit recollection may have influenced some of your responses as you likely indicated some statements true because you remembered them being shown in blue during learning and some statements false because you remembered them being shown as orange during initial presentation. If you relied on explicit recollection as the only process to influence your evaluation of statements, you would rate previous true statements as true most of the time and previous false statements as false most of the time, and you would probably guess when responding to new unfamiliar statements. In other words, your results would look similar to the orange bars in the summary of results.

Illusory Truth Effect

You and others do not rely exclusively on explicit recollection. If explicit recollection was the only factor responsible for truth judgments, then familiar false statements would not be rated as true more often than unfamiliar new statements. Do your data show this pattern? Results from this activity tend to show that familiarity in addition to explicit recollection affect truth judgments. Having just seen a statement before, regardless of whether it was coded as true or false, leads people to be more likely to judge the statement as true. This is known as the illusory truth effect and it is a robust finding that has been replicated in many experiments.

Familiarity and Judgment of Truth

If you are like most participants, you are more likely to rate a familiar false statement as true than an unfamiliar statement. The percentage reported as true is greater for the familiar false condition than for the unfamiliar new condition. This important finding demonstrates that familiarity plays a role in people’s judgment of what is true.