When people evaluate claims, they often rely on what comedian Stephen Colbert calls "truthiness," or subjective feelings of truth. In four experiments, we examined the impact of nonprobative information on truthiness. In Experiments 1A and 1B, people saw familiar and unfamiliar celebrity names and, for each, quickly responded "true" or "false" to the (betweensubjects) claim "This famous person is alive" or "This famous person is dead." Within subjects, some of the names appeared with a photo of the celebrity engaged in his or her profession, whereas other names appeared alone. For unfamiliar celebrity names, photos increased the likelihood that the subjects would judge the claim to be true. Moreover, the same photos inflated the subjective truth of both the "alive" and "dead" claims, suggesting that photos did not produce an "alive bias" but rather a "truth bias." Experiment 2 showed that photos and verbal information similarly inflated truthiness, suggesting that the effect is not peculiar to photographs per se. Experiment 3 demonstrated that nonprobative photos can also enhance the truthiness of general knowledge claims (e.g., Giraffes are the only mammals that cannot jump). These effects add to a growing literature on how nonprobative information can inflate subjective feelings of truth.

Upon learning the outcome to a problem, people tend to believe that they knew it all along (hindsight bias). Here we report the first study to trace the development of hindsight bias across the lifespan. 194 participants aged 3 to 95 years completed three tasks designed to measure visual and verbal hindsight bias. All age groups demonstrated hindsight bias on all three tasks; however, preschoolers and the elderly exhibited more bias than older children and younger adults. Multinomial processing tree analyses of these data revealed that preschoolers’ enhanced hindsight bias resulted from them substituting the correct answer for their original answer in their recall (a qualitative error). Conversely, older adults’ enhanced hindsight bias resulted from them forgetting their original answer and recalling an answer closer to, but not equal to, the correct answer (a quantitative error). We discuss these findings in relation to mechanisms of memory, perspective-taking, theory of mind, and executive function.

Theory of mind (ToM), or the ability to understand mental states, is a fundamental aspect of social cognition. Previous research has documented marked advances in ToM in preschoolers, and declines in ToM in older-aged adults. In the present study, younger (n=37), middle-aged (n=20), and older (n=37) adults completed a continuous false belief task measuring ToM. Middle-aged and older adults exhibited more false belief bias than did younger adults, irrespective of language ability, executive function, processing speed, and memory. The authors conclude that ToM declines from younger to older adulthood, independent of age-related changes to domain-general cognitive functioning.

In recognition tests, items presented in unusual ways (e.g., degraded, revealed in stages, or presented as anagrams)are often judged to be old more than are intact items. This revelationeffect has been observed only in episodic judgments about the occurrence or frequency of relatively recent events. The present work extends the boundary conditions of this effect. In three experiments, subjects unscrambled anagrams in the context of answering questions about their childhood (e.g., broke a dwniwo playing ball) or while answering questions pertaining to world knowledge (e.g., fastest animal-elpraod). In each case, a revelation effect was observed: Solving an anagram increased confidence in remote autobiographical memories and in memory for world facts. These results contradict claims that the effect is an episodic memory phenomenon and challenge existing explanations of the revelation effect.

A novel task, using a continuous spatial layout, was created to investigate the degree to which (in centimeters) 3-year-old children's (N = 63), 5-year-old children's (N = 60), and adults' (N = 60) own privileged knowledge of the location of an object biased their representation of a protagonist's false belief about the object's location. At all ages, participants' knowledge of the object's actual location biased their search estimates, independent of the attentional or memory demands of the task. Children's degree of bias correlated with their performance on a classic change-of-location false belief task, controlling for age. This task is a novel tool for providing a quantitative measurement of the degree to which self-knowledge can bias estimates of others' beliefs.