Date of Award

Summer 2023

Degree Type

Open Access Dissertation

Degree Name

Psychology, PhD


School of Social Science, Politics, and Evaluation

Advisor/Supervisor/Committee Chair

Andrew R.A. Conway

Dissertation or Thesis Committee Member

Lise Abrams

Dissertation or Thesis Committee Member

Kathy Pezdek

Dissertation or Thesis Committee Member

Lori E. James

Terms of Use & License Information

Terms of Use for work posted in Scholarship@Claremont.

Rights Information

© 2023 Sara Anne Goring


Cognitive Aging, Individual Differences, Semantic Illusions

Subject Categories

Cognitive Psychology | Statistics and Probability


Semantic illusions are recognition errors that occur when an individual fails to notice that information contradicts their prior knowledge (Barton & Sanford, 1993; Erickson & Mattson, 1981). For example, after hearing the question, “If a plane crashes while flying over state lines, where should the survivors be buried?” many start to consider the legality or appropriateness of the scenario despite knowing “survivors” should not be buried. Having more knowledge does not necessarily prevent individuals from overlooking illusory information/misinformation. Older adults tend to have greater crystallized intelligence than young adults, yet these age groups appear to detect illusory information at equivalent rates (Umanath & Marsh, 2012; Umanath, 2014). However, there is also evidence that older adults experience more semantic illusions than young adults in general (Umanath et al., 2012). Previous research demonstrates that the rate of semantic illusions is sensitive to specific language structure manipulations, such as syntax structure or word placement that facilitate overlooking the illusory information (Bredart and Modolo, 1988; Büttner, 2007; Wang, Hagoort, & Yang, 2009). Furthermore, there is evidence that disrupting processing fluency by increasing the difficulty of reading enables more frequent detection of illusory information (Song, 2009). Although this effect has been demonstrated using easy- versus difficult-to-read font, increasing syntax complexity also increases reading difficulty and requires more effort for comprehension (e.g., Kemtes & Kemper, 1997; Stromswold et al., 1996). The current study used a combined experimental-correlational approach to investigate the effects of age, language structure, and cognitive ability on the rate of semantic illusions experienced in response to general knowledge questions. The experimental approach compared the rate of semantic illusions between young and older adult age groups for illusory information embedded in sentences with either simple or complex syntax structures. The correlational approach examined the best cognitive predictors of increased detection of illusory information among composite scores for crystallized intelligence, fluid intelligence, and rationality. The sample of 203 participants, including 114 young adults ( M = 24.98, SD = 4.06) and 89 older adults ( M = 65.63; SD = 4.93), was administered a semantic illusion task, general knowledge check, and reading comprehension task, along with a battery of cognitive measures assessing fluid intelligence, crystallized intelligence, and rational thinking (Comprehensive Assessment of Rational Thinking [CART]; Stanovich, 2016). The semantic illusion task included general knowledge questions that either contained the correct information (target item), e.g., “How many animals of each kind did Noah bring on the ark?” or incorrect information (illusion item), e.g., How many animals of each kind did Moses bring on the ark?”. The sentence structure of the general knowledge questions varied across syntax complexity condition, such that participants experienced target items and illusion items in both simple (right-branching) versus complex (left-branching, middle-branching) syntax structures. Scoring procedures assessed frequencies for: (a) correct responses on target items (target score), (b) successful detection of illusory information (detection score), and (c) failures to detect illusory information (illusion score). The results of the experimental portion of the study confirmed an interaction of age and syntax for detection scores. Older adults detected illusory information more frequently than young adults, and complex versus simple syntax increased this advantage for the older adult age group. Alternatively, the pattern of results for illusion scores, or overlooking the illusory information, produced a main effect of age with older adults experiencing more semantic illusions than young adults regardless of syntax condition. Although counterintuitive, older adults had a higher baseline of prior knowledge, and therefore had more opportunities than young adults to detect and overlook the illusory information at higher rates. The correlational portion was largely data-driven, and investigated which cognitive composites for fluid intelligence, crystallized intelligence, and rationality best predicted detection scores. Results demonstrated varying patterns between age groups, such that young adult detection scores were most accurately predicted by the rationality composite scores. However, older adult detection scores were best predicted by crystallized intelligence. Although both crystallized intelligence and rationality are positively associated with detection of illusory information (Hannon & Daneman, 2001; Mata et al., 2014), a mediation analysis revealed a potential underlying cause to the age-differences in the outcomes. A bootstrap mediation analysis indicated the effect of age group on detection scores was fully mediated by crystallized intelligence. More specifically, older adults had more prior knowledge than young adults to such a disparity, variation in detection scores between age groups can be fully accounted for by differences in crystallized intelligence between young and older adults. Overall, increased syntax complexity facilitates detection of illusory information compared to simple syntax. Furthermore, increased crystallized intelligence is associated with more frequent detection of illusory information. Yet, with less prior knowledge, performance on rational thinking problems is the better predictor of detecting illusory information.