Individual differences, aging, and IQ in two-choice tasks

Abstract

The effects of aging and IQ on performance were examined in three two-choice tasks: numerosity discrimination, recognition memory, and lexical decision. The experimental data, accuracy, correct and error response times, and response time distributions, were well explained by Ratcliff’s (1978) diffusion model. The components of processing identified by the model were compared across levels of IQ (ranging from 83 to 146) and age (college students, 60-74, and 75-90 year olds). Declines in performance with age were not significantly different for low compared to high IQ subjects. IQ but not age had large effects on the quality of the evidence that was obtained from a stimulus or memory, that is, the evidence upon which decisions were based. Applying the model to individual subjects, the components of processing identified by the model for individuals correlated across tasks. In addition, the model’s predictions and the data were examined for the “worst performance rule”, the finding that age and IQ have larger effects on slower responses than faster responses.

Age-related differences in diffusion model boundary optimality with both trial-limited and time-limited tasks

“…For example, participants use different criteria when verbal instructions focus on speed versus accuracy, showing that criteria can be affected by goals that are defined very broadly. Moreover, participantlevel factors seem to play a large role, given that participants maintain fairly consistent criteria across a range of different decision tasks (Ratcliff, Thapar, & McKoon, 2006;Ratcliff, et al, 2010Ratcliff, et al, , 2011. Thus, a complete account of speedaccuracy settings must consider a broad range of influences and is likely to remain a challenge for quite some time.…”

“…Participants completed the numerosity discrimination taska decision task that has been used to explore aging differences with the diffusion model (e.g., Ratcliff et al, 2001Ratcliff et al, , 2010. For each trial, asterisks were displayed on the computer screen, and participants decided whether a "high" or "low" number was displayed.…”

Individual Differences in Language Acquisition and Processing

“…This means that two participants might have different means on a task despite being identical in the component process of interest, or have identical means despite differing in the component of interest. For example, while it is well known that children and older adults differ from young adults in lexical decision speed, parameter estimates from the drift diffusion model (a prominent cognitive process model of speeded decision making) show that older adults accumulate evidence at the same rate as college students but adopt more conservative response thresholds and take longer to execute a response [144], whereas children accumulate evidence more slowly in addition to adopting more-conservative response thresholds and taking longer to execute a response [145]. The development of similar process models for common psychological measures, such as the visual world paradigm [146], will be fruitful for careful individual differences research (see Outstanding Questions).…”

How many trials are required for parameter estimation in diffusion modeling? A comparison of different optimization criteria

“…More recently, the correlations between diffusion model parameters and external criteria have also constituted a research field (e.g., between drift rate and general intelligence; see Ratcliff, Thapar, & McKoon, 2010). On the basis of such observations, lately, the idea has been expressed that the diffusion model might also be used as a diagnostic tool (e.g., Aschenbrenner, Balota, Gordon, Ratcliff, & Morris, 2016;Ratcliff & Childers, 2015).…”