The inspection time not studied: Processing speed ability unrelated to psychometric intelligence

Individual differences in visual search: A systematic review of the link between visual search performance and traits or abilities

Visual search (VS) comprises a class of tasks that we typically perform several times during a day and requires intentionally scanning (with or without moving the eyes) the environment for a specific target (be it an object or a feature) among distractor stimuli. Experimental research in lab-based or real-world settings has offered insight into its underlying neurocognitive mechanisms from a nomothetic point of view. A lesser-known but rapidly growing body of quasi-experimental and correlational research has explored the link between individual differences and VS performance. This combines different research traditions and covers a wide range of individual differences in studies deploying a vast array of VS tasks. As such, it is a challenge to determine whether any associations highlighted in single studies are robust when considering the wider literature. However, clarifying such relationships systematically and comprehensively would help build more accurate models of VS, and it would highlight promising directions for future research. This systematic review provides an up to date and comprehensive synthesis of the existing literature investigating associations between common indices of performance in VS tasks and measures of individual differences mapped onto four categories of cognitive abilities (short-term working memory, fluid reasoning, visual processing and processing speed) and seven categories of traits (Big Five traits, trait anxiety and autistic traits). Consistent associations for both traits (in particular, conscientiousness, autistic traits and trait anxiety - the latter limited to emotional stimuli) and cognitive abilities (particularly visual processing) were identified. Overall, however, informativeness of future studies would benefit from checking and reporting the reliability of all measurement tools, applying multiplicity correction, using complementary techniques, study preregistration and testing why, rather than only if, a robust relation between certain individual differences and VS performance exists.

Fitting Partially Nonlinear Random Coefficient Models as SEMs

The nonlinear random coefficient model has become increasingly popular as a method for describing individual differences in longitudinal research. Although promising, the nonlinear model it is not utilized as often as it might be because software options are still somewhat limited. In this article we show that a specialized version of the model can be fit to data using SEM software. The specialization is to a model in which the parameters that enter the function in a linear manner are random, whereas those that are nonlinear are common to all individuals. Although this kind of function is not as general as is the fully nonlinear model, it still is applicable to many different data sets. Two examples are presented to show how the models can be estimated using popular SEM computer programs.

A Version of Quadratic Regression with Interpretable Parameters

The quadratic regression model is popular and effective in describing a wide variety of data, but it is based on a function whose parameters are not easy to interpret. We suggest an alternative form of the quadratic model that has the same expectation function, but also has the useful feature that its parameters are interpretable. Examples are provided of a simple regression problem and also of a nonlinear mixed-effects model. The models can be estimated with available software.

Multiphase mixed-effects models for repeated measures data

Behavior that develops in phases may exhibit distinctively different rates of change in one time period than in others. In this article, a mixed-effects model for a response that displays identifiable regimes is reviewed. An interesting component of the model is the change point. In substantive terms, the change point is the time when development switches from one phase to another. In a mixed-effects model, the change point can be a random coefficient. This possibility allows individuals to make the transition from one phase to another at different ages or after different lengths of time in treatment. Two examples are reviewed in detail, both of which can be estimated with software that is widely available.

Organization and components of psychomotor ability

We investigated the organization and components of psychomotor abilities by administering a diverse set of cognitive and psychomotor tasks to a group of recent high school graduates (N = 161). Confirmatory factor analyses identified two psychomotor factors: a general factor associated with all psychomotor tests and an orthogonal psychomotor learning factor associated exclusively with practiced psychomotor tests. Path analyses suggested that the general psychomotor factor could be largely accounted for by two cognitive factors, general working-memory capacity (r = .67) and an orthogonal time estimation factor (r = .32). Most of the psychomotor learning factor variance was unique, but psychomotor learning was somewhat related to processing speed (r = .49). We conclude that initial psychomotor performance is constrained by working-memory limits and the ability to keep track of time. Practiced psychomotor skill is additionally limited by processing speed, consistent with the literature on the development of process automaticity. The Discussion addresses (a) the small dimensionality of the psychomotor abilities space, (b) our discovery of the importance of time estimation and other cognitive factors in psychomotor learning, and (c) the changing nature of psychomotor skill with practice.