The Trail-Making-Test (TMT) is one of the most widely used neuropsychological tests for assessing executive functions, the brain functions underlying cognitively controlled thought and action. Obtaining a number of test scores at once, the TMT allows to characterize an assortment of executive functions efficiently. Critically, however, as most test scores are derived from test completion times, the scores only provide a summary measure of various cognitive control processes. To address this problem, we extended the TMT in two ways. First, using a computerized eye-tracking version of the TMT, we added specific eye movement measures that deliver a richer set of data with a higher degree of cognitive process specificity. Second, we included an experimental manipulation of a fundamental executive function, namely participants’ ability to emphasize speed or accuracy in task performance. Our study of healthy participants showed that eye movement measures differed between TMT conditions that are usually compared to assess the cognitive control process of alternating between task sets for action control. This demonstrates that eye movement measures are indeed sensitive to executive functions implicated in the TMT. Crucially, comparing performance under cognitive control sets of speed vs. accuracy emphasis revealed which test scores primarily varied due to this manipulation (e.g., trial duration, number of fixations), and which were still more sensitive to other differences between individuals (e.g., fixation duration, saccade amplitude). This provided an experimental construct validation of the test scores by distinguishing scores primarily reflecting the executive function of emphasizing speed vs. accuracy and those independent from it. In sum, both the inclusion of eye movement measures and of the experimental manipulation of executive functions in the TMT enabled a more specific interpretation of the TMT in terms of cognitive functions and mechanisms, which offers more precise diagnoses in clinical applications and basic research.

Faced with inhomogeneous representations, the visual system has to rely on pre- and postsaccadic processing mechanisms to assure perceptual continuity across eye movements. While postsaccadically, memorized peripheral and postsaccadic foveal information are integrated according to their reliabilities, here we investigated whether this also holds true for the presaccadic combination of peripheral input and internal associated foveal images. In three experiments, participants learned associations between objects changing transsaccadically in one feature dimension (spatial frequency in Experiment 1 and color in Experiments 2 and 3). Subsequently, participants judged the respective feature of only peripherally presented objects. Importantly, the reliability of this peripheral input was manipulated by lowering the contrast (Experiment 1) or adding color noise (Experiment 3). We hypothesized that participants’ presaccadic peripheral percepts would be biased toward the internal associated foveal image and that the biasing effect would be stronger the lower the peripheral reliability. In all experiments, perception was biased in the direction of the associated foveal image. However, the strength of the bias did not differ between reliability conditions. The presaccadic perceptual bias effect had previously not been tested with the feature color. By showing that yet another feature incorporates prior transsaccadic knowledge, our results highlight the scope of the effect. Furthermore, they point to important differences between pre- and postsaccadic processing mechanisms.

Acting upon target stimuli from the environment becomes faster when the targets are preceded by a warning (alerting) cue. Accordingly, alerting is often used to support action in safety-critical contexts (e.g., honking to alert others of a traffic situation). Crucially, however, the benefits of alerting for action have been established using laboratory tasks assessing only simple choice reactions. Real-world actions are considerably more complex and mainly consist of sensorimotor sequences of several sub-actions. Therefore, it is still unknown if the benefits of alerting for action transfer from simple choice reactions to such sensorimotor sequences. Here, we investigated how alerting affected performance in a sequential action task derived from the Trail-Making-Test, a well-established neuropsychological test of cognitive action control (Experiment 1). In addition to this task, participants performed a classic alerting paradigm including a simple choice reaction task (Experiment 2). Results showed that alerting sped up responding in both tasks, but in the sequential action task, this benefit was restricted to the first action of a sequence. This was the case, even when multiple actions were performed within a short time (Experiment 3), ruling out that the restriction of alerting to the first action was due to its short-lived nature. Taken together, these findings reveal the existence of an interface between phasic alertness and action control that supports the next action.