The Movement Imagery Ability Task Platform

The Dual Virtual Radial Fitts’ Task (dual-VRFT) is an adaptation of the Virtual Radial Fitts’ Task (VRFT; e.g., Caeyenberghs et al., 2009), based on Fitts’ law (Fitts, 1954). Participants tap and imagine tapping between a central circle and five radially arranged targets in a specified order. Movement difficulty varies across trials by manipulating target width. To ensure identical measurement of movement times in execution and imagery, participants press the space bar with their non-dominant hand for each executed and imagined tap.

In the dual-VRFT, Fitts’ law applies to both execution and imagery, with imagery being slower than execution (Czilczer et al., in preparation). The dual-VRFT assesses timing-related movement imagery ability by capturing how accurately the difficulty of a movement is reflected in imagery.

The current version (Czilczer et al., in preparation) includes one block each for execution and imagery, with five difficulties presented across trials. A familiarization with tapping targets of varying sizes, a comprehension check, and practice trials precede the main task. The task requires a stylus with a fine tip. While a touchscreen is recommended to ensure a stable tapping surface, it is not strictly required.

The Final Position Judgment Task (FPJT) builds on previous imagery–stimulus comparison tasks (Madan & Singhal, 2013; Schott, 2013). Participants hear a sequence of auditory instructed movements. Starting from an upright standing position, participants imagine how it feels and looks like to execute these movements. In the FPJT, a single visual stimulus showing a human figure in a specific position is presented after the final auditory instruction. In 50% of trials, the visual stimulus includes one incorrect movement. Unlike earlier imagery–stimulus comparison tasks, requiring a selection among multiple visual stimuli, the FPJT involves a binary judgment: whether the visual stimulus matches the imagined final position. This allows for the measurement of both response times and accuracy.

The FPJT requires participants to generate and manipulate their imagery based on the auditory instructions, maintain it throughout the sequence of instructions, and inspect their imagery to evaluate it against the visual stimulus. Response times and error rates tend to increase with an increasing number of sequential instructions (Czilczer et al., in preparation).

Throughout the FPJT (Czilczer et al., in preparation), four to seven auditory instructions are presented per trial, each involving a movement of the head, torso, or a limb (left or right arm or leg). The main task is preceded by a familiarization with auditory and visual stimuli, a comprehension check, and practice trials.

The FST is adapted from various sequence-learning paradigms frequently used to study motor control (Doyon et al. 1997). Participants are asked to type and imagine finger sequences, and the time employed is measured (Dahm et al. 2023). During imagery, participants must simulate pressing the keys until the sequence is completed, hence the paradigm assesses the ability to maintain movement imagery.

This version of the task, as developed by Moreno-Verdú et al. (in prep.), consists in typing/imagining different 8-digit sequences with the index, middle, ring and little fingers of the dominant hand. The present implementation employs two types of sequences that differ based on their complexity (considering the number of changes in direction, with equivalent number of repeats per digits). This allows to observe effects of sequence complexity on both execution and imagery times, as a fundamental effect of the paradigm.

The HLJT was first introduced by Cooper and Shepard (1975), who proposed that participants "determine whether a visually presented hand is left or right by moving a mental "phantom" of one of their own hands into the portrayed position and by then comparing its imagined appearance against the appearance of the externally presented hand." Many variants of the task have subsequently been examined in the context of studies of motor imagery.

The "biomechanical constraints effect", an effect where hands presented in more physically easy to achieve (medial) rotations are processed faster than those with more difficult (lateral) rotations is considered to be a hallmark of the use of motor imagery in the task.

This version of the task, as developed by Moreno-Verdu et al., (2025), presents hands at 8 angles (0° through 315° in 45° increments) in a 'palmar' or 'dorsal' view. This implementation has been verified to provide equivalent results when participants responded using different effectors (e.g. the feet, bimanually, or unimanually), making it feasible for use with participants with impairments in a specific effector.

The mental body rotation task is a cognitive test used to assess a person's ability to mentally simulate changes in body position (Steggemann et al., 2011). Participants are shown images of human figures in various orientations and are asked to judge whether the figure's left or right hand (or foot) is raised (Dahm et al., 2022). To do this correctly, they either mentally rotate their own body or the pictured figure in order to establish a perspective overlap of both.

Response times are usually longer the larger the rotational angle. Hence for mental rotations on the horizontal axis, responses take longer for head-down pictures than for head-up pictures. On the vertical axis, responses take longer for face-to-face pictures than for back-view pictures (that are already aligned with the own perspective).

This version of the task, as developed by Dahm et al. (2022), presents 64 gender neutral avatar pictures of a human being including back and front view perspectives with either a raised foot or hand. The rotational angels include head-up pictures (-45, 0, 45) and head-down pictures (-135, 180, 135). To check participants’ understanding of the instruction, the main block is preceded by eight familiarization trials.

In the mental paper folding task participants are presented with two-dimensional grids representing the unfolded net of a cube, with specific edges highlighted. Their task is to mentally fold the grid into a three-dimensional cube and determine whether the highlighted edges would overlap in the folded structure (Shepard & Feng, 1972).

The mental paper folding task, as utilized in the study by Dahm and Sachse (2024), is a cognitive assessment designed to evaluate individuals' visuospatial transformation and action imagery abilities. To perform this task, participants must engage in dynamic visualizations, mentally simulating each fold required to transform the flat grid into a cube. This process involves tracking the sequence of folds and spatial relationships between different parts of the grid. Response times and error rates increase with the number of folds and directional changes required, indicating higher cognitive load and complexity.

This version of the task, presents 24 grids including three, four and five folds. In half of the items the highlighted edges overlap. To check participants’ understanding of the instruction, the main block is preceded by four familiarization trials.