Copy of Cube Task

Version: v1 (current)

A visuospatial construction task assessing the ability to reproduce a three-dimensional cube drawing.

Overview

The Copy of Cube task asks participants to copy a drawing of a three-dimensional cube (Necker cube). This classic neuropsychological test assesses visuospatial perception, constructional ability, and spatial reasoning. Performance reflects the integration of visual perception, motor planning, and spatial representation.

The task is sensitive to right parietal lobe dysfunction, dementia, and visuospatial deficits. It's commonly included in cognitive screening batteries (e.g., MoCA, MMSE variants) and neuropsychological assessments.

Scientific Background

Classic Findings:

• Developmental Trajectory: Children acquire 3D drawing ability around ages 7-9
• Aging Sensitivity: Older adults may show reduced accuracy, especially with Alzheimer's disease
• Neuroanatomical Correlates: Right parietal lobe lesions impair performance
• Scoring Criteria: Parallel lines, correct angles, 3D perspective

Why Researchers Use This Task

1. Dementia Screening: Sensitive to visuospatial decline in Alzheimer's disease
2. Neuropsychological Assessment: Evaluate constructional apraxia and spatial deficits
3. Developmental Studies: Track visuospatial development in children
4. Parietal Function: Assess integrity of parietal spatial processing

Where to Configure

Study Form → Tasks → Copy of Cube → Configure.

Configuration Parameters

Parameter	Type	Default	Description
Main Instructions	rich text	(empty)	Instructions shown to the participant
Hint Instructions	rich text	(empty)	Optional hint text
Trials Instructions	rich text	(empty)	Instructions shown above the drawing canvas

Unlike other tasks, where trials instructions appear on a pre-trial page, the Trials Instructions here are rendered as a persistent caption above the drawing canvas during the drawing period.

The reference cube image (a Necker cube) is built in and always displayed; it is not configurable. There is no time limit, canvas-size, or show/hide-reference setting.

Participant Flow

1. The participant sees a fixed reference cube image displayed above a blank drawing canvas.
2. The participant draws their copy of the cube using mouse, touchscreen, or stylus (pointer) input.
3. The participant can press Clear to erase the canvas and start over (each non-blank clear is captured as a snapshot).
4. The participant clicks the Next button to submit their drawing and advance.

Data Output

Markers and Responses

The task records the following markers:

Marker	Data	Description
stimulus_shown	trial_index	Reference cube shown / task started
stroke_start	stroke_index	Pointer pressed down (stroke begins)
stroke_end	stroke_index	Pointer released (stroke ends)
canvas_cleared	clear_index	Clear button pressed

No response_recorded marker is emitted for this task.

Response Data

A terminal response row is always written on submit, and an additional row is written for each non-blank Clear:

{
  "clear_index": null,
  "is_final": true,
  "responded": true,
  "artifact_filename": "copy_of_cube_0.png",
  "type": "image/png",
  "size": 45231
}

Per-Clear snapshot rows carry is_final: false, the 1-based clear_index, and (when captured) artifact_filename, type, and size.

Drawing Artifact

The participant's final cube drawing is saved as a PNG image (copy_of_cube_<taskIndex>.png). Each non-blank Clear additionally saves a snapshot PNG (copy_of_cube_<taskIndex>_<clearIndex>.png). These images can be scored manually using established rubrics (e.g., MoCA cube scoring criteria).

Scoring Criteria

Traditional scoring assesses:

1. Parallelism: Opposite sides parallel
2. 3D Perspective: Front face and back face correctly positioned
3. Line Quality: Straight lines, clean connections
4. Overall Accuracy: Resemblance to target cube

Design Recommendations

• Reference: The reference cube stays visible throughout the drawing, allowing continuous comparison.
• Scoring: Use established scoring rubrics (e.g., MoCA cube scoring criteria) for consistent evaluation.
• Instructions: Tell participants to copy the cube as accurately as possible; emphasize that it should be three-dimensional.
• Input Devices: Stylus or touchscreen input is preferred for more natural drawing. Mouse drawing may reduce drawing quality.

Common Issues and Solutions

Issue	Solution
Participants draw a 2D square instead of a 3D cube	Ensure instructions emphasize copying the 3D cube exactly as shown
Drawing quality is poor with mouse input	Consider using stylus or touchscreen; adjust scoring expectations for mouse input
Participant erased the drawing by accident	Each non-blank Clear is captured as a snapshot artifact, so earlier attempts are not lost

References

• Nasreddine, Z. S., et al. (2005). The Montreal Cognitive Assessment, MoCA: A brief screening tool for mild cognitive impairment. Journal of the American Geriatrics Society, 53(4), 695-699.
• Trojano, L., & Gainotti, G. (2016). Drawing disorders in Alzheimer's disease and other forms of dementia. Journal of Alzheimer's Disease, 53(1), 31-52.

See Also

• Drawing Task - General drawing capability
• WCST - Executive function assessment