Technical and methodological report

Pintagrow
Guided observation of early childhood graphomotor development

An EdTech system that integrates pedagogical design, structured observation, computer vision and Artificial Intelligence to transform mark-related metrics into understandable information about each child's development over time. It does not diagnose. It supports.

1 to 5 yearsAge range
No screen for the childPrinted activity sheets
Montessori + WaldorfPedagogical framework
InternationalReach

The mark as a window, not as an outcome

Pintagrow is a guidance-oriented system for observing early childhood development. Its purpose is to provide families and professionals with an accessible tool for supporting the child's graphic process by observing signals that may be associated, in a guidance-oriented and non-diagnostic way, with developing abilities such as sustained attention, persistence with a task, initiation, gesture control, spatial planning and graphic intentionality.

Pintagrow combines personalized digital books, pedagogically designed printed activity sheets, image capture by an adult, computer-vision analysis of the child's marks, Artificial Intelligence processing and a longitudinal guidance report that always compares the child with their own previous experience.

However, technology is not the starting point of the system.

Pintagrow begins with the pedagogical design of each book.

Each book is an organized, progressive and auditable pedagogical structure

Each Pintagrow book is designed as its own sequence of graphic experiences. It is not a collection of independent activity sheets or a set of drawings to which Artificial Intelligence is later applied.

Each activity sheet occupies a specific position within its book, fulfills a particular technical and pedagogical function and contributes concrete information to the observation process.

Progression does not simply mean making drawings increasingly difficult. Throughout a book, different demands involving attention, spatial exploration, gesture control, coordination, repetition, following references and graphic intentionality may be maintained, introduced or combined.

This means that two activity sheets that look visually similar may serve different purposes within the system.

It also means that two Pintagrow books may share the same four universal observation dimensions—sustained attention, motor skills and gesture control, mark pressure and graphic intentionality—while having different objectives, sequences, relevant metrics and levels of demand.

This is why each book is described as auditable: Pintagrow can identify why an activity sheet belongs to a particular sequence, what it is intended to observe, which technical information it uses and which criterion supports a subsequent decision.

The MPG Contract: translating each book's methodology into observable rules

Each book has its own MPG Contract.

The MPG Contract is the technical and pedagogical specification that translates the methodological intention of a book into concrete criteria that the system can observe and process.

In simple terms, it answers questions such as:

What is this activity sheet intended to observe?
Defines the primary observational purpose of the activity.
What is its function within the book?
Establishes its primary function and the secondary functions it may contribute within the sequence.
Which visual elements are relevant?
Defines anchors, target areas and elements that structure the graphic experience.
Which metrics may the system use?
Determines which technical observables are relevant to that specific activity.
What evidence is required?
Establishes the minimum conditions that allow the experience to be interpreted within the defined limits.
Which decisions may follow?
Defines possible pedagogical alternatives such as advancing, repeating, maintaining or reviewing.

In this way, Artificial Intelligence does not simply receive a photograph and freely decide what it means.

First, there is a defined pedagogical intention. Then there is an MPG Contract that establishes which aspects are observable and within which limits. The computer-vision engine then obtains metrics from the image. Finally, that information is interpreted together with the objective of the activity sheet and the child's own history.

In simple terms Methodology defines what to observe; the MPG Contract establishes how to observe it; technology measures what is observable; and Artificial Intelligence helps transform that information into an understandable explanation.

Advancement and repetition rules: how the child progresses within each book

Each book also has its own advancement and repetition rules.

These rules define how the child progresses through the sequence and prevent activity sheets from being used as isolated activities with no relationship to one another.

Instead of simply thinking in terms of “turning pages,” Pintagrow observes whether there is sufficient information to continue toward the next objective.

Depending on the design of each book and the information obtained, the appropriate action may be:

Advance
Continue to a new activity sheet when sufficient information is available to introduce the next objective.
Repeat
Carry out the experience again when it is methodologically useful to obtain a new comparable observation.
Return
Go back to a previous activity when it is appropriate to review or reinforce an earlier experience.
Maintain
Keep a particular level of demand without increasing complexity yet.
Continue observing
Gather additional information before introducing a new objective or modifying the sequence.

Repeating an activity sheet does not mean that the child has failed.

Within Pintagrow, repetition may be methodologically useful because it provides a familiar experience and a new opportunity for observation. This is particularly important during the early years, when small differences from one session to another may reveal changes in persistence, return to references, movement organization or intentionality.

For this reason, the system does not measure progress according to the number of pages completed.

Progress is interpreted by observing how the same child changes within comparable experiences.

Baseline and longitudinal comparison

Each book begins by establishing an individual reference point for the child.

This initial information means that later observations do not depend exclusively on general age expectations or comparisons with other children.

As new activities are completed, Pintagrow builds a longitudinal history.

The central question therefore changes from:

“How did the child perform compared with other children?”

to:

“What changed compared with the child's own previous experiences?”

This makes it possible to observe small but relevant processes: longer persistence, less fragmentation, more frequent return to a visual reference, greater continuity of gesture, changes in mark intensity or a clearer relationship between movement and the objective of the activity sheet.

The mark as an observable trace of the process

In early childhood, drawing and scribbling are accessible activities that simultaneously involve movement, visual perception, spatial exploration and attentional participation.

When a child works on an activity sheet, they are not simply “coloring.”

During that experience, the child may look, initiate movement, stop, begin again, change direction, explore different areas, return to a visual reference, repeat a gesture or briefly maintain an intention.

The mark leaves a visible trace of part of that process.

This is why Pintagrow's central conceptual shift is to stop viewing the drawing as a final product and begin observing it as a window into how the child participated in the experience.

Pintagrow does not seek to determine whether a drawing looks attractive, correct or similar to a model.

Nor does it interpret drawings as psychological symbols.

It observes previously defined graphic and contextual characteristics that can be followed over time.

Innovation begins before the image

A fundamental difference in Pintagrow is that analysis does not begin when the photograph is taken.

It begins much earlier:

Pedagogical book design → MPG Contract → advancement and repetition rules → child's experience → activity-sheet capture → observable metrics → technical analysis → longitudinal comparison → pedagogical decision → understandable report.

Computer vision and Artificial Intelligence are important components, but they operate on top of a previously designed pedagogical architecture.

For this reason, Pintagrow's value does not lie only in its books, only in its activity sheets or only in Artificial Intelligence.

It lies in the integration of pedagogical design, observable rules, technology, longitudinal monitoring and adult support.

⚠ Methodological warning Pintagrow does not replace clinical assessments and does not issue formal medical, psychological, speech-language, therapeutic or educational diagnoses. It observes graphic and contextual signals for guidance purposes and primarily compares each child with their own history. Any professional use must operate under informed consent from the responsible adult.

What Pintagrow is and what it is not are not minor distinctions: they are operational boundaries maintained consistently throughout the product, reports, communication with families and professional use.

✓ Pintagrow is ✗ Pintagrow is not
A guidance-oriented system for observing childhood development through structured graphic experiences A clinical test, diagnostic assessment or neurological screening tool
A set of books with their own pedagogical architecture, MPG Contract and advancement and repetition rules A collection of independent or printable activity sheets without methodological structure
A pedagogical and interdisciplinary support tool for the child's graphic process A platform whose primary value is selling printable activity sheets
A mark-analysis engine with an auditable technical basis that extracts observable metrics A system that allows AI to freely interpret any drawing
A longitudinal system that compares the child with themselves within comparable objectives and experiences A system that compares the child with other children or uses a single session to define development
A platform useful to families, educators and authorized child-development professionals A platform that permits professional access without the guardian's explicit and revocable authorization
A system that translates mark-related metrics and signals into understandable guidance for the caregiver A substitute for consultation with a speech-language pathologist, occupational therapist, psychologist or other professional
A feedback tool: what was observed, how it evolved and what to do next A system for emotional analysis, mood reading or symbolic interpretation of drawings

Attention is sustained, concentration emerges, and the mark allows the process to be observed

During the first years of life, the ability to concentrate for prolonged periods is still developing. A young child does not need to remain engaged in an activity for many minutes in order to be developing attention. At first, this process may appear in very brief periods: approaching a task, exploring it, maintaining interest for a few moments, becoming interrupted and later returning to it.

From a developmental perspective, sustained attention refers to the ability to maintain focus on an activity or stimulus for a period of time. Together with other processes—such as attentional control, inhibition, self-regulation and the ability to redirect focus—it progressively contributes to what we commonly call concentration.

These abilities begin to organize during the earliest years and gradually evolve together with the development of executive functions. For this reason, Pintagrow does not understand concentration as a skill that should be demanded from the child or as a behavior that appears suddenly. It is understood as a developing process that requires appropriate opportunities to grow.

Repetition as a learning experience

Especially between 1 and 3 years of age, repetition plays an important role within Pintagrow's methodological approach.

Repetition does not mean requiring the child to perform an activity until a correct result is achieved. It means offering simple, recognizable and low-demand experiences that the child can encounter again at different moments.

When an activity is familiar, the child needs to devote fewer resources to understanding what is happening and has another opportunity to explore movement, return to a reference, repeat a gesture or remain engaged with the experience for a little longer.

The same activity may produce very different responses from one session to another. During the first experience, the child may make only a few marks and quickly move away. Later, the child may return to the sheet several times, repeat a movement, explore an area for longer or resume the activity after an interruption.

For Pintagrow, these small changes are relevant because they allow us to observe how the child's participation progressively becomes organized, without requiring a particular graphic result.

Repetition therefore does not seek to mechanize a response. Its purpose is to provide a sufficiently familiar and secure context in which the child has new opportunities to exercise attention, movement, exploration and self-regulation.

Pintagrow uses repetition as a pedagogical condition for support and observation, not as a treatment or clinical attention-training method.

Brief activities rather than prolonged demands

In early childhood, more time does not necessarily mean a better experience.

Pintagrow prioritizes brief activities, simple objectives, organized materials, low visual and cognitive load and a calm adult presence. The intention is to reduce unnecessary demands so that the child can devote their resources to exploring the activity.

For this reason, a session lasting only a few minutes can still be methodologically valuable.

What matters is not how long the child remains engaged according to an adult expectation, but whether, across repeated experiences, the child:

Begins more easily
Approaches the activity with less preparation or assistance from the adult.
Remains engaged
Maintains interest for periods that are meaningful relative to their own previous experience, even when those periods are brief.
Returns after an interruption
May become distracted or stop and then spontaneously return to the activity.
Returns to visual references
Returns to figures, target areas or elements that structure the activity sheet.
Repeats movements
Some gestures that initially appear only once begin to occur repeatedly with greater organization.
Needs less support
The experience begins to become more organized and autonomous compared with previous sessions.

Pintagrow records these signals longitudinally. The reference point is not another child of the same age; it is the same child in previous experiences.

The mark as a window for observation

Pintagrow chose graphic mark-making because, during the early years, drawing, scribbling and graphic exploration are accessible activities that simultaneously involve movement, visual perception, use of space and attentional participation.

When a child works on an activity sheet, they are not simply “coloring.” To carry out the activity, the child must organize, to varying degrees, a series of processes: looking, initiating movement, sustaining it, stopping it, changing direction, returning to a reference, exploring space and deciding—even at a very early level—where to continue.

The mark leaves an observable trace of part of that process.

This is why Pintagrow's central conceptual shift is to stop viewing the drawing as a product that must look correct and begin observing it as a window into how the child participated in the experience.

Pintagrow does not interpret the emotional or symbolic content of a drawing. It observes graphic and contextual characteristics that can be followed over time.

Three foundations that converge

Montessori
Repetition, autonomy and the prepared environment.

Pintagrow incorporates the importance of an organized environment, understandable objectives, simple materials, gradual progression and the opportunity for repetition. The adult prepares the conditions and allows the child to explore without constantly correcting the result. A familiar experience gives the child an opportunity to return to an action and progressively organize it.
Waldorf
Rhythm, experience and low demand.

Pintagrow incorporates the importance of rhythm, bodily and sensory experience and valuing the process over the final product. This is reflected in brief, fluid activities that respect the child's individual rhythm and avoid turning mark-making into a performance demand.
Kellogg + Lowenfeld
Scribbling as a stage of graphic development.

Scribbling is not a “poorly made drawing” or a phase that should be rushed. It is a legitimate stage of graphic development in which changes in movement, spatial organization, progressive gesture control and intentionality can be observed.

An activity sheet is more than an image to color

Pintagrow activity sheets are units of experience and observation designed according to technical and pedagogical criteria.

Each one has an objective, a function within the sequence of the book, specific visual anchors, an expected cognitive load and a motor demand consistent with what is intended to be observed.

Some experiences are designed to be repeated. Others allow progression once the system has sufficient information. The goal is never to obtain a “correct” activity sheet, but to create comparable experiences that make it possible to observe change over time.

A book by itself can provide graphic activities.

Pintagrow adds sequence, recording, analysis and longitudinal observation, transforming those activities into useful information for supporting the child's process.

Complete pipeline: from the mark to the report

Pintagrow’s workflow takes place in six steps, from the child’s physical activity to the narrative report received by the family. The child never needs to use a screen.

1
The child works on the printed activity sheet
A physical sheet designed with visual anchors, low cognitive load and a defined pedagogical objective. The adult accompanies without directing or correcting.
2
The adult photographs the activity sheet
Using a smartphone, without special equipment. The photograph must meet minimum lighting and framing conditions, automatically validated by the system before processing.
3
The system validates the individual PG-Code
Each book has a personal, non-transferable code. The system verifies identity, book ownership and the correct position in the pedagogical sequence before analysis begins.
4
Computer-vision engine (OpenCV)
Analyzes the photograph and extracts observable metrics: spatial coverage, mark density, stroke fragmentation, relative pressure, quadrant organization, return to visual anchors, graphic continuity and intentionality.
5
Generative AI engine
Translates the metrics, the child’s history and the activity sheet objective into an understandable narrative report. It always compares the child with themselves. The Pintagrow platform supports six operational languages; this explanatory page is available in Spanish and English.
6
Guidance report and pedagogical decision
The family receives a PDF report covering four dimensions, evolution relative to previous sessions, and a concrete recommendation: advance, repeat, simplify or continue observation.

The sequence of activity sheets is strictly controlled: the child cannot skip forward, but can repeat or go back. The first activity sheet in every book is always the free page—the child’s individual baseline—without which the system operates in a limited mode.

Four dimensions. One child compared with themselves.

Pintagrow maintains four universal, guidance-oriented dimensions. They are the simplest way to show families and professionals which aspects of the child's graphic process were observed during an activity.

These dimensions are not intended to determine whether a child “did well or badly,” nor to compare their performance with that of other children. Their purpose is to help explain how the child carried out the activity, what characteristics appeared in their marks, and how those characteristics may change as activities are repeated or the child progresses through a book.

Each dimension is built from several technical metrics obtained from the image of the activity sheet and, when appropriate, from the child's own previous history. Pintagrow translates those metrics into understandable language while avoiding diagnostic or clinical conclusions.

👁
Sustained attention

This dimension observes, for guidance purposes, how the child remains engaged with the activity during the time it lasts.

For young children, sustaining attention does not mean working continuously for long periods. Attention may appear in short periods: beginning an activity, making a few marks, stopping, looking at the sheet again and returning to the task.

Pintagrow observes graphic and contextual signals such as brief persistence with the activity, returning to areas of interest on the sheet, continuity of participation and the overall duration of the session.

For example, a child may initially make marks in many different parts of the page and gradually begin returning more often to a particular figure or area. This may indicate an increasing ability to maintain a visual reference during the activity.

A child may also make only a few marks and quickly leave the task. One isolated situation does not allow conclusions to be drawn. For this reason, Pintagrow primarily observes how the same child evolves over time.

This dimension helps consider questions such as: did the child remain briefly engaged with the activity?, did they return after an interruption?, did they return to particular areas or targets on the sheet?, has their persistence in similar activities changed over time?

Pintagrow does not diagnose attention disorders. The information is guidance-oriented only.
Motor skills and gesture control

This dimension observes how the child uses their hand and organizes movement to produce marks on paper.

During the first years of life, control of a pencil, crayon or other graphic material changes progressively. At first, movements may be broad, fast or poorly controlled. With experience, marks may begin to show greater continuity, more intentional changes in direction, curves, pauses, restarts or more organized paths.

Pintagrow analyzes characteristics such as stroke direction, continuity, where the stroke begins and ends, fragmentation, curvature and the relationship between hand movement and the available space on the page.

For example, in an activity that invites circular movements, a child may initially produce broad or fragmented lines. In later sessions, more curved movements, more continuous paths or attempts to repeat a particular trajectory may begin to appear.

The objective is not to produce a “perfect” stroke. What matters is observing how the child's graphic movement becomes progressively organized.

This dimension helps observe whether movements are broad or more contained, whether the stroke is continuous or divided into several segments, whether the child changes direction, begins repeating certain movements, and whether there is evolution compared with their own previous productions.

It does not replace psychomotor, neurological or occupational therapy assessment.
Mark pressure

This dimension observes the intensity with which the child leaves a mark on the paper and how that intensity behaves throughout the activity.

When a child uses a pencil, crayon or other graphic material, some marks may appear stronger and others lighter. Pressure may also remain relatively stable or vary considerably within the same activity sheet.

Pintagrow uses visual information from the image to analyze the relative density and intensity of the marks. This makes it possible to observe whether the stroke appears relatively uniform, whether some areas are considerably more marked, or whether intensity changes during the activity.

For example, a child may initially produce very light marks that are barely visible on the paper. In later activities, the marks may become more visible or their intensity may remain more consistent.

The opposite may also occur: very strong marks may alternate with lighter ones. These differences form part of the longitudinal information recorded by Pintagrow.

This dimension helps observe whether marks are generally light, medium or strong, whether intensity remains relatively stable, whether important differences exist between different areas of the sheet, and whether the child's way of marking the paper has changed compared with previous activities.

Mark pressure cannot determine emotions, personality or psychological states.
Graphic intentionality

This dimension observes whether the child's marks begin to show an increasingly clear relationship with what they are trying to do within the activity.

In the earliest stages, a child may freely explore the paper without attempting to create a particular shape. This exploration is completely valid and is a natural part of graphic development.

Over time, signs of intention may begin to appear: repeatedly returning to a figure, trying to follow a direction, repeating a movement, surrounding an element, closing a shape or using a specific area of the page.

Pintagrow observes signals such as stroke direction, meaningful repetition, return to visual anchors, attempts at closure and the relationship between the movements made and the objective of the activity sheet.

For example, if an activity contains a circle as a visual reference, a young child may initially make marks throughout the page. Later, they may begin repeatedly approaching the circle, following part of its outline or producing circular movements near it.

Pintagrow does not expect the child to reproduce a figure exactly. It observes whether greater organization or purpose begins to appear within the child's graphic activity.

This dimension helps observe whether the child returns to particular elements on the sheet, repeats some movements in an apparently intentional way, attempts to follow a direction or path, begins making attempts to close shapes, and shows a clearer relationship between their marks and the objective of the activity.

Pintagrow does not symbolically interpret drawings or attribute psychological meanings to the figures produced.

The four dimensions are interpreted together. None of them should be analyzed in isolation.

A child may show changes in their ability to remain with a task without yet showing a major change in gesture control. Another child may develop more organized graphic movements while continuing to freely explore the space on the page.

For this reason, Pintagrow analyzes the four dimensions as complementary information and, above all, observes the longitudinal evolution of the same child.

The objective is not to determine whether the child is “ahead” or “behind,” but to provide the family with a simple understanding of the process: what was observed, what has changed compared with previous activities, and how to support the next graphic experience.

Internally, the system organizes six levels of analysis, ranging from observable metrics—such as coverage, fragmentation and density—to governance of use—consent, authorization and audit. The four dimensions are the visible layer; the six levels are the technical architecture that supports them.

N1
Observable metric
Coverage, density, relative pressure, fragmentation, center of mass, return to anchors, duration and interruptions. Auditable base derived from image, session or history.
N2
Pintagrow dimension
The four visible dimensions: attention, motor skills, pressure and intentionality. Translates metrics into language understandable to families and teams.
N3
Associated functional signal
Persistence, inhibitory control, spatial planning, initiation, monitoring and flexibility. Internal technical reading without turning it into a diagnosis.
N4
Guidance-oriented interpretation
Reading contextualized by child, book, activity sheet, objective and history. Avoids categorical conclusions and compares the child with themselves.
N5
Pedagogical action
Advance, repeat, simplify, maintain or review. Brief, concrete recommendations for the caregiver and/or authorized professional.
N6
Use governance
Consent, guardian authorization, revocation, audit and non-diagnostic limits. Enables professional participation without losing control over children's data.

So the adult observes better, not evaluates more

The Grow Method is adapted in Pintagrow as a support logic for the adult caregiver. It is not intended to make the adult perform a clinical assessment, but to help them observe more accurately, record calmly and make simple, concrete decisions based on the report. The report guides the caregiver through four movements:

G
Goal · Objective
What was this activity sheet intended to activate?
The report explains the pedagogical intent of the sheet: its observational function, the visual anchors that define it and the interaction expected from the child.
R
Reality
What actually happened?
The system describes what occurred: duration, interruptions, initial help required, return to anchors and attitude toward the task—in language understandable to the adult.
O
Options
How can the adult support without over-intervening?
The report suggests simple ways to create better conditions for the next session: environment, materials and adult attitude, without forcing or directing the child’s marks.
W
Will · Next step
What should be done before the next session?
A brief, realistic recommendation: move to the next activity sheet, repeat the same one, simplify the instruction or continue observing for one more session.

For all children ages 1 to 5, with or without a diagnosis

Pintagrow can operate in two different scenarios. The difference is not that the system changes its nature, but the role it plays within the support process for each child.

Without diagnosis
Preventive family stimulation
An observation and support tool for the graphic process of any child ages 1 to 5. It offers brief, low-pressure experiences that help observe persistence, exploration, task initiation and evolution of gesture.
With diagnosis
Complementary support for the professional
For children with a diagnosis, developmental lag, suspected difficulty or support needs, Pintagrow can serve as a complementary record of evolution between professional sessions. The treating professional defines the intervention plan; Pintagrow contributes an orderly, guidance-oriented record.

For one-year-old children, the focus is on exploring materials, contact with crayons/pencils/paper, very brief persistence and broad gestures. For children ages 3 to 5, the system can observe trajectory following, selection among anchors, closure attempts and more structured signals of spatial planning.

📌 Important notePintagrow does not compete with stimulation centers or special language schools. Those systems intervene when a diagnosis has already been identified. Pintagrow acts before that point, with all children, from home, without prior referral or diagnosis.

Interdisciplinary collaboration under guardian authorization

Pintagrow can support professional accompaniment or intervention plans, but it does not clinically design them and does not replace the treating professional’s assessment. Sustained attention, fine motor skills, gesture control, persistence, following instructions and the relationship with the adult are dimensions that can inform speech-language pathology, occupational therapy, child psychology, psychotherapy, educational psychology and education.

Professional
Possible contribution
Limit within Pintagrow
Occupational therapist
Reading of fine motor skills, grasp, gesture regulation, participation in activity, tolerance and play as a childhood occupation.
Does not replace formal occupational assessment or define a therapeutic plan.
Speech-language pathologist
Complementary observation of understanding simple instructions, adult-child interaction, communicative intent and representational use of drawing.
Does not assess standardized language or diagnose communication disorders.
Child psychologist
Understanding play as a means of relationship, expression and process observation, without automatic symbolic interpretation of the drawing.
Does not interpret emotions or clinical traits from an isolated activity sheet.
Educator / Educational psychologist
Support for sequences, progression, prepared environment, low cognitive load and caregiver guidance.
Does not use Pintagrow as a grade, score or comparison between children.

Referral Module — Guardian authorization

The main rule is that the professional cannot activate the relationship with a child on their own. They can only create a request. The link becomes active only when the guardian validates their identity and expressly accepts the rules of use. Authorization is traceable, revocable, limited and non-diagnostic.

1
The professional creates the request
Enters basic child and guardian data, a clear reason and the requested permissions.
2
Pintagrow generates a secure token
Associated with the request, professional, guardian email, identity document and date of birth. Valid for 24 hours.
3
The guardian receives an email and validates identity
They must enter identity-document information and date of birth. If the data do not match, the system blocks acceptance.
4
The guardian reviews permissions and accepts or rejects
They see who is requesting access, why, which permissions are included and how to revoke them. They accept or reject the complete relationship.
5
Conditional access and continuous audit
The professional can operate only while the relationship is accepted, active and not revoked. Every action is recorded in the audit trail.
Pintagrow does not sell activity sheets as an end in themselves. It uses them as an observation instrument to turn a brief graphic experience into pedagogically, familially and professionally useful information that is longitudinal, understandable and auditable.

Scientific and methodological basis

Pintagrow’s methodological framework draws on research in children’s graphic development, developmental neuroscience, speech-language pathology, occupational therapy, Montessori and Waldorf pedagogy, and Chilean and international legislation on the protection of children’s data. The complete technical document with extended bibliography is available at:

Kellogg — Scribbling as a universal language

Rhoda Kellogg (1898–1987) analyzed more than one million drawings made by children around the world, half of them by children under age 6, identifying 20 basic marks—vertical lines, zigzags, spirals and arcs—that she described as patterned manifestations of developing graphic behavior rather than merely random products. For Pintagrow, her work supports the idea of treating free mark-making as observable developmental evidence rather than judging the artistic resemblance of the final drawing.

Kellogg describes graphic development as a progression of basic forms that emerge during childhood: from placement patterns and emergent forms to diagrams, combinations and aggregates before more recognizable human representations appear. Her cross-cultural observations are relevant to Pintagrow because they emphasize recurring graphic sequences while still allowing individual developmental variation.

Kellogg stageApprox. ageSignal observable in Pintagrow
Basic scribbles (20 types)1–2 yearsSpatial coverage, mark density, stroke direction
Placement patterns2–3 yearsSpatial organization, return to areas of interest
Emergent forms and diagrams3 yearsFragmentation, intentionality, gesture continuity
Combinations and aggregates3–4 yearsSpatial planning, use of space, gesture control
Early representations4–5 yearsGraphic intentionality, shape closure, persistence with the task

Lowenfeld — Stages of scribbling and integral development

Viktor Lowenfeld (1903–1960), in Creative and Mental Growth (1947; later editions), articulated a systematic theory of children’s graphic development in relation to cognitive, affective and psychomotor development. A central idea is that drawing is not isolated from development—it can provide a visible record of aspects of that process.

Lowenfeld subdivides scribbling into progressive phases: disordered scribbling, controlled scribbling and named scribbling, followed later by the pre-schematic stage. These distinctions are relevant to Pintagrow because they help frame changes in motor control, intentionality and graphic organization without converting a single drawing into a diagnosis.

A recent empirical study (Gil-Ruiz et al., 2025, Education Sciences) examined children’s drawings in relation to Lowenfeld’s developmental stages and reported statistically significant associations while also documenting individual variation. That variability supports Pintagrow’s decision to compare each child primarily with their own longitudinal history rather than treating age bands as diagnostic cutoffs.

Developmental neuroscience — relevant empirical evidence

Research in developmental neuroscience and motor development provides empirical context for Pintagrow’s decision to observe motor behavior, attention and executive-function-related signals within children’s graphic activity.

Motor abilities and executive function develop in interaction
Developmental research supports meaningful relationships between motor performance and executive functions in preschool-aged children. Pintagrow treats these as associated domains rather than as a basis for diagnosis from graphic output alone.
Executive functions begin developing very early
Research on the first years of life documents early emergence of inhibitory control, working memory and related executive processes. Pintagrow therefore treats early behavior as developmental and longitudinal, not as a fixed trait.
Fine motor skills are associated with later school readiness
Studies such as Grissmer et al. (2010) report that fine motor measures are meaningful predictors of later academic outcomes, reinforcing the value of observing motor development as one component of a broader developmental picture.
Motor development, executive functions and psychosocial outcomes can be related
Recent preschool research has examined executive functions as a mediator between motor skills and psychosocial health. Pintagrow uses this literature as contextual support, not as evidence that its own graphic metrics diagnose psychosocial status.
Graphomotor development is a recognized developmental observation domain
Monitoring graphomotor development during early childhood has long been used by developmental professionals to observe grasp, motor organization and the progression of graphic abilities. Pintagrow digitizes part of that observation while maintaining non-diagnostic limits.

Complete references

Kellogg, R. (1969). Analyzing Children's Art. National Press Books.
Lowenfeld, V. & Brittain, W.L. (1987). Creative and Mental Growth (8th ed.). Macmillan.
Gil-Ruiz, N. et al. (2025). Children's Drawing and Graphic Development: An Empirical Study of the Developmental Stages According to Lowenfeld. Education Sciences, 15(6), 681.
Wang, Z., Lu, Y. & Qin, G. (2026). Predictive associations between brain functional connectivity, motor abilities, and executive function development in early childhood. Journal of NeuroEngineering and Rehabilitation.
Morgan, B., Fiske, A. & Holmboe, K. (2024). Early executive function development: The first three years. Reference Module in Neuroscience and Biobehavioral Psychology. Elsevier.
Li, S. et al. (2025). Mediation of executive functions in the relationship between motor skills and psychosocial health in preschool children. Journal of Exercise Science & Fitness.
Grissmer, D. et al. (2010). Fine motor skills and early comprehension of the world. Developmental Psychology, 46(5), 1008–1017.
American Speech-Language-Hearing Association (ASHA). Scope of Practice in Speech-Language Pathology.
American Occupational Therapy Association (AOTA). Occupational Therapy Practice Framework (4th ed.).
Yogman, M. et al. (2018). The Power of Play. American Academy of Pediatrics.
WHO/UNICEF (2018). Nurturing Care for Early Childhood Development.
Law No. 19,628 (Chile). Protection of Private Life.
Law No. 21,719 (Chile). Protection and Processing of Personal Data.
INE. 2024 Census. National Statistics Institute of Chile.
Ministry of Social Development. CASEN Survey 2022.