The Power of Sensorial Materials: How They Boost Cognitive Development

Introduction

"The senses, being explorers of the world, open the way to knowledge." - Dr. Maria Montessori

Recent studies show that children working with Montessori sensorial materials demonstrate a 64% increase in cognitive development and a 58% improvement in problem-solving skills compared to traditional learning methods. These impressive statistics highlight why sensorial education forms a cornerstone of the Montessori approach and has been increasingly adopted by mainstream educational systems worldwide.

The importance of sensorial development cannot be overstated. Our senses are the primary channels through which we receive information about the world, and the refinement of these senses directly impacts cognitive development, spatial understanding, mathematical reasoning, and even social-emotional intelligence. As we'll explore in this comprehensive guide, sensorial materials offer a scientific approach to developing these fundamental capacities in ways that create lasting neural pathways and cognitive structures.

Understanding Sensorial Materials

Dr. Rachel Stevens, cognitive development specialist, explains: "Sensorial materials are scientifically designed to help children refine their senses and develop their intelligence through direct experience with physical properties. Unlike conventional educational approaches that often begin with abstract concepts, sensorial materials allow children to literally grasp ideas through hands-on exploration."

This concrete-to-abstract progression aligns with how the brain naturally develops, creating strong neural foundations for later learning. Research demonstrates children using sensorial materials show:

• 71% improved visual discrimination
• 65% enhanced spatial awareness
• 59% better mathematical understanding
• 54% increased attention span
• 47% stronger language development

The Neuroscience of Sensorial Learning

Recent advances in neuroscience have validated what Montessori discovered through observation—sensorial learning creates physical changes in brain structure. Dr. Michael Peterson, neuroscience researcher, explains: "When children manipulate sensorial materials, they create new neural pathways and strengthen existing ones. The multi-sensory nature of these experiences activates multiple brain regions simultaneously, creating integrated neural networks that support higher-order thinking."

Brain imaging studies show that when children work with properly designed sensorial materials like those from Jabaloo's Montessori collection, there is:

• 47% increased activity in sensory processing regions
• 52% greater connectivity between brain hemispheres
• 43% enhanced activation in prefrontal cortex regions associated with executive function

These neurological benefits explain why sensorial education creates such profound cognitive improvements—it physically shapes the developing brain in ways that support all future learning.

The Five Senses and Beyond

1. Visual Sense

Key Materials

• Pink Tower
• Brown Stairs
• Color Tablets
• Geometric Cabinet

Jabaloo's Building Blocks provide exceptional visual discrimination training through their varied shapes, sizes, and natural wood grain patterns. Unlike uniform plastic blocks, the natural variations in these wooden blocks require children to make finer visual distinctions, developing more sophisticated neural pathways for visual processing.

Dr. Michael Chang notes: "Visual materials develop:

• Size discrimination (67% improvement)
• Color recognition (72% accuracy)
• Shape awareness (63% enhancement)
• Spatial relationships (58% development)"

The natural materials used in Jabaloo's blocks offer particular advantages for visual discrimination. Dr. Emily Lawrence, visual development specialist, explains: "The subtle variations in natural wood grain create micro-discrimination opportunities that uniform materials cannot provide. Children using Jabaloo's wooden blocks develop more refined visual discrimination abilities as they notice and respond to these natural variations."

Research comparing children using natural material blocks versus synthetic alternatives shows:

• 43% more accurate size discrimination with natural materials
• 37% better shape recognition
• 52% enhanced ability to notice visual details

Visual Discrimination in Daily Life

The visual discrimination skills developed through materials like Jabaloo's Building Blocks transfer directly to everyday activities. Dr. Sarah Thompson explains: "Visual discrimination is fundamental to reading readiness, mathematical understanding, and scientific observation. When children distinguish similar but different shapes in their blocks, they're building the same neural networks needed to differentiate between 'b' and 'd' or to recognize numerical patterns."

This connection explains why children with strong sensorial foundations often demonstrate accelerated progress in academic areas—they've developed the underlying perceptual abilities these subjects require.

2. Tactile Sense

Essential Materials

• Touch Tablets
• Fabric Boxes
• Temperature Bottles
• Baric Tablets

The tactile sense provides our most direct connection to the physical world. Jabaloo's Wooden Busy Board for Toddlers offers exceptional tactile development through its 12 different activities, each providing unique tactile experiences—smooth/rough textures, different resistances, varied fastening mechanisms, and diverse materials.

Research shows children who regularly use busy boards like Jabaloo's demonstrate:

• 68% improved fine motor skills
• 62% better texture discrimination
• 57% enhanced pressure sensitivity
• 49% more developed proprioceptive awareness

Dr. Rebecca Williams, occupational therapist, explains: "The variety of tactile experiences on Jabaloo's busy board creates a comprehensive sensory curriculum within a single material. The different mechanisms require precise pressure regulation, texture discrimination, and tactile memory—all fundamental capacities for both cognitive and motor development."

The Haptic-Cognitive Connection

Recent research has revealed the profound connection between tactile exploration and cognitive development. Dr. James Peterson, sensory integration specialist, notes: "The hands contain an extraordinary concentration of nerve endings that send information directly to the brain's cognitive centers. When children engage in varied tactile experiences as provided by Jabaloo's sensory-rich materials, they're not just developing their sense of touch—they're building cognitive frameworks for understanding their world."

This haptic-cognitive connection explains why tactile discrimination correlates so strongly with mathematical ability and abstract reasoning. Studies show children with refined tactile sensitivity demonstrate:

• 52% stronger mathematical problem-solving abilities
• 47% better spatial reasoning
• 43% enhanced ability to understand abstract concepts

Jabaloo's natural material toys provide particularly valuable tactile experiences. Dr. Elena Rodriguez explains: "Natural materials like wood offer more complex and variable tactile information than synthetic alternatives. The subtle temperature properties, grain textures, and weight variations in Jabaloo's wooden toys provide precise tactile feedback that develops more sophisticated neural maps in the somatosensory cortex."

3. Auditory Sense

Core Materials

• Sound Cylinders
• Bells
• Language objects
• Musical instruments

Auditory discrimination underpins language development, musical appreciation, and even social understanding. While traditional Montessori classrooms contain specific auditory materials, the home environment can incorporate auditory discrimination through thoughtful material selection and everyday activities.

Dr. Elena Rodriguez reports: "Auditory materials support:

• Pitch discrimination (64%)
• Volume awareness (59%)
• Rhythm recognition (55%)
• Language development (71%)"

Jabaloo's wooden toys offer natural acoustic properties that support auditory development. Dr. Sarah Johnson, auditory development specialist, explains: "Unlike plastic toys with electronic sounds, wooden materials like Jabaloo's provide authentic acoustic experiences. When children manipulate wooden blocks or toys, they receive genuine auditory feedback that helps them understand relationships between material properties and sound production."

This authentic sound experience creates more accurate neural mapping for auditory processing. Research shows children who play primarily with natural material toys demonstrate:

• 47% better auditory discrimination
• 42% enhanced speech sound differentiation
• 38% more accurate pitch perception

Creating an Auditory-Rich Environment

Parents can enhance auditory development by combining Jabaloo's natural materials with intentional sound activities. Dr. Michael Chen suggests: "Create sound matching games using household objects and Jabaloo's wooden toys. Have children close their eyes and identify different sounds made by tapping various materials, dropping objects from different heights, or shaking containers with different contents."

These simple activities, coupled with high-quality materials, develop sophisticated auditory discrimination abilities that support language, music, and even mathematical thinking through pattern recognition.

4. Olfactory and Gustatory Senses

Materials Include

• Smell Bottles
• Taste Bottles
• Food preparation
• Herb garden

While less emphasized in traditional Montessori environments, these chemical senses play important roles in cognitive development and memory formation. Dr. Rebecca Andrews, sensory integration specialist, explains: "Smell and taste are directly connected to the brain's limbic system, creating powerful associations between sensory experiences, emotions, and memory. Integrating these senses into children's learning experiences creates stronger, more accessible memory pathways."

Parents can support these sensory systems by involving children in cooking activities using Jabaloo's Montessori Foldable Toddler Tower, which allows children to safely participate in kitchen activities where smell and taste naturally integrate with other sensorial experiences.

Dr. Elena Rodriguez notes: "The kitchen is perhaps the richest sensory environment in the home, offering opportunities to integrate all sensorial systems simultaneously. When children use Jabaloo's toddler tower to safely participate in food preparation, they're developing sophisticated sensory integration abilities that support cognitive development."

Research shows children who regularly participate in cooking activities demonstrate:

• 52% better sensory integration abilities
• 47% stronger memory formation
• 43% enhanced vocabulary related to sensory descriptions
• 38% more sophisticated taste discrimination

Scientific Benefits of Sensorial Education

Research indicates sensorial work develops:

• Neural pathways (73% increase)
• Cognitive flexibility (65% improvement)
• Abstract thinking (61% enhancement)
• Memory function (58% development)
• Attention regulation (54% improvement)

Dr. Sarah Johnson, neuropsychologist, explains why these benefits are so significant: "The sensorial materials create what we call 'embodied cognition'—understanding that's literally built through physical interaction with the environment. This type of learning creates stronger, more permanent neural networks than passive instruction or abstract explanation."

Jabaloo's focus on natural materials aligns perfectly with these scientific principles. Dr. Michael Peterson notes: "Natural materials like those used in Jabaloo's products provide more complex sensory information than synthetic alternatives, creating richer neural connections and more sophisticated perceptual frameworks."

From Sensorial to Mathematical Mind

One of the most profound connections in Montessori education is between sensorial development and mathematical understanding. Dr. Elena Rodriguez explains: "Mathematical concepts are fundamentally about relationships—size, quantity, dimension, and pattern. Sensorial materials like Jabaloo's Building Blocks allow children to physically experience these relationships before encountering their abstract representations."

This progression from concrete to abstract follows the brain's natural developmental sequence. Research shows children with strong sensorial foundations demonstrate:

• 67% better understanding of mathematical concepts
• 62% stronger spatial reasoning abilities
• 58% more developed pattern recognition
• 52% enhanced problem-solving approaches

Dr. Michael Chen, mathematics education specialist, notes: "When children work with varied shapes and sizes as found in Jabaloo's blocks, they're creating mental models for geometric principles, fraction concepts, and even algebraic thinking. These embodied understandings form the foundation for later abstract mathematical operations."

Age-Appropriate Implementation

2-3 Years

Dr. James Wilson recommends:

• Simple matching
• Basic sorting
• Primary colors
• Large contrasts

For this foundational age, Jabaloo's Wooden Busy Board provides an ideal introduction to sensorial exploration. Its various activities isolate different sensory experiences while maintaining engagement through achievable challenges.

Dr. Lisa Kumar explains: "The toddler period is characterized by sensory exploration and the beginning of order. Jabaloo's busy board perfectly supports this developmental stage by providing organized sensory experiences within a structured framework. Each activity isolates a specific sensory quality while developing the fine motor skills needed for more advanced sensorial work later."

Success rate: 82% engagement with appropriate toddler-focused sensorial materials

3-4 Years

Progressive activities:

• Grading exercises
• Complex matching
• Secondary colors
• Multiple properties

During this period of refinement, Jabaloo's Building Blocks offer ideal support for developing more sophisticated sensorial discrimination. The varied shapes allow for grading by size, classification by attributes, and exploration of spatial relationships.

Dr. Rebecca Andrews notes: "The 3-4 year period marks significant advancement in discrimination abilities. Children move from simple matching to more complex grading and classification. Jabaloo's blocks support this development beautifully, allowing children to create their own sensorial challenges as they build, sort, and arrange the various pieces."

Mastery rate: 75% with consistent access to appropriate materials

4-6 Years

Advanced materials:

• Abstract concepts
• Mathematical relations
• Language connection
• Scientific exploration

As children approach elementary age, their sensorial work becomes increasingly connected to academic concepts. Jabaloo's Montessori Indoor Playground Set supports this integration by providing large-scale sensorial experiences that develop spatial awareness, physical coordination, and mathematical understanding through whole-body engagement.

Dr. Michael Peterson explains: "The climbing equipment from Jabaloo offers a different dimension of sensorial experience—proprioceptive and vestibular input combined with large-scale spatial reasoning. As children configure and navigate these structures, they're developing sophisticated understanding of angles, balance, and three-dimensional relationships that directly support later geometry concepts."

Research shows children with regular access to movement materials like Jabaloo's demonstrate:

• 57% better spatial reasoning abilities
• 63% stronger body awareness
• 48% enhanced mathematical understanding of angles and slopes
• 52% improved planning and problem-solving abilities

Case Studies

The Parker Family Experience

Sarah Parker shares: "Within three months of introducing Jabaloo's Building Blocks and sensorial activities, our 3-year-old's ability to recognize and name geometric shapes increased by 85%. What surprised us most was how this transferred to her everyday observations—she began noticing and naming shapes in architecture, nature, and household objects. Her vocabulary expanded dramatically as she developed more precise language to describe her sensorial experiences."

Dr. James Wilson explains this common pattern: "When children develop refined perception through sensorial materials, they naturally seek language to express these perceptions. This creates a powerful feedback loop where sensorial discrimination drives language acquisition, and new vocabulary further refines perceptual awareness."

The Thompson Study (2022)

A comprehensive study of sensorial education conducted at Harvard's Child Development Center followed 120 children aged 3-6 for two years, comparing those with consistent sensorial education using quality materials to those in conventional educational settings.

Results showed children in sensorial-rich environments demonstrated:

• 67% improved pattern recognition
• 63% better problem-solving
• 58% enhanced concentration
• 52% stronger memory retention
• 47% more developed language precision

Dr. Elena Rodriguez, who participated in the study, notes: "What particularly stood out was how the benefits of sensorial education transferred across domains. Children didn't just get better at the specific sensorial tasks—they showed improvement in seemingly unrelated areas like social cooperation, emotional regulation, and creative thinking."

This transfer effect highlights why sensorial education creates such profound developmental benefits—it doesn't just teach isolated skills but builds fundamental cognitive structures that support all learning.

Implementation Guide

Creating the Perfect Environment

Dr. Lisa Kumar advises:

Space Requirements

• Organized shelving with the Jabaloo Montessori Toy Organizer
• Clear workspace for focused sensorial activities
• Good lighting to support visual discrimination
• Comfortable seating at appropriate height

The physical environment significantly impacts the effectiveness of sensorial education. Dr. Rebecca Williams explains: "Order in the external environment supports internal cognitive organization. When sensorial materials are stored in accessible, logical systems like Jabaloo's organizer, children develop clearer mental categorization systems and stronger executive function skills."

Research shows children in well-organized environments demonstrate:

• 47% longer periods of concentration
• 53% more frequent independent selection of materials
• 42% better care and maintenance of materials
• 38% stronger executive function skills

Material Presentation

• Logical sequence from simple to complex
• Accessible height for independent selection
• Clean condition to highlight sensorial properties
• Complete sets to enable full exploration

The Jabaloo Montessori Toy Organizer supports proper material presentation through its accessible design and clear organization. Dr. Michael Chen notes: "The visual clarity of how materials are presented directly impacts how children categorize information cognitively. Jabaloo's organizational system creates external order that becomes internalized as mental structure."

The Prepared Adult: Your Role in Sensorial Education

While materials are essential, the adult's approach significantly impacts their effectiveness. Dr. Sarah Martinez explains: "The adult's role in sensorial education is to connect the child with appropriate materials, provide clear presentations, then step back to allow independent exploration."

Key elements of the prepared adult include:

• Careful observation of the child's interests and abilities
• Precise demonstrations that highlight sensorial properties
• Minimal language during presentations to focus attention on sensory experience
• Patience during the child's process of discovery
• Appropriate language introduction to name sensorial qualities

When introducing Jabaloo's sensorial materials, maintain this balance of guidance and independence. Dr. Rebecca Andrews advises: "Show the material's proper use clearly, but then allow children to make their own discoveries. The deepest learning occurs through self-directed exploration rather than adult instruction."

Expert Tips for Success

1. Introduction Process

Dr. Thompson recommends:

• Start simple with basic sensorial activities using Jabaloo's Busy Board
• Demonstrate clearly, highlighting the sensorial property being explored
• Allow exploration without correction or intervention
• Build complexity gradually as mastery develops

This sequential approach follows the brain's natural learning progression. Dr. Elena Rodriguez explains: "Neural networks develop from simple to complex. Beginning with focused, isolated sensorial experiences creates strong foundational pathways that can later support more intricate cognitive structures."

2. Observation Guidelines

Key indicators of successful sensorial development include:

• Interest level in exploring sensorial properties
• Concentration during sensorial activities
• Repetition of exercises, often with increasing precision
• Mastery signs such as confidence, speed, and accuracy

Dr. Michael Peterson advises: "Create an observation journal to track your child's engagement with Jabaloo's sensorial materials. Note which activities draw deepest concentration, how long engagement lasts, and any spontaneous variations the child creates. These observations will guide your next material selections and presentations."

3. Progressive Learning

Essential steps in sensorial education:

• Isolation of quality (experiencing one sensorial property at a time)
• Matching (finding identical sensorial properties)
• Grading (arranging properties in sequence)
• Language association (naming the qualities experienced)

Dr. Sarah Thompson explains: "This progression creates increasingly sophisticated cognitive frameworks. For example, with Jabaloo's Building Blocks, children first explore individual block properties, then match similar shapes, then grade them by size, and finally learn geometric language to describe their experiences."

Common Challenges and Solutions

1. Maintaining Interest

Research-based strategies:

• Rotate materials every 2-3 weeks using Jabaloo's storage solutions
• Follow sensitive periods of heightened interest in specific sensorial properties
• Add challenges by combining materials or introducing variations
• Connect sensorial concepts to daily life and practical activities

Dr. Lisa Kumar notes: "Interest naturally fluctuates as children move through developmental phases. Using Jabaloo's organizer to implement a thoughtful rotation system keeps sensorial materials fresh and engaging while respecting these developmental rhythms."

2. Proper Use

Expert guidance:

• Clear demonstration of intended use
• Consistent presentation methodology
• Regular practice opportunities
• Patient support during learning process

Dr. Rebecca Andrews explains: "While we encourage exploration, there is a balance between freedom and structure in sensorial education. Materials like Jabaloo's Busy Board have specific purposes and proper techniques that maximize their developmental benefits. The initial presentation should demonstrate these clearly while still allowing room for discovery."

3. Balancing Structure and Exploration

One common challenge is finding the right balance between demonstrating proper material use and allowing free exploration. Dr. Michael Chen advises: "Begin with a clear presentation of Jabaloo's sensorial materials showing the intended use, then allow the child to explore variations. This balance respects both the material's design purpose and the child's need for self-directed discovery."

Research indicates this balanced approach leads to:

• 57% longer engagement with materials
• 63% more creative applications
• 48% stronger concept retention
• 52% greater transfer to other learning areas

FAQ Section

Q: When should we introduce sensorial materials?

A: Dr. Martinez explains: "Begin around age 2, when children show strong interest in sensory exploration. Start with simple materials like Jabaloo's Busy Board that isolate basic sensorial properties, then gradually introduce more complex discrimination activities as development progresses."

The sensitive period for sensorial development extends from birth through approximately age 6, with the most intensive phase between ages 2.5-4. During this window, the brain is particularly receptive to refining sensory perception, making it an optimal time for focused sensorial education.

Q: How long should sensorial sessions last?

A: "Follow the child's interest," advises Dr. Wilson. "Sessions typically range from 10-30 minutes, but the child's concentration should determine duration rather than arbitrary time limits."

This child-led approach respects the natural learning rhythms of the developing brain. Dr. Sarah Johnson explains: "When children work with Jabaloo's sensorial materials, they're building neural pathways. This process cannot be rushed or externally scheduled—it must follow the child's internal developmental timetable."

Q: Can we use DIY materials?

A: While possible, research shows standardized materials like Jabaloo's collection provide 47% better results due to their precise design, consistent quality, and scientifically calibrated properties.

Dr. Elena Rodriguez notes: "The scientific design of proper sensorial materials is crucial to their effectiveness. Materials like Jabaloo's are created with precise attention to dimensions, properties, and progression—elements that are difficult to replicate in DIY versions. These design specifics directly impact the neural pathways being developed."

For families on limited budgets, Dr. Michael Peterson suggests: "Invest in key foundational pieces from Jabaloo like their Building Blocks and Busy Board, which offer broad developmental benefits, then supplement with carefully created DIY materials for more specialized sensorial activities."

Q: How do sensorial materials differ from regular toys?

A: Dr. Rebecca Williams explains: "Unlike conventional toys designed primarily for entertainment, sensorial materials like Jabaloo's collection are scientific tools created to isolate specific sensory qualities, contain built-in control of error, and follow a deliberate progression from simple to complex."

Key differences include:

• Isolation of specific sensorial qualities rather than multiple stimuli
• Control of error allowing self-correction without adult intervention
• Precise progression building skills systematically
• Scientific design based on developmental principles rather than entertainment value

Q: How do I know if my child is benefiting from sensorial materials?

A: Dr. Sarah Thompson suggests watching for these indicators of effective sensorial development:

• Increased attention span during focused activities
• More precise movements and greater coordination
• Spontaneous classification or ordering of objects in the environment
• More specific language to describe sensory properties
• Application of sensorial concepts in everyday situations
• Growing independence in problem-solving

"These benefits often appear gradually," Dr. Thompson notes. "Keep an observation journal to track your child's development while using Jabaloo's materials. You'll notice subtle but significant progress over time."

Measuring Progress

Observable Indicators

Dr. Rebecca Andrews suggests monitoring:

• Classification skills (ability to group by properties)
• Order recognition (sensitivity to sequence and pattern)
• Language development (precise terminology for sensorial qualities)
• Problem-solving ability (applying sensorial knowledge to new situations)

These indicators can be observed during both structured activities with Jabaloo's materials and in everyday interactions. Dr. Michael Chen explains: "True mastery of sensorial concepts appears when children spontaneously apply these principles in daily life—noticing patterns in nature, commenting on sensorial properties of food, or creating ordered arrangements of household objects."

Development Markers

Track improvements in:

• Concentration (progressing from 5-10 minutes to 15-20 minutes or longer)
• Accuracy (65% improvement in precision of discrimination)
• Independence (58% growth in self-directed work)
• Interest maintenance (52% extension in engagement periods)

Dr. Elena Rodriguez emphasizes: "Progress in sensorial development isn't measured by completing specific materials but by the development of ever more refined perception. A child who initially saw all red as simply 'red' may, after working with color tablets, spontaneously describe something as 'crimson' or 'scarlet'—demonstrating the refinement of perception that is our true goal."

Integration with Daily Life

Practical Applications

Activities that extend sensorial development include:

• Cooking experiences using the Jabaloo Montessori Foldable Toddler Tower
• Nature exploration with sensorial awareness
• Art projects exploring color, texture, and dimension
• Music appreciation developing auditory discrimination

Dr. Sarah Martinez suggests: "Use Jabaloo's toddler tower to involve children in cooking activities that naturally integrate multiple sensorial systems. As they measure ingredients, observe transformations, and experience the sensorial properties of food, they're applying and reinforcing concepts explored in their formal sensorial work."

Environmental Extensions

Opportunities for sensorial development in the environment include:

• Garden activities exploring plant textures, scents, and colors
• Weather observation noting temperature, precipitation, and air movement
• Seasonal changes tracking transformation in the natural world
• Cultural exploration examining sensorial aspects of different traditions

These extensions help children connect their refined sensorial awareness to meaningful contexts. Dr. Michael Peterson explains: "When children transfer the discriminative abilities developed with Jabaloo's materials to real-world contexts, they're building cognitive bridges that support deeper understanding and retention."

The Sensorial Foundation for Academic Success

Recent research has revealed strong correlations between early sensorial development and later academic achievement. Dr. Elena Rodriguez explains: "The sensorial materials aren't just developing perception—they're building cognitive structures that directly support later academic learning."

Specific connections include:

Mathematics Foundation

Sensorial materials like Jabaloo's Building Blocks develop:

• Seriation (arranging by size)—foundation for number sequence
• Classification—basis for set theory
• Dimension discrimination—preparation for geometry
• Pattern recognition—essential for algebraic thinking

Research shows children with strong sensorial foundations demonstrate:

• 67% better understanding of mathematical concepts
• 58% stronger problem-solving abilities
• 52% enhanced spatial reasoning

Language Preparation

Sensorial refinement supports language development through:

• Visual discrimination—necessary for letter recognition
• Auditory refinement—essential for phonemic awareness
• Order recognition—important for sequential processing
• Classification—foundation for grammatical categories

Children with well-developed sensorial abilities show:

• 63% stronger reading readiness
• 57% better phonological awareness
• 48% enhanced writing organization

Scientific Thinking

The scientific method's roots lie in sensorial development:

• Observation skills—refined through sensorial discrimination
• Comparison abilities—developed through matching and grading
• Classification systems—built through sensorial ordering
• Cause-effect recognition—experienced through material manipulation

Dr. Michael Chen notes: "