Developmental psychology is very important in the field of early years education as educators and teachers need to understand how children develop and the rates they develop and the fact that these stages aren’t concrete and could happen at different points for each child. Developmental psychology needs to be understood by educators and teachers as children’s needs are different at each age group, for example, toddlers (2-3)would have different abilities to babies (birth-1). Developmental psychology is crucial for Montessori teachers and early years educators as recognising developmental issues or progressions is part of the profession.Jean Piaget was born in 1896 in Switzerland, he was intrigued by how young children think differently to adults. These observations lead Piaget to develop a theory of cognitive development. Piaget believed in four different stages of childhood development, the sensorimotor stage approximately between birth and the age of two, the preoperational stage from about two and seven years of age, the concrete operational stage from the age of about seven to eleven and then the formal operational stage from approximately eleven to fifteen years of age. Development happens from one stage to another through interaction with the environment. These stages may occur abruptly and kids will differ from how long they stay in each stage because development occurs naturally in children, for example, cognitive development can only happen after physical development. Each stage has significant differences between them, for example in the sensorimotor stage there is rapid change where the child will explore the world through senses and motor activity throughout this whole stage, the younger side of this stage believe if they can’t see something then it doesn’t exist but the older side of this stage start to follow an object or person with their eyes whereas newborns wouldn’t be able to keep concentration. Whereas in the preoperational stage the children have better speech skills, develop basic numerical ability, can imagine a future and reflect on the past, has difficulty distinguishing between fantasy and reality and this stage are quite egocentric in a way which for example if they can see the television but are standing in your way they will simply presume you can still see. These differences, therefore, benefit educators by distinguishing the differences and being able to work with the children by noticing the stages they are in. (O’Brien, 2013)Piaget’s theory might be beneficial to a prospective Montessori teacher or early years educator because knowing about the development of children will help decide activities to do and help planning lessons for that specific age group. Piaget’s theory considers the child’s knowledge and level of thinking to facilitate learning rather than direct learning and encourages the educators to turn the classroom into a setting of exploration and discovery and promotes the students intellectual health. This theory is beneficial to prospective teachers due to knowing the stages helps prepare for lessons, for example distinguishing the differences between the stages and noticing the different stages the children are in benefits educators by knowing how to work with that group of children or that specific child. Knowing the sensorimotor stage is helpful with teaching babies and wobblers because they learn through senses and motor activities, for example doing sensory activities such as jelly play, messy spaghetti, slime, and gloop or even finger painting to let children experience and use their senses to discover everything around them. Educators understanding the preoperational stage is beneficial by starting to introduce numbers and more vocabulary at a slow enough pace for them to grasp better speech and numerical ability. Educators knowing the concrete operational stage is helpful by adding abstract thinking to lessons and encouraging children to think more for themselves and think outside of the box. The formal operational stage is emerging abstract thinking where thinking becomes much more advanced with the use of logic to come up with creative solutions to problems (www.verywell.com). Educators will plan lessons and such around this stage and encourage problem-solving and more abstract thinking. Sensory development is the development of the senses, there are seven senses, touch, smell, sound, taste, sight, proprioception and vestibular input. Everything a person does involves one or more of their senses and therefore senses are very important in everyday lives. Humans experience these sensations through interactions with the environment and the means of these sensations or actions is called sensory processing. Sensory development begins at gestation and continues through childhood. The somatosensory system is part of the nervous system and is made up of several touch receptors. These touch receptors are how pain, pressure, and temperature is felt. There are four million pain receptors found all over the body, sensing pain is important because it warns the body of possible danger or harm to the body. Taste is a chemical sense that allows humans to process information through different sensations, for example, sweet or salty, as well as different textured foods. Vestibular system or movement sensations is about balance and works in conjunction with the other sense, this is important in infants as they learn to hold their head up or sit up even standing and walking. Auditory system or sense of hearing, develops during gestation but continues to develop in the first year, children may turn their ears or head toward a sound. When born babies can only focus on something about eight inches away from their face, have red and green coloured vision and are sensitive to light, by the time their two months old they can track smooth pattern movements and by three months they are better able to focus on objects far away and start to develop depth perception. The sensory systems connect and work in conjunction with each other. Sensory development is important for children as it is part of everyday lives.Sensory development might be beneficial to prospective Montessori teachers or early years educators as it could be an important observation if these senses don’t develop properly or at all, there could be further issues that need to be looked at. Issues relating to sensory development such as sensory integration disorder is a neurological disorder that results from the brain’s inability to integrate, process and respond to certain information received from the body’s basic sensory systems (Autismawarenesscentre.com). Understanding sensory development may also be beneficial to prospective Montessori teachers and early years educators by knowing what the children need, it is very important to allow children to discover their senses and naturally children will. Children will pick anything up from the outdoors just to feel and understand what that object is, teachers and educators will need to know that this development is inevitable and to therefore encourage this development. Sensory development is crucial in the early years as children will see new colours, taste new food, hear new sounds, feel new textures, smell new aromas and from every new experience they will learn and develop in many ways.In conclusion, Piaget’s theory of the four stages of development is beneficial to prospective Montessori teachers and early years educators by creating a basis in which these teachers can create an activity or lesson plans in advance. Understanding and knowing Piaget’s theory as educators is beneficial in many aspects but understanding where the children are developmentally for their age group is crucial for the teachers to know what to do.Knowing and understanding sensory development is also a very important aspect of developmental psychology that is beneficial to Montessori teachers and early years educators to recognise issues with sensory development or just to plan sensory activities.