LT1 – Cognitive Development – The Nervous System, Neurons and Synapses The Nervous System Neurons Synapses

The nervous system acts as the body’s control centre. It interprets the sensory information that enters the body via the senses like touch and taste, and sends information through to the glands and muscles with orders for how they should react.The central nervous system includes the brain and the spinal cord, and the peripheral nervous system consists of the nerves that branch out from the brain and spinal cord throughout your body.

The nervous system is made up of neurones. Each neuron has a cell body. The cell body is covered in dendrites, which look a bit like fingers and an axon, which looks like its tail. The dendrites receive information from other neurons and transmit information via an electrical impulse to the cell body. The impulse is then transmitted to another neuron by the axon.

• The synapse is located as the end of the axon.

• As the electrical impulse travels along the axon, it triggers the release of neurotransmitters, which are chemical messengers.

• One they reach the synapse the neurotransmitters diffuse across the synapse, which is the gap between two neurons.

• When they reach the other side, the neurotransmitters will bind with the receptors on the next neuron.

• There are different kinds of receptors and the neurotransmitters will only bind with the receptors that are designed specifically to receive them, like going into a lock.

• The message is then passed along the neuron to the next one in the same way.

LT1: Developmental Psychology – Brain developmentPre-natal Childhood Adolescence Adulthood

During the first 16 days the human embryo develops a neural tube, this is what will become the brain and spinal cord. After the cells have been created, from approximately 8-26 weeks gestation, they go through a period of migration where they move to their correct location in the brain.

At around 29 weeks the cerebral cortex is formed. It is divided into four parts: the frontal, parietal, occipital and temporal lobes.

After the child is born the brain develops many new neural connections.For example the amount of synapses in the visual cortex nearly doubles which allows the baby to see in 3D and colour (something it cannot do at birth).Around the age of 3 the density of the synapses in the pre-frontal cortex is at its peak. This allows the child to start using their past experiences to guide their behaviour.These vast neural connections then go through a process of pruning – where connections which are not needed or not used are gotten rid of.

Grey matter which is found on the surface of the brain and is composed of the cell bodies of neurons, nerve fibres and support cells reaches its maximum density.The limbic system (an area which regulates emotion) is one of the first brain areas to mature.The pre-frontal cortex (which controls your rational decision making and moderates pro-social behaviour) is one of the last brain areas to mature.This difference in time taken to mature for different brain areas is thought to account for the risk-taking behaviour observed specifically in teenagers.

At around 25 years old the rational part of the brain (prefrontal cortex) finally matures. This helps the individual make rational and sensible decisions as an adult.

During later adulthood individuals can develop a neurodegenerative disease, diseases that get progressively worse over time. An example of this is Alzheimer’s which results in cognitive issues such as memory and clarity of thinking.

LT1: Developmental Psychology – IQ as a measure of intelligenceHistory of IQ Additional examples of how

intelligence can be measuredAn example of the use of IQ testing as a

form of social controlEvaluation of this example.

Alfred Binet was one of the first psychologists to develop a measure of intelligence – the intelligence quotient (IQ).Binet was asked by the French government to find a way of identifying school pupils who were at risk of struggling so extra support could be provided.The IQ test tested memory skills, attention and problem-solving skills. The test was found to be a good indicator of a wide range of abilities in pupils.Binet noted that intelligence was far more complex than the IQ test he devised.

The Cattell-Horn-Carroll System suggested that different abilities are all mixed into one over-arching ability which can be defined as overall intelligence.

Fluid/Crystalized Intelligence.Fluid Intelligence can be described as the working memory, it is procedural memory which increases as STM does.Crystalized intelligence can be described as accumulative intelligence where our overall knowledge and facts of the world increase with our experience of it. This continues to develop into late 60’s.

During WW1 an IQ test was developed (by an American psychologist, Yerkes) in order to assess who would make good officers and leaders. 3 tests were written: Alpha (for literate recruits), Beta (for illiterate recruits) and the final test given to those who failed the beta test (a spoken test). Some recruits were immigrants to the USA and therefore performed poorly on the assessment.

P – One issue with the use of IQ as a measure of intelligence is that it can be used negatively as a form of social control.E – For example, the IQ tests used as a measure of intelligence during WW1 were culturally biased meaning that individuals who did not speak English as a first language or were ‘illiterate’ were less able to perform well on the IQ test.E – This is an issue because it required specific cultural knowledge in order to achieve high marks which therefore reduced the validity of the test.L – This reduces the credibility of IQ tests being used a measure of intelligence.