What you'll learn

• How early visual input can shape the developing brain.
• The full AO1 “story” of Blakemore and Cooper (1970): background, method, results and conclusions.
• How to evaluate the study using validity, reliability, ethics and sampling issues.
• How to compare it with Maguire et al. (2000) for the key theme of brain plasticity.

The big idea: brain plasticity

Blakemore and Cooper (1970) is a classic core study in the Biological area of OCR H567. It sits under the key theme of brain plasticity.

This study matters because it suggests that the visual environment during early development can affect how the brain processes the world later on. In other words, perception is not only “built in”; it can also be shaped by experience.

Prerequisite ideas

The visual cortex

The visual cortex is the area at the back of the brain that processes visual information, such as edges, movement, shape and orientation.

A neuron is a nerve cell that transmits information using electrical and chemical signals. Some neurons in the visual cortex are orientation-sensitive, meaning they respond best to lines or edges at a particular angle, such as vertical, horizontal or diagonal.

Normally, an animal’s visual cortex contains neurons that respond to many different orientations. Blakemore and Cooper tested whether this pattern depends on early visual experience.

Sensitive periods

A sensitive period is a stage of development when the brain is especially responsive to particular experiences. If the right stimulation is missing during this period, later development may be affected.

You may also see the term critical period, which is often used when a developmental window is treated as more strict or biologically necessary.

Background to the study

Before Blakemore and Cooper, biological psychologists already knew that the visual cortex contained neurons that responded to specific features, including line orientation. The question was: are these neural responses fixed from birth, or can they be shaped by early visual experience?

Blakemore and Cooper used kittens because cats have a well-studied visual system and, like humans, they rely heavily on vision. However, this immediately raises an AO3 issue: findings from cats may not apply perfectly to humans.

Aim

The aim of Blakemore and Cooper (1970) was to investigate whether early visual experience affects the development of the visual cortex and later visual perception.

More specifically, they wanted to see whether kittens raised in an environment containing only vertical or only horizontal lines would later be able to perceive both types of orientation.

Method: telling the AO1 story

Design

This was a laboratory experiment, meaning it took place in a highly controlled setting.

An independent variable, or IV, is the factor deliberately changed by the researcher. Here, the IV was the type of visual environment: vertical stripes or horizontal stripes.

A dependent variable, or DV, is what the researcher measures. Here, the DVs included:

• the kittens’ behaviour when later placed in a normal visual environment
• the responses of neurons in the visual cortex

Sample

The participants were kittens. The sample was small and non-human, which is important for evaluation. The study is therefore strong for control but weaker for generalising to humans.

Apparatus and materials

The kittens were reared in special cylindrical environments. The inside walls were covered with either vertical black-and-white stripes or horizontal black-and-white stripes.

The kittens wore collars that prevented them from seeing their own bodies, and they stood on a clear platform. This meant their visual input was restricted mainly to the striped pattern around them.

Procedure

From early life, the kittens were kept in darkness except for controlled exposure to one of the striped environments. They spent time each day in either the vertical-stripe cylinder or the horizontal-stripe cylinder.

After several months, they were placed in a normally lit room and observed. Researchers looked at how they responded to objects, edges and visual threats.

Finally, the researchers examined neural responses in the visual cortex to see which orientations the neurons responded to.

Results

The kittens were not simply blind. Their eyes worked, and some basic visual responses were present. However, their perception was strongly affected by the environment they had experienced.

Kittens reared with vertical stripes responded well to vertical edges but had difficulty detecting horizontal ones. Kittens reared with horizontal stripes showed the opposite pattern.

The physiological recordings supported this behavioural evidence. Neurons in the visual cortex responded mainly to the orientation the kitten had experienced during early development.

Conclusions

Blakemore and Cooper concluded that early visual experience can shape the development of the visual cortex.

This supports the idea that perception is influenced by nurture, because the kittens’ later visual abilities depended on what they had experienced early in life. However, it is not nurture-only: the kittens still had a biological visual system. The study is best understood as showing an interaction between biology and environment.

AO2: applying the study

In an exam, AO2 might ask you to apply this study to a new situation, such as a child born with cataracts or a young animal raised in a visually restricted environment.

A cataract is a clouding of the lens of the eye that can reduce visual input. If a child receives very little patterned visual stimulation early in life, Blakemore and Cooper would suggest that normal visual processing may be affected.

AO3 evaluation

Strength: high control

The study had strong control over the kittens’ visual experience. Because the researchers carefully restricted what the kittens could see, they could make a stronger cause-and-effect claim: the visual environment caused changes in perception and neural response.

This is a strength for internal validity, which means the study measures the causal relationship it claims to measure.

Strength: objective biological evidence

The study did not rely only on behavioural observations. It also used physiological evidence from the visual cortex.

This is useful because the behavioural findings and neural findings supported each other. That makes the conclusion more convincing.

Weakness: low ecological validity

The rearing environment was highly artificial. Kittens do not naturally grow up seeing only vertical or only horizontal stripes.

This lowers ecological validity, which means the findings may not fully reflect visual development in real-life environments.

Weakness: generalisability

The study used kittens, not humans. Cats and humans both have complex visual systems, but they are not identical.

This creates a problem of sampling bias, because the sample was narrow: one species, a small number of animals, and highly controlled laboratory conditions.

Ethics

This study raises serious ethical concerns. The kittens were visually deprived during early development, which could cause distress or long-term impairment. The later examination of the visual cortex also involved invasive biological procedures.

The BPS Code of Ethics and Conduct is mainly written for human research, but its principles still help us think ethically: psychologists should show responsibility, minimise harm, and justify the value of the research. Modern animal research would also be judged using principles such as reducing the number of animals, refining procedures to minimise suffering, and replacing animal research where possible.

Debates and wider issues

Nature versus nurture

This study is excellent for the nature-nurture debate. The kittens had a biological visual system, but the way that system developed depended on the environment.

A strong essay point is that Blakemore and Cooper show an interactionist view: nature provides the brain structures, while nurture helps organise how they function.

Reductionism

The study is biologically reductionist because it explains perception by focusing on neurons in the visual cortex. This is useful because it gives a precise, scientific explanation, but it may ignore broader influences such as movement, exploration and natural social experience.

Psychology as a science

Blakemore and Cooper supports psychology as a science because it used controlled conditions and objective physiological recordings. However, the artificiality of the procedure means scientific control came at the cost of everyday realism.

Usefulness

The study is useful because it helps explain why early sensory experience matters. It has implications for child development, treatment of early visual problems, and understanding sensitive periods in the brain.

Comparison with Maguire et al. (2000)

The paired contemporary study for the brain plasticity theme is Maguire et al. (2000), which studied London taxi drivers and found differences in hippocampal structure linked to navigation experience.

Both studies show that the brain can change with experience, but they do this in different ways.

Blakemore and Cooper used animals in a controlled laboratory experiment, focusing on early visual development and the visual cortex. Maguire et al. used human adults and brain scans, focusing on navigation experience and the hippocampus.

How to write it in an essay

For AO1, tell the study as a clear story: background, aim, method, results and conclusions.

For AO2, apply the logic of the study to a new example: restricted early experience can affect later brain function and perception.

For AO3, avoid generic evaluation. Link every point directly to this study: kittens, striped cylinders, visual cortex recordings, early deprivation, and animal ethics.