Specification: Holism and reductionism: levels of explanation in Psychology. Biological reductionism and environmental (stimulus-response) reductionism.

The holism and reductionism debate focuses on an important question in the philosophy of science: Can complex behaviours be reduced to their simpler components?

Extension: An interactionist approach

An interactionist approach argues that several levels of explanation are necessary to explain a particular behaviour, ranging from lower (biological) to higher levels (social and cultural). Interactionism is subtly different from holism (see below), as interactionism considers how different levels of explanation interact. In contrast, holism is more concerned with understanding the whole experience, rather than individual explanations. 

Types of reductionism

Biological reductionism refers to the way that biological psychologists try to reduce behaviour to a physical level and explain it in terms of neurons, neurotransmitters, hormones, brain structure, etc.

For example, explanations of psychological disorders are often biologically reductionist, as genes and neurochemical imbalances are offered as the leading cause. For example, a meta-analysis of 14 twin studies of OCD found that monozygotic twins were more than twice as likely to develop OCD in comparison to dizygotic twins if their co-twin also had the disorder (Billett et al., 1998), thus suggesting a genetic link.

Environmental reductionism is also known as stimulus-response reductionism. Behaviourists assume that all behaviour can be reduced to the simple building blocks of S-R (stimulus-response) associations and that complex behaviours are a series of S-R chains. For example, behaviourists reduce the complex behaviour of attachment down to a stimulus-response link, where the mother becomes the conditioned stimulus who becomes associated with the pleasure of feeding. Therefore, the child comes to feel pleasure (conditioned response) when he or she encounters their mother, leading to the formation of an attachment.

Note: While experimental reductionism is not detailed in the specification, it is useful to understand this term, as it applies to the Cognitive Approach. However, you should not be asked a specific question on experimental reductionism in your exam.

Experimental reductionism is where complex behaviour is reduced to a single (isolated) variable for the purpose of testing. For example, while the multi-store model of memory suggests that memory consists of three stores, and each store has its own coding, capacity and duration, cognitive psychologists often examine memory in terms of isolated variables. For example, Miller (1956) discussed the capacity of short-term memory, and Peterson and Peterson (1959) examined the duration of short-term memory. Experimental reductionism underpins the experimental approach; complex behaviours are reduced to operationalised isolated variables in order to measure and determine causal relationships.

Holism

Holism comes from the Greek word ‘holos’, which means ‘all’, ‘whole’ or ‘entire’ and is the idea that human behaviour should be viewed as a whole integrated experience, and not as separate parts.

Gestalt psychology adopts a holistic approach to perception: when we perceive something in the real world, we do so as a whole rather than as a collection of bits and pieces. What we see only makes sense when we consider the entire image, rather than the individual elements that make up our vision. Consequently, some cognitive psychologists also take a holistic approach. For example, within the area of perception, visual illusions demonstrate that humans perceive more than the sum of the sensations on the retina. [If you examine the image on the right, what you will instantly perceive is the outline of a cube. However, there is, in fact, no cube in the image and your mind has created a cube due to the position and configuration of the black shapes].

Humanistic psychology also advocates a holistic approach, as it argues that humans react to stimuli as an organised whole, rather than as a set of stimulus-response links. As an approach, it uses qualitative methods to investigate all aspects of the individual, as well as the interactions between people.

Evaluation

Scientists (including psychologists) are drawn to reductionist explanations as a method of research. For example, most experimental psychology assumes that human behaviour can be studied effectively through relatively simple experiments, where complex behaviour is reduced to isolated variables (known as experimental reductionism). This allows researchers to study the different factors that influence human behaviour in a controlled manner while establishing a causal relationship. This would not be possible if psychologists attempted to study all the factors that influence human behaviour at once, as it would be too complex to interpret the findings.

• Counterargument: However, although experimental research has produced a wealth of findings, the results of highly controlled laboratory studies are often questionable. For example, the findings of laboratory research examining the reliability of eyewitnesses (e.g. Loftus and Palmer) have not been confirmed by studies examining real-life witnesses (e.g. Yuille and Cutshall).

Furthermore, both biological and environmental reductionism are viewed as scientific. Breaking complex behaviours into small constituent parts means that they can be scientifically tested, and over time explanations based on scientific evidence will emerge. Also, biological reductionism has led to the development of biological therapies, such as drugs. For example, SSRIs are more effective than placebos at treating the symptoms of OCD and reduce the symptoms for up to three months after the treatment (Soomro et al., 2008). The use of SSRIs in patients with OCD has helped to reduce the anxiety associated with OCD, thus providing relief for some patients.

Criticism of reductionism takes many forms. Some psychologists argue that biological reductionism can lead to errors of understanding because it ignores the complexity of human behaviour. For example, to treat conditions like ADHD with drugs in the belief that the condition consists of nothing more than neurochemical imbalances is to mistake the symptoms of the phenomenon for its exact cause. Ritalin may reduce these symptoms, but the circumstances which gave rise to the ADHD have not been addressed. Whether or not this is true depends on what one thinks of as causation. Still, since success rates of drug therapy are so highly variable, the purely biological understanding seems inadequate.

The critique of environmental reductionism is as much methodological as it is substantive. Much of the relevant research in the behaviourist tradition has made use of non-human animals as subjects. The classic Pavlovian experiments are an iconic example. But is human behaviour merely a scaled-up version of that of dogs or rats? Critics of reductionism point to the social context in which humans are embedded from the earliest moments of life, and to hard-to-measure factors like cognition, emotion, and intentionality. In this case, as well, the reductionist position seems, if not incorrect, then at least inadequate.

The holistic explanation attempts to blend different levels of explanation; holistic theory and approaches strive to provide a complete and realistic understanding of human behaviour. However, holistic explanations do not establish causation because they do not examine behaviour in terms of operationalised variables that can be manipulated and measured. This means that holistic explanations are viewed as unscientific.

Possible exam questions

1. Explain what psychologists mean by ‘levels of explanation’ in relation to reductionism. (3 marks)

2. Give an example of biological reductionism from an area of psychology you have studied. (3 marks)

3. Explain one similarity and one difference between biological reductionism and environmental reductionism. (6 marks)

4. Outline and evaluate reductionist explanations in psychology. (8 marks)

5. Discuss holism and reductionism in psychology. (16 marks)