Biological Psychology
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Biological Psychology

Minna Lyons, Neil Harrison, Gayle Brewer, Sarita Robinson, Rob Sanders

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eBook - ePub

Biological Psychology

Minna Lyons, Neil Harrison, Gayle Brewer, Sarita Robinson, Rob Sanders

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About This Book

This accessible introductory text addresses the core knowledge domain of biological psychology, with focused coverage of the central concepts, research and debates in this key area. Biological Psychology outlines the importance and purpose of the biological approach and contextualises it with other perspectives in psychology, emphasizing the interaction between biology and the environment. Learning features including case studies, review questions and assignments are provided to aid students? understanding and promote a critical approach. Extended critical thinking and skill-builder activities develop the reader?s higher-level academic skills.

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Information

Year
2014
ISBN
9780857256942
Edition
1

Chapter 1 Introduction to Biological Psychology

Learning Outcomes

By the end of this chapter you should:
  • have an understanding of what is meant by the term biological psychology;
  • have the ability to describe the diverse research methods used in biological psychology;
  • have an understanding of the differences between proximate and ultimate levels of explanation.

Introduction

From understanding the role of genetics in the development of anxiety in rodents to looking at brain functioning in schizophrenia, biological psychology is an extremely diverse sub-discipline of psychology, utilising many different methods in finding answers to a large number of different questions. This textbook is a collaboration of five academics who engage in both teaching and research in biological psychology. Indeed, we are hoping that our individual experiences using methods such as EEG (Meyer et al., 2013), hormonal (Robinson et al., 2008) and genetic analyses (Hamshere et al., 2011), as well as experimental methods in evolutionary psychology (Brewer and Hendrie, 2011; Lyons et al., 2013), will allow us to provide an informed, balanced account of recent research in the field. The main purpose of this book is to provide you with a critical introduction to the field of biological psychology while engaging you in an active exploration of many different topics. We hope that you enjoy completing the tasks and exercises we have included in each chapter, as this will be an excellent aid in helping you to learn about each topic.

What is Biological Psychology?

Biological psychology is the study of biological and evolutionary influences on behaviour. The behaviour may be that of our own species or the behaviour of a number of non-human animal species. For example, researchers investigating biological influences might be interested in the genetic make-up (and especially the interaction between genes and environment, or G X E) affecting individual differences in behaviour (Caspi and Moffitt, 2006). Some of this research is experimental, using rodent models; other research is looking at genotypes of humans and linking them to different environmental factors and behaviours. Biological psychology is a rapidly developing field, using innovative new methods to discover answers to important questions on varied human behaviours and traits, including mental disorders, memory, mate choice and language.
Further, the questions that we ask can be analysed at different levels. Proximate questions are interested in the immediate, mechanistic influences on behaviour, such as the effects of a baby's cry on the mother's behaviour. When a baby cries, the ‘care’ hormone oxytocin is released in the mother, which elicits care-giving behaviour in the mother. Thus, oxytocin can be analysed as an immediate, proximate cause for maternal care. Ultimate questions are interested in historical, evolutionary influences. Why has evolution produced infant vocalisations that elicit care-giving by the mother? Why do mothers look after their babies? Ultimate-level analyses are trying to find the possible evolutionary functions of behaviours. It is possible that in the ancestral babies, individuals who cried for attention received more care-giving, and had higher chances of survival. Thus, the genes of the ‘cry-babies’ would have been selected for by evolutionary processes.
The proximate causes often deal with biological and developmental influences on an individual. These can be things such as the neural circuitry, brain structures, hormones and neurotransmitters, learning and other social influences. These are factors that happen within the lifetime of an individual, often within the body of an individual. Ultimate causes deal with historical explanations, things that happened before the individual, in the ancestors who had genetic combinations that were selected for because they made the ancestors better adapted to their environment.
It is important to take both proximate and ultimate theories into account when trying to understand behaviour, as these interact with each other in producing behaviour that is often adapted to specific environmental circumstances. There is plenty of evidence to suggest that children may use parental care (or the lack of it) as an indicator for environmental circumstances (Del Giudice and Belsky, 2011). When care is low, children mature earlier, start reproduction earlier, and engage in more anti-social and risk-taking behaviours. Proximate explanations could look at things such as the social learning of behaviour (which would not explain the earlier maturation, though) and the role that care has on the development of biological (often neuronal and hormonal) systems that affect behavioural strategies. Ultimate explanations deal with the possible adaptiveness of different behavioural strategies. Perhaps in harsh environments it is better to start early reproduction as people die earlier, and, evolutionarily speaking, passing on your genes before you die is adaptive behaviour. Thus, although it is crucial to understand the proximate causes of behaviour, they are meaningless unless understood from the ultimate perspective too – or, as the famous evolutionary biologist Dobzhansky once wrote, ‘Nothing in biology makes sense except in the light of evolution’(Dobzhansky, 1973).

Research Methods in Biological Psychology

Biological psychologists have at their disposal a large array of techniques to measure behavioural responses and activity in the nervous system. The number of available techniques increases almost yearly due to advances in technology; often the newer techniques are able to measure more accurately, and less invasively, than the older techniques. The choice of method for a particular research study is, of course, motivated by the biological variable the researcher is interested in, but it also depends on the availability of the relevant equipment, and on ethical considerations regarding the welfare of the participants. In this section we give a brief description of the main techniques used in contemporary biological psychology. You will see that many of the experimental results you read about in later chapters have come from studies using one or more of these techniques.
When investigating the nervous system, a particular technique will generally enable researchers to examine either its structure or its function. The structure of the nervous system refers to its anatomy, and the function refers to its activity. A good way of thinking about this is to imagine that you are inspecting a car engine. Its structure would be the physical make-up of the various parts – for instance, whether they are made of metal or plastic, whether they are rusty, and so on. To get a good idea of the structure of the engine, the engine would need to be turned off. The function of the engine is how the engine actually works when it is switched on – how the various parts of the engine are coordinated to allow the car to move. To gain a full understanding of the car engine, you would need to know about both its structure and its function, and this principle is exactly the same for the nervous system.

Brain Imaging Techniques

You need to be aware of the main technologies that allow data about the structure and function of the nervous system to be recorded. Technologies to create structural images of the brain include CT scans (computerised tomography – a series of X-rays of the brain) and MRI (magnetic resonance imaging), which can produce very high-resolution pictures. Going beyond purely structural data, several relatively new imaging techniques can measure the function, or activity, of the brain while it is performing a task. Positron emission tomography (PET) measures the activity of the brain at work, but it involves the ingestion of a radioactive substance. The big breakthrough in brain imaging technology occurred in the 1990s with the discovery of functional magnetic resonance imaging (fMRI), which allows the activity of the brain to be precisely recorded without the need for any radioactive substance to be ingested. The ability of fMRI to record the activity of the brain relies on the fact that regions of the brain that are active use more oxygen than regions at rest. Because of brain activation, there is a change in the ratio of oxygenated to deoxygenated blood, and it is this change that the fMRI scanner is able to detect. This allows the researcher to pinpoint very precisely (in the region of several square millimetres) the regions of the brain that are working. In other words, fMRI has high spatial resolution. A limitation of fMRI is that it cannot provide very precise information about when a particular brain region becomes active, i.e. it has low temporal resolution. Other problems with fMRI are that it is expensive and that the environment inside the scanner is very noisy and movements are restricted, which limits the experiments that can be conducted. It is common for researchers to combine fMRI with a structural MRI scan during the same experiment, to provide both structural and functional data on the same participant.

Electrophysiological Techniques

PET and fMRI are both indirect techniques for the recording of brain activity, as they infer neural activity from a secondary source (e.g. blood oxygen level in the case of fMRI). However, other techniques can directly record the activity of either single nerve cells or large groups of nerve cells. These techniques rely on recording the electrical activity produced by the brain cells, and thus they are called electrophysiological techniques. EEG (electroencephalography) uses electrodes placed on the scalp to record the electrical activity of large numbers of cells (hundreds of thousands of simultaneously active neurons) in the underlying brain tissue. A main advantage of EEG is the accuracy with which it can detect the time that a particular brain region becomes active. In other words, it has a very high temporal resolution, and is accurate to within a few milliseconds (thousandths of a second). Further advantages of EEG are its low cost and the fact that it is non-invasive, i.e. it causes minimal discomfort to the participant. Two main analysis techniques are applied to the EEG signals – the event-related potential (ERP) reflects averaged brain electrical activity in response to a particular experimental event, and event-related oscillatory analysis allows the researcher to investigate how the brain's rhythmic activity is influenced by an external event. A drawback is that EEG has rather poor spatial resolution, so it is very difficult to tell precisely which region of the brain is active at a particular time. MEG (magnetoencephalography) has higher spatial resolution than EEG because it measures the magnetic field changes caused by the electrical activity in the brain, and these fields are less disrupted by the layers of skull and skin through which they must pass before being recorded. However, the spatial resolution of MEG is still much lower than that of fMRI. More invasive electrophysiological techniques such as intracranial EEG (where electrodes are placed on the surface of the cortex) can increase the spatial resolution of the signals, but this is generally used only with humans who are being surgically treated for a medical disorder such as epilepsy. Finer spatial resolution is provided by recording electrical activity from small groups of cells (multiple-unit recording) or a single cell (single-unit recording), using a microelectrode. Multiple- and single-unit recordings allow a direct moment-by-moment measure of the electrical changes of single neurons or groups of neurons. They provide high spatial and temporal resolution and can be used to provide important information about the association between brain structure, brain function and behaviour. The main limitation of the multiple- and single-unit recording technique is that it is highly invasive, so it is suitable only for non-human subjects (although it is occasionally used with human patients, for example, those with Parkinson's disease.) It is also rather labour intensive to collect the data, and each study usually produces data from only one brain region.

Psychophysiological Techniques

Researchers in biological psychology also need to record activity related to other processes in the body besides the central nervous system. For instance, when investigating emotions or stress, researchers want to be able to record their effects on various biological systems that are responsive to these variables. Many of the most useful measures can be recorded from the surface of the skin (these methods are known as psychophysiological measures). Among the most important psychophysiological measures are the electromyogram (EMG), which records muscle tension, the electrooculogram (EOG), which monitors eye movements, and the skin conductance response (SCR), which records the ability of the skin to conduct electricity,...

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