Foreign Perspectives

Archive for the ‘Psychology’ Category

Chapter 4, on Biological processes and psychological explanation, runs to 60 pages and takes us into the depths of biology so for non-biologists there’s a lot of new terminology introduced very quickly with relatively little depth. As the second option in TMA2 is based on this chapter, the notes on the appropriate sections will probably be more detailed.

I’ve highlighted the key exam topics.

This chapter is very much a whistle-stop tour of how psychology depends on the underlying biology and was formerly covered in somewhat more detail in SD226 Biological Psychology. It’s broken into four basic sections: a brief introduction as to how biology supports psychology, some basic biology, how the nervous system and brain work, and how everything fits together.

We start off with Crick’s (1994) concept of reductionism i.e. that all psychology can ultimately be explained by processes going on within the biology of the brain which the chapter then goes on to knock down. For example, the effects of amphetamine on behaviour can only be understood by considering the position in the social hierarchy of the individual injected (Cacioppo and Berntson, 1992). Similarly, to treat depression one can go down the psychological therapy route or the medicinal route or a combination of the two. Likewise there is the split between the signal that the senses receive and how the brain perceives it: was it just a pattern of dots or was it an exit sign? Finally, the concept of the dualism, the idea that the mind can have an existence independent of the brain.

From here, we dive into some basic biology with quite a lot of terminology introduced along the way. The body is made up of billions of cells which themselves consist of a membrane enclosing a number of organelles e.g. the nucleus, the mitochondria, vesicles, etc. Collectively the cells in the body aim to maintain the levels of a number of key parameters such as temperature and sugar level within acceptable levels (homeostasis) through the regulation of various controls e.g. using sweating to cool down. Cells come in a number of different types but for the purposes of psychology it is the neuron that is the most important as that is the type of cell that transmits information around the body and collectively these form the nervous system. Neurons consist of a cell body which has a number of dendrites and a long tail (process). The brain and spinal cord form the central nervous system with the neurons outside that core forming the peripheral nervous system. Detectors in, for example, the skin relay sensations via the peripheral nervous system to the central nervous system where they are interpreted by the brain whilst motor neurons work in the other direction and cause muscles to move. In addition to neurons, hormones also transmit information and commands around the body by way of the blood and can also affect behaviour. Cells reproduced by replicating the chromosomes within the nucleus, the process of sexual reproduction occuring by the mixing of the chromosomes within the egg and those within the sperm (referred to as the gametes) with the fertilised ovum subsequently reproducing and differentiating billions of times, ultimately forming a new individual. The collection of genes within the original fertilized egg are the genotype with the expression of that genotype within the environment called the phenotype. This is where the nature vs nurture argument originates: even with an identical starting point (e.g. in identical twins), you wouldn’t necessarily get two identical individuals as they would be very unlikely to experience the same environment.

So, how does the nervous system actually work? If you stick a pin in your finger, one or more of the sensory neurons will generate an action potential (i.e. a change in its electrical activity). This electrical activity is transmitted along the neuron (a higher frequency of pulses represents a higher intensity of stimulation) until it reaches the end of the neuron where neurotransmitters in the neuron are passed out of the neuron into the synaptic gap and taken up by receptors in the next neuron in the chain to be passed along by it in turn (the two adjacent neurons are called the synapse, hence the synaptic gap between them). Once sufficient neurotransmitters are taken up by the next neuron in the sequence, this causes excitation; note that inhibition can also occur, depending on the nature of the stimulus. Defects in this transmission process can lead to a range of mental illnesses such as schizophrenia (caused by some sections of the brain being abnormally active). The eye consists of a network of receptor cells called cones (colour sensitive) and rods (sensitive to the light level) which are collectively called the optic nerve (SD329 covers this in lots more detail). A whole range of things can interfere with this information transmission process such as diseases (e.g. Parkinson’s results from a loss of dopamine), prescription medication (e.g. Prozac) and various drugs (e.g. alcohol, heroine, etc.) and these processes can be deliberately modified by reducing the reuptake of the neurotransmitters (e.g. Prozac) but can cause problems (e.g. cocaine by rapidly blocking reuptake means that the production of dopamine can’t keep up which in turn leads to the down).

Moving up from the extreme detail of cells, we look next at how the brain is built and how it functions. It consists of two hemispheres joined by the corpus callosum. The outer creased layer is the cerebral cortex and overall it’s considered to consist of a number of lobes which perform specific activities. Thus, the eyes are wired through the brain to the lateral genuculate nucleus at the back. We know this courtesy of a range of accidents that have happened over the years and, more recently, some techniques that have been developed. Thus, epilepsy which arises from one hemisphere tended to roll over to the other one so Sperry (1969) looked at cutting the connection which in turn permitted a range of quite interesting experiments to be done addressing a single hemisphere. Damage caused by accidents or strokes (brain lesions) also revealed what some sections of the brain got up to (e.g. Phineas Gage lost the sections related to emotional control). Animals have controversially had bits of their brain cut out but these days brain imaging techniques are, of course, preferred. In terms of imaging, there is a wide range of options including positron emission tomography (PET) which looks at the blood flow indicated by the amount of a radioactive tracer injected.

This is all controlled by the somatic nervous system which acts on the skeletal muscles that operate our voluntary behaviour all under control of the motor cortex. The autonomic nervous system runs the involuntary systems (e.g. control of the cardiac muscle in the heart and smooth muscle in the throat etc.). Finally, a couple of areas are largely glossed over including language development and depression.

For the exam, the key topics for this chapter are highlighted above and are:

Neurotransmitter
Phenotype
Genotype
Action potential
Brain lesions

The numbers were well down with the tutorial on Saturday with only two of us there at the start and one arriving later.

The focus on this tutorial was mainly on the types of psychology experiments that can be done and the broad statistical analysis that you can do once the data is in. It probably surprises a lot of people but there is a considerable emphasis on statistical analysis in psychology and one of the texts that we have is quite a chunky one on SPSS which is used in at least one assignment and also in the summer school.

What I’m wondering is whether the drop-off in numbers is due to the recent assignment or if it’s just down to the Christmas season.

Chapter 3, on Three approaches to learning, runs to 46 pages is back to proper psychology. This is the first of the part 2 exam chapters so isn’t tested in any TMA which means that my notes will initially be less fleshed out on this but will improve as the exam approaches.

I’ve highlighted the key exam topics.

This chapter looks at three basic approaches to learning starting with conditioning which is essentially the basis for rote learning, moving on to category learning and finally looking at social and cultural aspects to learning. Quite a fundamental thing and a topic that is covered in some depth in the Child Development module as you would expect.

The comparative approach looks at how different species and generally does this through the methods of behaviourism which look at actual behaviours and ignore the possibility of any internal mental states that may exist.

Classical conditioning introduces a whole raft of terminology, taking up around 1/3rd of the chapter along the way i.e. it’s a pretty important topic. It all started with the physiologist Pavlov who was interested in reflexes. He began by creating a contingency by pairing a neutral stimulus (e.g. a bell) with a natural one (e.g. salivating when food is in the mouth) and found that after a number of repetitions, the neutral stimulus was sufficient to create the salivation (the conditional response) i.e. it had become a conditioned stimulus (or conditioned stimulus), this process being called classical conditioning with the reflex linking the bell to the salivation being the conditional reflex; the food itself is the unconditional stimulus and its salivation is the unconditional response. Watson went on to screw up little Albert by banging a lump of metal behind him whenever he saw a rat which he initially wasn’t scared of.

Instrumental conditioning is where the subject taking a particular action is either rewarded for doing this (positive reinforcement) or something undesirable for them is stopped by their action (negative reinforcement). If the subject is required to so something specific to obtain their reward this is operant conditioning e.g. rats pressing a lever to gain food pellets. Punishment is the initiation of something as a consequence of their actions that would cause negative reinforcement. These techniques have been used in behaviour modification. Experiments based on instrumental conditioning include Tolman with the fan of maze routes showing that there they develop a mental model rather than just having their behaviour modified and variations on this based on room layout.

Category learning arises when we realise that things are generally not unique but rather fall into specific categories which can aid application of knowledge acquired in one context in an entirely different one e.g. we can identify a creature with scales as a “fish” which in turn means that we know it can swim even if we don’t know the specific species. However, that begs the question: how do we build these categories in the first place and a plethora of experiments have looked at that e.g. Bruner and his stimulus cards revealed a number of different strategies used to identify categories (eliminating categories by focusing on one property rather than just randomly scanning works best). Criticisms include that these are artificial categories and that natural categories are quite different e.g. birds need wings to fly and aren’t just things with wings. There’s the issue of whether we can learn new categories and how we do so: is it by hypothesis testing as Bruner would argue, or are the categories innate as Chomsky and Fodor would say? Quite a complex area and these notes don’t really cover it properly yet (see p196-200 of the book).

The sociocultural perspective considers the use of tools and how it depends on interpersonal relationships and is embedded in the society and culture in which it takes place. For example, you could learn to do calculations on paper, on a calculator or perhaps with an abacus. This moves on to the issue of the use of language in problem solving and the differences between cumulative talk (that merely sums up what has gone before) and exploratory talk (that moves the conversation onwards). Finally there is the business of enculturation or indoctrination into the school system: making sense of how school works or learning how to learn in a school context.

For the exam, the key topics for this chapter are highlighted above and are:

Behaviourism
Sociocultural perspective
Operant conditioning
Classical conditioning
Category learning

I went along to the seminar run by the Dementia Services Development Centre last week to try and get more of a handle on the condition. As you’d expect, the majority of those attending were there to pick up some information in respect of an elderly relative though there were also a handful of care organisations represented as well.

Quite a lot of the morning sessions were on the various strategies that the organisation are involved in and the things that are starting to come to fruition of those. Not really of immediate benefit to most of those there but it’s nice to see that there is work going on behind the scenes.

The rest of the sessions were much better targeted at the audience starting with a good session on the behaviours that one could expect and some strategies to overcome some of the more troublesome ones. I’d not realised that having a diagnosis of vascular dementia is quite a different thing from altzheimer’s and that the development pathway is substantially different so that’s useful to know. De-cluttering is often suggested but the explanation that it’s down to the person being unable to cope with the complexity is rarely given. Having said that, some people can’t cope with the de-cluttering and prefer a bit of chaos so it’s important to take account of the person with the dementia.

Depression is a problem on two fronts. For one, dementia can be mistaken for depression but equally if you’ve got dementia you’re more likely to have depression too. Not really an easy thing to address but things like reminiscence and memory books can help.

They went into aggression quite a bit as it can be a particular problem. Ways of coping with it are to try and avoid it in the first place by noting triggers, having a calm environment  and keeping to a routine. Related to that is the issue of communication which can be a trigger and it’s worth noting the little things like hearing aid batteries and eye sight tests which can kill communication.

Chapter 2, on Evolutionary Psychology, runs to 46 pages and is quite a change in content from the identity chapter. It’s split into four basic sections with two essentially biological and two more psychological in nature. One of the options in the second TMA is based around the final section on altruism so the notes on that will probably be better than those on the other sections initially.

I’ve highlighted the key exam topics.

The chapter begins by looking at the different types of evidence which evolutionary psychologists use. Archaeological evidence includes the relative sizes of males and females, pelvis size, tools, cave paintings and evidence of social groupings from excavations. Genetic evidence looks over a longer time-scale considering the evolutionary split between apes and our human ancestors and any breeding that may have taken place between the various human species in the past. Studies on present day non-human primates and hunter-gathers looks at the social structures but recognising that these populations are not the same as our distant ancestors and that the presence of modern humans may distort the findings. Studies looking at the universality of behaviours and what modern humans actually do consider that if a behaviour is universal these days then it has derived from a common behaviour amongst our ancestors e.g. the male preference for features that indicate fertility in females.

The chapter moves on to consider the various evolutionary processes which generated all the differences that we see in the present day in what feels very much a whistle-stop tour of evolutionary biology. The genes which collectively form the DNA are at the core of this with the mixing of the chromosomes during sex forming a unique individual from the contribution of the genetic content of the egg and sperm. Selection is at the core of this with natural selection relying on 1) variation in individuals 2) part of this variation being due to genetics and 3) there being some competition in terms of resources. This selection process leads to adaptations with the fittest for the particular circumstances out-breeding the less fit. Sexual selection is the process though which reproductive success is improved by passing on physical and behavioural characteristics to one’s descendants; males by having a lower investment in their offspring would generally tend towards having more of them whereas females tend to invest more in each so look for long term mates. This section finishes with a brief overview of the hominine family touching on the super-family of apes from 30 million years ago, to hominoids (apes and humans) 22 million years ago and our human ancestors around 5 to 7 million years ago, noting that up to around 30,000 years ago there were multiple human species around at the same time.

From the biology, we have a bit of a lurch into psychology with the theory of mind, which is the ability to think from the perspective of another and to thereby predict what someone else is likely to do. That it is not fully present in chimpanzees indicates that it evolved after the split some 5-7 million years ago. The Maxi (Sally-Anne) [Wimmer and Perner, 1983] test indicates that we develop a theory of mind by around 6 years old although the false-belief that it tests is not all that encompasses theory of mind and alternatives (e.g. Chandler’s 1989 hide and seek test) have indicated that it is present from around 2 years of age. Although children generally follow the same developmental trajectory, the age at which it arises differs across cultures. As one might expect, it is much less developed in those with autism. Apes exhibit the deception aspect of this. It is illustrated in archaeology in terms of art from 30,000-40,000 years ago but the lack of human evolution for some 200,000 years indicates that it has been around for quite a while despite the lack of concrete evidence for it earlier than the cave paintings.

Finally, the related issues of altruism and reciprocity are covered. Since natural selection is all about reproductive success, you might think that altruism would play no part in the selection process. However, the reproductive success is not about the success of a particular individual but rather about the reproductive success of the genes involved. Therefore, through the process of kin selection one can see that it is advantageous to help individuals with whom we have a lot of genes in common i.e. our relatives and that we would tend to help those with whom we had a greater number of genes in common i.e. the closer the relative, the more the help that would be offered. Outside our relatives we also help complete strangers which is generally on the basis that a helpful act will be repaid later (reciprocal altruism) which brings into play a certain amount of game theory. This is illustrated in psychology by the prisoner’s dilemma where the best strategy is usually to defect (i.e. not to make the initial altruistic act) although in an ongoing relationship, it’s better to be altruistic first then do whatever the other guy did on you; it also has cultural biases and the students that it’s generally tried out on would be expected to be somewhat more clued in than actual criminals. Indirect reciprocity covers the situation where others benefit but there is no direct benefit to the altruist, the assumption here being that the altruist will gain brownie points as their benefit which in turn helps them. Evidence for altruism in animals is mixed with initial studies looking at food sharing indicating that it didn’t happen (but they tend not to share food at all) whereas later studies looking at general helpfulness showed that they were altruistic; there are issues with all of these studies as they were using animals raised in captivity.

For the exam, the key topics for this chapter are highlighted above and are:

Theory of mind
Natural selection
Sexual selection
Reciprocal altruism

The next chapter is on learning which is an exam rather than a TMA topic but I’ll be covering it over the next week anyway.