biological psychology Flashcards
interactionist (hollistic) approach
uses different approaches -biological, cognitive, and sociocultural- to get a richer understanding
reductionist approach
analyzes a complex behaviour by studying the simplest, most basic mechanisms that are believed to be responsible for the behaviour
localization of function theory
a theory that assumes that every behaviour and cognitive process is controlled by specific areas in the brain e.g (aggression, happiness)
supported by 2 studies: HM case study, Maguire study
evaluation of theory of localisation of function
- Lashley presented the theory of distribution of brain function, many brain functions are distributed across the whole brain
- reductionist approach, attempts to explain a complex behaviour through purely biological factors, ignores cognitive and sociocultural factors
distributive processing theory
a theory that parts of the brain rarely work in isolation, states that several parts of the brain have to work together in order to help us create and retrieve memories.
Some parts of the brain do play specific roles in behaviour, but rarely do they work in isolation
connectome
map of the brain that looks at neural connections
cerebellum
small, wrinkled structure at the back of the brain that coordinates movement and balance
brainstem
connects spinal cord to brain, responsible for autonomic functions, e.g breathing, heart rate
cerebral cortex
outer layer of neurons with folded surface covering the brain: divided into four lobes: frontal, temporal, parietal, occipital
frontal lobe
where executive functions and higher cognitive processes take place e.g planning, problem solving
temporal lobe
auditory processing and memory
occipital lobe
visual processing
parietal lobe
perception of stimuli
The limbic system
- amygdala: emotion centre of the brain, especially anger and fear (if it is working properly we should only fear dangerous things)
- hypothalamus: size of a pea- hunger, thirst, sexual arousal and sleep. animals with damage to it either lose all interest in food or eat compulsively: also part of the endocrine system
- hippocampus: important for forming new memories. anterior- responsible for encoding new emotional memories posterior- previously learned spatial memories and navigation. damage to the hippocampus destroys ability to form new long term memories
strict localisation
a clear correspondence between psychological functions and brain areas, all functions can be clearly mapped onto the brain
maguire study
a study to support the theory of localisation
aim: to see whether brains of london cab drivers would be different to people who are not cab drivers as a result of their exceptional knowledge of the city and the many hours that they spend driving in london
procedure: participants- 16 right-handed male london cab drivers compared with 50 right-handed male non-cab drivers’ MRI scans
quasi experiment- IV was not manipulated by the researcher, they wanted to see if there was a relationship between the number of years driving and the anatomy of one’s brain.
single-blind study: (advantage), researcher did not know whether she was looking at the MRI of a taxi driver or control, no researcher bias
Results:
- taxi drivers have a higher volume of grey matter in their posterior hippocampus
- the volume of the posterior hippocampus correlated with the amount of time spent as a taxi driver
- hippocampus may change in response to environmental demands
link to theory of localisation:
this study supports the theory of localisation as the redistribution of grey matter in the brain can be explained by attributing different functions to the two regions. It is now accepted that the posterior hippocampus is involved when previously learned spatial information is used. In this case of the taxi drivers, this is due to their vast experience of navigation, whereas the anterior hippocampus is responsible for learning new information.
techniques used to evaluate MRI scans
- VBM (voxel based morphometry)
measures the volume of parts of the brain and density of grey matter - pixel count
measures the area of parts of the brain
evaluation of maguire study
- quasi- experiment: no cause-and-effect relationship can be established
+ single blind procedure used, no researcher bias
HM: Milner case study
case study supports the theory of localisation
procedure:
longitudinal case study: began after his surgery where his entire hippocampus was removed. He suffered from anterograde amnesia post surgery, could not form new memories.
method triangulation used:
- psychometric testing (IQ tests, results above average)
- direct observation
- interviews for HM and his family
- cognitive testing (memory recall + reverse mirror testing)
- MRI scans
Findings:
- HM could not acquire new episodic knowledge
- HM could not acquire new semantic knowledge
- procedural memory was still working
- suggests that brain structures that were removed were more important for the transfer of information from SM to LM
- revealed through the MRI scans that the damage he had was much less severe than previously thought
evaluation of HM case study
+ longitudinal: observes change in behaviour over time
+ method triangulation: reliable, in-depth
+ high ecological validity
- retrospective: we don’t have a lot of data of HM’s cognitive abilities aka memories before the surgery
contradiction of strict localisation: karl lashley study
claimed that memory of a maze in rats is distributed rather than localised (many different parts of the brain are responsible for memory)
he destroyed virtually all parts of rats brains in varying amounts in an effort to find the location of memory
procedure: train rat to run with no error through maze for food. then removed an area from the cortex and put rat at the start of the maze, noting down the behaviour. for different rats, different amounts of the cortex were removed from 10-50%.
supports the theory of mass action/ idea of equipotentiality
theory of mass action
the larger the amount of damage the more affect it has on cognitive processes
equipotentiality
one part of the brain can take over the function of another
relative localisation
relative localisation suggests that while certain areas are dominant for specific functions, other areas may also contribute under certain conditions.
currently, neuroscience supports relative localisation which means that localisation exists for some functions under some conditions but recognises limits for localisation
theory of brain neuroplasticity
the brain is a dynamic system that interacts with the environment and is physically sculpted by experience. behaviour and the environment can change the brain.
brain plasticity: refers to the brain’s ability to rearrange the connections between its neurons- the changes that occur in the structure of the brain as a result of learning or experience
dendrite branching: every time we learn something new, the neurons connect to create a new trace in the brain, this is known as dendrite branching because the dendrites of the neurons grow in numbers and connect with other synapses
long-term potentiation: when synapses (connections between neurons) become stronger through repeated use
synaptic pruning: when a synapse is not used or is under-stimulated
neural network: neural circuit, a group of neurons interconnected by synapses to carry out a specific function when activated, they develop in the brain by making and breaking of synaptic connections between neurons.
during neuroplasticity, neural networks in the brain change their shape
draganski (2004) juggling study
supports the theory of brain plasticity
aim: to investigate whether structural changes in the brain would occur in response to practicing a simple juggling routine
procedure: self-selected sampling of 24 (21F +3M) volunteers with no prior experience of juggling took part in the field experiment
method:
- jugglers: spent 3 months learning a classic juggling routine with 3 balls, followed by 3 months of no practice
- non-jugglers: never practiced juggling, control group
- 3 MRI scans were done, one before the experiment, one 3 months after, the other 6 months after
results:
- before study: no brain structure differences between the groups
- 3 months: jugglers had significantly more grey matter in mid-temporal area of the cortex in both hemispheres (areas known tot be responsible for coordination of movement)
- 6 months (3 months of no practice): the difference decreased, but jugglers still had more grey matter in these areas than the first brain scan
conclusion: grey matter grows in the brain in response to environmental demands (e.g learning to juggle) and shrinks in the absence of stimulation (lack of practice)
how maguire (2000) study supports the theory of brain plasticity
correlation observed between the number of years of taxi driving experience and the volume of grey matter in the hippocampus, longer they drove a taxi (more practice), the larger the volume of their posterior hippocampus
distribution of grey matter in the hippocampus occurs in the taxi drivers in response to gaining navigational experience
this study demonstrates the plasticity of the hippocampus in response to environmental demands
evaluation of draganski’s study
+ study used a pre-test, post-test design (prospective) to show differences in neural density over time to help establish cause-and-effect relationship
+ IV manipulated (field experiment)
+ control group to compare results
- small sample size so low population validity
- low internal validity because EV’s not controlled
- study needs to be replicated for reliability
