Biological Psychology in Sec A

Question 1

What is the assumption, focus, the theme and the studies in biological psychology?

Answer 1

Assumption: our biological makeup affects our behaviour, many behaviours have a psychological cause which may be genetically or environmentally altered

Focus: psychologists should study brain, nervous system, and other biological systems acting on brain to explain behaviour

Theme: REGIONS OF THE BRAIN

• classic study: Sperry (1968)
• contemporary study: Casey et al (2011)

Question 2

Describe the context and background of Sperry.

Answer 2

• research to explore localisation of function
• localisation: extent to which particular jobs are performed by particular parts of brain
• so,e functions demonstrate lateralisation
• lateralisation: difference between roles of left and right hemispheres of brain, so is the specialisation of diff brain hemispheres
• contralateral control: movement of one side of body is controlled by opposite side of brain
• corpus collosum: joins left and right side of brain and exchanges info and messages across brain
• studies particular focus explores when two hemispheres are split (hemispheric separation)
• corpus collosum is therefore cut which prevents cross talk and communication of two hemispheres.

Question 3

Describe the aim of Sperry.

Answer 3

• to test effects of hemisphere disconnection in humans
• specifically to investigate whether cognition, including perception and memory, differs between hemispheres, and extent to which hemispheres would normally interact to achieve these functions

Question 4

Describe the method of Sperry in terms of design.

Answer 4

• research method was a quasi experiment
• done in a lab environment with control over specific variables
• IV: fact they had split brains
• DV: measuring effect on individuals performance in tests of cognition

Question 5

Describe the method of Sperry in terms of participants.

Answer 5

• 11 split brain patients = at least one woman
• all had history of advanced, severe epilepsy that could not be controlled by medication
• all had sever epilepsy for at least ten years

Question 6

Describe the method of Sperry in terms of procedure.

Answer 6

• quasi experimental method involved comparing performance of pps on tasks with performance of people who had not undergone hemisphere disconnection, to investigate localisation of brain function
• study was also a case study method, so an in depth investigation of the 11 pps
• specialised equipment used and were highly standardised
• all tasks involved asking pps to respond to visual information with one eye blindfolded and using other to fixate on a point in middle of screen
• stimulus then projected on either left or right side of fixation point for less than a tenth of a sec
• such short time of showing stimulus to ensure pp did not have time for eye movement as this would pass info across both sides of visual field and so both brain hemispheres
• language only processed in left hemi of brain, so when stimulus presented to left visual filed of split brain patients, they should not be able to name stimulus as right hemi controls left visual field and vice versa
• another task involved asking pps to respond to tactile info: presented with stimulus to one hand so could not see it, then asked to name it, if stimulus presented to left hand then should not be able to name it as left hand goes to right hemi which does not control language
• also possible to present auditory (sound) and olfactory (smell) stimuli to one side of brain by blocking unused ear / nostril

Question 7

Describe the results of Sperry.

Answer 7

• when pps presented with an image in one half of visual field, and then present with same image in other, they responded as if had never seen image before
• if same image presented in original field again, were able to recognise image
• not able to give description of an image presented in left hand side of visual field, either not noticed or appeared as a flash
• although, could respond verbally by pointing with left hand to a matching picture or selecting one object among others - only works with right handed pps tho as means info goes to left hemi which controls language
• if two symbols presented simultaneously, one in each visual field, and pps asked to draw what they saw with their left hand, they would only draw left visual fields pic as left hand controlled by right hemi which controls only left visual field aswell
• when required to then say what they had just drawn, pp would name object from right visual field, not object they drew, as lang comes from left hemi which controls right field so they’d say name of that image
• objects put in hand for identification by touch could be named if in right hand, but only completely guessed if in left hand or were unaware anything was in hand at all
• if object taken from left hand and placed in ‘grab bag’ among other items, pp able to retrieve with left hand and identify it
• Sperry found hemisphere disconnection did not affect pps intelligence (measured by IQ test) or personality
• worth noting patients are only affected from surgery compared normal pps when tasks set up to show Info through diff visual fields and parts of body to send to only one side of brain, but would not be affected in everyday lives as use all fields and limbs.

Question 8

Describe the conclusions of Sperry.

Answer 8

• argued that his studies give considerable support to argument of lateralisation of function: that diff areas of brain specialise on diff tasks e.g. Left for language
• also argued that each hemisphere of the brain has its own perceptions, memories and experiences.

Question 9

Evaluate the research method of Sperry.

Answer 9

• was a lab ‘experiment’, but a lab procedure as only some parts were truly experimental
• many comparisons were to non split brain people, although they weren’t part of sample included
• a control group of non-split brain epileptics would have provided better comparison

Question 10

Evaluate the data on Sperry.

Answer 10

• depth and detail of data collected was a strength of study as is both quantitative and qualitative so has strengths of both types of data
• having both types is useful for interpreting findings e.g. Qualitative data supporting tests help to show that understanding of effects of hemisphere disconnection is correct.

Question 11

Evaluate the ethical considerations of Sperry.

Answer 11

• although were ethical issues involved in surgery itself, these are not issues with sperrys research
• understanding reasons for mental tiredness, and discovering there are ways in which split brain patients outcompete normal people may slightly helped patients make progress

Question 12

Evaluate the validity of Sperry.

Answer 12

• took place in highly controlled environment so possible to eliminate extraneous variables and be confident IVs being tested are those affecting DV
• stimuli only being displayed for short time ensured not possible to glance away from fixation point and view stimulus through other eye
• potential weakness with lab studies is lack of realism of environment and pps tasks, I.e. Low ecological validities because findings may not generalise beyond lab setting, difficult to set up lab procedures where people behave completely natural
• study was concerned w discovering problems rather than helping in real world, but Sperry did note that in day-to-day life split brain patients have little impairment

Question 13

Evaluate the reliability of Sperry.

Answer 13

• reliability = consistency
• is reliable if can be precisely replicated + obtains same results consistently
• lab experiments = easy to replicate, and sperrys has been
• but, further evidence of some language ability in right hemi presents some concern, as damage to left hemi can cause compensation to have some reorganisation of Lang ability in right hemi
• this would make epileptic sample unrepresentative, this pattern seen in brain scanning studies (e.g. Thompson 2000)

Question 14

Evaluate the ethnocentrism of Sperry.

Answer 14

• are some diffs in lateralisation between people using diff languages
• so for e.g. If some cultures were less lateralised in speech function, individuals from these cultures who undergo split brain ops would produce diff results
• this suggests sperrys results may only apply to cultures sharing same lateralisation patterns as English speakers
• so low generalisability and ethnocentrism.

Question 15

Evaluate the sampling bias of Sperry.

Answer 15

• 11 sound like small sample, but is impressive due to rarity of patients and depth of their study
• all sufferers of epilepsy so is a restricted sample, so generalisation to whole pop may be invalid
• extent of disconnection varied between patients, presenting individual diffs in results
• no of both men and women used is not known, and there are gender diffs in lateralisation of function (e.g. In language) so this important in terms of generalisability.

Question 16

Evaluate the practical applications of Sperry.

Answer 16

• demonstration of hemispheric lateralisation and finding there are so few debilitating effects of the surgery are main practical implications here
• provides an indication of surgical safety, so all patients unlikely to suffer noticeable cognitive effects
• though subsequently, some effects on memory identified
• also offers warning: unilateral damage could have profound effects

Question 17

Describe the aim of Casey et al.

Answer 17

• considered extent to which ability to resist temptation at preschool age affected same pps in adulthood
• control over impulses and sensitivity to social cues at behavioural and neural level examined

Question 18

Describe the general method of Casey et al.

Answer 18

• longitudinal study, tracked some pps from age of 4-40’s
• composed of two quasi-experiments, as IV naturally occurring
• individuals ability to delay gratification was IV, operationalised as ‘high delayers’ or ‘low delayers’

Question 19

Describe the method of Casey et al in terms of participants.

Answer 19

• sample drawn from initial group of 562 pupils aged 4 who attended stanfords Bing nursery school and completed original delay of gratification task during late 60’s and early 70’s
• then 155 from original group completed self control scale in their 20s, reducing to 135 undertaking same measure again in 30s
• 117 of those with above or below average scores for delay of grat and self control across all tests contacted again
• 59 of these consented to take part in exp 1 (23 males, 36 females)
• 27 of these then also took part in exp 2 (13 males, 14 females)
• one male pps results excluded from exp 2 due to poor performance on behavioural task

Question 20

Describe the method of Casey et al in terms of design and procedure of experiment 1.

Answer 20

• sample in this exp divided into 32 High delayers (12 male, 20 female) and 27 low delayers (11 male, 16 female)
• gave consent to take part in behavioural version of a ‘hot’ and ‘cool’ impulse control task
• exp completed in pps own homes via pre programmed laptops
• two versions of ‘go/ no go task’ completed where instructed to either press button (go) or withhold from pressing (no-go)
• ‘cool’ version of task included presentation of male and female faces w neutral expressions; one sex was go stimulus, other was no go
• faces drawn from ‘NimStim’ set facial expressions
• prior to task pps read on screen instructions saying to respond as quickly and accurately as poss, and said which sex was which stimulus for each trial
• each face appeared for 500 milliseconds, w one sec interval between faces
• 160 trials presented per run in total in a pseudo-randomised order (120 go, 40 no go)
• so task described as 2 trial (go and no go) x2 (stimulus sex: male and female) design.
• ‘hot’ and ‘cool’ versions differed only in use of happy or neutral and fearful expressions, and were chosen to explore influence of alluring social cues
• accuracy and reaction times acquired in four runs representing each combination of stimulus sex and trial type (go/no-go).

Question 21

Describe the method of Casey et al in terms of design and procedure of experiment 2.

Answer 21

• sample of 15 high delayers (5 male, 10 female) and 11 low delayers (7 male, 4 female)
• pps scanned w functional Magnetic Resonance Imaging (fMRI) scanner while completing ‘hot’ version of go / no go task similar to exp 1
• electric response pad used to record responses to facial stimuli and reaction times
• 48 trials per run (35 go, 13 no go)
• each face present for 500 milliseconds, w intervals of 2 secs to 14.5 secs between faces
• imaging data for 26 no go trials and 70 go trials per expression collected.

Question 22

Describe the results of Casey et al for experiment 1.

Answer 22

• both groups highly accurate in correct responses to go trials in both ‘cool’ and ‘hot’ commotions (99.8% and 99.5% correct)
• low delayers slightly more likely to respond wrong in no go trials and performed slightly worse than high delayers in ‘hot’ version of task
• but, low delayers, identified at age of 4, showed greater difficulty in surpressing responses to happy faces than high delayers

Question 23

Describe the results of Casey et al from experiment 2.

Answer 23

• no significant diff between two delay groups on reaction times in correct go trials
• accuracy for both groups v high again for go trials as in exp 1
• low delayers had higher false alarm rates in no go trials (14.5%)
• right inferior frontal gurus appeared critical in withholding responses, so low delayers showed reduced activity in this region in no go trials
• high levels of activity in reward related region (ventral striatum) for low delayers, most prominent during happy no go trials for low delayers.

Question 24

Describe the conclusion of Casey et al.

Answer 24

• resistance to temptation appears a stable characteristic of an individual over time (stays consistent)
• cognitive control can be strongly influenced by contextual factors
• ventral frontostriatal circuitry supports resistance to temptation, with combination of lowered activity in inferior frontal gyrus and increased activity in ventral striatum in low delayers

Question 25

Evaluate the research method in Casey et al.

Answer 25

• exp 2 done in lab conditions so poss to control extraneous variables
• exp 1 used carefully standardised programme to present stimuli and recorded pp responses w high level of reliability and accuracy, so avoiding human error
• pps performed behavioural task from exp 1 on own homes so a greater poss of distractions and extraneous variables in environment

Question 26

Evaluate the data in case et al.

Answer 26

• data gathered was quantitative
• strength of this is allows for direct comparison of conditions, so shows young children who performed poorly in original delay of grat task later showed diminished cognitive control in alluring situations as adults
• but, this omits qualitative details e.g. Analysis of cognitive strategies employed by individual pps when approaching such situations
• researchers able to observed diffs between low and high delayers, but obtained no info about why their brains and behaviour varied significantly

Question 27

Evaluate the ethical considerations in Casey et al

Answer 27

• informed consent given by pps for both experiments
• as a brain imaging technique, fMRI considered low risk, and protection from harm of pps was assured.
• so overall ethically sound

Question 28

Evaluate the validity of Casey et al.

Answer 28

• ecological validity could be a weakness of study
• nature and representation of go / no go task was artificial and diff from how we normally encounter / respond to facial expressions
• use of fMRI scanning in task may have had impact on way in which pps respond to stimuli
• likely that genuine, social interactions are more complex and may mean our brains behave differently from how they do under artificial conditions like this

Question 29

Evaluate the reliability of Casey et al.

Answer 29

• method is fairly reliable as is high levels of control in lab experiments
• used an fMRI scanner to examine results + is likely that if experiment was repeated, similar results would occur if same had same equipment

Question 30

Evaluate the sampling bias in Casey et al.

Answer 30

• sample is limited even though initially drawn from large pool of 562 pps
• limited to individuals who attended one nursery during specific time period, meaning findings of study are geographically limited and may only represent people from similar family bckgrnds
• also, not all children from original delay of grat task took part and so in individual conditions there were much smaller no’s of pps.

Question 31

Evaluate the ethnocentrism in Casey et al.

Answer 31

• study looks at brain functions that are independent of cultural influences so does Sperry.
• so unlikely that findings of study are ethnocentric.
• but, might be that impulse control is nurtured diff in diff societies, so might mean cross cultural differences could be noted.

Question 32

Evaluate the practical applications in Casey et al.

Answer 32

• useful as has provided further evidence about localisation of neural function for tasks involving rewards and resisting temptation
• also found our ability to exercise self control is influenced by contextual cues greatly
• ability to delay immediate gratification in favour of long term goals is useful for individuals personal and social well being
• study shows how individual and situational factors can influence self control

Question 33

Compare the similarities between Sperry and Casey et al.

Answer 33

• both about biological psychology, specifically the role of diff regions of brain and both considered specific bran structures and their functions
• both studies conducted in labs, may reduce ecological validities
• both had restricted samples
• specific selection of pps was necessary in both for aims of studies
• both produced quantitative data
• both contributed to our knowledge of localisation of brain function, so useful to understand specific problems arising from damage to diff brain parts.

Question 34

Compare the differences between Sperry and Casey et al.

Answer 34

• S investigated consequences of split brain ops on perception and memory but C investigated differences in areas of brain activity that could be linked to delay of gratification
• C was longitudinal but S was not
• S full study conducted in lab, but C was only part in lab for use of an fMRI scanner
• tasks in S were relatively artificial but tasks in C were more realistic to day to day life