W3 Neuroscience Research Design Flashcards

1
Q

What are the IVs and DVs in a purely experimental design?

A
  1. IV = the variable being manipulated
  2. DV = the variable being measured, to see if changing levels of the IV is linked with changes in the DV
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2
Q

How does the IV differ in cognitive neuroscience?

A

the IV is also measured, and not necessarily manipulated

Example = Effect of age on brain function, eg. AGE = IV even though you are not manipulated age

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3
Q

How does cause and effect link to IV and DV?

A
  1. Cause (IV)
  2. Effect (DV)

Example: neuropsychological condition (IV) is linked with changes to cognition (DV)
However if IV is still measured, it is harder to establish casualty

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4
Q

What’s an example of using multiple IVs and DVs in a study?

A

Manipulate working memory load (IV) and measure individuals working memory capacity (IV) to determine effect on a vigilance task (DV)

The 3 DVs include reaction time, accuracy and BOLD activation

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5
Q

How can a psychological process either be a DV or an IV?

A
  1. it depends on the context
  2. Example = measuring memory (DV) or manipulating memory load (IV)

effects of caffeine (IV) on anxiety (DV)?
Or effects of anxiety (IV) on caffeine consumption? (DV)

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6
Q

What are the top 7 common DVs in cog. neuroscience?

A
  1. Electroencephalopathy (EEG)
  2. Eye tracking
  3. Event related potentials ERPs
  4. Diffusion tensor imaging (DTI)
  5. fMRI
  6. Magnetoencephalography (MEG)
  7. Accuracy, response time (RT)
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7
Q

What are the top 4 common IVs in cog. neuroscience?

A
  1. presence of a neuropsychological condition vs. healthy controls
  2. Presence of a type of stimulus over another, fear vs. neutral
  3. Performance on a task vs. another task, spatial vs. verbal
  4. transcranial magnetic stimulation (TMS)
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8
Q

What are the pros and cons of repeated measures design?

What is the solution?

A

Pros: increased Power as individual differences are accounted for as they are constant across all conditions

Cons: potential order effects, practice effects, fatigue

Solution: counterbalancing

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9
Q

What does counterbalancing achieve?

A
  1. alternating the order of conditions that participants enter into first,
  2. practice effects still occur, but is balanced across conditions, but it mitigates order effects, without you can have a confound of order effects
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10
Q

Why does the time period between RM experimental conditions need to be considered?

A

anything you do to participants (experimental manipulation) that may affect them for several hours,

eg. drinking coffee, inducing a negative mood, might have an effect on the next IV condition they go into

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11
Q

What are the pros and cons of independent groups design?

What is the solution?

A

Pros: no potential order effects

Cons: pre-existing individual differences on the DV from different individuals being in different conditions

Solution: random assignment to conditions, and large N sample, balances out individual differences and reduces risk of outliers, more likely that scores reflect the effect of the IV instead of individual differences

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12
Q

What are manipulation checks?

A

to check whether the IV is functioning as intended, as it can affect results if IV is not working on DV

(Not always feasible to do manipulation check, eg. age, but is useful)

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12
Q

What is an example of a mixed design study?

A

3 age groups of people and 2 working memory conditions,
- separate age groups (IG IV) but everyone is in both memory conditions (RM IV)

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13
Q

What is an example of a manipulation check?

A

EXAMPLE - Mood on memory -
IV: inducing positive, neutral or negative mood

MC = ask people to rate their mood on a likert scale of pos-neg - and check whether conditions produced significantly different mood ratings corresponding to the IV conditions, positive moods should produce high positive moods, etc.

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14
Q

What if the manipulation check didn’t pass, eg. people rated similar mood ratings on a mood induction IV?

A

If you got similar mood ratings throughout the conditions, you can’t draw conclusions about mood on memory if you haven’t effectively manipulated mood to study memory

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15
Q

What is error variance and what do you need to check?

A
  1. variables that are not the focus of the study, need to determine if it significantly influenced the IV:
  2. ASK = has this error variance systematically varied with the levels of the IV?
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16
Q

What are cofounding variables? + example?

A
  1. A type of variance systematically varied with the levels of the IV and could impact the DV

Example: order effects - in a within-groups design, if all participants do A and then B, and performance on a task is significantly lower in B for no other reason apart from the fact that they did B second

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17
Q

What makes order effects a potential confounding variable?

A

Order is a confounding variable because it is impossible to determine whether the decreased performance was due to order effects, the IV or a combination of both

Solution = Counterbalancing this means that the decrease in performance is no longer co-varying with levels of the IV, easier to make a statement that performance is due to the IV memory load rather than the order effect

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18
Q

What are non-systematic sources of error variance?

A

are often present and cause background noise - can’t get rid of - make sure they don’t systematically co-vary with levels of the IV

Eg. background noise in a laboratory study that could impact participants performance

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19
Q

How does Non-systematic sources of error variance differ between IG and RM designs?

A
  1. In an independent-measures design, if ONE IV group is affected by background noise, and the other is NOT = CONFOUND

In RM design, if something is affecting their performance in ALL of their conditions, NOT IDEAL BUT NOT A CONFOUND, because it’s not systematically impacting ONE level of the IV over the OTHERS

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20
Q

What is the Difference Score Approach?

A

1.when a DV (accuracy, RTs, ERP) is compared between two conditions, and these two conditions are the same except for one topic of interest

  1. mostly used in RM conditions
  2. If there is a difference between conditions, then it can be attributed to the one difference between conditions
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21
Q

What is the difference score in the Stroop effect?

A

RTs on the congruent - incongruent condition produces a difference score for semantic processing

Differences in trials strongly suggest its due to a difference in congruency of words and colours, and not colour processing, because everything else but the congruency of the words/colours is kept constant

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21
Q

What is an example of the Difference Score Approach in attentional orienting?

A

Cueing Scores from Cueing Paradigm

  1. reaction time is compared with VALID trials to INVALID trials

Everything else but the valid/invalid trial is kept constant so it makes it easy to attribute it to the location of the cue to target

RT of valid trial - RT of invalid trial = cueing difference score

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22
Q

What is the difference score in the Attentional Blink?

A

RT + accuracy on T2 on single task trials - dual task trials
= attentional blink (difference score)

Easy to attribute difference from the two conditions to the attentional requirement of having to find T1 and not error variance

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23
Q

Why are difference scores mostly used in RM designs?

A

because since individual differences are kept constant, they can’t be responsible for the difference in conditions, so it can easily isolate the topic of interest being measured

24
Q

What is the difference score in N170 ERP Component? FACE PROCESSING

A

ERP amplitude on trials with faces - ERP amplitude on trials with objects

(Key difference between faces and objects helps researchers isolate specifically the face processing aspects of an ERP)

25
Q

What is the difference score in neural emotional responsivity between fear vs. neutral images?

A

BOLD signals in amygdala of emotional image - BOLD signals in amygdala of neutral image

26
Q

Why are difference scores used?

A

Without controlling for difference scores, it is harder to rule out error variance that could be influencing the IV on the DV

27
Q

What are relative and absolute differences?

A
  1. differences between conditions
  2. differences from a baseline
28
Q

why is absolute difference important?

A

absolute performance can influence the sensitivity of a design to detecting differences between conditions

Example = Results: 0% relative differences between real and sham conditions but 25% accuracy absolute different object recognition for both conditions, but since 1 of 4 options to chose, 25% of getting it right, so people performed only at chance level

29
Q

What is the effect for chance level performance?

A

FLOOR EFFECTS

30
Q

Why do FLOOR AND CEILING EFFECTS IMPAIRS YOUR ABILITY TO DETECT DIFFERENCES ?

A

IT MIGHT LOOK LIKE THERE IS NO DIFFERENCE IN CONDITIONS, EVEN WHEN IV DOES HAVE AN EFFECT

If both conditions produced exactly chance level performance - NOT A SENSiTIVE PART OF THE PSYCHOMETRIC FUNCTION, EVEN WHEN YOU’RE NOT PLOTTING A PSYCHOMETRIC FUNCTION -

31
Q

What’s wrong with 98%-100% performance level?

A

cannot determine which is better, ceiling effects obscure detecting differences between conditions

If all conditions scores were 75%, it would be easier to draw conclusions

32
Q

Example of ceiling effects?

A

Object-Substitution Masking = when a target and a mask are presented closely together in space and time
Masking occurs = when target and mask are perceptually treated as the same object, reducing perception of real target

Conclusion: there appears to be an interaction between set size and trailing mask duration (OSM)
But! At absolute performance (when set size is 1) there are ceiling effects across all trailing mask duration

33
Q

How to get rid of ceiling effects, and example of how this can produce different results?

A
  1. make the task harder
  2. Once performance was ‘off ceiling’ the interaction between set size (attention) and trailing mask duration (OSM) disappeared
34
Q

How can we tell that the ceiling effects disappeared in the OSM study? and that the effect disappeared?

A
  1. no change in the effect of mask duration performance with increasing set size, the performance goes down at the same rate across all the set size conditions
  2. PERFORMANCE AT SET SIZE 1 IS NOW DECREASING AT THE SAME RATE AS SET SIZE 16
35
Q

What are necessary vs. sufficient conditions?

A
  1. A necessary condition is a condition that must be present for an event to occur, eg. a prerequisite but doesn’t guarantee an outcome
  2. A sufficient condition is a condition that will DEFINITELY produce an event, but is not necessary for that even to happen
36
Q

What’s an example of necessary vs. sufficient conditions?

A
  1. it is a necessary condition to take psyc2008 before psyc3015, but it DOES NOT GUARANTEE that you will pass psyc3015
  2. it is a sufficient condition to get 80% to pass the course, but it’s not necessary to get 80% to pass the course
37
Q

What is an class example of both a necessary and sufficient condition?

A

getting a grade of 80% on a course is both NECESSARY to get a HD and SUFFICIENT to get a HD

  1. Need at least 80 as prerequisite for HD
  2. Getting an 80 is sufficient to definitely produce a HD
38
Q

What is an neuropsych example of both a necessary and sufficient condition?

A

If fusiform gyrus responds to faces and not other stimuli, it is both NECESSARY (only lights up face processing) and SUFFICIENT (definitely processes faces) conditions for the FFA to be face–selective

39
Q

What is an example of a single dissociation?

A
  1. patients to have damage to V5 and have difficulty piercing motion but not visual forms
  2. this suggests V5 is implicated in motion, and that motion and form processing are distinct
  3. show impairment to 1 psych process, but another psych process is intact
40
Q

What is the problem with only having single dissociation evidence?

A

Problem: difficulty confound = motion processing might just be more complex/sensitive, and more susceptible to cortical damage

41
Q

What is a double dissociation and why is it better than single dissociation?

A
  1. Double dissociation = 2 groups: 1st group with damaged V5 and struggle processing motion but not form, 2nd group with damaged V4 and struggle processing form and not motion
  2. Stronger evidence that motion and form processing are distinct because it RULES OUT the idea that difficulty confound
42
Q

How are variables and participants set up in a stats spreadsheet?

A
  1. Participants = in rows
  2. Variables = in columns
43
Q

How does RM design differ in stats spreadsheet?

A

each column represents the different times / conditions participants are in, eg. T1 and T2

44
Q

What are the 2 things that an IG groups study can explore?

A
  1. An IV and DV
  2. The correlation between two things
45
Q

What were the differences in effects whether the study was IG or RM

A
  1. RM study = significant
  2. IG study = non significant
46
Q

Why might a RM study produce a significant result on the same data scores?

A

because in RM study, the subjects effect is not included as an error term so it results in a greater attribution of explained variance in the RM compared to IG design

47
Q

What was the study on how attention modulates the effect of emotionally salient stimuli on the brain? (Vuilleumier et al. 2001)

A

IV - fearful vs. neutral faces
IV - location of expressive faces with cue with valid / invalid trials
Cued with 2 of the 4 possible stimuli, and asked whether the houses / or the faces are the same

Picture = faces are task relevant, same spot as cue
Some trials cued house task, other cued face task

48
Q

What were the Vuilleumier findings on attention of emotional stimuli?

A

In the attended trials - FEARFUL faces generated bigger amygdala response than neutral

In the unattended trials - fearful faces STILL generated higher amygdala response than neutral, but much less than attended trails, appearing in the location that was not task relevant

Conclusion: attention does not significantly modulate the effects of emotional stimuli, both attended and unattended trials still produce amygdala activation when presented with fearful faces

49
Q

What criticism did Pessoa et al. (2002) express about Vuilleumier findings on attention of emotional stimuli?

A
  1. They argued that Viuilleumier’s findings stemmed from having an insufficiently powerful manipulation of attention
  2. Argued that the unattended trials were actually still being attended to
50
Q

What did Pessoa change about the attention on emotion study?

A

Pessoa changed the design of the study to make the unattended condition more difficult and rigorous

  1. Attended condition - “attend faces” - cue - face shown
  2. Unattended condition - “attend bars’ - cue - two bars shown and figure out, are they the same length?

The bar length task is argued to have a stronger manipulation of participant’s attention

51
Q

With stronger manipulations, what are the findings and conclusion of the Pessoa study?

A
  1. significantly higher amygdala activation in the attended conditions, of valenced emotion stimuli fearful and happy and neutral faces
  2. Significantly lower amygdala activation, in the unattended

Conclusion = when you effectively modulate attention, attention DOES moderate the effect of emotional faces in the amygdala,

attention can silence the emotional response in the brain, if the fearful faces aren’t been attended to and when you have to focus on a stronger attentional task

52
Q

What’s the experimental control in the Pessoa study?

A

Experimental control = the bars are still present in the ‘attend faces’ condition, to rule out if any differences between conditions could just be attributed to low level perception of stimuli

53
Q

What is the issue with a study getting an RM study of participants to learn material without a study technique, then with a study technique?

What is the solution?

A
  1. Problem = Practice effects could be causing the enhanced results, because people are familiar with the study material on the second time
  2. Partial solution = Counterbalancing but people who did the study technique first might still use it in the condition without a study technique
  3. Solution = Independent groups might be the most appropriate design for this study
54
Q

What’s wrong with allocating the first 50 people to one condition who sign up and then the next to the other condition?

A
  1. There is a confound by allocating the first 50 participants into 1 condition, the first group may have slightly different characteristics to the slower second group, eg. higher conscientiousness, reaction speed
  2. Need random allocation in independent groups!
55
Q

What manipulation check is important for an attentional blink?

A

are you actually getting an attentional blink? Does the IV actually have an effect?
If the attentional blink didn’t work/was too easy, you can’t make conclusions about the DV (semantic processing of words)

56
Q

What manipulation check is important for testing whether broad attentional breadth from happy states leads to weaker activation in the visual cortex?

A
  1. measuring attentional breadth, What do you really need to check to make conclusions about the study?
  2. thus MC is on baseline attentional breadth compared to broad
57
Q

What’s wrong with a study testing attentional bias intervention pre and post only for anxious people?

A
  1. Need a control group!

To establish a difference in whether there are attentional bias differences in clinical and nonclinical populations

As variations in the environment influence feelings of anxiety over time, a baseline control group controls for external variables that might influence the anxious groups results

58
Q

What is a rebuttal that cueing scores in the Posner Cueing paradigm just reflect non-spatial alerting and not actual shifts of attention?

(Non-spatial alerting is when there is a cue telling you that a target will appear in some location, but some people stop focusing on the cue location, and thus the cueing score might reflect non-spatial alerting instead of shifts of attention)

A
  1. Since the cueing score is the difference between types of trials, if both trials would affected by the effect of non-spatial alerting, it would be present in both the valid and non valid trails - IT CANCELS OUT AND THUS DOES NOT IMPACT THE CUEING SCORE

It is possible to draw a conclusion about attention orienting from cueing score because the valid/invalid trials are kept constant except for the predictiveness of the target’s location

59
Q

What do you need to support evidence that ffa is face-only processing after finding a single dissociation?

A
  1. Since it could be argued that face processing is similar more straining / thus more vulnerable to damage but still an element of object processing
  2. We need divergent evidence in the form of DOUBLE DISSOCIATION
  3. Example = fmri activated in different parts of the brain of healthy participants for object tasks vs. face tasks
    OR a group of patients with damage to another part of brain who can recognise faces but struggle with objects