Week 3: Inferential Goals and Brainstem and Cerebellum Function

Question 1

What is scientific inference in psychology?

Answer 1

Scientific validation of ideas relies on making inferences based on available evidence

Data are not all created equal! - Differences in “quality”

Inference requires judging how strongly data support a claim

Question 2

What are the requirements for making an inference?

Answer 2

Evaluating the quality of the evidence
Does the measure assess what the researcher says it assesses?
Is the evidence reliably reproducible?
Is the evidence measured quantitatively and objectively?

Evaluating how the evidence relates to theory
Is the evidence consistent with one theory or multiple theories?
Do any theories fail to explain the evidence?

Question 3

What is a quantitative measurement?

Answer 3

Allows us to put a numerical value on a measurement
“Tall” is no longer subjective or relative
Permits objective measurement by others

Perhaps most importantly, quantitative measurement allows for comparison
Of groups of individuals
Of the same individual through time

Question 4

What do we do with samples and populations and what are the potential pitfalls?

Answer 4

In most cases, we measure something about a sample of people and seek to form generalized conclusions about the population at large

What is true of the sample/population need not be true of the individual

What is true of the sample need not be true of another sample (even if both are drawn from the same population)

Question 5

What two factors should measures contain for valid inferences?

Answer 5

Measures should be both reliable and valid

Question 6

What is reliability?

Answer 6

Refers to how “repeatable” or consistent a measure is

If you were to assess the same construct in the same way using the same method of measurement, do you tend to get the same results?

Question 7

What is Validity?

Answer 7

Refers to the degree to which a measure assesses the thing it is purported to assess

Is the construct you seek to measure actually related to the measurement?

Question 8

What was the hot topic of the 19th century that was discussed?

Answer 8

Racial hierarchy, tried to use cranial capacity to determine that whites were smarter. Used mustard seeds but was not repeatable and then used buckshot.

Question 9

What was the problem with the cranial capacity issue in terms of reliability and validity?

Answer 9

Problem: Cranial capacity does not really relate to intelligence… It’s not the size, it’s how you use it

But cranial capacity does relate to overall body size
Morton’s measure is conflated with body size (and potentially nutrition, etc.)

If the measure is not a valid reflection of the construct of interest, neither are the inferences based on the measure.

Question 10

What are the three measures of central tendency?

Answer 10

Mean (average score)
Median (the “middle” score in a distribution)
Mode (the most common score)

Question 11

What are the measures of variability?

Answer 11

Range Measures

Standard Deviation

Question 12

What can occur between the use of different measures?

Answer 12

Quantitative measurement provides the basis for making defensible scientific inferences that are grounded in data

However, choosing an appropriate measure is not always straightforward—measures must be reliable and valid

Even with good measures though, there is a problem that is created by variability of data across different samples

Question 13

How likely would a difference be between a treatment and control group of an unsuccessful drug?

Answer 13

A truly ineffective treatment would mean both groups score the same
So a large difference would be very unlikely if the treatment were ineffective
If we see a large difference, conclude the treatment is effective

Question 14

What can alter the values of two sample groups?

Answer 14

Due to variability in samples though, the groups won’t have exactly the same mean score even if the treatment is ineffective

Usually small differences, sometimes positive, sometimes negative …but sometimes a very large difference will occur due to chance

Question 15

Why are multiple studies needed?

Answer 15

False positives, cause the wrong effect to be accounted for.

Question 16

What is the difference between practical significance and statistical significance?

Answer 16

Differences that are larger than would be expected by chance are considered to be “statistically significant”

This is a separate issue from “practical significance” (useful result).

Question 17

What are some of the issues relating evidence to theory?

Answer 17

Issues when evaluating scientific claims based on statistical evidence
Can another theory explain the same data?
Are there theories that cannot explain the data?

If other theories can explain the same data, future work will need to try and distinguish between those theories!

If there are theories that are unable to explain the current data, they may need to be modified, or potentially abandoned

Question 18

What is the brainstem/ANS associated with?

Answer 18

States of consciousness

Question 19

What is the Cerebellum/Motor System associated with?

Answer 19

Feedback control of movement

Question 20

What comprises the central nervous system (CNS)

Answer 20

Brain and spinal cord

Question 21

What comprises the peripheral nervous system (PNS)

Answer 21

Somatic Nervous System
– Voluntary
– Motor and Sensory

Autonomic Nervous System
– Involuntary
– Heart-rate, respiration, sweating
– Stress, arousal, “fight-or-flight”

Question 22

What are the two divisions of the ANS? (autonomic nervous system)

Answer 22

Sympathetic Nervous System
– Emotional arousal, stress, fear
– “Fight or Flight” response
– Increases heart-rate, respiration,
perspiration, pupils dilate.

Parasympathetic Nervous System
– “Rest and digest”
– Lowers heart-rate, respiration
– Increases stomach, intestine
activity (digestion)
– “opposes” the sympathetic nervous
system

Question 23

What are some functions of the Brainstem

Answer 23

Autonomic nervous system functions

Relay between cortex and spinal cord cortex and cerebellum

Question 24

What comprises the Brainstem?

Answer 24

Medulla oblongata, pons, and midbrain

Question 25

What is the function of the Medulla?

Answer 25

Autonomic nervous system functions

Controls heart-rate, respiration, regulation of blood pressure, body temperature
Reflex centres for coughing, sneezing, swallowing, vomiting

Question 26

What are the two discussed disorders of consciousness?

Answer 26

Persistent Vegetative State and “Locked-in” Syndrome

Question 27

What occurs during a persistent vegetative state?

Answer 27

Severe damage to upper brain (hemispheres and cortex)

If brainstem is not damaged, autonomic nervous system functions can remain

sometimes normal respiration, control of heart rate, some face and eye movements remain

Patients have no conscious awareness

Question 28

What occurs during a “Locked in syndrome” state? What causes this?

Answer 28

Amyotrophic Lateral Sclerosis (ALS) or Motor Neuron disease – Loss of motor neurons to spinal cord
or Brain injury (following accident)

Intact cerebrum and brainstem, but
“disconnected” from spinal cord

Normal cognitive function, vision, and
hearing, but patients cannot move

Patients may be fully conscious and
aware, but totally unresponsive

Question 29

How can Persistent Vegetative State and “Locked-in” Syndrome be distinguished?

Answer 29

“Locked-in” patients appear the same as those with persistent vegetative state

Cortex is fully functioning in Locked-in patients
What is their conscious awareness?
Functional MRI to detect brain activity
and allow some communication

Question 30

What are the functions of the Cerebellum

Answer 30

Hind brain (latin for little brain)

Sense of balance and co-ordination of complex movement

Motor learning – fine adjustment of movement based on feedback

Question 31

What does primary motor cortex activity lead to?

Answer 31

Movement (muscle contraction), found anterior to central sulcus

Remember Homunculus distribution.

Question 32

What does sensory cortex cortex activity lead to?

Answer 32

Leads to sensation, found posterior to central sulcus

Remember Homunculus distribution.

Question 33

What are motor programs for movement?

Answer 33

Movements planned and “programmed” in the brain before initiation, like a computer program (theory from 1960’s)

Brain creates program just before movement.
OR
Brain retrieves program for learnt skilled actions – eg signature, tennis swing, etc

Question 34

What is the feedback loop for a planned action?

Answer 34

Vision/Proprioception/sensation is compared to the desired and expected result, learning occurs

Question 35

What are the three levels of the brain and their functions?

Answer 35

Going from Lower to higher

1. Brainstem, Cerebellum Autonomic nervous system functions (heart-rate, respiration, blood pressure) Movement co-ordination (Low Level)
2. Limbic System Fear/threat learning (amygdala) memory, navigation through environment (hippocampus) (Higher Level)
3. Cerebral Hemispheres – Cortex Planning, reasoning, problem-solving (frontal lobe)
   Language (temporal lobe)
   Visual Perception and Action – perceiving complex world and interacting within it. (occipital and parietal lobe; motor cortex) (Highest Level)

Question 36

What did the Stroop experiment show?

Answer 36

Reading seems to be an autonomic process which are hard to override.