RESEARCH METHODS (3)

Question 1

What are two main psychophysiological measures of autonomic nervous system activity?

Answer 1

Skin Conductance – measures sweat gland activity linked to emotions.

Cardiovascular Activity – measures heart and blood vessel responses like heart rate, blood pressure, and blood volume.

Question 2

What is skin conductance?

Answer 2

It’s the skin’s ability to conduct electricity, which increases when a person is emotionally aroused (due to sweat gland activity).

Question 3

What are the two main types of skin conductance measures?

Answer 3

Skin Conductance Level (SCL) – measures overall or background level of skin conductance in a situation.

Skin Conductance Response (SCR) – measures short-term spikes in conductance caused by emotional or specific experiences.

Question 4

Why does emotional arousal increase skin conductance?

Answer 4

Emotional states activate sweat glands, causing sweat to increase electrical conductivity on the skin’s surface.

Question 5

Which parts of the body show the strongest skin conductance responses?

Answer 5

Hands, feet, armpits, and forehead — because they have many sweat glands that react to emotional stimuli.

Question 6

What does skin conductance tell researchers?

Answer 6

It helps track emotional and psychological arousal (like fear, excitement, or anxiety) by observing bodily responses.

Question 7

What is cardiovascular activity and why is it important?

Answer 7

It involves heart and blood vessel function, which deliver oxygen and nutrients and react strongly to emotions (e.g., blushing, increased heart rate).

Question 8

What are the three main measures of cardiovascular activity?

Answer 8

Heart Rate (HR)

Blood Pressure (BP)

Blood Volume (BV)

Question 9

What is an electrocardiogram (ECG or EKG)?

Answer 9

A recording of the electrical signals from each heartbeat using electrodes on the chest.

Normal resting heart rate: ~70 bpm in adults.

Can quickly increase with emotional stimuli (e.g., hearing a dentist drill).

Question 10

How is blood pressure measured and expressed?

Answer 10

Measured in millimeters of mercury (mmHg).

Expressed as systolic/diastolic (e.g., 130/70 mmHg).

Systolic: peak pressure when the heart contracts.

Diastolic: minimum pressure when the heart relaxes.

Normal: ~130/70 mmHg

High (hypertension): over 140/90 mmHg.

Question 11

What tool measures blood pressure?

Answer 11

A sphygmomanometer — cuff, bulb, and gauge that measures arterial pressure.

Modern studies often use automated digital monitors for accuracy.

Question 12

What is blood volume and how does it change?

Answer 12

Blood volume is the amount of blood in a body region. It can change with psychological or emotional states — like genital swelling during sexual arousal.

Question 13

What is plethysmography?

Answer 13

A method for measuring blood volume changes in a specific body part. (“Plethysmos” means enlargement.)

Question 14

What are two methods of plethysmography?

Answer 14

Strain Gauge Method: Wrap a sensor around the tissue to detect changes in size (used for fingers or similar organs).

Light Absorption Method: Shine light through tissue — more blood = more light absorbed.

Question 15

Why do psychologists study cardiovascular and skin conductance measures?

Answer 15

Because they both reflect autonomic nervous system arousal, which links to emotions, stress, and physiological changes in the body.

Question 16

What is stereotaxic surgery?

Answer 16

A procedure used to precisely position experimental devices (like electrodes or lesion tools) deep inside the brain. It’s the first step in many animal brain experiments.

Question 17

What two things are needed for stereotaxic surgery?

Answer 17

Stereotaxic Atlas – a brain map that shows coordinates for each brain structure.

Stereotaxic Instrument – a machine that positions the device accurately in 3D.

Question 18

What is a stereotaxic atlas and how does it work?

Answer 18

It’s like a map of the brain, showing 3D locations (anterior–posterior, dorsal–ventral, and lateral–medial). Each page shows a 2D brain slice, and all distances are measured from a reference point called bregma (where two skull seams meet).

Question 19

What are the main parts of the stereotaxic instrument?

Answer 19

Head Holder – keeps the subject’s head still and in position.

Electrode Holder – holds and moves the tool (electrode, needle, etc.) in three dimensions with precision gears.

Question 20

What are lesion methods used for?

Answer 20

To study brain function by damaging or deactivating specific areas and observing how behavior changes.

Question 21

What are the four types of lesion methods?

Answer 21

Aspiration Lesions

Radio-Frequency Lesions

Knife Cuts

Reversible Lesions

ARK reverse

Question 22

What is an aspiration lesion?

Answer 22

Used for surface (cortical) areas of the brain. The tissue is sucked out using a small glass pipette. The white matter and blood vessels underneath are left mostly unharmed.

Question 23

What is a radio-frequency lesion?

Answer 23

Uses a stereotaxically placed electrode that sends high-frequency current. The heat destroys nearby brain tissue. Size and shape of lesion depend on current intensity, duration, and electrode tip shape.

Question 24

What is a knife cut lesion?

Answer 24

A small, deliberate cut made to interrupt neural connections without major damage. Often used to cut nerve tracts or pathways in the brain.

Question 25

What is a reversible lesion?

Answer 25

Temporary inactivation of a brain region (no permanent damage). Achieved by: Cooling the target area, or Injecting an anesthetic (e.g., lidocaine). Allows testing of the same animal with and without the lesion, making results more reliable.

Question 26

Why must we be cautious when interpreting lesion effects?

Answer 26

Because: Brain structures are tiny and close together, so nearby areas can also be damaged. It’s easy to mislabel a lesion (e.g., calling it an “amygdala lesion” when nearby tissue is also harmed). This can lead to incorrect conclusions about what each brain region actually does.

Question 27

What’s the main advantage of reversible lesions over permanent ones?

Answer 27

They let researchers compare the same subject’s behavior before, during, and after inactivation — controlling for individual differences.

Question 28

What’s a real-world example of using lesion methods?

Answer 28

Researchers might lesion the amygdala to study how it affects fear or aggression — but must ensure surrounding regions aren’t unintentionally affected.

Question 29

Why must we be cautious when interpreting amygdala lesion studies?

Answer 29

Not all 'amygdala lesions' damage the entire amygdala. If a lesion leaves part of the amygdala intact and damages nearby areas, effects may be wrongly attributed to the amygdala. If researchers assume all lesions include the whole amygdala, they might wrongly conclude the amygdala isn’t involved in certain behaviors.

Question 30

What is the difference between unilateral and bilateral lesions, and how do they affect behavior?

Answer 30

* Unilateral lesions: damage only one side of the brain; effects are usually mild and sometimes hard to detect. * Bilateral lesions: damage both sides; effects are generally stronger and more noticeable. Most experimental studies focus on bilateral lesions because they produce clearer behavioral results.