Arousal & Attention
Complete summary of articles
2013/2014
,1.
A. PS: What are the effects of stress on performance?
BS:
B. PS: What are the physiological effects of stress?
BS: Biology of arousal. Autonomic Nervous System: Parasympathic and
sympathic nervous system. Cortisol short term an advantage, on the long
term a disadvantage: HPA-axis.
Heart rate decreases -> freeze response, orienting attention towards the
noise.
Short term: adrenaline, long-term: cortisol (negative feedback loop)
I've read: Andreassi, Purves, Stern & Bear
C.
D.
Learning goals:
A. What is arousal?
B. How is arousal related to performance and how can you describe
this in a model? What is the additive factor model? General arousal theory,
(Andreassi), Additive model (Hockey), Cumulative model (Hockey).
General arousal model: inverted U-shape. Jerks Dotson law: performance is
related to arousal in an unverted U-shape, performance is best at medium
level.
Stressors can alter the degree of external (noise, temperature) or internal
stimulation (sleep deprivation or anxiety) . Additive: noise increases errors by
5% and heat by 10%, you can add these up, and the total error increase is
15%.
Cumulative depletion: a stressor not only adds up, but the outcome is more
than the sum up, because you cannot handle the second stressor.
C. What are the strengths and weaknesses of the models? (Hockey)
There are five weaknesses in Hockey. Falsifiability. Directional fractionation,
measure of some arousal dimensions can go up, but others can go down.
Methodology criticism, manipulations that increase arousal level, it is difficult
to define the effects of stressors on arousal level independently on
performance. The manipulation can have its own effect on performance
, independently of the effect on arousal. Evidence of the combination of
stressors is inconsistent, reticular formation seems to consist of multiple
neural systems. Dependent on the stressor, e.g. alcohol can be a stimulator
in small dosages but a depressant in big dosages.
D. What is the Easterbrook hypothesis? (Hockey)
Increase in arousal restricts the range of environmental events that could be
(…). Arousal high, important stimuli get suppressed when it is low only
distracters get suppressed. Task that is easier to perform with low arousal?
When you're too high aroused you can't make a test (stressed).
Hypothesis: low levels of arousal are better than high levels of arousal. More
arousal narrows down your attention, performance goes up first and than
after that it goes down. This is added to the Jerks Dotson law.
E. What is the Autonomous Nervous System? What are the
subsystems? Which neurotransmitters are involved? (Bear)
F. How is arousal measured? (Purves)
G. How does the HPA-axis function? What is the role of cortisol?
H. Which phenomena are behind the examples in the task? Explain
them (e.g. habituation).
I. Symphato Adrenal Medullar (Clow)
Releases adrenaline in to the bloodstream to prepare to fight or flight. The
adrenal medulla and the adrenal cortex. Your heart will beat faster and there
are changes in the blood vessels, contraction muscles and this effect is
instant and it doesn't last long. The body needs more oxygen and energy
which leads to the fight or flight response. The blood flow to the skeletal
muscles and brain increases while the
Stressor -> startle response (SNS) -> fight or flight: SAM -> escape, PNS.
Identify stressor, higher brain processes, integration of information,
perceived threatening: limbic system emotional responses. The limbic system
(hippocampus amygdala) directs behavior to survival ->hypothalamus gets
activated -> physical responses coordinated. The hypothalamus controls the
SAM and the HPA-axis (Clow). (!) there are two seperate systems, SAM and
HPA. SAM is also involved in pleasure.
Andreassi JL (2000) Activation. In JL Andreassi (Ed.) Psychophysiology: human
behavior and physiological response. Mahwah NJ: Lawrence Erlbaum Associates. (Pp
401-405) (The pdf in the Ereader contains the entire chapter. Focus on the pages
indicated here)
Activation
Relationship between variations in level of physiological activity and changes in
behavior. The intensity of behavior is called activation or arousal. Physiological
measures increased activation: increasing heart rate, blood pressure, muscle
potentials, skin conductance and EEG desynchronization. Decreased levels would
indicate lowered activity.
Experiment: shocks to mice, medium intensity shock led to more efficient learning
than weak or strong shock. For medium and difficult discrimination levels, shock led
to best performance -> intensity of stimulation and task difficulty must be taken into
account, studying influence of external stimuli on performance.