Applications

Question 1

what are the three As?

Answer 1

• avoidance
• anxiety
• aversion
• phobias are very common and debilitating
• leads to poor health and/or poor quality of life
• these are inevitably learnt fears

Question 2

what is conditioned aversion?

Answer 2

• “Anticipatory Nausea and Vomiting” is likely to be due to conditioning
• Patients anticipate sickness prior to treatment (i.e., the absence of the US).
• The US is the treatment drug.
• The UR is nausea (which becomes a CR)
• What is the CS?

Question 3

what did Rodriguez, Lopez, Symonds & Hall 2000 study?

Answer 3

• Rats placed in a “context” and given an injection of Lithium Chloride (LiCl).
• LiCl makes animals feel very sick, however…
• …rats don’t tend to vomit from this. So what can we measure?
• Low consumption of a novel flavour indicates nausea is present.
• Rodriguez et al. (2000) used this logic to test conditioned nausea to “context”.

Question 4

what is conditioned nausea?

Answer 4

• These data demonstrate how “context” can become associated with nausea.
• Hugely problematic: e.g., chemotherapy patients anticipate nausea in the setting in which treatment was given
• And experience worse effects of the treatment as a result.
• This reflects what is termed a “nocebo” effect…

Question 5

what is the Nocebo effect?

Answer 5

• The act of taking a drug can promote positive outcomes, over and above those attributable to the active ingredient
• In ANV we are seeing what is termed a “Nocebo” effect: the outcomes are worse as a result of psychological factors (i.e., conditioning)

Question 6

how do we combat ANV in humans?

Answer 6

• Galvanic Vestibular Stimulation
• Stimulation causes a mismatch of the vestibular and visual systems
• This has a strong nauseating effect.
• The GVS generates substantial nausea
• Critically the nauseating effect can be turned ON and OFF
• Does conditioning lead environmental stimuli to become aversive (i.e., a nocebo effect)?
• Quinn, Livesey & Colagiuri (2017)
• Does conditioning lead to increased nausea (a “nocebo effect”)?
• Can we alleviate those symptoms?
• Placebo = GVS not active (but lights displayed and is worn by participant)

Question 7

what is latent inhibition?

Answer 7

• We know from work on animal cognition, that pre-exposure of a stimulus (or context) leads to impaired learning.
• Seen in many animals, including goldfish, goat, sheep, rat, mouse, rabbit, dog, snails.

Question 8

what are the conclusions from placebo studies?

Answer 8

• Subjective reports of nausea are influenced by aversive context cues
• These cues enter into associations with the outcome (nausea) and exacerbate symptoms
• Could have a meaningful consequence on seeking treatment
• Treatment? Can be alleviated with pre-exposure!

Question 9

what is the prevalence of targeting?

Answer 9

• Checking bags is hard!!!
• Target difficulty; Object similarity; Varied arrays; Target prevalence
• If targets occur on 50% of trials, miss rate is fairly low (7%)
• If targets occur on 2% of trials, miss rate is very high (30%)
• Security experts know this. They project dangerous items onto baggage during screening

Wolfe et al., 2013
- How does target prevalence affect search in the training of security screeners?
- High prevalence blocks appear to boost detection, even for subsequent low prevalence blocks
- Potentially important technique for improving baggage screening

Question 10

what did Evans et al., 2013 study?

Answer 10

• Low prevalence effects might be adaptive – but in critical life or death situations, this is BAD.
• How does “target prevalence” affect the detection of cancer for expert mammographers?
• Selected 100 real cases: 50 with cancer; 50 without

Question 11

what were the methods used in Evans study?

Answer 11

• Low prevalence condition:
  -100 cases introduced in a “slow trickle” manner
  - During regular screening workflow of clinicians over a 9-month period.
  - Minor increase in prevalence rate from 0.3% to 1%.
• High prevalence condition:
  
  • All 100 cases seen in a single ~3 hour sitting
  • Conducted in experimental laboratory setting.
  • Substantial increase in prevalence rate from 0.3% to 50%.
• limitations of this design
  
  • Many factors not controlled: environment; motivation; time of day, etc.
  • It is a trade-off between control and practicality.

Question 12

what were the results of the Evans study?

Answer 12

• False negatives decrease, and false positives increase, under HIGH prevalence conditions
• Decreasing false negatives (not detecting a cancer when it is present) is certainly more important that the downside (FP: falsely detecting cancers that are not there).
• How might we embed this to aid detection in the real world?

Question 13

what quick is detection made?

Answer 13

• “Global image statistics” can be extracted in just 500 milliseconds
• Enough for above chance detection of abnormalities by experts
• Experts cannot state where the abnormality lies in this time.
• This aligns with the two-stage model of visual search (Triesman, 1985).
  - Parallel extraction of sensory information
  - Serial bindings of features for target detection.

Question 14

how does visual search work in the real world?

Answer 14

• Low prevalence can substantially reduce target detection
• Artificially high prevalence conditions may provide a means to negate this effect
• Gist results support classic two-stage models of visual search
• Rapid gist extraction may offer a cost-effective boost to effective screening method (combined with other methods)