L20 - Conditioned Taste Aversions

Question 1

hedonic reactions to tastes (4)

Answer 1

Sweet - react positively
salty - react positively when deprived
Bitter - taste alkaloids (poison) evoking disgust, can be accepted
Sour - detect presence of H+ ions in acids elicit disgust, easily learn to tolerate or even like

Question 2

Garcia affect “Conditioned taste aversion”

Answer 2

Animals consumes attractive thing, later animal made sick (normally with some sort of drug), animal with then avoid by association to food

Question 3

Bait shyness (1954)

Answer 3

WW2 failed attempts to poison rats, association between food and illness when consumed with poison
Radiation

Question 4

Radiation induced sickness (1951)

Answer 4

Garcia noticed disturbed eating in rats that had been irradiated

Question 5

CTA as a form of Pav conditioning (1955)

Answer 5

Conditioned aversion to saccharin resulting from exposure to gamma radiation - limited impact

Question 6

Garcia 2 big impacts

Answer 6

Stimulus-specificity of radiation based learning - aversion to just the taste of something
Conditioning despite long delays

Question 7

Practicality in the real world of taste aversion

Answer 7

The idea that taste aversion learning is specialised that serves the purpose in the real world to guide animals away from poisonous tastes

Question 8

Garcia’s 6 big claims

Answer 8

1. Stimulus selectivity: sickness associated with tastes, separately from audio
2. Long delay learning: occur when sickness follow many hours after taste
3. 1 trial learning
4. resistance to extinction (2 bottle test)
5. taste potentiation (tapping into an old memory) of odour aversion learning
6. Involves different brain structures

Question 9

Stimulus selectivity: Garcia and Koelling 1996: Noisy water experiment method

Answer 9

Rat drinks from bottle, experiences either audiovisual feedback or sweet taste, O - nausea of shock

Question 10

Garcia and Koelling 1996: Noisy water experiment

results

Answer 10

• If the animal had flashing light followed by nausea it shows no avoidance, if shock it would
  ○ Can easily mate light shock association but not easy to learn to avoid taste
• When animal got a sweet taste followed by nausea it avoided, followed by shock it didn’t
  ○ Later tests used lots of shocks under certain conditions and got some results but extremely difficult

Question 11

Long delay learning: Revusky (1971)

Answer 11

Relative lack of interference provides basis for long delay CTA, interference form other tastes can prevent delay learning

Question 12

Conditions long delay 2 conditions

Answer 12

1. Taste has to be novel, pre-exposing stimulus leads to slower learning, very pronounced with taste aversion learning, even one day exposure, long delay learning is much more difficult to obtain
2. Sickness has to be strong

Question 13

Relevance of blocking timing for long delay (Kwok, Harris and Boakes)

Answer 13

The later the overshadowing event, the greater the impact

Time matters, closer to sickness more overshadowing

Question 14

One trial learning

Answer 14

One-trial learning only occurs when taste is novel and strong as pre-x to taste retards later conditioning due to latent inhibition.

Question 15

Resistance to extinction

Answer 15

• 2 bottle test: that seems to suggest resistance as they aren’t making contact as they can always drink water
• 1 bottle: Nothing irreversible about taste aversion
• Shows orderly decline when tested

Question 16

Potentiation of odour aversion learning by taste (Rusiniak, Hankins, Harcia and Brett_

Answer 16

Drinking from sweet + almond smell later they show strong aversion to almond and saccharin, against overshadowing, expectation was that sweet taste would overshadow odour but not the case.

○ Instead opposite of overshadowing

Question 17

Gate hypothesis

Answer 17

Taste switches odour gut into gut defence learning system (didn’t last long)

Question 18

Reasons for gate hypothesis: rescorla and durlach

Answer 18

§ Depended on the idea of simultaneous associations, experiencing almond odour at the same time as sweet taste, odour reminds them of the sweet taste, not because of direct association but because it reminds the animal of taste

Question 19

Which of Garcias claim hold?

Answer 19

Stimulus selectivity
Long delay - based on SS
Taste potentiation: Based on 1
Brain structures - Yes but true for other kinds of learning

Question 20

Human taste aversion

Answer 20

Independence from cognition: Happens during cancer therapy, nausea triggerd by smells and taste, despite knowing chemo made them sick

• Different kinds of taste aversion learning, some involve disgust
• Paradoxical effects that support taste aversion learning (psychoactive drugs)

Question 21

How much percent of human CTA is connected to over-consumption, physical illness, food poisoning, allergic reaction etc.?

Answer 21

80%