11 - Biological dispositions Flashcards
Define preparedness.
- An innate tendency for an organism to more easily learn certain types of behaviors or to associate certain types of events with each other
→ innate tendency for animals to condition to certain stimuli faster than to others
→ They are prepared to associate some stimuli
→ (especially biologically relevant stimuli)
___ plays a very important role in fear conditioning.
Preparedness
What is conditioned taste aversion (CTA)?
- Food item paired with gastrointestinal illness becomes a conditioned aversive stimulus.
- You become sick (UR) after ingesting a food item.
- You associate the food with the illness and subsequently avoid (CR) the food (CS)
→ very common - This process is adaptive when we learn to avoid substances that make us ill
- Sometimes we develop CTA of for substances that are only coincidentally associated with the onset of illness
Why are rodents very picky about what they eat?
- Rodents are unable to vomit
- CTA is an adaptive evolutionary trait, it is thus not good for rodents to not have this because it allows to get rid of what may be causing the illness
How does experimental conditioned taste aversion work?
- Can be learned if ingestion of a novel flavor (CS) is followed by illness (US)
- When later given a choice, the rat will avoid the sucrose water (because, even though the rat typically prefers sweet water over normal water, the sweet water became an aversive conditioned stimulus through its association with the illness)
–> Sweet water (NS): X-ray irradiation (US) -> Nausea (UR)
–> Sweet water (CS) -> Nausea (CR)
Why is conditioned taste aversion a unique form of classical conditioning?
→ conditioning occurs after just one trial (highly adaptive), they make the association very quickly and easily
→ conditioning can occur even if the CS-US interval is very long (i.e., illness occurs hours after novel flavor)
→ powerfully resistant to extinction
→ shows evolutionary preparedness to learn these pairings
How does stimulus generalization play into conditioned taste aversion?
- The food items that taste similar to the aversive item are also perceived as aversive
→ p.ex: if you don’t like shrimp, because of generalization you’ll likely avoid all sushi even if it isn’t shrimp, simply because seafood tastes similar
How does extinction play into conditioned taste aversion?
- If the aversive food item is repeatedly ingested without further illness, the CS (food) may no longer elicit an avoidance response
→ although it might take a long time
Define latent inhibition.
- A familiar stimulus is more difficult to condition than an unfamiliar (novel) stimulus
How does latent inhibition play into conditioned taste aversion?
- We are more likely to associate a relatively novel item, with sickness than we would a more familiar item
→ p.ex: if you’ve never tasted something before, your first response won’t be general agreeableness, it would be more cautious because of an evolutionary perspective to view anything that’s novel with a high degree of caution, so you might associate it with sickness - Latent inhibition helps explain why it is often difficult to poison a rat
→ When a rat encounters a novel food item, it will most likely eat only a small amount of the item before moving on to other, more familiar items
→ If the rat later becomes ill, it will associate the illness with the novel item
What happened in the CTA experiment with rats who drank bright, noisy, sweet water?
- Rats drank ‘bright, noisy, sweet’ water (paired with the bright light, and a noise)
- Rats then received one of two treatments:
→ foot shock (inducing pain/fear)
→ radiation (inducing nausea) - Rats given choice between bright, noisy water, and sweet water
- This experiment suggests that tastes are more readily associated with sickness than with shock (peripheral pain) and that audiovisual cues (light & noise) are more readily associated with pain/shock than with sickness
→ the rats that had been made nauseous by the x-ray avoided the sweet water and drank the bright noisy water and this is consistent with the notion that nausea is more readily associated with taste than with any other kind of stimuli
→ the rats that received a shock avoided the bright noisy water, and drank the sweet water; developed a fear of the noise and the light associated with the water, but not the taste of it
How does CS-US relevance play into conditioned taste aversion?
- An innate tendency to more readily associate certain types of stimuli with each other.
- Rats are predisposed to:
→ Associate nausea with taste
→ Associate painful events with visual and auditory stimuli
Give an example of how there are species differences in CTA.
- Rats and quail drank dark blue sour water, followed by injection of hydrochloric acid.
- Later given choice of dark blue or sour water
-
Rats showed a strong aversion to the sour flavour
→ Rats are nocturnal; depend of sense of smell for foraging
→ they thus avoided the sour water and preferred the dark blue water; they associated the taste of the sour water with nausea -
Quail showed aversion to the visual properties
→ Birds depend on sight for foraging
→ they thus avoided the blue water and preferred the sour water; they rely heavily on vision, and are thus more predisposed to associate the visual aspects rather than the taste aspects - These results show that there can be significant differences in what constitutes an effective CS across species
___ are typically better than ___ in detecting odors and discriminating amongst them
Females; males
- and also better able to associate it with nausea, thus women are more prone to developing taste aversions
Most women report that their sense of smell and taste is enhanced during the early stages of pregnancy, what is the benefit of this?
→ the fetus is highly susceptible to toxins at this stage, which is why they’re likely to develop a dislike of foods, especially bitter foods, and thus have higher chance to develop taste aversions because it enables them to highlight and identify dangerous bacteria that could be present and therefore avoid them
