Learning about time Flashcards
What is periodic timing and give an example?
Periodic timing is learning to respond at a particular time. An example is Circadian rhythms-internal 24 hour clock.
What is interval timing?
Learning to respond after a particular interval of time.
What did Roberts find when studying rats and cockroaches?
They seem to have an internal 24hr clock like a circadian rhythm that continues even without external visual cues that tell us what time of day it is. This clock is more consistent when cues are available.
Is the apparent internal 24-hour clock the result of environmental experience? Describe Bolles & Stokes (1965) study.
Bolles & Stokes reared rats under either 19, 24 or 29 light/dark cycles. The light was changed just before they were fed at the same time every day.
What did Bolles & Stokes (1965) conclude from their study?
The 24 hour rats had increased activity when the light was turned off but the other rats showed no anticipation of the food. This shows that there is an intrinsic 24 hour clock that can’t be shifted by changing their experience.
What is a possible physiological system responsible for the 24 hour clock?
The suprachiasmatic nucleus (SCN) of the hypothalamus.
What are 3 reasons why the SCN could be the source of circadian rhythms?
- The metabolic rate in the SCN appears to vary as a function of the day/night cycle.
- Lesions of the SCN abolish circadian regularity in rats.
- SNC receives direct and indirect inputs from the visual system which is essential for synchronising the internal and external clocks.
What other evidence is there regarding circadian rhythms?
There is evidence suggesting that every cell in the body has it’s own circadian rhythm.
Shift workers and more susceptible to physical illness possibly because of disrupted circadian rhythms.
This is also associated with several types of mental illness.
What did Church & Gibbon (1982) do in their operant conditioning study about interval timing?
Church & Gibbon put rats in a lit chamber with a lever and put the light off for different intervals at a time (CS). When the interval was 4s, if the rat pressed the lever they got food.
A peak shaped response was observed, where the optima response was 4 secs.
What law does the results from Church & Gibbon follow?
Weber’s Law. The rats trained on the 2s interval had a more accurate response rate than those trained on 8s.
What is Weber’s Law?
The just noticeable difference is proportionate to the initial intensity of the changed stimulus. It isn’t the absolute amount but the relative amount that enables us to notice a difference.
Timing follows Weber’s Law. What theory incorporates this?
Gibbon’s Scalar Expectancy Theory
What is Scalar Expectancy Theory.
It is a model that describes the behaviour of organisms in temporal tasks. It makes mathematical predictions about what responses will look like.
What are the components of Scalar Expectancy Theory?
A pacemaker- emits pulses at a constant rate Working memory Reference memory Comparator Response
What are some of the problems of the Scalar Expectancy Theory?
There is no physiological evidence for a pacemaker. Instead it has been proposed that an oscillator that has two states(on and off) exists. Based on the pattern of activation it can be used to determine the exact time.
