Lecture 2 Flashcards
who challenged locke
david Hume
is david hume an empiricist
yes, same with locke
he just pushed Locke’s ideas further
what does Hume agree with locke about
Three associative principles that govern the formation of ideas:
basiclaly;
sure and blue are 2 different simple ideas, you combine them and have blue square which is a complex idea and you do this because they happen to be specially combined
what is Three associative principles that govern the formation of ideas:
Ressemblance
Contiguity (in space and time)
Cause and effect
what does Hume have an issue with locke about
cause and effect
why does Hume have an issue with cause and effect
Cause and effect: Empirically, the only thing we can observe is constant conjonctions - uniform associations - but we don’t observe the causal connection
aka you see a man hit the microphone and hear a sound so you associate the 2 together but it is just coincidental there is no proof of the cause (Inference of necessary cause and effect (B has to follow A) relationship is invalid, but psychologically we believe there is cause and effect)
he doesn’t reject it, just says that we cannot find it in our sensory perception
what is Hume’s solution to the cause and effect issue
says that sensations are just belief of things happening
what are beliefs caused by (according to hume)
psychological «habits» (e.g. the sun has risen every morning so far, we should expect it to rise tomorrow again).
what does Immanuel Kant do
critique of pure reason
explain what kant attempts to achieve with the critique of pure reason
Attempt to reconcile rationalism with empiricism
what is the numenon
the thing itself (reality)– we will never know this perfectly according to Kant
what can we know according to kant
All we can know is the impression that the noumenon exerts on our senses (Phenoumenon).
can our sense tell us much about reality according to kant
no, we cannot infer causation from our sensations
kant says that in order to perceive external reality
Our minds have to contribute innate knowledge in order to make sense of our sensations (space, time, cause and effect).
basically; if we look at a pool table, our raw sensations tell us that there are balls on a table– we need prior knowledge that we can apply to the senerio and give them meaning
time is also something that we need to make sense of
causation is already in our brain
what does perception allow us to do according to kant
Perception is extremely rich and reliable and allows us to interact optimally with our environment
Such perception could not have arisen in an environment completely at odds with our sensations (i.e. there has to be an external reality with objects located in space and time and interacting with each other in a cause-and-effects manner).
essentially what does kant say
he brings empiricism and rationalisation together; says either one their own is not enough
raw sensations are like water, cannot hold it
reason is an ice cube tray; does nothing on its own
put water in tray and you can make something of it
does kant thing psych can be a science
no
why didnt kant think that psych could be a science
Empirical approach leads to a collection of facts (historical doctrine of nature), which is below the level of science
Natural science requires rational analysis, axioms and demonstrations.
A proper natural science requires the axioms and demonstrations to be written as mathematical laws
Chemistry isn’t a proper science
so Forget about psychology:
what parts of psych made is not considered a science
there is no substance or space in inner observations, only time, i.e. there is nothing to measure (nothing that we can measure, or quantify)
Inner observations cannot be separated and recombined at will (cannot redo the same experiement)
The act of introspection itself changes the content of the mind. (when we introspect we observe thoughts but then that changes our thoughts)
At most psychology can be a historical doctrine of nature. (collect facts and observation; something that resembles the a history doctrine)
who Is Ernst Heinrich Weber (1795 – 1878)
sets up foundations for Fechner
what did Weber study
recepters
he became fascinated with the Just Noticeable Difference (JND)
aka difference threshold
what is JND
What is the smallest weight difference that someone can perceive ?
what did weber find about JND
Weber fractions: the JND between the standard and comparison weights is always close to 1/40 (or 0.025) of the standard weight.
what else did weber study
he did the same JND but with other stimuli
what is the fraction for other sensors
For other types of stimuli, the fraction is different, but there is always a fraction
what are the different sensory dimensions
Touch (vibration) Taste Smell Loudness Pitch Brightness Length of lines
what is the weber fraction (k) for each of the sensory dimensions
Touch (vibration) 0.04 Taste 0.2 Smell 0.07 Loudness 0.3 Pitch 0.003 Brightness 0.08 Length of lines 0.001
what is the range of weber fractions
Loudness 0.3
Length of lines 0.001
can we better discriminate between lines or loudness
lines
what is Gustav Theodor Fechner (1801 – 1887) background
Background in medicine and physics and mathematics.
Suffered severe eye damage from gazing to much at the sun while performing his experiments, he then fell into a deep depression.
Then Fechner experiences what he believed to be a miracle when his vision began to recover. He became a very spiritual man and was obsessed with the relationship between mind and matter…
what did Fechner discover
Each JND is perceptually equivalent !!!
what is meant by Each JND is perceptually equivalent !!!
The 1 gram difference between 40 and 41 grams is exactly as perceptually salient as the 10 gram difference between 410 and 400 grams.
can JND be further fragmented
Since the JND is the smallest detectable difference, it cannot be further fragmented, i.e. perceptual «atom».
what is fechner’s fraction
S = k log(R) s= subjective perception (y axis) r= physical stimulus intensity (x axis)
What is the role of the k variable? in fechner’s fraction
k is closely related (but not identical to) to Weber’s fraction. It allows to account for different slopes of logarithmic functions for different senses
define discriminability
how easy it is to discriminate two different intensities
High Weber fractions means high or low dicriminability?
low
.3 is higher than .001 so it is harder to discriminate for the .3
High k value in Fechner’s function means high or low discriminability?
high
Therefore, are Weber’s fraction and k factor positively or negatively related?
inversely (so negatively)
As k increases, discriminability increases or decreases
increases
who proves Kant wrong
Fechner with his book
but Fechner called it psychophysics and not psychology (discussion of psychology comes later)
how many types of thresholds are there
4
what re the thresholds
difference threshold
absolute threshold
what is different threshold
smallest difference you can perceive
what is Absolute threshold:
smallest physical intensity you can perceive.
The limit at which a stimulus is « detected» vs. «not detected» is not sharp.
The function has a logistic («S») shape!
The threshold is defined as the sensory intensity at which a stimulus is detected 50% of the time.
is the absolute threshold suddenly there or not there?
The limit at which a stimulus is « detected» vs. «not detected» is not sharp.
The function has a logistic («S») shape!
The threshold is defined as the sensory intensity at which a stimulus is detected 50% of the time.
Why isn’t the threshold sharper?
Signal and noise: Because what we subjectively perceive isn’t 100% determined by the «signal» present in the environment, there is also «noise» in the signal.
- attention fluctuates - criterion for saying «yes» may also fluctuate - spontaneous activity in the nervous system - etc.
what is means by noise impacting threshold
not necessarily sound, but layers of signals coming at us
what are the methods of testing for threshold
Methods of constant stimuli:
Methods of limits – ascending/descending
Staircase method
Method of adjustment
what is Methods of constant stimuli:
Several intensities are systematically tested in a random order
what is pro and con to Methods of constant stimuli:
- Most accurate, but takes a long time!
what is Methods of limits – ascending/descending
Ascending/descending cycles; change direction when a «yes» or a «no»
what is the pro and con of Methods of limits – ascending/descending
quicker but A bit less accurate
Some intensities still don’t contribute much information
what is the Staircase method
Go back as soon as there is a change in response
this takes out the redundant ness of both other ones
what is the pro and con about Staircase method
Faster than the method of limits, and almost as accurate
what is the Method of adjustment
Let the participant increase/decrease intensity in order to identify the threshold
what is the pro and con of the method of adjustment
Really fast
Not very accurate (participant has too much control and don’t know what their inner criteria is to determine thresholds)
