Flashcards in Chapter 6 Deck (59):
What did Roger Shepard say about generalization gradients?
He said they are one of the most basic constant laws of psychology (declining rapidly on either side of peak)
This is a key issue for generalization. Identifying an inclusive set or range of stimuli with the same consequences as the training or target stimulus.
Shepard claimed what about the pigeons pecking the yellow-orange light?
He said that the pigeons are not confused by the yellow orange light, but it expects, based on what it learned from the yellow light, that pecking it will result in food.
Discrete component representation?
Each possible stimulus is represented by it's own unique node (or component) in the model
stimulus generalization network?
Has input nodes (green, yellow green, yellow etc), modifiable weights, output nodes, which leads to the response.
That network with the colors fails to show...?
A smooth generalization gradient shown by pigeons.
Discrete component situations are applicable to situations...?
in which the similarity between cues is small enough that there's a negligible response transfer from one to another.
Stimuli are represented by overlapping sets of nodes or stimulus elements.
What does it mean if the nodes are laid out in topographic representation?
Nodes responding to physically similar stimuli are placed next to each other.
The weights from internal representation nodes that have never been associated with reward remain ____.
Study with Box A and B? (Discrimination training)
Participants were given many squares differing in brightness and size. Then they were asked, are these physically identical? The participants trained in brightness discrimination showed much more confusing with size and vice versa.
Negative patterning? Why is it difficult?
When the response to individual cues is positive while the respond to the compound is negative. It required suppressing the natural tendency to generalize about similar stimuli.
The process by which animals and humans learn to classify stimuli into different categories.
Occurs when a huge number of possible combinations are created, too much for the mind to handle.
The stimuli are assumed to have the same meaning even though they do not have any relevant physical similarities.
Similarity based generalization?
Arises between two stimuli that are physically similar.
Co-occurrence of two stimuli is sufficient to produce meaning based generalization from on ____ to another.
A phenomenon in which prior training to treat 2 stimuli as equivalent increases generalization between them. So generalization occurring between two non-combined stimuli that share the same consequence.
Is physical similarity the only cause of generalization?
No, animals sometimes generalize because of co-occurrence.
What does faulty inverse reasoning in generalization mean?
80% of the NBA players are black. Most NBA players are black. Most black men are not NBA players.
Representations directly influence generalization behavior. Example?
New yorker has a map in their heads of all the different neighborhoods, making it harder to generalize in between them.
Important distinctions are ____. Why?
Enhanced. Because we have limited neurons, so it makes sense to use them towards something important.
Range of physical stimuli that activates a particular neuron.
Distorted neural representation of human figure, where highly sensitive regions are exaggerated
The primary sensory cortex is organized ____.
Topographically. Neighboring cortical regions respond to similar stimuli i.e. Neurons responding to teeth and gums tend to be adjacently placed.
Brain organization resembles distributed representation?
550 Hz tone activated neuron (nodes) 2 3 and 4, whilst 560 Hz activates 3 4 and 5. There is an overlap in both subsets. The 550 tone will likely generalize to 560.
Richard Thompson experiment with removing sensory cortex areas?
Removed A1, S1, V1 (one per one) in animals, and found that these sensory cortex areas are responsible for correct generalization, but the animals could still learn.
What happens if a part of a body becomes dysfunctional?
The homunculus will be modified to reduce it's representation, and increase the cortical representation of areas which will in turn be more sensitive/active.
Norman Weinberger study? (Guinea)
Guinea pigs received 2500 Hz tone paired with shock. Neuronal response to 2500 Hz increased, whilst response to other tones like 1000 decreased. If enough neurons changed their response, it would result in a modification of cortical representation.
Norman Weinberger study?
A tone presented alone, neuronal response decreases to the particular frequency. If shock and tone are not paired, no change occurs. Cortical plasticity is due to tone-shock pairing.
Stimulus presentation is ___ enough for cortical plasticity.
Not. It must have a meaningful consequence.
What happens to one sensory cortex area if there is change in another?
It will cause cortical plasticity because the sensory cortex doesn't receive anything specific about the stimulus but rather that cortical remapping is necessary
What is the basal forebrain important for?
Learning and memory.
Part of basal forebrain. Projects to cortex and amygdala. When activated, releases acetylcholine which enables cortical plasticity.
What releases acetylcholine?
Nucleus basalis when it is activated.
What does the neuromodulator acetylcholine do?
Enables cortical plasticity.
What is the nueromodulator released by the nucleus basalis?
When a conditioned stimulus is paired with an unconditioned stimulus, the nucleus balias becomes activated, and then...?
It releases acetylcholine which enables cortical remapping.
The amygdala encodes ____ information.
When the amygdala encodes emotional information, it signals the nucleus balias to do what?
Hippocampal region helps learning about ____ amongst stimuli.
Sensory preconditioning is a phenomenon of classical conditioning that demonstrates learning of an association between two stimuli during an initial phase where the two stimuli (S1 and S2) are presented together but never followed by reinforcement. During the first stage of the experiment, presentations of S1 are followed promptly by S2. In the second stage of the experiment, S2 is repeatedly paired with an unconditioned stimulus so that it becomes a conditioned stimulus. Finally, in the third stage of the experiment, S1 is presented by itself. The phenomenon is demonstrated if S1 elicits a conditioned response during stage 3.
In sensory preconditioning, if an animal has damage to hippocampal region, what will happen in stage 3?
They will not respond. They will display no sensory preconditioning.
We treat 2 things alike because they are associated with a common stimulus.
A detector for a unique configuration of two cues, such as a certain tone and light.
Hippocampus and associated brain regions (also referred to as medial temporal lobe)
A representation in which each individual stimulus (or stimulus feature) corresponds to one element (node) in the model.
When does latent inhibition occur?
When the CS-US association is slower in animals given prior exposure to the CS compared to animals given equivalent prior exposure to the context alone.
Latent inhibition in rabbit eyeblink conditioning is eliminated by what?
Hippocampal region damage.
Hippocampus ____ necessary for learning a stimulus-response association.
What is the hippocampal region important for?
Developing new representations.
fMRI reveals that hippocampal region is active during training (when learning and developing representations) but less active in training when representations are used to form behavioural responses
Hippocampal abnormalities are a core feature of ____.
Schizophrenics can ____ but have trouble ____.
Learn simple associations, transferring associations to new contexts.
Acquired equivalence study by Myers?
1. Brunette prefers blue over green fish. Blonde prefers blue over green fish. Particpants should learn that these women are equivalent in preference of fish. 2. Brunette prefers red over yellow fish. 3. Participants couldn't figure out if the blonde would prefer red or yellow, because they are unable to generalize (the schizo's)
Shohamy and Wagner realized what?
The hippocampal activity increased during the learning phase. Thus, hippocampal activity is necessary for FORMING stimulus representations.
Learned information guides later inferences. Schizo's are bad at this. Schizo' are bad at transfer generalization of previously learned rules in new contexts.
A graph showing how physical changes in stimuli (plotted on the horizontal axis) correspond to changes in behavioral responses (plotted on the vertical axis)