LECTURES 13-20 Flashcards
UNDERMATCHING
When the log reinforcer ratio is varied the animal’s choice changes less than strict matching would predict
BIAS
Over all log reinforcer ratios, there are more B1 responses than predicted by strict matching
BAUM (1974)
Generalized Matching Law
Log(B1/B2) = a log(R1/R2) + log c
If sensitivity is less than 1?
Undermatching
If sensitivity is greater than 1?
Overmatching
If log c is greater than 0?
Bias toward alternative 1
If log c is less than 0?
Bias toward alternative 2
If sensitivity is 1 and log c is 0?
Strict matching
If sensitivity is 1 and log c is NOT 0?
Biased matching
If sensitivity is 1 and log c is less than 0?
Biased undermatching
ALSOP & ELLIFFE (1988)
6 pigeons, 5 concurrent VI VI schedules. GML fitted data well. All birds showed undermatching and bias, and a higher sensitivity to time than response.
SCHROEDER & HOLLAND (1969)
Without a change over delay, reinforcers on one alternative will affect responses on the other
MILLER, SAUNDERS & BOURLAND (1980)
B1: lined yellow key, reinforced on VI
Changeover key is red
B2: lined yellow key of different orientation, reinforced at a different rate
Condition 1: lines separated by 45 degrees, pigeons were able to discriminate easily
Condition 2: lines separated by 15 degrees, discriminated much less easily
Condition 3: B1=B2, still discriminated - win stay bias - went off reinforcer rate
HOLLARD & DAVISON (1971)
B1 - left key, 3s food
B2 - right key, 15s electrical brain stimulation
Varied reinforcer ratio, found that the birds showed a bias to the food over EBS
TREVETT, DAVISON & WILLIAMS (1972)
Found that the sensitivities were not significantly different for concurrent VI FI vs concurrent VI VI
ELIFFE, DAVISON & LANDON (2008)
Reinforcer magnitude - varied both reinforcer rate and magnitude, found that sensitivity to rate was highest when the magnitudes were equal, and sensitivity to magnitude was highest when the rates were equal.
INDIFFERENCE POINT
When the larger, later reinforcer has been devalued to equal the smaller, sooner reinforcer.
PHYLOGENETIC CONTINUITY
The idea that there is a link from the simplest animals all the way up to the most complex, and that similar principles influence behaviour in humans and other animals.
CONCEPT FORMATION
A form of stimulus control - animals learn to respond to a large set of stimuli in the same way provided they share a common feature.
HERRNSTEIN & LOVELAND (1964)
Multiple VI 60s EXT trial, 80 different photographic slides, trying to teach concept of person. Positive instances included people and negative instances did not.
Found that the pigeons responded more to the positive instances, although this could have been due to responding to the contingencies not the concept.
HERRNSTEIN, LOVELAND & CABLE (1964)
Three different concepts of tree, water and specific person. Gave novel slides in the test to account for contingencies. Showed better evidence for concept formation but still could have been influenced by the reinforcers.
EMERGENT RELATIONS
Relations that we hope to see as a consequence of the trained ones but that we never train directly.
EQUIVALENCE CLASS
A stimulus group that exhibits reflexivity, symmetry and transitivity in the context of conditional discriminations.
A –> B and B–> C is called?
Linear series training
A–> B and A–> C is called?
One to many training, sample is always A
A–> B and C–> B is called?
Many to one training, comparison is always B
SIGMAN AND CRESSON (1973)
OTM training to produce equivalence relations between 20 pictures.
A - names read out
B - pictures
C - names written down
Trained A –> B and A –> C and through testing found that B –> C and C –> B relations emerged.
They also found D - names spoken aloud by child, and found that when shown a picture of a cat or the word cat they would choose the correct corresponding thing as well as say it out loud. They had learnt to read.
CONDITIONAL DISCRIMINATION
Symbolic matching to sample - the sample provided becomes a symbol for what comparison should be chosen - the correct choice response is conditional on the sample.
MCCARTHY AND DAVISON (1980)
Pigeons - samples were centre key durations.
S1: lit for 5 seconds - left key correct
S2: lit for 30 seconds - right key correct
then hard discrimination
S1: lit for 20 seconds - left key correct
S2: lit for 30 seconds - right key correct
bias toward Bw after S1
bias toward Bz after S2
DAVISON AND TUSTIN (1978)
If S1 and S2 are indiscriminable, then choice after S1 and S2 should be exactly the same
Log d
Describes the effect of the stimuli - discriminability or the stimulus bias
What four things can happen in an SDT
Hit, Miss, False alarm, Correct rejection
log d = log sq root BwBz/BxBy
Point estimate of discriminability - estimates the value of log d that we would get if we did a complete variation of the reinforcer ratio Rw/Rz. Also known as a stimulus function and an isobias.
SPP
Signal presentation probability
MCCARTHY AND DAVISON (1979)
One held SPP constant and varied the reinforcer ratio
The other held the reinforcer ratio constant at 1:1 and varied SPP
Reinforcer ratio produced a bias but SPP did not
DAVISON AND MCCARTHY (1980)
Pigeons, MTS, samples were centre key durations of 5s and 10s. Correct responses reinforced with an SPP of 0.7 - 70% of Bw and Bz responses were reinforced. Introduced reinforcement to error P = 0.1 - 0.9, only showed reduction in accuracy at 0.4. Shows that humans and animals cease to respond appropriately with increasing likelihood of the incorrect response being reinforced.
