memory

Question 1

Memory taxonomy (simplified from human memory theory)

Answer 1

• Working memory vs long term memory
– Short-term storage vs. long term retention

• Episodic vs semantic/reference
– My first day at University (What? Where? When?) vs knowing that Rescorla-Wagner is a model of associative learning (how the world works)

Question 2

what is delay of reinforcement

Answer 2

• In simple conditioning, learning is seriously impaired if there is a gap between stimuli, or between response and reinforcer (delay of reinforcement)

Question 3

what is delayed reaction

Answer 3

delay between stimulus and the possibility of response (delayed reaction) - often used with monkeys but also with rats (e.g. Smith 1951)

Question 4

what did Grice 1948 find

Answer 4

• In discrimination experiments with rats, Grice (1948) reckoned that impairment was evident with a 0.5-sec delay, and total with 10-sec delay

Question 5

What is proactive interference

Answer 5

– Proactive interference from information acquired PRIOR to target

Question 6

what is retroactive interference

Answer 6

– Retroactive interference from information acquired AFTER target

Question 7

how does decay occur

Answer 7

over time

Question 8

what is Delayed matching to sample (DMTS)

Answer 8

• Modern, Skinner-box technique for studying delayed reaction
• Despite the name, does not necessarily require recognition of identity of sample and comparison stimuli

Question 9

what are the variations of Delayed matching to sample (DMTS)

Answer 9

– oddity from sample - choose the comparison that does not match
– symbolic matching to sample (DSMTS): comparison stimuli are not the same as the sample, and the subject must learn the “code” connecting them
– multiple samples - in which case the design becomes a test of recognition memory or a list recognition task

Question 10

how did Grant adn Roberts 1973 show proactive interference

Answer 10

• Ordinary DMTS on some trials
• Other trials two samples are presented - either 10 sec or 0 sec apart.
• Animal must respond on basis of last sample.
• Result is that performance in the 0 sec condition, when one sample is immediately followed by the other, is worse.
• This is good evidence for proactive interference in DMTS

P gets a sample, then a delay and then another sample. They need to peck the stimulus which is the same as the last sample seen.

Question 11

How did Grant 1988 show retroactive interference

Answer 11

• Ordinary DMTS
• On some trials the brightness with which the chamber is illuminated is increased during the delay between sample and comparison.
• Result is that performance in the increased illumination condition is worse.
• This is good evidence for retroactive interference in DMTS? It’s something I suppose.

After the delay, the box they are in becomes illuminated or not. They then have both stimuli and need to peck the same as before.

Question 12

What is the Radial Arm Maze

Answer 12

• Radial Arm Maze experiments with rats.
• A means of presenting a list of items to the animal.
• In early experiments animals allowed to run down n (freely chosen) arms then removed for a delay interval then returned on test.
• Later experiments control the arms experienced on the study phase.

Rats go to central platform and the experimenter can flick switches to open up passages. The rat can then run down the aisle, run back after getting the food and wait

Question 13

what did Olton adn Samuelson 1976 find with the Radial arm maze

Answer 13

Perhaps the most striking aspect of these results is that performance is so good. But a free choice procedure suffers from the possibility that this is not so much due to memory as due to stereotyped response patterns on the part of the animal, e.g after exiting an arm, turn left and take the next one.
In the first choice, there are two aisles open to pick from. It is a mistake if they pick a aisle where they have already taken the food from (seen in 8).

Question 14

what is 2AFC

Answer 14

A 2AFC (two alternative force choice, e.g. one decision to make) procedure after forcing the animal to visit a set of randomly chosen arms (shown in blue). The animal is given a choice between two arms, one visited and one novel, and required to choose only one.

Question 15

how did Hoffman and Maki 1986 study proactive interference

Answer 15

In this experiment the eight arms of the radial maze were partitioned into two sets, A and B, of four arms each, then an initial phase of exposure to the arms in B was given, followed two hours later by a study phase in which the rats were forced to the arms in A. After a further two hours a test phase of free choices amongst all eight arms was given, with choices of the B set rewarded. A control group did not get the initial interference phase. Experimental animals performed worse than controls, indicating a PI effect of the initial exposure to the B arms.

Question 16

how did roberts 1981 study retroactive interference

Answer 16

In this experiment the eight arms of the radial maze were again partitioned into two sets, A and B, of four arms each, then an initial phase of exposure to the arms in B was given, followed by running 3 other similar mazes in different rooms to the test maze. Finally the animal was returned to the test maze and its performance in choosing the A set of arms was found to be worse than that of controls who had experienced the same delay between the initial phase and test, but not run the intervening mazes.

Question 17

How did Roberts and Smythe 1979 study decay

Answer 17

• This experiment used the basic 2AFC procedure
• Animals were forced to either 1, 3, 5 or 7 arms of the maze then given a choice between a visited and an unvisited arm
• A clever addition to this experiment is the one arm condition
• rats did worse on latter

Question 18

what did Roitblat find

Answer 18

Roitblat’s result is that the animals make more mistakes - make more confusions - when Blue and Orange are the sample. However, blue and orange are very different. He believes that in the sample, rats thought if one is horizontal and one is near horizontal, they are recoded and are similar. This is why they get a pattern

That is, they tend to give the correct response for Orange to the Blue sample and vice-versa. They make less confusions on trials where the sample is Red, even though some confusion with Orange might be expected. This suggests use of a prospective code

Question 19

What did Cook, Brown and Riley, 1985 find

Answer 19

produced evidence that suggested that rats could switch flexibly between retrospective and prospective codes. They used a 12 arm maze, but I’ll report my experiments with an 8 arm maze.

Rats were forced to either 2, 4 or 6 arms of the maze (Cook et al used 2, 6 or 10), then taken out for 15 min., and then tested on a visited vs. an unvisited arm. On the left is a study phase set of arms…

Question 20

what did McClaren 1990 find

Answer 20

Results from an 8 arm radial maze with 15 min. retention interval. Note that more errors are made in the 4 arm condition than the 6 arm condition.

Question 21

what is consolidation

Answer 21

• The idea here is that the initial memory trace is fragile and relatively short-term, and needs to be transformed (consolidated) into a more durable trace for the long term.
• Many studies looking at this idea have used avoidance learning in the shuttle box. In this paradigm the rat (typically) is trained to move from one side to the other to avoid shock.

Question 22

what is a shuttle box

Answer 22

Two sides to a box. Rat is placed on the light side. Rats tend to jump over the hurdle to the dark. If they stay in light for more than thirty seconds they get a shock.

They, therefore, jump between the two sides because they don’t like the dark or the foot shock.

Question 23

example of consolidation

Answer 23

ECS (electroconvulsive shock: Duncan 1949), sudden heating or cooling, drugs, concussive impact (American Football).

Question 24

What is retrieval

Answer 24

• The animal has to retrieve a memory to make use of it. Many studies indicate that most forgetting should be viewed as a failure to retrieve rather than a loss of storage.
• Perhaps the most impressive of these is the class of study that falls under the heading of “Reactivation”. In these experiments memories that are apparently “lost” are successfully retrieved following a reminder treatment.
• This type of study poses difficulties for consolidation theory. If a memory has not been consolidated, and hence is lost, how can it later be retrieved?

Question 25

what did Gordon 1981 find

Answer 25

Gordon’s (1981) paper reports this reactivation study in the shuttle box. Times are in seconds. The delay between training and test was three days. Reactivation can also restore memories after ECS (Gordon and Mowrer, 1980).

If you hold them where they were for 15 seconds, they remember stuff quicker. If you hold them there for longer (75 seconds), this is past the point of remembrance.

Question 26

what is an example of capacity of animal long term memory

Answer 26

Vaughan and Greene’s picture recognition experiment with pigeons

Question 27

what is Vaughan and Greene’s picture recognition experiment with pigeons

Answer 27

• random pseudoconcept task: slides of trees arbitrarily divided into positive and negative
original training with 40 positives, 40 negatives;
• new slides introduced once old ones mastered
• successful training up to 640 slides
• birds trained with 320 slides were then rested for 2 years; on re-testing there was some forgetting but quick recovery

Question 28

what did Roberts 2002 claim

Answer 28

• Roberts (2002) claims that animals are “stuck in time” – they cannot do what Suddendorf calls “Mental time travel”

Question 29

what did Clayton and Dickinson claim

Answer 29

• Clayton and Dickinson claim that food-storing birds e.g. scrub jays show true episodic memory
• Lab experiments show they can remember:
– What they stored (waxworms or peanuts) – recover worms rather than peanuts because they are preferred food
– Where they stored it (scatter hoarders are very good at this in general)
– When they stored it – recover peanuts instead of worms if they stored them more than 4 hours before, because worms are perishable