1Chapter 11 – Comparative Cognition 1: Memory Mechanisms OutlineWhat is Comparative CognitionAnimal Memory ParadigmsWorking and Reference MemoryDelayed Matching to SampleSpatial Memory in mazesMemory MechanismsRetrospective and Prospective CodingForgettingProactive and Retroactive InterferenceRetrograde AmnesiaDirected Forgetting
2Chapter 11 - Animal Cognition 1: Memory Mechanisms What is Comparative Cognition?Zentall (1993)Animal Cognition is often best understood by explaining what it is not.Learned behavior that is left after simpler associative-learning explanations have been ruled out
3We have already discussed an example of a cognitive experiment Identity learning (Sameness)Train (MTS)RR+G-GR-G+TestB B+Y-Y B-Y+Notice the test involves novel stimuliThis is often an important test in cognitive studiesIt makes it difficult to explain performance in test based on S-R –O relationships.There is no RF history of picking Blue following BlueSeems more likely performance is the result of an understanding of “sameness”A cognitive rulePick the thing that looks the same.
4What is Comparative Cognition? Continued DomjanTheoretical constructs and models used to explain aspects of behavior that cannot be readily characterized in terms of simple S-R or reflex mechanisms.Key featureAlways adopt the simplest possible explanation
5What is Comparative Cognition? Continued Must carefully avoid anthropomorphismMorgan’s CanonIn no case may we interpret an action as the outcome of a higher psychical faculty, if it can be interpreted as the outcome of the exercise of one that stands lower in the psychological scale.At first the allure is weak; there is a vague yearning and a mild agitation. Ultimately, the strength of desire grows irresistible; its head turns sharply and it skitters across the uneven floor to caress the objects of its affection with consummate raptureCoin drawn to a magnetThere are more parsimonious explanations for this behaviorClever Hans
6What is Comparative Cognition? Continued Often involves models of mental activityThe internal clock (chapter 12)A model for how a biological clock might workMental RepresentationsWhat is the nature of a memory?It is not just a snap shot.It is some how changed to a neural codeWhat is the nature of that code?
7Animal Memory Paradigms What is the difference between learning and memory?The main difference is how we study each.Study LearningWe vary aspects of acquisitionHold retention interval and retrieval variables constantStudy MemoryHold acquisition constantVary retention intervals or variables related to retrieval
9Types of memory Short term memory Long term memory the phone number for pizza placeLong term memoryEpisodicPicture yourself there (the episode)What did you have for dinner last night?What were you doing when you heard about the World Trade Center?Flash bulbSemanticFacts about the worldWho was the first president?What year were you born?ProceduralHow to do thingsride a bike, drive, swimsportsmusical instrumentswrite
10Explicit (declarative) Knowing that you know (conscious awareness)Episodic is clearly declarativethe person is clearly aware of learning they experienced.They have a conscious memory for it.Semantic is as wellYou know that-you-know the year you were bornClive Wearing had no episodic memory at allStill knew he had a wife and kidsNo memory of spending time with them
11Implicit (nondeclarative or procedural) This is learning that you are not consciously aware of.illustrated by priming experimentsAlso H.M.Mirror drawing taskAlso Clive WearingPianoMuch of the Pavlovian and Instrumental research we have discussed would fall under proceduralWe will discuss animal models of Episodic memory in Chapter 12
12Working Memory and Reference Memory another distinction that has received a lot of research interest in comparative cognition Reference MemoryLong-term retention of information necessary for the successful use of incoming and recently acquired informationThe rules of the gameWorking MemoryShort-term informationWhat did I just do?CookingGeneral reciperules for making the dishKeep track of where you areWhat have I already done
13Walter Hunter (1913). Problem with the study Rats, dogs, and raccoons. Light indicates which of three compartments are baited.animal is confined in start area.Turn light on; then off to indicate which compartment was correctThey are not allowed to choose for various lengths of time.Rats - 10 seconds.Racoons – 25 secondsDogs – 5 minutes.Reference Memory?Working Memory?Problem with the study
14Why is this technique better than Hunter’s? Matching-to sampleSimultaneousDelayedWhy is this technique better than Hunter’s?Eliminates behavioral explanation for retentionFace where you intend to go.Animal has no way of knowing which key will be correctLeft vs. right = 50%
15What affects an animals memory in a DMTS experiment? 1) nature of the sample stimulus affects DMTS performanceLines and shapesColors
162. Sample Duration? Grant (1976) DMTS 4 colors R,G,B,YEach trial begins with white center keyWarning stimulusPeck turns to sample (i.e., Red)Stays on for different durations1,4,8, or 14 sTest with Delays (retention intervals)0, 20, 40, or 60
17Results (Figure 11.2)trace-decay hypothesis (Roberts & Grant, 1976).A simple idea, but clearly too simple.
183) Similarity between training and testing conditions Instruction hypothesis (Zentall)What happens if animals are trained with a particular delay and tested with others?Sargisson and White (2001).Train with 0, 2, 4, or 6 s delays.Test with 0, 2, 4, 6, 8, and 10 s delays.
19What does this say about forget curves? Figure 11.30 – normal forget curve2 – forget curve does not start until 4 s4 – forget curve does not start until 6 s6 – no forget curve. What does this say about forget curves?Not just trace-decaySimilarity between training and testing conditions are important
20Spatial memory in mazes Spatial memory in mazes Morris Water Maze
21Train in a room with external cues DoorPicturesLight gradientsPlatform always in the same locationRelease from 4 different locationsRandomlyNorth, South, East, WestTest?Escape latency (figure 11.4)Probe trialsPath analysis.
24Spatial memory in the Radial arm maze Olton and Samuelson (1976)Food at end of each armOr a subset of armsReference Memory?Working Memory?
25You-tube vids of 8 arm maze Normal mouseKnockout mouse with memory probs
26How do the rats behave in radial arm maze? Not a set sequenceNo strategyNo odor cuesThey can handle long delaysLet them choose four arms – four hours later they choose the other 4Even after 24 hours they are performing above chance
27Retrospective and Prospective Coding How do the rats keep track of the arms of the maze?Retrospectivekeep track of where they have beenProspectivekeep track of where they are goingCook, Brown, and Riley (1985)12 arm mazeLet rats choose 1, 2, 3, 4, 5, 6, 7, 8 , 9, 10, 11 arms.Remove the rat for 15 minutesPut them back in and complete the maze.
28retrospective memory prospective memory memory load would start out lowincreases with arms visitedhaving a heavy memory load, should lead to more mistakespredicts few errors after 1 choicemany errors after 11 choices.prospective memoryMemory load starts out highHave 11 arms still in memoryDecreases with arms visitedPredicts many errors after 1 choiceFew errors after 11 choices
29Figure – Memory load following different numbers of places visited, out of a possible total of six, given retrospective and prospective coding strategies.
30These predictions are in direct contradiction to one another. What do rats do?People?
31Proactive and Retroactive interference Proactive interference ForgettingWhy does memory sometimes fail?Proactive and Retroactive interferenceProactive interferencePrevious memories disrupt current memoryWhere did I park my car today?Retroactive interferenceNew memories disrupt old memoriesCumulative exams?Phone number from last apartment?Address?
32Squire’s electroconvulsive shock study AmnesiaAnterogradeUnable to form memory for events that occurred after the injuryRetrogradeLoss of memory for events prior to injurySquire’s electroconvulsive shock studyIndicates that memories are vulnerable for an exceptionally long time1 year old memories were especially vulnerableOlder memories were relatively unaffectedImplies some active processing of memory (memory consolidation) over an extended period of time.
34Directed ForgettingIt is known that humans can exert cognitive control over memory.Give a list of words to subjects to rememberTell them “okay – that was just practice. Forget about that list and get ready for the real list”After a retention interval you tell them that you lied.Please write down as many words from the original list that you canCompare to a group told to remember the list.Memory for the list is much poorer for those told to forget.Perhaps because they did not initiate memory maintaining strategies (rehearsal)
35Can animals exert cognitive control over memory? Omission Procedure Phase 1 MTSR R+G-GG+R-Phase 2 DMTS with cuesR-VR+G-G-VG+R-R-HITIG-HITITestwith forget cuesR-HR+G-G-HG+R-Compare to remember cuesResult?Good performance on R-cued trialsPoor performance on F-cued trials
36Problems with Omission Procedure? Roper and Zentall (1993) 1. no response requirement following F-cuesPigeons are not used to making a choice following F-cuesThus, disrupts responding in test2. no RF following F-cues.F-cue could act as a conditioned inhibitorThus, disrupt responding in test3. Presentations of comparisons following F-cues is novelThe novel (or surprising) cues could disrupt performance
37The substitution procedure corrects for the above issues. Phase 1 MTSR R+G-GG+R-Phase 2 DMTS with cuesR-VR+G-G-VG+R-R-HB+Y-G-HB+Y-Testwith forget cuesR-HR+G-G-HG+R-Compare to remember cuesResult?Good performance on all trialsNo evidence for directed forgetting
38Compare the human situation to that of the pigeon Maintaining a bunch of words in memory is demandingDifficult to doThe pigeons do not have nearly the same demandsone sample to rememberRed or GreenThere may be little cost to remembering regardless of the trial type.What if we increase the memory demand?Reallocation experimentRoper, Kaiser, and Zentall (1995)Train the pigeons with F-cues that they have to rememberIf they have to reallocate memory to the F-cue perhaps it will disrupt memory for the original sample