Memory and Cognition

1. CHAPTER 14 Memory and Cognition

2. Memory and Behavior Theory Organisms must often change their behavior to adjust to changing events. Some events are not now present, but occurred in past. So, memory is a basic psychological process in behavioral adaptation. Without ability to remember, it is difficult to imagine ability to learn.

3. Memory and Behavior Theory Behaviorists have spent great time and energy over past 100 years devising suitable laboratory paradigms of Pavlovian and operant conditioning. But, basic behavioral preparations to study memory are not nearly so well-developed. Very little effort has been devoted to systematic study of memory.

4. Memory and Behavior Theory To early behaviorists, it was most important to understand learning of associations, not memory. Extreme conservatism governed theoretical efforts of early behaviorists. Delayed response paradigm did not allow researchers to study wide range of empirical and theoretical issues central to understanding memory.

5. Delayed Response Problem Hunter (1913) Site baiting Delay Choice

6. Delayed Response Problem

7. Delayed Response: Mediation Central representation Behavioral mediation Special tests for behavioral mediation Disorient animal during delay Remove animal during delay

8. Memory and Behavior Theory Neglect of memory is coming to an end. Learning alone simply cannot explain intelligent action; other cognitive processes (like memory, attention, and conceptualization) also promote adaptive behavior. Innovative experimental techniques can now disclose operation of memory and other cognitive processes.

9. Animal Memory We will focus on laboratory study of memory in animals. Research documents unprecedented flexibility in remembering past events. New memory methods can be also be used to illuminate other adaptive behavioral processes like attention, timing, counting, and navigation.

10. Animal Memory We will focus on study of short-term or working memory. Memory for changing events, not static rules of the game. Key method is delayed matching-to-sample and its numerous variants.

11. Delayed Matching-to-Sample Successive version Choice version

12. Successive Matching-to-Sample

13. Choice Matching-to-Sample

14. Delayed Choice Matching

15. Delayed Matching: Parameters Delay duration Sample duration Intertrial interval

16. Delay Duration

17. Sample Duration

18. Intertrial Interval

19. Memory Trace Theory Trace strength grows during sample. Trace strength fades after sample. Interfering traces fade during ITI.

20. Inadequacies of Trace Theory Effectiveness of cued delay intervals Effectiveness of cued test stimuli Prospective vs retrospective tasks Directed forgetting effect Serial position effect

21. Cued Delay Intervals Sample and test stimuli: two colors. Two retention intervals: 2 and 8 sec. Two tones are presented during sample stimuli: one signals 2-sec delay interval and other signals 8-sec delay interval. Do such delay cues have an effect? Control group given uncorrelated cues. Delay cues were effective.

22. Cued Delay Intervals

23. Miscued Delay Intervals After correlated training, miscuing given: Short delay signalled, but long delay given. Long delay signalled, but short delay given. Miscuing did affect performance.

24. Miscued Delay Intervals

25. Cued Test Stimuli Sample stimuli: two colors. Two pairs of test stimuli: two colors or two lines of different orientations. Two forms presented on sample stimuli: one signals color test and other signals line test. Do such test dimension cues have an effect?

26. Miscued Test Stimuli Test dimensions miscued. Got a color test after the line cue. Got a line test after the color cue. Each miscuing disrupted memory performance. Suggests that pigeons learned to anticipate particular test stimuli after particular prior cues.

27. Prospection vs Retrospection Trace theory is backward looking. At testing, one reflects back on past for clues concerning how to respond now. Retrospective memory is common. E.g., when two or more students raise their hands, a teacher refrains from calling on student who has recently answered question and calls on another student who has not recently done so.

28. Prospection vs Retrospection But, on other occasions, memory is forward looking. So, when his mother returns home, a son will tell her that she has received a phone call, something that he has been preparing to do since receiving the call. In effect, intention to tell his mother the message is a prospective memory that he actively holds until he conveys the information to her.

29. Prospection vs Retrospection Prospection and retrospection seem to be different memory processes. Prospection may prepare you to perform vital activities. Retrospection may prevent you from repeating them. Experimental tasks can be designed that promote prospection and retrospection in animal memory.

30. Prospection vs Retrospection

31. Prospection vs Retrospection

32. Directed Forgetting Effect Many theorists believe that humans rehearse information to prevent its loss. Do animals rehearse? One way to tell involves the directed forgetting paradigm: Give cues to remember or to forget after the sample stimulus. Remember cues precede a memory test; forget cues precede no memory test.

33. Directed Forgetting Effect To see if forget cues affect rehearsal, memory test follows forget cue. Poorer memory after forget cue than remember cue suggests discriminative control of rehearsal. Animal memory is lower on forget-cued trials than on remember-cued trials. Memory is not just a passive trace.

34. Serial Position Effect Lists of four visual stimuli were given one at a time on upper of two screens. Probe item shown on lower screen some time after fourth list item. If probe had been in list, then left key response?food. If probe had not been in list, then right key response?food. Otherwise, no food was given.

35. Serial Position Effect If probe item had been in list, then accuracy depended both on position of item in list and time between last list item and choice test. Similar patterns were seen for humans, monkeys, and pigeons, although exact values of parameters differed. Results again question completeness of trace theory of memory.

36. Serial Position Effect

37. Spatial Memory Delayed spatial matching-to-sample Olton radial-arm maze Naturalistic paradigms

38. Delayed Spatial Matching-to-Sample 3 x 3 stimulus array 1 position shown as sample 2 positions shown as tests Match to spatial location

39. Delayed Spatial Matching-to-Sample

40. Delayed Spatial Matching-to-Sample Pigeons learned spatial MTS task. Sample location memory increased the longer the sample was presented. Sample location memory decreased the longer the delay between sample presentation and choice test.

41. Olton Radial-Arm Maze 8 arms All baited Rat visits arms until all food is found Number of visits is behavioral measure 8 is minimum Pattern of visits is also recorded

42. Olton Radial-Arm Maze

43. Olton Radial-Arm Maze Task requires reference memory. Rat must learn rules of the game: layout of maze, return trips to visited arms should be avoided, and so on. Task also requires working memory. Rat must remember where it has been in order not to repeat a visit. At end of trial, rat can erase working memory and retain reference memory.

44. Olton Radial-Arm Maze Rats do very well in this task, visiting little more than 8 arms on each trial. How do they do it? Could processes other than spatial learning and memory be involved?

45. Olton Radial-Arm Maze Rats could visit maze arms in same order. This plan would ease working memory requirements, because responses could be run off automatically, each one triggering next. But, rats do not visit same arms in same order every day; indeed, pattern of arm visits is nearly random.

46. Olton Radial-Arm Maze Perhaps rats can smell food at end of arms or smell scents in visited arms. These possibilities have also been eliminated. Dousing maze with after-shave lotion does not impair performance. Also, if after rat has made several choices, arms that it has chosen are again baited with food, then rat does not return to those arms.

47. Olton Radial-Arm Maze If one rotates maze so that spatial cues outside maze no longer give accurate information about where rat has and has not been, then rat�s performance deteriorates. Even though odor cues are available, rat makes mistakes by visiting locations that used to contain unvisited arms, but now, after maze rotation, contain arms that were already visited.

48. Olton Radial-Arm Maze It seems as if rat masters task by learning the maze perhaps by constructing a cognitive map in reference memory. Rat then uses its working memory to keep track of where it has already been.

49. Olton Radial-Arm Maze Unlike results in delayed MTS studies--where forgetting is often complete after 30 sec to 1 min--rat�s memory for radial maze is remarkably durable. One can start a trial, and after rat�s first four choices, impose a delay of up to 4 hours spent outside maze. When rat is returned to maze, it goes to four unvisited arms almost as if there had been no delay at all.

50. Olton Radial-Arm Maze Introducing delays into rat�s sequential selection of maze arms has yielded another important discovery: Rats may use both prospective and retrospective memories in radial-maze performance.

51. Olton Radial-Arm Maze Rats first trained on 12-arm radial maze. Then, rats received testing trials on which they chose among 12 arms until they made 2, 4, 6, 8, or 10 selections. Rats then removed from maze and put into small holding cage for 15 min. Finally, rats returned to maze and allowed to make remaining choices.

52. Olton Radial-Arm Maze As choices before delay rose from 2 to 4 to 6, number of choices to complete maze increased. Suggests use of retrospective memory. But, as choices before delay rose from 6 to 8 to 10, number of choices to complete maze fell. Suggests use of prospective memory: more arms visited, fewer remaining arms need to be remembered.

53. Olton Radial-Arm Maze

54. Olton Radial-Arm Maze Rats may be able to switch memory codes due to difficulty of memory load. As visits accumulate, rat remembers each until 6 arms have been visited. Then prospective load (which starts at 12) falls below 6 items and continues to fall as more arms are visited. After 6 visits, it becomes easier for rat to switch to prospective code than to use more burdensome retrospective code.

55. More on Cognitive Maps: Chimpanzee Behavior

56. More on Cognitive Maps: Chimpanzee Behavior Chimpanzee on experimenter�s back Watched site bating: 18 locations Later released to retrieve food Most food found Retrieval route differed from baiting route Traveling distance was very efficient

57. More on Cognitive Maps: Chimpanzee Behavior Second experiment Same general plan 18 locations: 9 fruits and 9 vegetables First retrieval visits were to retrieve fruits, according with food preferences

58. More on Cognitive Maps: Chimpanzee Behavior Results suggest that chimpanzees have something like a cognitive map of compound. As they are carried around, chimpanzees store information about food locations not on the basis of the particular path that they are traveling, but on the basis of their cognitive map.

59. More on Cognitive Maps: Chimpanzee Behavior Chimpanzees work with this cognitive representation to determine most efficient route to travel in gathering food. This solution depends on cognitive mediation between inputs and behavior that transforms and organizes inputs. To explain chimpanzees� behavior without appeal to mediating processes would provide an impoverished view of what animal does.

60. Master Mnemonist: Clark�s Nutcracker

61. Master Mnemonist: Clark�s Nutcracker Nutcrackers collect pine seeds in small pouch under tongue. They drive seeds into soil with beak. Nutcrackers return to small feeding caches months later to retrieve seeds--even under cover of snow. In autumn, 33,000 seeds may be stored in 2,500 caches for later recovery in winter and spring.

62. Master Mnemonist: Clark�s Nutcracker This is truly a remarkable feat of spatial memory. But, what does it imply about general memory ability of this species?

63. Master Mnemonist: Clark�s Nutcracker Laboratory experiments studied this bird species and three others that do not store and recover food. Birds received two types of memory tasks: one for location of a stimulus and other for color of a stimulus. Clark�s nutcrackers won contest for spatial memory, but were in middle of pack in contest for color memory.

64. Master Mnemonist: Clark�s Nutcracker Data suggest that Clark�s nutcrackers do not have generally exceptional memory. Rather, they possess a more highly advanced spatial memory that may be a special adaptation to their particular evolutionary niche. Idea related to Seligman�s (1971) notion of preparedness.

65. Temporal Memory Uses a delayed discrimination task. Temporal discrimination also uses a peak procedure. Former technique is better suited to working memory; latter technique is better suited to reference memory.

66. Delayed Discrimination Procedure Animals can discriminate and remember duration of a stimulus. Delayed discrimination procedure is well-suited to documenting these facts.

67. Go/No Go Matching-To-Sample with Temporal Samples and Line Orientation Test Stimuli

68. Temporal Discrimination Learning Pigeons can remember different durations of a red sample stimulus and report that memory during test stimuli of different line orientations.

69. Temporal Discrimination Learning

70. Temporal Discrimination Behavior Birds not only remember two very different stimulus durations (2 sec versus 16 seconds), but a whole range of more or less different durations (2, 4, 6, 8, 10, 12, 14, and 16 sec).

71. Temporal Discrimination Behavior

72. Temporal Discrimination Memory Pigeons even remember sample stimulus durations over sample-test delays as long as 16 sec.

73. Temporal Discrimination Memory

74. Delayed Discrimination Procedure Beyond attributes of single stimuli, pigeons also remember temporal order (e.g., red-green) of two differently-colored stimuli. Spatial order (e.g., left-right) of two identically-colored stimuli. Relative duration (e.g., short-long) of two differently-colored stimuli.

75. Number Discrimination Delayed discrimination procedure. Other discrimination techniques.

76. Delayed Discrimination Task After two noise bursts, a left lever press produced food, but a right lever press did not. After four noise bursts, a right lever press produced food, but a left lever press did not. Rats learned.

77. Delayed Discrimination Task What about abstractness of rats� number discrimination? Trained with two or four auditory stimuli. Tested with two or four visual stimuli. Although there was some decrement in discrimination accuracy, rats showed transfer from auditory to visual stimuli.

78. Delayed Discrimination Task Pigeons can be taught to discriminate number of their own key pecks. After 35 center key responses, pecks to left key led to immediate food, but pecks to right key led to food after 1-min delay. After 50 center key responses, pecks to right key led to immediate food, but pecks to left key led to food after 1-min delay.

79. Delayed Discrimination Task Pigeons learned this task. As smaller response requirement was increased, accuracy of pigeons� discrimination steadily decreased. It takes longer for pigeons to peck 35 times than to peck 50 times. Perhaps true discriminative stimulus was duration of center key light rather than number of times it was pecked.

80. Delayed Discrimination Task Later work suggests that number rather than time controlled behavior. Critical results came from a statistical analysis that separated trials where time to complete required number of pecks was lower than average from trials where time to complete required number of pecks was higher than average.

81. Delayed Discrimination Task This temporal segregation had little effect on strength of discriminative behavior. So, it was number of pecks that were made in a trial and not total time that it took to complete those pecks that controlled pigeons� choice behavior.

82. Delayed Discrimination Task Another kind of study. Here, discriminative stimuli presented number and time as redundant stimuli--either or both could be used to solve the discrimination. Rats received two noise bursts in 2 sec and eight noise bursts in 8 sec; either number or time or both could then serve as discriminative stimulus.

83. Delayed Discrimination Task Tests followed in which number and time were uncorrelated. E.g., rats received two noise bursts in 8 sec and eight noise bursts in 2 sec. Data showed that rats discriminated both number and time cues. Similar results were found for pigeons similarly trained and tested with visual stimuli.

84. Complex Number Use In order to use numbers in mathematics requires: Cardinality: symbols stand for different numbers of items. Ordinality: different numbers of items can be placed along a continuous scale. Can animals use cardinality and ordinality?

85. Cardinality Arabic number control Involves association of arbitrary symbols with different numbers of items Chimpanzees were given an extended training regimen en route to final performance.

86. Cardinality

87. Cardinality

88. Ordinality Response order maps to numerical order. Does mapping imply appreciation of serial order in numerosity? Test involves transfer to larger numbers of paired items. Monkeys were successful in learning and transferring ordinality task.

89. Ordinality

90. Summary Animals are adept processors of a rich and varied world. Many attributes of single and multiple stimuli can be discriminated and remembered. Laboratory tests document those discrimination and memory abilities. Biological mechanisms can now be studied.