A pioneer of the scientific study of memory: Hermann Ebbinghaus (1850 – 1909) Worked as philosopher at university in Berlin Was inspired by lawfulness of relation between physical properties of perceptual stimuli and psychological sensations in psychophysics e.g. Fechner’s law; Weber’s law

Classic finding in psychophysics: Weber’s law

A pioneer of the scientific study of memory: Hermann Ebbinghaus (1850 – 1909) performed experiments on himself published in classic volume entitled: ‘Über das Gedächtnis’ (1885)

Memory experiments by Ebbinghaus Fame: pioneer of empirical approach; inventiveness as experimenter New: systematic and controlled study of memory in laboratory e.g. - created new stimulus material - applied scientific accuracy (metronome), - established method to quantify memory performance and describe regularities

Memory experiments of Ebbinghaus: Focus on retention of newly learnt material invented lists of 16 nonsense syllables to minimize influence of meaningful associations and learner’s history goal: study memory in ‘pure’ form introduced criterion for successful learning (2 errorless recitations) introduced savings method to measure retention/forgetting of lists

Memory experiments of Ebbinghaus: Example of memory task Memorize the following list: falem zeb xalvo monul rull namak

Memory experiments of Ebbinghaus: Examination of forgetting curve with savings method most forgetting happens immediately after learning -> not a linear relationship between forgetting and delay

Memory experiments of Ebbinghaus Other important findings List-length effect: ease of learning and amount of information not related in linear one-to-one fashion; disproportionate increase in difficulty with more than 7 syllables Beneficial effects of distributed practice for repetitions

Memory research of Ebbinghaus Why is it such a major contribution? discovery of important regularities (basic findings) memory can be studied empirically with experiments mental phenomena can be studied even if they are not linked momentarily to physical world via perceptual organs

Memory research of Ebbinghaus What was missing? research criticized as atheoretical But: emphasis on observations rather than theories typical for early research in new field

The Ebbinghaus Legacy: Verbal-learning research 1950s – 1970s systematic study of factors affecting verbal learning: e.g. numbers of repetitions, word frequency behaviourist tradition (S-R / S-S associations) mind as black box later replaced by information-processing approach: growing emphasis on mental representations

Richard Semon (1859 – 1918): An early memory theorist work strongly influenced by evolutionary biology (Darwin) emphasis on commonality between heredity and memory: elasticity of biological tissue that allows effects of experience to be preserved over time three stages of memory (new terms invented) Engraphy – acquisition of new information Engram – enduring change in nervous system that allows for retention Ecphory – recovery of stored information

Richard Semon (1859 – 1918): An early memory theorist concept of ‘engram’ motivated research on brain basis of memory in 20th century: What are the manifestations of memory traces in the brain? concept of ‘ecphory’ strongly influenced cognitive psychology of memory starting in 1970s (Tulving): How can a dormant memory trace be awaken? -> emphasis on processes at time of retrieval (recovery) of info from memory -> emphasis on presence of suitable retrieval cues

Information-processing approach to memory (starting 1960s) motivated by emerging of computers and computer science as scientific discipline human mind can be understood with computer metaphor: e.g. storage of information in different memory buffers RAM vs hard-disk <-> STM vs LTM central importance of information and mental representations (mind not a black box) focus on cognitive processes that deal with (e.g. create, access, compare) mental representations

Information-processing approach to memory: A practical example correct

Information-processing approach to memory: Basic framework 3 stages of processing for manipulation of mental representations: Encoding (acquisition of info) Storage (retention of info) Retrieval (recovery of info) Encoding Retrieval time

Information-processing approach to memory: Typical research questions do we store different types of memory representations? Are they retained equally well? e.g. ‘bear’

Information-processing approach to memory: Typical research questions (cont’d) do we need attentional resources to encode new information into memory? e.g. can be studied through examination of influence of distraction can we access information in memory unconsciously? e.g. can be studied in patients under anesthesia

Information-processing approach to memory: Application to Ebbinghaus’ research what were the syllables you memorized in the example I gave earlier?

Information-processing approach to memory: Application to Ebbinghaus’ research which of the following syllables was on the list? halek or xalvo -> forgetting curves will vary depending on whether syllables need to be recalled or recognized -> more detailed analysis of cognitive processes required to understand regularities in forgetting

Information-processing approach to memory: Application to Ebbinghaus’ research e.g. ‘zeb’ may or may not make you think of ‘zebra’ at encoding -> consequences for subsequent remembering -> even learning of simple stimuli such as non-sense syllables is affected by variations in cognitive processing and pre-existing knowledge -> memory can’t be investigated in pure form

Cognitive-neuroscience approach to memory multidisciplinary approach (psychology, computer science, neurology, radiology) emphasis on relationship between behavior, cognition, and the brain Central question: How is memory organized in the mind and brain? General idea: to understand the organization of memory (e.g. how many different types?) we should focus on neurological and cognitive aspects

Cognitive-neuroscience approach to memory: Different types of investigation Lesion studies in neurological patients examination of effects of different types of brain damage on memory processing Functional neuroimaging examination of brain activity in healthy individuals while they perform memory tasks Computational modeling testing of memory theories with computer models that incorporate a brain-like organization (neural networks; connectionist models)

Cognitive-neuroscience approach to memory: Example of functional neuroimaging study do different parts of the brain become active when we try to remember pictures as compared to words? pictures words

Cognitive-neuroscience approach to memory: Example of early finding in patient with brain lesion amnesic patient of Claparède (1911): pin-prick episode -> behavior can be influenced by past without conscious remembering supports distinction between implicit (unconsious) and explicit (conscious) form of memory proposed 70 years later