l 18 non ai , PS2020 L18 - Recognition memory and EEG

familiarity old/new effect ERP

mid-frontal

recollection old/new effect ERP

left parietal

what do with ecg data to get erps

A. Show participants old and new items randomly intermixed and record their response, while recording :

.B. Epoch (cut-up) the EEG time-locked tothe onset of the item. Pre-process datae.g. exclude artifacts, filter...

C. Average together trials ofthe same type e.g. hits,correct rejections.

old/neww effect ecg sudies overview

• Wilding et al. (1995)

Azimian-Faridani & Wilding (2006

Yu and Rugg (2010)

• Wilding et al. (1995)

At study words presented auditorily or visually.

At test: old or new ? + Auditory or Visual at study

(familiarity + recollection)

• Wilding et al. (1995) results

left parietal ERP was larger when participants make a correct source judgments compared to incorrect after a hit

left-parietal ERP old/new effect

• The effect:- onsets around 400-500 ms post-stimulus- often largest at left-parietal scalp locations- typically has a duration of 500-800 ms post-stimulus

Seems to bean index of Recollection

Azimian-Faridani & Wilding (2006)

studied the effects ofadopting a conservative or liberal decision criteria on themid-frontal effect

Results: hits in the conservative(C) condition were larger than those in the liberal (L) (where they are more sure)

The mid-frontal ERP old/neweffect

The effect is:- evident between 300-500 ms- largest at midline frontal sites- comprises a relatively greater positivity for hits compared to correct rejections.T

)Seems to bean index ofFamiliarity

remember know procedure

• One method to isolate the contributions of recollectionand familiarity (Tulving, 1985).•

For each judgment in the test phase participants areasked why they feel they recognise the item:- Remember: they consciously recollect the particulars ofthe study event.

- Know: they feel that they have seen the item before butthere is no memory for the details of the event

.- New: the item has not been presented in the studyphase.

Yu and Rugg (2010)

Aim: to electrophysiologically dissociate the neural correlates of Recollection and Familiarity

.Modified Remember/Know paradigm at test.

ask them confident old (Know), unconfident old (Know), unconfident new, confident new

Yu and Rugg (2010) Results

mid-frontal old/new effect

-covary with recognition confidence i.e. CO > UO >UN > CN-

left-parietal old/new effect?

-elicited by Remember items, but not either class as new item.

according to signal detection model

Memory (or familiarity) strength is a continuous variable. (plotted on x axis)

-memory traces vary in strength eg repeated more = higher

• Distribution assumed to be normal and to overlap

-old items should be higher on scale, stronger memory strength as they have been shown

-new items will still have some strength (an will have more if similar to old)

• Response criterion. - anything on left of is decided old • Discrimination sensitivity e.g. d'. (ability to discriminate between old and new items) (measured from average of old to new distributions (distance), the closer the distance the hearer to discriminate )

-can be effect by similarity of new to old and repitition of old • Different criteria e.g. conservative and liberal. (if you tell ppts to only give old answer when sure you are moving your criteria - more conservative)

Signal detection model suggests that there is one process which contributes to the recognition of events

Dual-process accounts

• Two processes contribute to recognition memory judgements: how familiar a stimulus seems (Familiarity) or by recalling the particulars of the experience (Recollection) - e.g. Yonelinas, 1999

. • Familiarity: awareness of a prior encounter but with no recovery of contextual details. Fast and automatic. (no saw it in test phase but don't know where is on screen)Modelled in the same way as the signal detection model

. • Recollection: recovery of contextual details e.g. location, colour, task....Slow, more attention demanding.

signal detection model

Recognition Memory

Decision-making on prior encounters and context.

Encoding Phase

Initial processing of information for memory.

Retrieval Phase

Accessing stored information from memory.

Distractors

New items that may confuse recognition.

Signal Detection Model

Separates real memory from guessing.

Dual-Process Accounts

Two processes contribute to recognition memory: familiarity and recollection

Familiarity

Awareness of prior encounter without details.

Recollection

Recovery of contextual details from memory.

Old/New Effects

Neural activity differences for old versus new items.

2 types: left parietal, mid-frontal

Left Parietal ERP Effect

Neural index of recollection at left-parietal sites.

Mid-Frontal ERP Effect

Neural index of decision criteria at frontal sites.

Wilding et al (1995)

Studied modality effects on source judgments.

- words presented audibly or visually and later asked what modality word was in.

- ERP larger (at left parietal) when ppts made correct source judgements

Remember/Know Procedure (Tulving, 1985)

isolates contributions of recollection and familiarity

- ppts asked to judge if they remember, know the stimuli or decide if its new

what does the remember-know procedure tell us about memory

- if remembered = retrieval form contextual/episodic memory

- if know = retrieval from semantic memory/recognition