13. Source Memory

13. Source Memory

1. Source Memory

   • Study: encoding = presenting p's with stimuli on R/L screen. Test = present words and new words (lures) and ask them to make left/right/new judgements
   • Regocnition memory = make decisions whether we have seen a stimuli or not
   • Source memory = involves judgements about contextual details of an event

2. Paradigms to measure SM

   • Remember / Know Paradigm (Tulving, 1985)
     • Measure the contribution of recollection and familiarity to overall memory performance (Tulving, 1985) but didn’t state how responses relate to underlying memory
     • Test phase: p's asked why they feel they recognise the item: Remember: consciously recollect particulars of the event, Know: they feel that they have seen the item before but there is no memory for the details of the event New: item was not presented in the study phase
     • Remember = recollection, know = familiarity
     • Definition of recollection is wide = many things, thoughts, feelings can influence
     • Limitations = subjective paradigm, method asumes processes are mutaully excluive
     • Independence remember-know method: assumes recollection and familiarity are independent,
   • Object / Source Task
     • Encoding = words presented red/green, retrieval = words presented in white, msut suggest whether they were in red/green or new
     • Process dissociation procedure: JAcoby (1991) p's presented list visually and heard them,
     • Receiver operating characteristics: examine effect of varying response criteria on hits/false alarms.
   • Task Dissociation
     • Response-Speed method: Familiarity faster, than recollection, to measure response speed to separate processes
     • Response-Time method: Recognition examined separately for fast and slow recognition responses under standard non speeded conditions. Fast response = familiarity, Slow responses = recollection
     • Response-Deadline method: subjects forced to make speeded responses, compared to non-speeded conditions. Fast = familirty, not = recognition & FAmiliairty
     • Speed-Accuracy trade off Method: subjects signalled to respond at variable intervals following the onset of each test item when performance exceeds chance, make inferences about retrieval speed
     • Recall-Recognition Method: performance on recall tests can be used to study recollection compare recall performance to recognition (recollection and familiarity)
     • Item-Associative recognition method: recollection = retrieval of qualitive info, familairty = memory strength of items

3. Models of SM

   • Signal Detection Theory
     • Green & Swets (1966) p's listen to tone, with white noise in background, press button if they detect tone. Hit, miss, false alarm or correct rejection
     • Memory trace = strength values, activation in memory dictate familiarity
     • Criterion levels, above = item test old, below = item test new
   • Source Monitoring Framework (Johnson et al, 1993)
     • process involved in examining origins of what we retrieve and whether it is from a particualr source
     • controlled processes mediated by prefrontal cortex
     • 3 types of SM = external, internal and reality monitoring
     • many decisions made rapidly and automatically
   • Dual-Process (Yolelinas, 1999)
     • 2 processes contribute to memory = familiarity and recollection
     • recollection more sensitive to distraction
     • recollection = hippocampus, familiarity = perirhinal cortex

4. SM and SCZ

   • Source monitoring in SCZ: 1 of the most profoundly affected cognitive domains is episodic memory. Frith (1992) suggested symptoms of SCZ may result from deficits in reality monitoring
   • Do SCZ have deficits in recollection / familiarity
     • Van-Erp et al (2008) 35 SCZ and 35 controls, saw screen and memorised items, test saw words and made RKN decision. SCZ significanlty worse recollection, not familiarity
     • Weiss et al (2008) objective source paradigm, 18 SCZ, 18 controls, saw words and indicate whether female/famle/new = SCZ perfoemd simmialr to contorl
     • Libby et al (2013) reviewed articesl of RKN, PD and POC sudies, SCZ effects both recolelction and familiarity, but recollection is more strognly impacted
   • Are there specific deficits in SM?
     • Vinogradov et al (1997): 26 SCZ and 21 controls gievn 40 sentences complete/incomplete, had to indiciate if word pair made my experienter, themslevs or new. SCZ geneated word themselves but more likely to say experimenter did = deficit in reality monitoring
     • Achim & Weiss (2008) meta-analysis for reality, external and internal SM studies, no evidence for spceific deficits
     • Gaweda et al (2012) instrctions to do or imagine doing a task, SCZ made errors in imagined/performed
   • Relation to symptoms
     • Mixed evidence
     • - SM deficits linked to positive symptoms (Anselmetti et al., 2007; Brebion et al., 2000, 2002; Startup et al., 2008)
     • - SM deficits linked to Thought disorganisation (Nienow & Docherty, 2004) SM linked to Negative symptoms (Brebion et al., 2002; Moritz et al., 2003)
     • SM not related to specific symptoms (Vinogradov et al., 1997)
     • Humpston, Linden & Evans = Deficits in reality and internal SM associated with positive dimension of schizotypy