The phonological loop is the part which deals with auditory information. Baddeley (1986) later added two parts to the store – the phonological store which holds the words you hear and the articulatory process – used for words that are seen and heard. ‘Loop’ refers to the words being silently repeated in your mind; a form of maintenance rehearsal. Shavice and Warrington (1970) found, through a case study of brain damaged man, evidence to support the existence of a phonological loop – the mans auditory processes were limited to verbal material like letters and digits but not for meaningful sounds like a doorbell. This therefore shows the damage was restricted to the phonological loop.
The visuo-spatial sketchpad is the name for the visuo-spatial store; visuo referring to what things look like and spatial to tasks such as counting windows. Logie (1995) divided this into two stores; visuo cache as the main store, and the inner scribe for spatial relations. Baddeley et al. (1975) demonstrated the existence of the different systems; he found a verbal task was less difficult for participants therefore showing that it used two systems, visuo spatial and phonological loop. This again supports this model is better than the MSM as it reflects more parts to the STM.
Lastly is the episodic buffer, added by Baddeley (2000). It was added because it seemed the model needed a general store for information and importantly, it links information from the model with LTM. Dolcos et al (2007) used fMRI scans to show the existence of all these separate stores. They observed dual task performance and found different areas of the prefrontal cortex to be activated when performing two tasks affecting the same store as predicted by the WMM. However D’Esposito (2007) suggested working memory might not exist as a separate system therefore going against the whole model.
Another alternative to the MSM is the levels of processing approach (LOP) as developed by Craik and Lockhart (1972). Their model was centered around the idea that there are different levels to memory and the depth or level of which we process things determines its place in the LTM. Unlike the MSM, the approach suggests encoding and processing is much more complicated. The approach also states that no rehearsal is needed instead, the more we process, the more we remember. This idea was supported by research by Mandler (1967) who’s participants were required to sort 52 word cards into 7 piles based on any system of categories until they were 95% consistent. Mandler found the best recall was observed when the participants used the most categories. This shows that organisation makes things memorable without any conscious effort; supporting the fact rehearsal isn’t needed to remember information.
The LOP approach suggests there are 3 levels of processing; shallow processing is when we analyse physical structure or a word, phonemic processing is when we are analyse the sound of a word and deeper processing is when we analyse a words meaning. Deeper processing therefore creates a more enhanced memory. Palamere et al (1983) gave participants a description of a made-up African nation and found recall was best when participants were given long-detailed paragraphs rather than short and snappy information. This research therefore supports the LOP approach as the deeper the processing (more detailed description), the better the recall.
On the other hand Morris et al (1977) researched transfer appropriate processing and found participants recalled words that rhymed (phonemic processing) better than words that had been deeply processed. This research therefore goes against the LOP approach and it could be argued that performance depends on what you need to recall and that there are other explanations for memory.
However Craik and Lockhart (1990) recognised this problem and suggested ‘depth’ refers to greater processing within the relevant domain.
Another major criticism of the LOP approach is the fact it becomes a circular definition e.g. something is remembered if its deeply processed and if its deeply processed, then you will be able to recall it better. This criticism makes the LOP seem reductionist but depth has been described to include organisation, distinctiveness, elaboration and effort; therefore showing depth is more complex.
In conclusion, although research has been found to support and refute both the WMM and the LOP approach, both theories cannot be known for sure if they are correct. The MSM is also at fault, therefore the mystery of our memory still remains; the ghost in the machine, we can observe the actions (machine) but never see inside the mind.
