The topic of my Master’s thesis last year was about prospective memory which is defined by Einstein and McDaniel (1990) as a kind of episodic memory centered on the future (i. e., to remember to buy some bread after work or to turn off the oven at some point, etc). Prospective memory is essential to everyday life’s activities (Eyseck, 2009) but is also especially vulnerable in the cases of brain damages due to head trauma, ischemic stoke, brain tumor, etc (Shum, Levin & Chan, 2011). To make up for prospective impairment, patients and healthy people often use reminders such as diaries or check-lists, yet other less constraining means exist. One of them is a cognitive strategy called implementation intentions developed by Gollwitzer (1999).
Implementation intentions is based on two methods used to remember and carry out an intended action more easily ; verbalization and mental imagery. First, the subject must repeat several times and out loud a wording such as « When I see X, I must do/tell him or her Y. » (i. e., « When I catch the sight of a bakery, I must stop to buy some bread. »). Secondly, the subject has to imagine himself doing the intended task at the right time or after having identified a sign in the environment (catching the sight of a bakery in the last example). This strategy was developed in three different ways: some researchers simply use verbalization, others only imagery, and a third kind combines both. Previous studies investigated the effects of the different kinds of implementation intentions on prospective memory performances (McDaniel, Howard & Butler, 2008 ; Grilli & McFarland, 2011 ; McFarland & Glisky, 2012 ; Mioni, Rendell, Terrett & Stablum, 2015). They either concluded that there was no significant difference of effectiveness between the three variants of implementation intentions, or the studies had either opposing results. However, a large majority of the researches was conducted on healthy people less concerned by prospective memory impairment or on subjects in whom there was no prospective memory impairment highlighted. Moreover researchers used a variety of procedures which can account for opposing findings.
Furthermore, the lack of data on clinical populations vulnerable to prospective memory failures lead us to explore the effects between the different types of implementation intentions on brain-damaged patients’ prospective performances. The study carried out during this thesis, was built to ascertain which strategy was the most effective against prospective impairment.
The study was undertaken with 11 brain-damaged subjects to whom we underlined a prospective memory deficiency first. To introduce the three implementation intentions variants, we submitted the participants to a number of various encoding conditions of the prospective task instructions (a pre-experimental and a post-experimental control conditions, verbalization, imagery, combination of both). Then subjects carried out another task alternating high and low levels of attentional demands, during which they must remember to produce the intended action at a specific time. We alternated the attentional demands of the task to see if each of the strategy variants was as efficient in the high attentional demands condition as in the low attentional demands condition.
The report of the results revealed that the three variants of implementations intentions had a beneficial effect on prospective performances but the combination of verbalization and imagery was more advantageous, the latter being more effective than verbalization. However we failed to highlight an effect of the variation of attentional demands on the prospective performances.
To conclude, this experiment insists on practical implications in the field of cognitive rehabilitation. Indeed, as long as the cognitive impairment is not too severe (i. e., no massive loss of memory, more or less preserved learning process, etc), implementation intentions combining verbalization and imagery can be a resort to external memory aides which are often considered as a burden by the patients. Further studies should test this strategy and its different variants on more ecological tasks with more clinical subjects while thinking of a better procedure to alternate attentional demands of the tasks.
References:
Einstein, G. O., & McDaniel, M. A. (1990). Normal aging and prospective memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 16(4), 717-726. DOI: 10.1037/0278-7393.16.4.717
Eyseck, W. M. (2009). Prospective memory. Dans A. Baddeley, W. M. Eyseck & C. M. Anderson (Eds.), Memory (pp. 343-356). New York: Psychology Press.
Gollwitzer, P.M. (1999). Implementation intentions: Strong effects of simple plans. American Psychologist, 54(7), 493-503. DOI:10.1037/0003-066X.54.7.493
Grilli, M. D., & McFarland, C. P. (2011). Imagine that: Self-imagination improves prospective memory in memory-impaired individuals with neurological damage. Neuropsychological Rehabilitation, 21(6), 847-859. DOI: 10.1080/09602011.2011.627263
McDaniel, M. A., Howard, D. C., & Butler, K. M. (2008). Implementation intentions facilitate prospective memory under high attention demands. Memory & Cognition, 36(4), 716-724. DOI: 10.3758/MC.36.4.716
McFarland, C. P., & Glisky, E. L. (2012). Implementation intentions and imagery: Individual and combined effects on prospective memory among young adults. Memory & Cognition, 40(1), 62-69. DOI: 10.3758/s13421-011-0126-8
Mioni, G., Rendell, P. G., Terrett, G., & Stablum, F. (2015). Prospective memory performance in traumatic brain injury patients: A study of implementation intentions. Journal of the International Neuropsychological Society, 21(4), 305-313. DOI: 10.1017/S1355617715000211
Paton, B. (2016). To many Post-It notes [Image found online]. Retrieved from https://paton.io/enough-with-the-post-it-notes-7eeb6cce0c07
Shum, D., Levin, H., & Chan, R. C. K. (2011). Prospective memory in patients with closed head injury: A review. Neuropsychologia, 49(8), Jul, 2156-2165. DOI: 10.1016/j.neuropsychologia.2011.02.006