when i say When I say … retroactive interference Kevin McLaughlin
For 3 years I could recall effortlessly the 16 digits of my credit card number. Realistically, I knew that was not a magical feat of memory, but I was still impressed at my ability to chunk and file those numbers in my long-term memory under ‘credit card’. Between 2008 and 2011 I crammed lots of new information into my memory – English words, Italian words, telephone numbers and countless passwords – none of which impacted the recall of my credit card number. Then came the dreaded chip update. In 2011 my bank forced me to update my credit card to one with enhanced security in the form of a ‘chip’… and 16 new digits. I immediately forgot my old number, yet my linguistic ability was unaffected, and I was still able to call up my friends and log on to my e-mail account. So why did I develop this selective amnesia? Retroactive interference (RI) occurs when newly acquired information inhibits the recall of previously learned information.1 It has been shown to impair recall of word associations, and can also affect other types of memory, including those of sound and taste. This phenomenon is typically seen when learners receive training in one area of content (conditioned stimulus) and are then exposed to new content (unconditioned stimulus) before being evaluated on the original content, which explains why viewing the 16 digits on my new credit card inhibited the recall of the old number. So where did the memory of my old credit card number go? Data stored in long-term memory are considered permanent, so it is unlikely that this memory trace was shredded along with the card. Indeed, a consistent finding from the literature on RI is that original learning is not ‘unlearned’ or Calgary, Alberta, Canada Medical Education 2014; 48: 655–656 doi: 10.1111/medu.12310
destroyed.1 Instead, the unconditioned stimulus provides an ‘extinction cue’ that temporarily dominates retrieval of the conditioned stimulus and, with time and lack of exposure to the unconditioned stimulus, the original learning should recover spontaneously. In real life, learning and retrieval overlap continually, yet successful retrieval is the norm. This implies that certain conditions are required to create RI. The first is similarity between stimuli and so it seems logical that a novel 4 9 4 number set should be more likely than an Italian verb to interfere with the retrieval of a learned 4 9 4 number set.2 As learning is bound to context, RI is more likely when stimuli are contextually similar, which explains why reading out 16 numbers from a new plastic card while in the act of purchasing led to the extinction of the memory trace for the number set on my old plastic card, whereas learning 10-digit telephone numbers did not.3 Timing of exposure is also important: RI is more likely when there is a short interval between the unconditioned stimulus and attempted recall of the conditioned stimulus.2 It was only when reading my new credit card number that I pondered whether I could still remember my old number – which is the worst possible time to ask this question! Finally, increased training on the conditioned stimulus reduces the likelihood of RI by strengthening the memory trace for this stimulus, which explains why we do not lose the ability to converse in our native language when we learn a new language. Beyond psychology experiments and credit card amnesia, is RI relevant to medical educators? In a recent study of simulation training, Fraser et al. 4 Correspondence: Kevin McLaughlin, Office of Undergraduate Medical Education, University of Calgary, 3330 Hospital Drive, Calgary, Alberta T2N 4N1, Canada. Tel: 00 1 403 220 4252; E-mail: [email protected]
ª 2014 John Wiley & Sons Ltd. MEDICAL EDUCATION 2014; 48: 655–656
655
K. McLaughlin randomised medical students to either standard or interference training protocols. In both protocols students were trained on a single murmur and then evaluated on this murmur along with a novel murmur 1 hour after training and then again 6 weeks later.4 The sequence for both evaluations in the standard cohort was trained murmur followed by novel murmur, whereas this order was reversed in the interference protocol (novel murmur followed by trained murmur). At 1 hour and at 6 weeks after training, students in the standard protocol gave a significantly better diagnostic performance on their trained murmur. By contrast, there was no difference in the diagnostic performances given on the trained and novel murmurs by students in the interference protocol.4 These findings suggest that medical education is not immune to the effects of RI and that medical educators should be aware of the conditions that may lead to RI during their teaching.
656
REFERENCES 1 Briggs GE. Acquisition, extinction, and recovery functions in retroactive inhibition. J Exp Psychol 1954; 47:285–93. 2 Miller RR, Greco C, Marlin NA, Balaz MA. Retroactive interference in rats: independent effects of time and similarity of the intervening event with respect to acquisition. Q J Exp Psychol 1985;37:81–100. 3 Brown JS, Collins A, Duguid P. Situated cognition and the culture of learning. Educ Res 1989;18:32–42. 4 Fraser K, Ma I, Teteris E, Lee M, Wright B, McLaughlin K. Learning during simulation training is prone to retroactive interference. Med Educ 2012;46: 299–305. Received 8 May 2013; editorial comments to author 27 June 2013; accepted for publication 16 July 2013
ª 2014 John Wiley & Sons Ltd. MEDICAL EDUCATION 2014. MEDICAL EDUCATION 2014; 48: 655–656
For 3 years I could recall effortlessly the 16 digits of my credit card number. Realistically, I knew that was not a magical feat of memory, but I was still impressed at my ability to chunk and file those numbers in my long-term memory under ‘credit card’. Between 2008 and 2011 I crammed lots of new information into my memory – English words, Italian words, telephone numbers and countless passwords – none of which impacted the recall of my credit card number. Then came the dreaded chip update. In 2011 my bank forced me to update my credit card to one with enhanced security in the form of a ‘chip’… and 16 new digits. I immediately forgot my old number, yet my linguistic ability was unaffected, and I was still able to call up my friends and log on to my e-mail account. So why did I develop this selective amnesia? Retroactive interference (RI) occurs when newly acquired information inhibits the recall of previously learned information.1 It has been shown to impair recall of word associations, and can also affect other types of memory, including those of sound and taste. This phenomenon is typically seen when learners receive training in one area of content (conditioned stimulus) and are then exposed to new content (unconditioned stimulus) before being evaluated on the original content, which explains why viewing the 16 digits on my new credit card inhibited the recall of the old number. So where did the memory of my old credit card number go? Data stored in long-term memory are considered permanent, so it is unlikely that this memory trace was shredded along with the card. Indeed, a consistent finding from the literature on RI is that original learning is not ‘unlearned’ or Calgary, Alberta, Canada Medical Education 2014; 48: 655–656 doi: 10.1111/medu.12310
destroyed.1 Instead, the unconditioned stimulus provides an ‘extinction cue’ that temporarily dominates retrieval of the conditioned stimulus and, with time and lack of exposure to the unconditioned stimulus, the original learning should recover spontaneously. In real life, learning and retrieval overlap continually, yet successful retrieval is the norm. This implies that certain conditions are required to create RI. The first is similarity between stimuli and so it seems logical that a novel 4 9 4 number set should be more likely than an Italian verb to interfere with the retrieval of a learned 4 9 4 number set.2 As learning is bound to context, RI is more likely when stimuli are contextually similar, which explains why reading out 16 numbers from a new plastic card while in the act of purchasing led to the extinction of the memory trace for the number set on my old plastic card, whereas learning 10-digit telephone numbers did not.3 Timing of exposure is also important: RI is more likely when there is a short interval between the unconditioned stimulus and attempted recall of the conditioned stimulus.2 It was only when reading my new credit card number that I pondered whether I could still remember my old number – which is the worst possible time to ask this question! Finally, increased training on the conditioned stimulus reduces the likelihood of RI by strengthening the memory trace for this stimulus, which explains why we do not lose the ability to converse in our native language when we learn a new language. Beyond psychology experiments and credit card amnesia, is RI relevant to medical educators? In a recent study of simulation training, Fraser et al. 4 Correspondence: Kevin McLaughlin, Office of Undergraduate Medical Education, University of Calgary, 3330 Hospital Drive, Calgary, Alberta T2N 4N1, Canada. Tel: 00 1 403 220 4252; E-mail: [email protected]
ª 2014 John Wiley & Sons Ltd. MEDICAL EDUCATION 2014; 48: 655–656
655
K. McLaughlin randomised medical students to either standard or interference training protocols. In both protocols students were trained on a single murmur and then evaluated on this murmur along with a novel murmur 1 hour after training and then again 6 weeks later.4 The sequence for both evaluations in the standard cohort was trained murmur followed by novel murmur, whereas this order was reversed in the interference protocol (novel murmur followed by trained murmur). At 1 hour and at 6 weeks after training, students in the standard protocol gave a significantly better diagnostic performance on their trained murmur. By contrast, there was no difference in the diagnostic performances given on the trained and novel murmurs by students in the interference protocol.4 These findings suggest that medical education is not immune to the effects of RI and that medical educators should be aware of the conditions that may lead to RI during their teaching.
656
REFERENCES 1 Briggs GE. Acquisition, extinction, and recovery functions in retroactive inhibition. J Exp Psychol 1954; 47:285–93. 2 Miller RR, Greco C, Marlin NA, Balaz MA. Retroactive interference in rats: independent effects of time and similarity of the intervening event with respect to acquisition. Q J Exp Psychol 1985;37:81–100. 3 Brown JS, Collins A, Duguid P. Situated cognition and the culture of learning. Educ Res 1989;18:32–42. 4 Fraser K, Ma I, Teteris E, Lee M, Wright B, McLaughlin K. Learning during simulation training is prone to retroactive interference. Med Educ 2012;46: 299–305. Received 8 May 2013; editorial comments to author 27 June 2013; accepted for publication 16 July 2013
ª 2014 John Wiley & Sons Ltd. MEDICAL EDUCATION 2014. MEDICAL EDUCATION 2014; 48: 655–656
