Involuntary autobiographical memories

How can they be measured? Over the decades since Ebbinghaus first described these types of memories, different methods have been used to study them. Some writers followed the self-testing approach advocated by Ebbinghaus, such as Esther Salaman (1970), who analysed systematically her own involuntary memories, but there were few empirical studies. It was only in the final decade of the 20th century that involuntary memories became an area of interest to cognitive psychologists, and it is now becoming a steadily growing field of research (e.g. Berntsen, 1996, 2009, 2010; Mace, 2007, 2010). Involuntary memories can be difficult to trigger experimentally because they require personal, or idiosyncratic, cues, and once a person becomes aware of trying to bring back a memory it becomes a voluntary memory. Most studies performed in the last 10 to 15 years have consisted of diaries and questionnaires, requiring participants to keep records of any involuntary memories that occurred over a specific time period, with details of how they were cued, and their content, vividness, etc. These studies have produced interesting and replicable findings concerning the frequency and nature of IAMs. However, more recently, several laboratory paradigms have been developed to study IAMs under controlled conditions. For example Mace (2006) showed that participants reported experiencing IAMs when recalling specific memories in response to cue phrases such as ‘being at a picnic’ – so called ‘memory chaining’. Ball (2007) elicited IAMs in college students using the free word association method, with participants instructed to generate continuous associations cued by words such as ‘coffee’ or ‘thunder’, until the experimenter stopped them after 20 to 30 seconds. The responses were recorded and after three word-association trials participants listened to their replies and stated whether or not a past personal experience had come to mind during the trials. IAMs were reported during 86 per cent of the trials. In our replication study with 31 adults, aged 21 to 86 years, we showed that a word association task led to the generation of vivid IAMs in 90 per cent of our participants (Bradley & Moulin, 2009). For example, a 73-year-old male recalled a violent hailstorm in North Wales that he experienced 55 years before, triggered by the word ‘storm’. He remembered the sight of the storm coming, and feeling concerned, wet and annoyed. Furthermore, Schlagman and Kvavilashvili (2008) developed a laboratory paradigm that enables researchers to measure retrieval times of IAMs while participants are engaged in an easy vigilance task requiring the detection of target vertical lines amongst a stream of horizontal lines. The IAMs are mostly reported as being triggered by random words, that participants were told to ignore, displayed in the centre of the array of lines. Results from these and other studies have consistently shown that IAMs are more likely to be of a specific event, and come to mind significantly faster than voluntary autobiographical memories. They are also more likely to result in bodily reactions and impact on current mood than voluntary memories (Berntsen & Hall, 2004). However, no differences were observed in terms of perspective experienced in memory (field vs. observer) and the accuracy (measured by participants’ own confidence ratings) of recorded memories (Mace et al., 2011).