The I-AMT provoked differential patterns of AM retrieval across the social mentality conditions. Contrary to expectations, these revealed reduced retrieval specificity and longer retrieval latencies for recall of events when the drive system was active, in comparison to experiences of threat or compassion. Retrieval specificity and latency were however similar for compassion and threat-based events. It is unclear whether these patterns of AM retrieval reflect the operation of variable social mentalities, or other methodological sources of variance.
It still remains possible that, as predicted, functional avoidance of threat-based experiences is occurring (Conway & Pleydell-Pearce, 2000). Without a control group, it is unclear whether our sample exhibited reduced specificity of threat-cued retrieval relative to healthy individuals. However, this seems likely given previous evidence of overgeneral memory in these populations. Nonetheless, other factors may additionally be influencing retrieval to the different social mentality cues, which could account for the pattern of results observed.
55 There are a number of possible reasons why AM retrieval impairments were more prominent in response to drive cues. Firstly, the drive system is an energising system that motivates us to seek goals, follow desires and achieve status. One hypothesis is that patients have difficulty accessing the drive system when presented with drive-related cues, resulting in resignation in challenging situations or adoption of a subordinate rank position. Consistent with this, negative symptoms of avolition and apathy are prevalent in schizophrenia, and strongly linked to functional outcomes (see Foussias & Remington, 2010, for review). Furthermore, half the complex trauma sample met caseness for depression, for which apathy is also a common feature (American Psychiatric Association, 1994). Retrieval to drive cues may therefore have been more difficult for our sample due to a paucity of experiences of feeling driven or competitive, and a resultant lack of stored memory representations that match these cues. This is likely to have increased the effort required to produce a specific response, and increased the likelihood of failing to meet task demands, either because a matching memory representation could not be found, or the patient lacked the necessary drive or competitiveness to persist and achieve this more difficult task.
Poor executive functioning capacity may also contribute towards the occurrence of overgeneral memory to drive cues (Williams et al., 2007). Multiple executive functions have been implicated in AM retrieval, for example in generating descriptions of the event to be retrieved or inhibiting irrelevant material (Burgess & Shallice, 1996). The cognitive effort required for successful retrieval varies according to features of the eliciting cue, such as how well it maps to target items stored in memory.
Aspects of the I-AMT drive cues could therefore account for the poor retrieval observed. Anecdotally, participants reported poor comprehension of the drive cue words (e.g. “driven”, “motivated”). Retrieval to these cues may have required greater cognitive resources, due to infrequency of the words used or because the words were more abstract than in the other conditions. Abstract words do not contain the additional perceptual information that concrete words do, making them less imageable (de Groot, 1989). For example, the abstract word ‘justice’ conveys a semantic meaning, whilst the concrete word ‘fire’ additionally insinuates visual, auditory and tactile information. Cues of low imageability have been shown to prompt overgeneral retrieval with longer latencies compared to highly imageable cues in non-clinical populations (Williams et al., 1999). This is hypothesised to occur because concrete words provide an analogue representation of the item to be retrieved, in addition to the semantic label, reducing the executive functioning capacity required for successful retrieval. As executive functioning is impaired in schizophrenia (Reichenberg & Harvey, 2007), and trauma populations (e.g. Stein et al.,
56 2002), our sample may have been particularly susceptible to differences in task difficulty between experimental conditions. The original AMT cue words were shown to elicit appropriately valent responses (Williams & Broadbent, 1986), and subsequent adaptations have selected words based upon their frequency in the spoken language and imageability (e.g. Cuervo-Lombard et al., 2012). The I-AMT cue words were selected based upon ratings from a non-clinical sample, roughly half of whom had worked within mental health settings and thus may have had different levels of education and psychological understanding compared to our clinical sample. Future research may wish to re-select the I-AMT cue words based upon ratings from a sample that is more representative of the individuals to be assessed and, if possible, should aim to employ more commonly used, imageable words to minimise this experimental bias.
Interestingly, post hoc exploratory analyses suggest that those with schizophrenia had a more overgeneral retrieval style compared to the complex trauma sample, whilst retrieval latencies for the groups were similar. No previous studies have compared retrieval in these populations. The presence of overgeneral memory in schizophrenia is consistent with the AM literature (Watson et al., 2012), but the absence of a non-clinical control group prevents definitive interpretation of the trauma group’s performance. It is likely that this represents an impairment, given previous evidence of overgeneral AM in trauma populations. It is proposed that these individuals develop a habitual overgeneral retrieval style to prevent recall of distressing traumatic events (Williams et al., 2007).