Voluntary and involuntary emotional memory following an analogue traumatic stressor: The differential effects of communality in men and women

Highlights

• We examine voluntary and involuntary (intrusive) memories in an analogue trauma study.

• Communality (also referred to as ‘femininity’ in some research) was associated with involuntary memory only in men.

• Communality was associated with voluntary memory only in women.

• Instrumentality was not associated with memory.

• Communality may confer vulnerability in men and women through different mechanisms.

Abstract

Background

Men and women show differences in performance on emotional processing tasks. Sex also interacts with personality traits to affect information processing. Here we examine effects of sex, and two personality traits that are differentially expressed in men and women – instrumentality and communality – on voluntary and involuntary memory for distressing video-footage.

Methods

On session one, participants (n = 39 men; 40 women) completed the Bem Sex-Role Inventory, which assesses communal and instrumental traits. After viewing film-footage of death/serious injury, participants recorded daily involuntary memories (intrusions) relating to the footage on an online diary for seven days, returning on day eight for a second session to perform a voluntary memory task relating to the film.

Results

Communality interacted with sex such that men with higher levels of communality reported more frequent involuntary memories. Alternatively, a communality × sex interaction reflected a tendency for women with high levels of communality to perform more poorly on the voluntary recognition memory task.

Limitations

The study involved healthy volunteers with no history of significant psychological disorder. Future research with clinical populations will help to determine the generalizability of the current findings.

Conclusion

Communality has separate effects on voluntary and involuntary emotional memory. We suggest that high levels of communality in men and women may confer vulnerability to the negative effects of stressful events either through the over-encoding of sensory/perceptual-information in men or the reduced encoding of contextualised, verbally-based, voluntarily accessible representations in women.

Introduction

Distressing involuntary (intrusive) memories are a common experience in psychological disorders (Brewin, Gregory, Lipton, & Burgess, 2010) especially after stressful life-events, as in Postraumatic Stress Disorder (PTSD). However, susceptibility to these symptoms varies as a function of pre-existing vulnerability factors (DiGangi et al., 2013). Amore complete understanding of these vulnerabilities depends on prospective studies which are time-consuming and expensive. In the meantime, the contribution of specific risk factors to symptom-development can be fruitfully explored using experimental approaches which model psychological distress in healthy individuals. One commonly-used laboratory approach for investigating intrusive memories is the stressful-film paradigm (Holmes & Bourne, 2008). This approach has been used, for example, to examine the role of psychological traits such as positive schizotypy (Steel, Fowler, & Holmes, 2005) and trait mood variables (Laposa & Alden, 2008) in the development of intrusive memories.

Sex has rarely been investigated in well-powered analogue studies of intrusive memories. This is perhaps surprising given that (female) sex is an established risk factor for the development of psychological disorders. On the other hand, sex per se may not be sufficient to determine risk. For example, in the case of elevated risk of Posttraumatic Stress Disorder (PTSD) in women, pre-existing and habitual information-processing styles may also play an important role in aetiology (Olff, Langeland, Draijer, & Gersons, 2007). However the nature of sex-specific information-processing factors in the onset and maintenance of psychological distress remains unclear, although clues from related research suggest that ‘gender-role¹’ rather than sex may be an important determinant of how emotional information is processed. These studies suggest that an individuals' self-concept, particularly their social identity, defined in terms of stereotyped masculine (agentic, instrumental) and feminine (communal, expressive) traits, affect the way in which emotional information is perceived and encoded.

These traits are influenced by both biological and socialisation processes in childhood (Eagly & Wood, 2013) such that women are more likely to (be encouraged to) develop affiliative, empathic and interpersonally-oriented behaviours whereas men develop task-focused, assertive and systemizing behaviours.

A relatively small number of studies have investigated the relationship between emotional information processing, and instrumentality and communality. For example, Bourne and Maxwell showed that an interaction between participant sex and instrumentality (referred to as ‘masculinity’) predicted lateralization of facial emotion recognition (Bourne & Maxwell, 2010). Similarly, Cahill and colleagues showed that voluntary recognition memory for peripheral, visual aspects of a negatively-valenced story was higher in individuals with high levels of communality (referred to as ‘femininity;’ Cahill, Gorski, Belcher, & Huynh, 2004). ‘Central’ information, conveying the gist of the story on the other hand, was better recognised in those with higher levels of instrumentality.

Behavioural responses to negatively valenced stimuli may also be influenced by communality and instrumentality. For example while women showed higher levels of anxiety and avoidance in a behavioural avoidance task, low levels of instrumentality, regardless of sex, were associated with higher levels of avoidance (McLean & Hope, 2010). These studies suggest that processing of threat-relevant stimuli is at least partially determined by gendered personality traits rather than sex alone.

It remains unclear how these traits affect memory for highly negatively-valenced and arousing material such as that designed to simulate (within ethical limits) aspects of the highly stressful or traumatic experiences associated with the onset of psychological disorders (e.g. PTSD and depression). According to some clinical theories of PTSD, highly emotional events result in memory representations formed at a sensory level (involving, for example, perceptual priming) as well as verbally-based, conceptual and contextual-level representations (Brewin et al., 1996, Brewin et al., 2010, Ehlers and Clark, 2000). Distressing intrusive memories reflect the preferential encoding of sensory/perceptual detail during highly stressful events, whereas the contextual/conceptual memory system is simultaneously inhibited by stress, resulting in impoverished verbally-based, voluntarily retrievable memory for the event. As such, clinical theories of disorders characterised by intrusive memories predict impairment in voluntary memory for highly stressful events (Brewin, 2014), at least in some vulnerable individuals.

Here we investigate both voluntary and involuntary memory for distressing film scenes involving death and injury (i.e. an analogue traumatic stressor), focussing on sex, and the gender-related personality constructs, instrumentality and communality as predictors, in a study that also investigated the effects of a post-encoding working memory task. To date only a single study has reported a role for instrumentality and communality in emotional memory performance, although that study focused exclusively on voluntary memory (Cahill et al., 2004). No study that we are aware of has yet examined the role of these traits on the occurrence of involuntary emotional memories.

Given the higher prevalence of psychological disorder characterised by intrusive memories in women, our main hypothesis was that sex, and/or communality would predict frequency of involuntary memories for the stressful film. Further, given that one theory of intrusive memories (Brewin et al., 1996) proposes that separable systems subserve voluntary and involuntary emotional memory, and the suggestion that voluntary memory suppression may accompany the over-encoding of sensory/perceptual aspects of events (Brewin, 2014), we also explored the possibility of a negative association between communality and/or (female) sex and voluntary memory performance. Instrumentality has, by and large, been associated with psychological well-being (Helgeson, 1994) rather than psychopathology so was not predicted to be associated with the occurrence of involuntary memories.