Modulation of long-term memory by arousal in alexithymia: The role of interpretation

Assessing alexithymia: the proposal of a psychometric tool based on spheric videos

The present perspective introduces a novel psychometric tool designed to enhance the evaluation of alexithymia. Alexithymia, a condition marked by difficulties in recognizing and expressing emotions, along with a propensity to direct attention outside rather than toward one's own interior experiences, is commonly investigated through self-report questionnaires. These instruments assume that individuals have sufficient self-awareness and abstraction capabilities, which restricts the understanding of the underlying mechanisms of emotional recognition in individuals who do not possess these capacities. To address this lack, emerging technologies like virtual reality (VR) and 360° videos facilitate the recreation of immersive contexts, enabling subjects to engage with scenarios even remotely. Our innovative tool employs spherical video technology to recreate social and non-social scenarios that elicit emotions. Psychophysiological measures are collected during video observation; then, questions are asked to investigate how the subject consciously processes the emotions they experienced. This multimodal approach aims to capture both implicit and explicit emotion processing, providing a comprehensive assessment. Overall, the proposed psychometric tool offers the potential for a more nuanced understanding of alexithymic traits and their real-life impact, empowering clinicians to tailor treatment processes to individual needs based on a richer set of information.

Gender difference in association between clinical symptoms and alexithymia in chronic schizophrenia: A large sample study based on Chinese Han population

BACKGROUND

Alexithymia, a prevalent social cognitive impairment in schizophrenia, remains insufficiently studied. Though some studies propose a link between alexithymia and clinical symptoms of schizophrenia, this connection lacks consistent confirmation. Additionally, there is limited research on gender difference in alexithymia among schizophrenia patients. To fill this gap, our study aimed to conduct a large-sample survey of Chinese Han patients with chronic schizophrenia to explore whether there are gender differences between clinical symptoms and alexithymia.

METHODS

We obtained sociodemographic characteristics of 987 schizophrenia patients, measured their clinical symptoms using the Positive and Negative Syndrome Scale (PANSS), and assessed their self-reported alexithymia using the Toronto Alexithymia Scale (TAS-20).

RESULTS

In patients with chronic schizophrenia, the prevalence of alexithymia did not differ between genders (male: 35.51 % vs. female: 26.91 %, P = 0.018). Correlation and linear regression analyses revealed that PANSS scores and TAS-20 scores were widely correlated in both male and female patients. In particular, multiple linear regression analysis showed that the TAS total score was positively correlated with negative symptoms and cognitive symptoms in male patients, while it was positively correlated with negative symptoms and depressive symptoms in female patients.

CONCLUSION

Our study suggests that the prevalence of alexithymia in patients with chronic schizophrenia does not differ between genders. Negative symptoms are related to the TAS-20 total score in both male and female patients, while cognitive symptoms are only related to the TAS-20 total score in male patients, and depressive symptoms are only related to the TAS-20 total score in female patients.

Cognitive-emotional processing in alexithymia: an integrative review

Alexithymia is a multifaceted personality construct characterised by difficulties identifying one's feelings and distinguishing them from bodily sensations, difficulties describing one's feelings to others, and an externally oriented cognitive style. Over the past 25 years, a burgeoning body of research has examined how alexithymia moderates processing at the cognition-emotion interface. We review the findings in five domains: attention, appraisals, memory, language, and behaviours. The preponderance of studies linked alexithymia with deficits in emotion processing, which was apparent across all domains, except behaviours. All studies on behaviours and a proportion of studies in other domains demonstrated emotional over-responding. Analysis at the facet level revealed deficits in memory and language that are primarily associated with externally oriented thinking, while over-responding was most often linked to difficulty identifying feelings and difficulty describing feelings. The review also found evidence for contextual modulation: The pattern of deficits and over-responding was not restricted to emotional contexts but also occurred in neutral contexts, and in some circumstances, emotional over-responding in alexithymia was beneficial. Taken together, this review highlights alexithymia as a central personality dimension in the interplay between cognition and emotion.

Alexithymia

Humans are highly adept at differentiating, regulating, and responding to their emotions. At the core of all these functions is emotional awareness: the conscious feeling states that are central to human mental life. Disrupted emotional awareness-a subclinical construct commonly referred to as alexithymia-is present in a range of psychiatric and neurological disorders and can have a deleterious impact on functional outcomes and treatment response. This chapter is a selective review of the current state of the science on alexithymia. We focus on two separate but related issues: (i) the functional deficits associated with alexithymia and what they reveal about the importance of emotional awareness for shaping normative human functioning, and (ii) the neural correlates of alexithymia and what they can inform us about the biological bases of emotional awareness. Lastly, we outline challenges and opportunities for alexithymia research, focusing on measurement issues and the potential utility of formal computational models of emotional awareness for advancing the fields of clinical and affective science.

The influence of alexithymia on memory for emotional faces and realistic social interactions

High levels of alexithymia are typically associated with impaired memory for emotional, but not neutral words. We conducted two experimental studies to establish if this effect generalises to non-verbal socially relevant stimuli. Thirty-nine female undergraduates (Study 1) viewed faces with different expressions (neutral, angry, happy or sad) and 38 female students (Study 2) viewed videos of realistic social interactions (featuring anger, happiness, sadness or neutral affect). Participants were asked to identify the emotion portrayed and were subsequently given an intentional recognition memory test for the stimuli. They also completed self-report measures of alexithymia and mood (depression & anxiety). In Study 1, memory for emotional (especially angry), but not neutral faces was negatively related to the "difficulty describing feelings" facet of alexithymia. In Study 2, memory for emotional (particularly those featuring anger), but not neutral videos was negatively related to the "difficulty identifying feelings" and "externally oriented thinking" facets of alexithymia. In both studies, these memory deficits were independent of the effects of age and mood. Furthermore, the deficits appear to be most evident in the conscious recollection of the emotional stimuli. Our findings confirm that the memory deficit for emotional words in alexithymia generalises to important non-verbal socially relevant stimuli.

Post-encoding positive emotion impairs associative memory for English vocabulary

There is evidence that emotion induced during encoding impairs associative memory (e.g., Bisby, Horner, Bush, & Burgess, 2018), yet the effect of post-encoding emotion (particularly positive emotion) on associative memory remains largely unclear. Two experiments were conducted to examine the effect of post-encoding positive emotion on associative memory for English vocabulary. In Experiment 1, high school students memorized Chinese definitions of a list of English words, immediately recalled the Chinese definitions, watched a neutral or comic video, and took a delayed memory test 25 minutes after encoding. The result showed a significant impairing effect of post-encoding positive emotion on memory for Chinese definitions. In Experiment 2, primary school students encoded English words with their associative pictures, took an immediate test where, on each trial, they were asked to choose the correct English word that matches a picture. Following the test, they watched a neutral or comic video, and took a memory test 10 minutes after encoding. Consistent with Experiment 1, Experiment 2 showed an impairing effect of positive emotion. Taken together, these findings support the hypothesis that post-encoding positive emotion can impair associative memory, providing important implications for acquisition of vocabulary of English as a foreign language.

Childhood trauma and adult declarative memory performance in the general population: The mediating effect of alexithymia

BACKGROUND

Previous studies suggested that childhood maltreatment is associated with altered memory performance in adulthood. Deficits in identifying and describing feelings as captured by the alexithymia construct are strongly linked with childhood trauma and may mediate the associations with memory function.

OBJECTIVE

To investigate the associations of childhood trauma with verbal declarative memory performance and the putative mediating role of alexithymia.

METHOD

Associations of the different dimensions of childhood trauma with adult declarative memory performance were tested in two large, independent general population samples comprising a total of N = 5574 participants. Moreover, we tested whether associations were mediated by alexithymia.

RESULTS

In both samples, childhood emotional neglect, but not abuse emerged as a negative statistical predictor of early (sample 1: β=-1.79; p < 0.001, sample 2: β=-0.26; p < 0.001) as well as delayed recall (β=-0.78; p < 0.001; β=-0.24; p < 0.05). Likewise, childhood emotional neglect was the strongest predictor for alexithymia (β = 3.2; p < 0.001; β = 3.54; p < 0.001). Finally, the association between childhood emotional neglect and early (Total Mediated Effect (TME): 13.2, CI: 0.087-0.302; TME: 20.1; CI: 0.123-0.619) as well as late recall (TME: 13.2, CI: 0.086-0.301; TME: 9; CI: -0.442-0.699) was significantly mediated by alexithymia.

CONCLUSIONS

Our findings suggest that childhood emotional neglect is particularly detrimental to memory functioning in adulthood. In comparison, childhood abuse was not associated with reduced declarative memory capacity. Our results contribute to explain the mechanism underlying the relation of childhood trauma and memory deficits: Finding specific associations with emotional neglect and a mediating role of alexithymia highlights the relevance of emotion processing capacities for memory functioning.

Alexithymia disrupts verbal short-term memory

While some research has now started to suggest that there are long-term memory (LTM) deficits in alexithymia, short-term memory (STM) in alexithymia remained largely unexplored. This study investigated whether the STM trace for emotion and neutral words might also be disrupted by alexithymia. Forty-four participants were randomly assigned to Study 1 in which the to-be-memorised six-word lists were composed of words belonging to the same valence (i.e. pure lists condition, Study 1), and 44 other participants were randomly assigned to Study 2 in which six-word lists were composed of embedded neutral and emotional words (i.e. mixed lists condition). All the participants completed the Toronto-Alexithymia Scale (TAS-20) and a current mood states scale (PANAS). Results showed that the main effect of alexithymia was observed in the pure lists condition while no alexithymia groups effect emerged in the mixed lists condition. In the pure lists condition only correlation analyses confirmed that alexithymia significantly and negatively correlated with recall accuracy. The results are discussed with regard to the influence of alexithymia on the proposed role of (1) semantic organisation of LTM on STM performance in the pure lists condition and (2) attentional capture by emotional words in the mixed lists condition.

The role of alexithymia in memory and executive functioning across the lifespan

Alexithymia is a personality trait characterised by difficulties identifying feelings (DIF), describing feelings (DDF), and externally oriented thinking (EOT). Alexithymia has been associated with poorer memory, at least for emotive materials, and recently, with executive and neural dysfunction. Aging is also accompanied by poorer memory and executive functioning (EF), neural dysfunction, and increasing alexithymia. Thus, the hypothesis of a general cognitive impairment in alexithymia, particularly in elders, needs investigation. Three large, independent, cross-sectional experiments (n = 296, 139 and 121, respectively) investigated memory and EF in healthy adults, ranging from young to old adulthood, with age, sex, and the three Toronto Alexithymia Scale-20 subscales (DIF, DDF, EOT) as predictors in hierarchical regressions. Across studies, alexithymia contributed to poorer memory (via EOT) and EF (via DIF), in younger and older adults. Additionally, these effects occurred in non-emotive contexts with neutral stimuli. Moreover, although memory was worse with greater age and poor EF contributed to poor memory, those who had both high EOT and poor EF had particularly poor memory. Thus, alexithymia (particularly via high DIF or high EOT) is a risk factor for age-related cognitive decline. Further research should clarify the direction and nature of these complex relationships.

Memory for emotional information and alexithymia A systematic review

Alexithymia is a deficit in the recognition, expression and regulation of emotions, which has the following features: difficulty in identifying or describing feelings, difficulty distinguishing between feelings and bodily sensations, stringent imaginal processes, and externally oriented cognitive style. This personality trait is associated with many psychiatric and psychosomatic disorders, as well as with risky behaviors.

The Prospective Influence of Trait Alexithymia on Intrusive Memories: What Is the Role of Emotional Recognition Memory?

Posttraumatic stress disorder (PTSD) is often considered to be a disorder of memory as patients suffer from fragmented uncontrollable memories (intrusions) whilst experiencing difficulties in intentionally retrieving details of the traumatic event. Recent research suggests that trait-related deficits in the identification of emotional states (alexithymia) may impact emotional memory processes in a way that promotes intrusion formation in PTSD. Therefore, we investigated the influence of alexithymia on intrusive re-experiencing and emotional recognition memory in a prospective analog study. Twenty-six healthy participants took part in a laboratory experiment, which combined two independent paradigms. Participants were exposed to a traumatic film (first session) and completed an episodic memory task comprising neutral and emotional stimuli (second session). In between sessions, participants recorded intrusive memories of the film. Individuals with higher trait alexithymia (HTA) reported an increased number of intrusions on the day of film presentation. Moreover, analyses of memory performance revealed a negative correlation between alexithymia and emotional recognition memory. Further analyses suggest that reduced emotional recognition memory, as evident in individuals with HTA, may, in turn, be associated with enhanced intrusive re-experiencing. As such, the current findings provide first indications regarding the role of alexithymia in emotional learning and PTSD. Future studies should further investigate these associations as well as potential implications for the treatment of PTSD.

Dynamic Influence of Emotional States on Novel Word Learning

Many researchers realize that it's unrealistic to isolate language learning and processing from emotions. However, few studies on language learning have taken emotions into consideration so far, so that the probable influences of emotions on language learning are unclear. The current study thereby aimed to examine the effects of emotional states on novel word learning and their dynamic changes with learning continuing and task varying. Positive, negative or neutral pictures were employed to induce a given emotional state, and then participants learned the novel words through association with line-drawing pictures in four successive learning phases. At the end of each learning phase, participants were instructed to fulfill a semantic category judgment task (in Experiment 1) or a word-picture semantic consistency judgment task (in Experiment 2) to explore the effects of emotional states on different depths of word learning. Converging results demonstrated that negative emotional state led to worse performance compared with neutral condition; however, how positive emotional state affected learning varied with learning task. Specifically, a facilitative role of positive emotional state in semantic category learning was observed but disappeared in word specific meaning learning. Moreover, the emotional modulation on novel word learning was quite dynamic and changeable with learning continuing, and the final attainment of the learned words tended to be similar under different emotional states. The findings suggest that the impact of emotion can be offset when novel words became more and more familiar and a part of existent lexicon.

Psychophysiological decoupling in alexithymic pain disorder patients

Considering that impaired coping with stress is closely linked with emergence of stress-sensitive disorders most notably in alexithymic individuals, we conducted the first study examining stress-related autonomic reactivity in alexithymic pain disorder patients. Twenty-one pain disorder patients with high and an equivalent patient group with low alexithymia scores were exposed to three types of affect-inductive stimuli with variable affective involvement: arithmetic task, watching arousing video material and giving an oral presentation. Subjective appraisal of the induced emotional experience and physiological reactivity (heart rate, muscle tension and skin conductance) was documented. During oral presentation high alexithymia patients showed significantly lower skin conductance in combination with increased subjective negative affect compared to low alexithymia patients. Our results thus demonstrate a decoupling between physiological and affect processing in pain disorder patients with high alexithymia during a stressful situation that was subjectively associated with negative affect.

Timing matters: negative emotion elicited 5 min but not 30 min or 45 min after learning enhances consolidation of internal-monitoring source memory

Two experiments examined the time-dependent effects of negative emotion on consolidation of item and internal-monitoring source memory. In Experiment 1, participants (n=121) learned a list of words. They were asked to read aloud half of the words and to think about the remaining half. They were instructed to memorize each word and its associative cognitive operation ("reading" versus "thinking"). Immediately following learning they conducted free recall and then watched a 3-min either neutral or negative video clip when 5 min, 30 min or 45 min had elapsed after learning. Twenty-four hours later they returned to take surprise tests for item and source memory. Experiment 2 was similar to Experiment 1 except that participants, without conducting an immediate test of free recall, took tests of source memory for all encoded words both immediately and 24 h after learning. Experiment 1 showed that negative emotion enhanced consolidation of item memory (as measured by retention ratio of free recall) regardless of delay of emotion elicitation and that negative emotion enhanced consolidation of source memory when it was elicited at a 5 min delay but reduced consolidation of source memory when it was elicited at a 30 min delay; when elicited at a 45 min delay, negative emotion had little effect. Furthermore, Experiment 2 replicated the enhancement effect on source memory in the 5 min delay even when participants were tested on all the encoded words. The current study partially replicated prior studies on item memory and extends the literature by providing evidence for a time-dependent effect of negative emotion on consolidation of source memory based on internal monitoring.

Negative emotion elicited in high school students enhances consolidation of item memory, but not source memory

The study examined the effect of negative emotion on consolidation of both item and source memory. Participants learned words read by either a male or female. Then they watched either a negative or a neutral video clip. Memory tests were carried out either 25min or 24h after learning. The study yielded the following findings. First, negative emotion enhanced consolidation of item memory as measured by recognition memory in the 25-min delay, and enhanced consolidation of item memory as measured by free recall in both the 25-min and the 24-h delay. Second, negative emotion had little effect on consolidation of source memory, either in the 25-min or the 24-h delay. These findings provide evidence for the differential effects of negative emotion on item memory and source memory and have implications for using emotion as a strategy to intervene memory consolidation.

Positive Arousal Enhances the Consolidation of Item Memory

Emotional arousal induced after learning has been shown to modulate memory consolidation. However, it is unclear whether the effect of postlearning arousal can extend to different aspects of memory. This study examined the effect of postlearning positive arousal on both item memory and source memory. Participants learned a list of neutral words and took an immediate memory test. Then they watched a positive or a neutral videoclip and took delayed memory tests after either 25 minutes or 1 week had elapsed after the learning phase. In both delay conditions, positive arousal enhanced consolidation of item memory as measured by overall recognition. Furthermore, positive arousal enhanced consolidation of familiarity but not recollection. However, positive arousal appeared to have no effect on consolidation of source memory. These findings have implications for building theoretical models of the effect of emotional arousal on consolidation of episodic memory and for applying postlearning emotional arousal as a technique of memory intervention.

Effect of time delay on recognition memory for pictures: the modulatory role of emotion

This study investigated the modulatory role of emotion in the effect of time delay on recognition memory for pictures. Participants viewed neutral, positive and negative pictures, and took a recognition memory test 5 minutes, 24 hours, or 1 week after learning. The findings are: 1) For neutral, positive and negative pictures, overall recognition accuracy in the 5-min delay did not significantly differ from that in the 24-h delay. For neutral and positive pictures, overall recognition accuracy in the 1-week delay was lower than in the 24-h delay; for negative pictures, overall recognition in the 24-h and 1-week delay did not significantly differ. Therefore negative emotion modulates the effect of time delay on recognition memory, maintaining retention of overall recognition accuracy only within a certain frame of time. 2) For the three types of pictures, recollection and familiarity in the 5-min delay did not significantly differ from that in the 24-h and the 1-week delay. Thus emotion does not appear to modulate the effect of time delay on recollection and familiarity. However, recollection in the 24-h delay was higher than in the 1-week delay, whereas familiarity in the 24-h delay was lower than in the 1-week delay.

Joint effect of alexithymia and mood on the categorization of nonverbal emotional vocalizations

The role of stable factors, such as alexithymia (i.e., difficulties identifying and expressing feelings, externally oriented cognitive style), or temporary factors, such as affective states (mood), on emotion perception has been widely investigated in the literature. However, little is known about the separate or joint effect of the alexithymia level and affective states (positive affectivity, negative affectivity) on the recognition of nonverbal emotional vocalizations (NEV) (e.g., laughs, cries, or sighs). In this study, participants had to categorize NEV communicating 10 emotions by selecting the correct verbal emotional label. Results show that the level of alexithymia is negatively correlated to the capacity to accurately categorize negative vocalizations, and more particularly sad NEV. On the other hand, negative affectivity appeared negatively correlated with the ability to accurately categorize NEV in general, and negative vocalizations in particular. After splitting the results by the alexithymia level (high vs. low scorers), significant associations between mood and accuracy rates were found in the group of high alexithymia scorers only. These findings support the idea that alexithymic features act across sensory modalities and suggest a mood-interference effect that would be stronger in those individuals.

Muscle tension induced after learning enhances long-term narrative and visual memory in healthy older adults

Arousing events are better remembered than mundane events. Indeed, manipulation of arousal, such as by muscle tension, can influence memory even when it occurs shortly after learning. Indeed, our founding study showed this approach can raise delayed memory performance in older adults to a level comparable to that of unaided young adults. Yet, systematic studies, especially those investigating different modalities or types of memory, have not been done. This study investigated the effects of a brief bout of isometric exercise via handgrip on narrative and visuospatial episodic memory in healthy elders. Forty-seven participants completed the Logical Memory subtest of the Wechsler Memory Scales III (LM) and the Benton Visual Retention Test (BVRT), followed alternately by no treatment and by moderately squeezing a sand-filled latex ball for 1-min (counterbalanced order and test forms). Isometric exercise significantly increased both positive and negative affect ratings. Retention was tested 2 weeks later. Delayed recall and recognition of LM was enhanced by arousal relative to control, as was recognition of the BVRT. The results extend past findings that muscle tension induced after learning modulates memory consolidation, extending findings in elders to suggest that a simple form of isometric exercise can have practical effects, such as aiding memory for stories and images.

Memory modulation in the classroom: selective enhancement of college examination performance by arousal induced after lecture

Laboratory studies examining moderate physiological or emotional arousal induced after learning indicate that it enhances memory consolidation. Yet, no studies have yet examined this effect in an applied context. As such, arousal was induced after a college lecture and its selective effects were examined on later exam performance. Participants were divided into two groups who either watched a neutral video clip (n=66) or an arousing video clip (n=70) after lecture in a psychology course. The final examination occurred two weeks after the experimental manipulation. Only performance on the group of final exam items that covered material from the manipulated lecture were significantly different between groups. Other metrics, such as the midterm examination and the total final examination score, did not differ between groups. The results indicate that post-lecture arousal selectively increased the later retrieval of lecture material, despite the availability of the material for study before and after the manipulation. The results reinforce the role of post-learning arousal on memory consolidation processes, expanding the literature to include a real-world learning context.

The effects of post-encoding stress on recognition memory: examining the impact of skydiving in young men and women

Prior studies have indicated that post-encoding stress can protect memories from the effects of forgetting, and this has been taken as evidence that stress facilitates memory consolidation. However, it is not known whether stress acts by directly influencing the strength of the underlying memories or whether it influences the generation process that plays a critical role in tests such as free recall. To address this issue, we examined the effects of stress produced by skydiving on recognition memory for negative and neutral pictures. Relative to a non-stress control condition, post-encoding stress in males was found to increase recognition memory for neutral pictures. However, stress was not found to improve recognition for emotional pictures, nor was it found to influence recognition memory in female participants. Additional analysis of recognition performance suggested that stress increased familiarity-based recognition rather than recollection. This study indicates that stress can improve familiarity-based recognition, thus showing that stress directly increases the strength of the underlying memories.