Time-course of eye movement-related decrease in vividness and emotionality of unpleasant autobiographical memories

The time-course of changes in vividness and emotionality of unpleasant autobiographical memories associated with making eye movements (eye movement desensitisation and reprocessing, EMDR) was investigated. Participants retrieved unpleasant autobiographical memories and rated their vividness and emotionality prior to and following 96 seconds of making eye movements (EM) or keeping eyes stationary (ES); at 2, 4, 6, and 10 seconds into the intervention; then followed by regular larger intervals throughout the 96-second intervention. Results revealed a significant drop compared to the ES group in emotionality after 74 seconds compared to a significant drop in vividness at only 2 seconds into the intervention. These results support that emotionality becomes reduced only after vividness has dropped. The results are discussed in light of working memory theory and visual imagery theory, following which the regular refreshment of the visual memory needed to maintain it in working memory is interfered with by eye movements that also tax working memory, which affects vividness first.     

Blurring of emotional and non-emotional memories by taxing working memory during recall

Memories that are recalled while working memory (WM) is taxed, e.g., by making eye movements (EM), become blurred during the recall + EM and later recall, without EM. This may help to explain the effects of Eye Movement and Desensitisation and Reprocessing (EMDR) in the treatment of post-traumatic stress disorder (PTSD) in which patients make EM during trauma recall. Earlier experimental studies on recall + EM have focused on emotional memories. WM theory suggests that recall + EM is superior to recall only but is silent about effects of memory emotionality. Based on the emotion and memory literature, we examined whether recall + EM has superior effects in blurring emotional memories relative to neutral memories. Healthy volunteers recalled negative or neutral memories, matched for vividness, while visually tracking a dot that moved horizontally (“recall + EM”) or remained stationary (“recall only”). Compared to a pre-test, a post-test (without concentrating on the dot) replicated earlier findings: negative memories are rated as less vivid after “recall + EM” but not after “recall only”. This was not found for neutral memories. Emotional memories are more taxing than neutral memories, which may explain the findings. Alternatively, transient arousal induced by recall of aversive memories may promote reconsolidation of the blurred memory image that is provoked by EM.     

Horizontal eye movements foster approach to negative pictures but do not change emotional valence: A dopaminergic regulation hypothesis

A new dopaminergic regulation hypothesis is proposed based on two experiments exploring eye-movement effects. In the Eye Movement Desensitization and Reprocessing (EMDR) and Saccade-Induced Retrieval Enhancement (SIRE) domains, eye-movement mechanisms are mainly studied with explicit measures. Here implicit and explicit measures of emotion and memory for positive and negative pictures were investigated after eye movements or fixation in extreme right-handers. Eye movements enhanced explicit recognition predominantly for negative pictures. The absence of implicit repetition priming in both experiments supported a dissociation between implicit and explicit memory. Motivational eye-movement effects emerged but implicit and explicit affect remained unchanged. Experiment 2 revealed, after initial freezing to negative pictures, an acceleration, particularly of approach responses. Eye movements are postulated to foster approach towards negative memories, and promote, though dopaminergic pathways from the Superior Colliculus, enhanced explicit memory and active emotion regulation, primarily in persons with a collateralization of eye and dopamine dominance.     

A facilitative effect of negative affective valence on working memory

Gotoh, F., Kikuchi, T. &Olofsson, U. (2010). A facilitative effect of negative affective valence on working memory. Scandinavian Journal of Psychology, 51, 185–191. Previous studies have shown that negatively valenced information impaired working memory performance due to an attention‐capturing effect. The present study examined whether negative valence could also facilitate working memory. Affective words (negative, neutral, positive) were used as retro‐cues in a working memory task that required participants to remember colors at different spatial locations on a computer screen. Following the cue, a target detection task was used to either shift attention to a different location or keep attention at the same location as the retro‐cue. Finally, participants were required to discriminate the cued color from a set of distractors. It was found that negative cues yielded shorter response times (RTs) in the attention‐shift condition and longer RTs in the attention‐stay condition, compared with neutral and positive cues. The results suggest that negative affective valence may enhance working memory performance (RTs), provided that attention can be disengaged.     

Tones inferior to eye movements in the EMDR treatment of PTSD

Eye Movement Desensitization and Reprocessing (EMDR) is an effective treatment for posttraumatic stress disorder (PTSD). During EMDR, patients make eye movements (EMs) while recalling traumatic memories, but recently therapists have replaced EMs by alternating beep tones. There are no outcome studies on the effects of tones. In an earlier analogue study, tones were inferior to EMs in the reduction of vividness of aversive memories. In a first EMDR session, 12 PTSD patients recalled trauma memories in three conditions: recall only, recall + tones, and recall + EMs. Three competing hypotheses were tested: 1) EMs are as effective as tones and better than recall only, 2) EMs are better than tones and tones are as effective as recall only, and 3) EMs are better than tones and tones are better than recall only. The order of conditions was balanced, each condition was delivered twice, and decline in memory vividness and emotionality served as outcome measures. The data strongly support hypothesis 2 and 3 over 1: EMs outperformed tones while it remained unclear if tones add to recall only. The findings add to earlier considerations and earlier analogue findings suggesting that EMs are superior to tones and that replacing the former by the latter was premature.     

Organization in autobiographical memory

Three experiments investigated timed autobiographical memory retrieval to cue words and phrases. In the first experiment, subjects retrieved memories to cues that named semantic category members and were primed with the superordinate category name or with a neutral word. No prime effects were observed. In the second experiment, subjects retrieved memories to primed and unprimed semantic category cues and to personal primes and personal history cues. Personal primes named lifetime periods (e.g., “school days”) and personal history cues named general events occurring in those lifetime periods for each subject (e.g., “holiday in Italy”). Only personal primes were found to significantly facilitate memory retrieval. A third experiment replicated this finding and also failed to find any prime effects to primes and cues naming activities not directly related to an individual’s personal history. In this experiment, characteristics of recalled events (e.g,, personal importance, frequency of rehearsal, pleasantness, and specificity of the memory) were found to be strongly associated with memories retrieved to personal cues and only mildly associated with memories retrieved to other types of cues. These findings suggest that one way in which autobiographical memories may be organized is in terms of a hierarchically structured abstracted personal history.     

The effects of eye and limb movements on working memory

Three experiments examined the role of eye and limb movements in the maintenance of information in spatial working memory. In Experiment 1, reflexive saccades interfered with memory span for spatial locations but did not interfere with memory span for letters. In Experiment 2, three different types of eye movements (reflexive saccades, pro-saccades, and anti-saccades) interfered with working memory to the same extent. In all three cases, spatial working memory was much more affected than verbal working memory. The results of these two experiments suggest that eye movements interfere with spatial working memory primarily by disrupting processes localised in the visuospatial sketchpad. In Experiment 3, limb movements performed while maintaining fixation produced as much interference with spatial working memory as reflexive saccades. These results suggest that the interference produced by eye movements is not the result of their visual consequences. Rather, all spatially directed movements appear to have similar effects on visuospatial working memory.     

Attentional localization prior to simple and directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection measures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance effects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions between response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

Eye movements reveal mechanisms underlying attentional biases towards threat

Mechanisms underlying attentional biases towards threat (ABTs), such as attentional avoidance and difficulty of disengagement, are still unclear. To address this issue, we recorded participants' eye movements during a dot detection task in which threatening or neutral stimuli served as peripheral cues. We evaluated response times (RTs) in trials where participants looked at the central fixation cross (not at the cues), as they were required, and number and duration of (unwanted) fixations towards threatening or neutral cues; in all analyses trait anxiety was treated as a covariate. Difficulty in attentional disengagement (longer RTs) was found when peripheral threatening stimuli were presented for 100?ms. Moreover, we observed significantly shorter (unwanted) fixations on threatening than on neutral peripheral stimuli, compatible with an avoidance bias, for longer presentation times. These findings demonstrate that, independent of trait anxiety levels, disengagement bias occurs without eye movements, whereas eye movements are implied in threat avoidance.     

Attentional localization prior to simpleand directed manual responses

The relationship between attention and the programming of motor responses was investigated, using a paradigm in which the onsets of targets for movements were preceded by peripheral attentional cues. Simple (button release) and reaching manual responses were compared under conditions in which the subjects either made saccades toward the target location or refrained from making eye movements. The timing of the movement onset was used as the dependent measure for both simple and reaching manual responses. Eye movement latencies were also measured. A follow-up experiment measured the effect of the same peripheral cuing procedure on purely visual processes, using signal detection mea-sures of visual sensitivity and response bias. The results of the first experiment showed that reaction time (RT) increased with the distance between the cued and the target locations. Stronger distance ef-fects were observed when goal-directed responses were required, which suggests enhanced attentional localization of target positions under these conditions. The requirement to generate an eye movement response was found to delay simple manual RTs. However, mean reaching RTs were unaffected by the eye movement condition. Distance gradients on eye movement latencies were relatively shallow, as compared with those on goal-directed manual responses. The second experiment showed that the peripheral cue had only a very small effect on visual detection sensitivity in the absence of directed motor responses. It is concluded that cue-target distance effects with peripheral cues are modulated by the motor-programming requirements of the task. The effect of the peripheral cue on eye movement latencies was qualitatively different from that observed on manual RTs, indicating the existence of separate neural representations underlying both response types. At the same time, the interactions be-tween response modalities are consistent with a supramodal representation of attentional space, within which different motor programs may interact.     

How prior knowledge,WMC, and relevance of information affect eye fixations in expository text

This study examined how prior knowledge and working memory capacity (WMC) influence the effect of a reading perspective on online text processing. In Experiment 1, 47 participants read and recalled 2 texts of different familiarity from a given perspective while their eye movements were recorded. The participants' WMC was assessed with the reading span test. The results suggest that if the reader has prior knowledge related to text contents and a high WMC, relevant text information can be encoded into memory without extra processing time. In Experiment 2, baseline processing times showed whether readers slow down their processing of relevant information or read faster through their relevant information. The results are discussed in the light of different working memory theories.     

Merging and modifying hypotheses on the emotional and cognitive effects of eye movements: The dopaminergic regulation hypothesis

The integration of hypotheses from Eye-Movement Desensitization and Reprocessing (EMDR) and Saccade Induced Retrieval Enhancement (SIRE), both of which have been met with considerable skepticism, may lead to significant gains in both domains. Cognitive accounts of EMDR, the orienting response (OR) and working memory (WM) hypotheses, and of SIRE, the interhemispheric interaction (IHI) and the top-down attentional control (TDAC) hypotheses, are discussed. The accounts show several blind spots and frictions, for instance, on re-imagining during EMs, on hemispheric lateralization, and on emotional influences of eye movements. The failure to consider these factors across and within domains may well explain the many disparate findings. This perspective aims to remove the artificial separation and seeks a theoretical integration of the domains. It combines elements of OR and TDAC into a new dopaminergic regulation hypothesis while replacing affective (i.e., positive vs. negative) by motivational mechanisms (i.e., fostering approach and recoding). EMs are posited to result in a short-latency, targeted release of dopamine, which is the central neuromodulator in approach tendencies. According to this hypothesis, the largest effects are obtained in individuals with collateralized eye dominance and dopamine dominance. Concrete suggestions are made to improve research conditions and therapeutic efficacy.     

Visual and verbal working memory loads interfere with scene-viewing

Working memory is thought to be divided into distinct visual and verbal subsystems. Studies of visual working memory frequently use verbal working memory tasks as control conditions and/or use articulatory suppression to ensure that visual load is not transferred to verbal working memory. Using these verbal tasks relies on the assumption that the verbal working memory load will not interfere with the same processes as visual working memory. In the present study, participants maintained a visual or verbal working memory load as they simultaneously viewed scenes while their eye movements were recorded. Because eye movements and visual working memory are closely linked, we anticipated the visual load would interfere with scene-viewing (and vice versa), while the verbal load would not. Surprisingly, both visual and verbal memory loads interfered with scene-viewing behavior, while eye movements during scene-viewing did not significantly interfere with performance on either memory task. These results suggest that a verbal working memory load can interfere with eye movements in a visual task.

     

Effects of saccadic bilateral eye movements on memory in children and adults: an exploratory study

The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30s of bilateral vs. vertical vs. no eye movements. For studied information, the results for adults replicated previous work; bilateral eye movements were demonstrated to increase the accuracy of memory by increasing the hit rate and reducing the false alarm rate for related and unrelated recognition test lures. The results for children also indicated an improvement in memory accuracy, and like adults, was due to both an increase in the hit rate and a reduction in the false alarm rate. In spite of these similarities, the effects of bilateral eye movements differed between adults and children for critical unstudied words; i.e., those associated with the theme of the list. Only in adults did, bilateral eye movements reduce associative false memories; children did not show a reduction in false memory for critical associates. This produced a dissociation between the effects of eye movements on associative false memory as a function of age. The results are discussed from a developmental perspective in terms of potential mechanisms underlying true and false memory.     

No effects of eye movements on the encoding of the visuospatial sketchpad and the phonological loop in healthy participants: Possible implications for eye movement desensitization and reprocessing therapy

Horizontal eye movement is an essential component of the psychological intervention “eye movement desensitization and reprocessing” (EMDR) used in posttraumatic stress disorder. A hypothesized mechanism of action is an overload of the visuospatial sketchpad and/or the phonological loop of the working memory.     

Effects of handedness and saccadic bilateral eye movements on components of autobiographical recollection

The effects of handedness and saccadic bilateral eye movements on autobiographical recollection were investigated. Recall of autobiographical memories was cued by the use of neutral and emotional words. Autobiographical recollection was assessed by the autobiographical memory questionnaire. Experiment 1 found that mixed-handed (vs. right handed) individuals demonstrated greater levels of autobiographical recollection on the components of seeing, hearing, and emotion. Experiment 2 found that following 30 s of bilateral eye movements, greater levels of autobiographical recollection were demonstrated on the components of reliving, seeing, hearing, emotion, self-perspective and veridicality. The results extend previous research by showing that the recollective components of real world memories can be enhanced by either mixed-handedness or eye movements. In addition, these results provide a bridge between laboratory studies of recollection and autobiographical recollection. The findings are considered in terms of research on the cognitive neuroscience of autobiographical memory.     

Autobiographical memory in dysphoric and non‐dysphoric college students using a computerised version of the AMT

On autobiographical memory tests (AMTs) using positive and negative cue words, research has consistently found that depressed individuals (relative to nondepressed controls) are more likely to recall overgeneral memories (OGMs) and are less likely to recall specific memories. A total of 56 undergraduates who scored high or low on a measure of depression were shown positive and negative word cues and event cues in a computerised AMT. Dysphoric college students made significantly fewer specific and more categoric (overgeneral) responses than controls, but did not differ from controls in terms of extended responses. Results suggest that the difference in memory specificity between low and high dysphoric students generalises across word and event cues and that a computerised version of the AMT can be used as an alternative to interviews as a form of administration.     

The influence of social and symbolic cues on observers' gaze behaviour

Research has shown that social and symbolic cues presented in isolation and at fixation have strong effects on observers, but it is unclear how cues compare when they are presented away from fixation and embedded in natural scenes. We here compare the effects of two types of social cue (gaze and pointing gestures) and one type of symbolic cue (arrow signs) on eye movements of observers under two viewing conditions (free viewing vs. a memory task). The results suggest that social cues are looked at more quickly, for longer and more frequently than the symbolic arrow cues. An analysis of saccades initiated from the cue suggests that the pointing cue leads to stronger cueing than the gaze and the arrow cue. While the task had only a weak influence on gaze orienting to the cues, stronger cue following was found for free viewing compared to the memory task.     

Evidence for spontaneous retrieval of suspended but not finished prospective memories

McDaniel and Einstein (2007) argued that prospective memories can be retrieved through spontaneous retrieval processes stimulated by the presence of a target cue. To test this claim, we investigated whether presenting a prospective memory cue during a task that did not require an intention to be performed spontaneously triggered remembering of that intention. In two experiments, participants performed an image-rating task in which a prospective memory task (to press the “Q” key when a target word appeared) was embedded. Then, participants were told that their intention was finished or suspended. Finally, participants performed a lexical decision task in which each target (and a matched control) word appeared. RTs were slower to target words than to control words when the intention was suspended but not when it was finished. These results suggest that target cues associated with suspended intentions can spontaneously trigger remembering but that finished intentions are quickly deactivated.     

Impaired autobiographical memory in complicated grief

This study investigated the relationship between autobiographical memory and goals in complicated grief (CG). Twenty-four individuals with CG and 21 bereaved individuals without CG completed an autobiographical memory task and a personal goals task. CG participants were more likely to recall memories related to their loss, particularly in response to negative cues. There was a positive relationship between the proportion of loss-related memories recalled and the proportion of grief-related goals held by individuals after controlling for symptom level. Individuals with CG also showed impaired retrieval of specific autobiographical memories in response to both positive and negative cues. These results suggest that CG is characterised by impaired and biased retrieval of specific autobiographical memories. These patterns are consistent with propositions stemming from the self-memory models of autobiographical memory.