Gender differences in the effects of post-learning emotion on consolidation of item memory and source memory

Emotional learning retroactively enhances item memory but distorts source attribution

An adaptive memory system should prioritize information surrounding a powerful learning event that may prove useful for predicting future meaningful events. The behavioral tagging hypothesis provides a mechanistic framework to interpret how weak experiences persist as durable memories through temporal association with a strong experience. Memories are composed of multiple elements, and different mnemonic aspects of the same experience may be uniquely affected by mechanisms that retroactively modulate a weakly encoded memory. Here, we investigated how emotional learning affects item and source memory for related events encoded close in time. Participants encoded trial-unique category exemplars before, during, and after Pavlovian fear conditioning. Selective retroactive enhancements in 24-h item memory were accompanied by a bias to misattribute items to the temporal context of fear conditioning. The strength of this source memory bias correlated with participants' retroactive item memory enhancement, and source misattribution to the emotional context predicted whether items were remembered overall. In the framework of behavioral tagging: Memory attribution was biased to the temporal context of the stronger event that provided the putative source of memory stabilization for the weaker event. We additionally found that fear conditioning selectively and retroactively enhanced stimulus typicality ratings for related items, and that stimulus typicality also predicted overall item memory. Collectively, these results provide new evidence that items related to emotional learning are misattributed to the temporal context of the emotional event and judged to be more representative of their semantic category. Both processes may facilitate memory retrieval for related events encoded close in time.

Effect of post-encoding emotion on long-term memory: Modulation of emotion category and memory strength

Although studies have shown that post-encoding emotion enhances long-term memory, it is unclear whether the effect varies depending on a specific category of emotion and whether the effect depends on memory strength. In the current study, participants encoded a list of words, half of which were presented once and the remaining half of which were presented four times. Afterwards participants watched a video that was neutral, or induced one of the following emotions: anger, sadness, disgust, fear, or happiness. Overall recognition was lower in the anger-inducing condition than in the sadness-inducing or happiness-inducing condition. Recollection (i.e., adjusted rate of correctly identifying a word as old while being able to retrieve details related to the study episode) was lower in the anger-inducing condition than in the sadness-inducing condition. No significant effect of emotion was found on familiarity (i.e., adjusted rate of correctly identifying a word as old without being able to retrieve any details related to the study episode). Furthermore, memory strength modulated the effect on familiarity: Familiarity for prioritized words was lower than for non-prioritized words only in the "anger" and "sadness" conditions but not in other emotion conditions. The effect of post-encoding emotion differs depending on a specific category of emotion and modulation of memory strength relies on a specific component of recognition memory.

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.

Time-dependent effects of discrete post-encoding emotions on item memory and source memory

This study examined time-dependent effects of discrete emotions on item and source memory. In Experiment 1, after encoding, participants watched a comic, disgust-inducing, anger-inducing or neutral video at different delays. Positive emotion did not affect item memory but enhanced source memory (only in the 5 min delay). Anger impaired recognition in all delays, but a trend occurred for anger to impair source memory only in the 50 min delay. Disgust did not affect item memory, but a trend emerged for it to enhance and impair source memory in the 5 and 35 min delays, respectively. Experiment 2 showed that positive emotion and disgust had no effect on recognition, and consistent with Experiment 1, positive emotion, not anger or disgust, enhanced source memory. A trend occurred for positive emotion and disgust to impair source memory in the 0 min delay but not in the other delays. Consistent with Experiment 1, Experiment 3 showed that anger impaired both recognition and source memory (for males). Taken together, these findings suggest that the effect of emotion does vary depending on nature of memory tasks, category of emotion, and delay in emotion elicitation.

Differential effects of emotion induced after encoding on item memory and reality-monitoring source memory

Although studies have examined the effect of emotional stimuli on reality-monitoring source memory, it is poorly understood whether the effect observed would remain if emotion is induced after encoding. In addition, although there has been evidence that post-encoding emotion enhances item memory but not external monitoring source memory, it is unclear whether such a null effect extends to other types of source memory. To address these gaps, in the current study, participants encoded a list of words. For half of the words they were asked to think about the corresponding opposite words, and for the remaining half of words they viewed the corresponding opposite words. Following encoding they watched a neutral, positive or negative video. Replicating prior studies, both positive and negative emotions enhanced consolidation of item memory. Furthermore, participants at a high level of state anxiety, trait anxiety and depression were more likely to benefit from the enhancement effect of post-encoding emotion. However, no significant effect was observed on reality-monitoring source memory. Taken together the current study suggests that the enhancement effect of post-encoding emotion on item memory does not necessarily extend to reality-monitoring source memory.

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.

Effect of post-encoding emotion on recollection and familiarity for pictures

Although prior studies have examined the effect of post-encoding emotional arousal on recognition memory for words, it is unknown whether the enhancement effect observed on words generalizes to pictures. Furthermore, prior studies using words have showed that the effect of emotional arousal can be modulated by stimuli valence and delay in emotion induction, but it is unclear whether such modulation can extend to pictures and whether other factors such as encoding method (incidental vs. intentional encoding) can be modulatory. Five experiments were conducted to answer these questions. In Experiment 1, participants encoded a list of neutral and negative pictures and then watched a 3-min neutral or negative video. The delayed test showed that negative arousal impaired recollection regardless of picture valence but had no effect on familiarity. Experiment 2 replicated the above findings. Experiment 3 was similar to Experiment 1 except that participants watched a 3-min neutral, negative, or positive video and conducted free recall before the recognition test. Unlike the prior two experiments, the impairment effect of negative arousal disappeared. Experiment 4, where the free recall task was eliminated, replicated the results from Experiment 3. Experiment 5 replicated Experiments 1 and 2 and further showed that the impairment effects of negative arousal could be modulated by delay in emotion induction but not by encoding method or stimuli valence. Taken together, the current study suggests that the enhancement effect observed on words may not generalize to pictures.

Post-Encoding Emotional Arousal Enhances Consolidation of Item Memory, But not Reality-Monitoring Source Memory

The current study examined whether the effect of post-encoding emotional arousal on item memory extends to reality-monitoring source memory and, if so, whether the effect depends on emotionality of learning stimuli and testing format. In Experiment 1, participants encoded neutral words and imagined or viewed their corresponding object pictures. Then they watched a neutral, positive, or negative video. The 24-hour delayed test showed that emotional arousal had little effect on both item memory and reality-monitoring source memory. Experiment 2 was similar except that participants encoded neutral, positive, and negative words and imagined or viewed their corresponding object pictures. The results showed that positive and negative emotional arousal induced after encoding enhanced consolidation of item memory, but not reality-monitoring source memory, regardless of emotionality of learning stimuli. Experiment 3, identical to Experiment 2 except that participants were tested only on source memory for all the encoded items, still showed that post-encoding emotional arousal had little effect on consolidation of reality-monitoring source memory. Taken together, regardless of emotionality of learning stimuli and regardless of testing format of source memory (conjunction test vs. independent test), the facilitatory effect of post-encoding emotional arousal on item memory does not generalize to reality-monitoring source memory.

P300 correlates with learning & memory abilities and fluid intelligence

Background

Educational psychology research has linked fluid intelligence with learning and memory abilities and neuroimaging studies have specifically associated fluid intelligence with event related potentials (ERPs). The objective of this study is to find the relationship of ERPs with learning and memory recall and predict the memory recall score using P300 (P3) component.

Method

A sample of thirty-four healthy subjects between twenty and thirty years of age was selected to perform three tasks: (1) Raven’s Advanced Progressive Matrices (RAPM) test to assess fluid intelligence; (2) learning and memory task to assess learning ability and memory recall; and (3) the visual oddball task to assess brain-evoked potentials. These subjects were divided into High Ability (HA) and Low Ability (LA) groups based on their RAPM scores. A multiple regression analysis was used to predict the learning & memory recall and fluid intelligence using P3 amplitude and latency.

Results

Behavioral results demonstrated that the HA group learned and recalled 10.89 % more information than did the LA group. ERP results clearly showed that the P3 amplitude of the HA group was relatively larger than that observed in the LA group for both the central and parietal regions of the cerebrum; particularly during the 300–400 ms time window. In addition, a shorter latency for the P3 component was observed at Pz site for the HA group compared to the LA group. These findings agree with previous educational psychology and neuroimaging studies which reported an association between ERPs and fluid intelligence as well as learning performance.

Conclusion

These results also suggest that the P3 component is associated with individual differences in learning and memory recall and further indicate that P3 amplitude might be used as a supporting factor in standard psychometric tests to assess an individual’s learning & memory recall ability; particularly in educational institutions to aid in the predictability of academic skills.

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.

Time-limited effects of emotional arousal on item and source memory

Two experiments investigated the time-limited effects of emotional arousal on consolidation of item and source memory. In Experiment 1, participants memorized words (items) and the corresponding speakers (sources) and then took an immediate free recall test. Then they watched a neutral, positive, or negative video 5, 35, or 50 min after learning, and 24 hours later they took surprise memory tests. Experiment 2 was similar to Experiment 1 except that (a) a reality monitoring task was used; (b) elicitation delays of 5, 30, and 45 min were used; and (c) delayed memory tests were given 60 min after learning. Both experiments showed that, regardless of elicitation delay, emotional arousal did not enhance item recall memory. Second, both experiments showed that negative arousal enhanced delayed item recognition memory only at the medium elicitation delay, but not in the shorter or longer delays. Positive arousal enhanced performance only in Experiment 1. Third, regardless of elicitation delay, emotional arousal had little effect on source memory. These findings have implications for theories of emotion and memory, suggesting that emotion effects are contingent upon the nature of the memory task and elicitation delay.

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.

Source discrimination in adults with attention deficit hyperactivity disorder

Objectives

The context of memory experiences is referred to as source memory and can be distinguished from the content of episodic item memory. Source memory represents a crucial part of biographic events and elaborate memory experiences. Whereas individuals with attention deficit hyperactivity disorder (ADHD) were shown to have inefficient item memory, little is known about the context of memory experiences.

Methods

The present study compared 37 adult patients with a diagnosed ADHD with 40 matched healthy participants on a word list paradigm. Memory functions of encoding, retention and source discrimination were assessed. Furthermore, standardized measures of memory and executive control were applied in order to explore a qualitative differentiation of memory components.

Results

Adult patients with ADHD showed impaired performance in encoding of new information whereas the retention of encoded items was found to be preserved. The most pronounced impairment of patients with ADHD was observed in source discrimination. Regression models of cognitive functions on memory components supported some qualitative differentiation.

Conclusions

Data analysis suggests a differential pattern of memory impairment in adults suffering from ADHD with a particular deficit in source discrimination. Inefficient source discrimination in adults with ADHD can affect daily functioning by limiting biographic awareness and disturbing general cognitive processes.

Gender difference in recognition memory for neutral and emotional faces

Research has shown females' advantage in face memory, but few studies have used emotional faces as stimuli. In addition, it is unclear whether gender difference in memory for faces is mediated by individual factors especially associated with emotion. This study examined gender difference in recognition memory for neutral and emotional faces and whether arousal predisposition, emotion reappraisal, and emotion suppression can play a mediation role. Females (N=48) and males (N=45) viewed and memorised neutral, happy, and angry faces, and then took an immediate recognition test. The findings are: (1) Females outperformed males in recognition memory for happy faces, but not for neutral and negative faces. (2) Gender difference in recognition memory (including recollection and familiarity) was not mediated by arousal predisposition and emotion regulation. (3) Females had an own-sex bias in that they outperformed males with regard to recognition memory only for female faces, but not for male faces. The findings suggest that females' advantage is mediated by valence of face emotionality but not by arousal predisposition and emotion regulation, thus extending the literature by demonstrating the boundary condition for occurrence of females' advantage.