CogBlog – A Cognitive Psychology Blog

Imagine this: You enter your dorm room after a long, difficult day, and you’re in a bad mood. You’ve been in the library all afternoon, you’re drenched to the core from walking back in the rain, and you still have what feels like an actual mountain of homework left. As you’re unpacking your bag, events from the day run through your mind, and they’re all negative: the test that didn’t go so well, the lunch that wasn’t great, the workout that felt particularly hard… the list goes on. Your day was not entirely bad, yet you’re only able to remember the not-so-great moments.

If you can relate to the above story, you’ve experienced the effects of mood-congruent memory, which is the idea that the memories we retrieve tend to be consistent with our current emotional state. This explains why people who are in a bad mood recall negative memories, and the same goes for all types of moods. Mood-congruency affects people’s attention, too, but I’m going to focus on memory. Essentially, individuals’ moods dictate the types of memories to which they have access, which in turn reinforce their current mood state. This can be helpful when the positive memories contribute to the happy mood, and it’s generally not a big deal when the bad mood is temporary, since the negative memories will likely soon be replaced by more cheerful ones. That being said, the reciprocal relationship between mood and memory can be dangerous when the sad mood state is constant. Consider, for instance, individuals who suffer from depression.

Depression is a mood disorder that is characterized by symptoms such as persistent unhappiness and a loss of interest in once pleasurable activities (“Depression Basics,” 2016). Mood-congruent memories play a harmful role in reinforcing the depressed mood, creating a somewhat inescapable cycle. This means that individuals with depression are especially likely to have depressing memories –– memories that contribute to their already-depressed state, perpetuating this cycle. Why does this occur?

Mood-congruent memory, in general, can be explained by the cognitive psychology principle of encoding specificity, or the concept that memory retrieval (accessing stored memories) is easiest when the retrieval context matches the context in which the encoding (the initial formation of the memory trace) took place. For a relatable example of encoding specificity, picture this: You’re in the kitchen, and you decide you need to get paper towels from the basement. You walk down the stairs to the basement, only to realize that you no longer remember your reason for leaving the kitchen. So, you go back to the kitchen, and as soon as you do, you immediately remember that you’re in need of paper towels and must make the trip again. Does this scenario ring a bell?

Relatable?!
(https://en.dopl3r.com/memes/dank/when-you-walk-into-a-room-but-forget-why-youre-there/765495)

If so, you’re familiar with the effects of encoding specificity: You’re better able to remember what you wanted to bring up from the basement (retrieval) once you return to the kitchen, since you’re now standing in the same room you were in when you initially decided to walk downstairs (encoding). The next time you experience some variation of this situation, you’ll know why!

Ok, so now you understand the gist of the encoding specificity principle. However, you might be wondering how remembering what you need from the basement when standing in the kitchen relates to mood-congruent memory and depression. Here’s the connection:

When we encode memories, we take in information about the encoding context, such as location in the above scenario. Emotions are also a form of contextual information, so when an individual’s current emotional state is similar to his/her emotional state at the time of encoding, the memory trace is most accessible (McBride & Cutting, 2019). This is why mood-congruent memories powerfully affect people with depression: The depressed mood upon retrieval matches the mood at the time of encoding, so these individuals are biased toward retrieving depressing memories.

It is easiest to access memories when the mood during encoding matches that upon retrieval. (https://twitter.com/ap_psychology/status/1072132699605950466)

Interestingly, existing research suggests that these mood-congruent memories need not even be accurate to be retrieved by people with depression. 

In one study on mood-congruent memory and depression, Howe and Malone (2011) compared depressed and non-depressed participants’ false memory for different types of words. The researchers utilized the Deese-Roediger-McDermott (DRM) paradigm, presenting participants with positive, negative, neutral, and depression-relevant word lists. For example, the negative list included words like hell, rape, and danger, whereas the depression-relevant list included words that are more specific to depression, such as clinical, void, and unhappiness (Budson et al., 2006, as cited in Goodman et al., 2011; Moss & Older, 1996). After studying the four word lists, participants took a memory test, and here’s where the study became really interesting: As opposed to the non-depressed participants, participants with depression had a significantly greater number of false memories for the critical lure –– a non-list word that fit the category of the list –– when the word was depression-relevant (Howe & Malone, 2011). In other words, both groups performed similarly when the words were positive, negative, and neutral, but participants with depression were more likely to incorrectly believe that they’d seen a word when it was depression-themed.

I use these findings to highlight two significant points related to mood-congruent memory: First, considering that participants with depression had higher false memory for depression-relevant, but not negative, critical lures, it is clear that these false memories were specific to the depressed mood state; second, if individuals with depression are not only accurately remembering depressing memories, but are also falsely remembering them, this means that they are particularly vulnerable to the harmful effects of mood-congruent memory. Why is this the case?

Individuals with depression are biased toward retrieving depressing memories, which –– in conjunction with an inability to easily suppress these memories –– maintains a dangerous mood-memory cycle. (https://www.ft.com/content/b02fd44e-13ba-11e2-9ac6-00144feabdc0)

Well, some psychologists have hypothesized that individuals with depression have a higher resting automatic activation of depression-related stimuli (Roediger et al., 2001, as cited in Joormann et al., 2009). By activation, I mean that depression-related information –– words, in the case of the above study –– is so relevant for people who are depressed that it quickly brings forth other, similar information, such as the depression-themed critical lure (Joormann et al., 2009). Additional findings suggest that individuals with depression are often unable to suppress these harmful (and sometimes false) mood-congruent memories. So, in addition to their increased access to true and false depressing memories, individuals who are depressed have a hard time getting rid of the memories, which means they remain stuck in the cycle of depression. Let me elaborate:

In a study conducted by Joormann and Gotlib (2008), participants with and without depression were instructed to memorize two lists of emotional words, some of which were negative and some of which were positive. The researchers used an inventory that rates words according to their emotional valence, or the degree to which they elicit positive/negative feelings. Then, participants took a test to assess their memory for the words. The tricky part of this test was that participants were told to solely focus on one of the word lists, meaning they were instructed to inhibit one (Joormann & Gotlib, 2008). In other words, the participants needed to reject the words from the irrelevant list. Here are the results:     

Unlike non-depressed participants (even those who listened to sad music at the start of the study to experience a temporary negative mood), participants with depression had a significantly more challenging time rejecting the irrelevant list words and also took much longer to do so. Interestingly, this was only the case for the negative irrelevant words –– the more mood-congruent ones. The researchers concluded that individuals with depression have less working memory control, or more difficulty eliminating the mood-congruent memories on which they focus (Joormann & Gotlib, 2008).   

Individuals with depression tend to focus on mood-congruent memories due to their limited working memory control. (https://www.everydayhealth.com/depression/depression-and-ruminative-thinking.aspx)

I believe that these findings are significant for a few reasons. First, given that participants with depression had an especially hard time inhibiting the memories of studied negative irrelevant words, it is evident that a lack of working memory control is an obstacle facing people who suffer from this mood disorder. Also, these results help illuminate why people with depression focus on the depressing memories that are worsening their mood: Because ignoring depressing memories is particularly challenging for them. Before reading this, it’s possible that you assumed that individuals with depression could choose to block out these harmful memories. If you did believe this to be the case, I hope that my blog post and Joormann and Gotlib’s (2008) research have helped to change your mind!

Let’s now connect the dots. We’ve established that individuals who are depressed do not only have an increased number of mood-congruent memories; they also have a harder time blocking out these mood-congruent memories once they surface, which contributes to their perpetual cycle of depression. At this point, a logical question to ask could be whether mood-incongruent memory (the opposite of mood-congruent memory) is an effective solution for individuals with depression. I mean, this makes a lot of sense: If depressing memories fuel an already-negative mood and cannot be blocked out easily, wouldn’t happy memories break this cycle?

It is not easy for individuals with depression to repair their mood. (https://neurosciencenews.com/depression-memes-15716/)

Although existing research shows that people have a natural and automatic tendency to use mood-incongruent memories to improve negative moods, it turns out that mood repair is not actually so simple for individuals with depression. This was shown in a study (the last one, I promise!) conducted by Foland-Ross et al. in 2014. The researchers used functional magnetic resonance imaging (fMRI) –– a technique for measuring changes in blood oxygenation to detect brain activity –– to compare formerly depressed and non-depressed individuals’ recall of happy, mood-incongruent autobiographical memories after a sad mood induction procedure (Devlin, 2020; Foland-Ross et al., 2014). Any guesses as to what they found? 

Strikingly, Foland-Ross et al. (2014) observed differential brain activity in formerly depressed and non-depressed individuals. As opposed to non-depressed participants’ activation in the left ventrolateral prefrontal cortex and cuneus –– two brain regions involved in the mood-incongruent recall of autobiographical memories to repair sad moods –– formerly depressed participants showed decreased activation in these areas (Foland-Ross et al., 2014). What does this mean, and why does it matter?

Well, in general, we can think of brain activity like a form of communication. The brain is either communicating with itself as it carries out a certain process or communicating with/listening to other brain regions (Neuroskeptic, 2011). Different brain regions communicate at different times, meaning separate brain regions show increased activity in certain situations. In the case of the study I just described, activation in the left ventrolateral prefrontal cortex and cuneus indicates that these two brain regions are helping to facilitate the improvement of a negative mood. Considering that individuals without depression showed activation in these two specific areas, it’s clear that brain activity there is necessary for healthy mood regulation. This is important, since formerly depressed participants had very different results: Their decreased activation in these two regions (less internal communication!) demonstrates that depression is associated with brain abnormalities, such as an inability to use this healthy and automatic mood regulation mechanism (Foland-Ross et al., 2014). In other words, these findings reveal that the depressed mood state –– even a former one –– hinders people’s helpful and natural mood repair process.

Let’s review!
(http://www.quickmeme.com/)

Ok, let’s now go back to the beginning and tie this all together: Individuals with depression retrieve depressing memories because of encoding specificity –– the match in mood state at the times of encoding and retrieval increases memory accessibility. Depressing memories are so relevant to individuals with depression that they can automatically activate other mood-congruent memories, regardless of their accuracy. The problem, though, is not just the access to depressing memories, but also the difficulty eliminating them: The harmful memories persist, reinforcing the constant depressed mood and sustaining a toxic cycle of unhappy emotions and distressing memories. And, on top of all of that, people who are (and who used to be) depressed show dysfunction in brain regions that should be helping them break this cycle and feel better.

So… returning to my opening anecdote: While natural mood-incongruent techniques might be enough to improve your temporary negative mood after a hard day at Colby if you do not have depression, mood repair is a lot more challenging for people who are depressed. Telling individuals with depression to simply cheer up isn’t all that helpful, since they cannot overcome their depression so effortlessly. The next time you meet someone with a mood disorder such as depression, please be sensitive, and remember this: In addition to some of the more obvious ways in which the depression may be impacting the individual’s life, there are invisible yet powerful and unavoidable cognitive forces –– like mood-congruent memories –– at work behind the scenes.

References

Depression basics. (2016). National Institute of Mental Health.

Devlin, H. (2020, July 30). What is functional magnetic resonance imaging (fMRI)? Psych Central.

Foland-Ross, L. C., Cooney, R. E., Joormann, J., Henry, M. L., & Gotlib, I. H. (2014). Recalling happy memories in remitted depression: A neuroimaging investigation of the repair of sad mood. Cognitive, Affective, & Behavioral Neuroscience, 14(2), 818-826. https://doi.org/10.3758/s13415-013-0216-0

Goodman, G. S., Ogle, C. M., Block, S. D., Harris, L. S., Larson, R. P., Augusti, E.-M., Cho, Y. I., Beber, J., Timmer, S., & Urquiza, A. (2011). False memory for trauma-related DRM lists in adolescents and adults with histories of child sexual abuse. Development and Psychopathology, 23(2), 423-438. https://doi.org/10.1017/S0954579411000150

Howe, M. L., & Malone, C. (2011). Mood-congruent true and false memory: Effects of depression. Memory, 19(2), 192–201. https://doi.org/10.1080/09658211.2010.544073

Joormann, J., & Gotlib, I. H. (2008). Updating the contents of working memory in depression: Interference from irrelevant negative material. Journal of Abnormal Psychology, 117(1), 182–192. https://doi.org/10.1037/0021-843X.117.1.182

Joormann, J., Teachman, B. A., & Gotlib, I. H. (2009). Sadder and less accurate? False memory for negative material in depression. Journal of Abnormal Psychology, 118(2), 412–417. https://doi.org/10.1037/a0015621

McBride, Dawn M., and J. Cooper Cutting. Cognitive Psychology: Theory, Process, and Methodology. Sage, 2019.

Moss, H., & Older, L. (1996). Birkbeck word association norms. Hove, UK: Psychology Press.

Neuroskeptic. (2011, October 19). What is brain “activation” on fMRI? Discover Magazine.