The Survival Advantage: Underlying Mechanisms and Extant Limitations

Survival processing occupies the central bottleneck of cognitive processing: A psychological refractory period analysis

Words judged for relevance in a survival situation are remembered better than words judged for relevance in a nonsurvival context. This survival processing effect has been explained by selective tuning of human memory during evolution to process and retain information specifically relevant for survival. According to the richness-of-encoding hypothesis the survival processing effect arises from a domain-general mechanism-namely, a particularly rich and distinct form of encoding. This form of information processing is effortful and requires limited cognitive capacities. In our experiment, we used the well-established psychological refractory period framework in conjunction with the effect propagation logic to assess the role of central cognitive resources for the survival processing effect. Our data demonstrate that the survival memory advantage indeed relies on the capacity-limited central stage of cognitive processing. Thus, rating words in the context of a survival scenario involves central processing resources to a greater amount than rating words in a nonsurvival control condition. We discuss implications for theories of the survival processing effect.

Survival processing and directed forgetting: enhanced memory for both to-be-remembered and to-be-forgotten information

In a recently published study, (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) examined directed forgetting in a survival processing context using the list-method directed forgetting procedure. (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) found that the costs of directed forgetting were greater when engaging in survival processing than when making moving relevance or pleasantness ratings. However, according to most current accounts of directed forgetting, engaging in survival processing should not have enhanced the directed forgetting effect but rather should not have impacted the directed forgetting effect. In the present study, we further investigated how survival processing impacts directed forgetting using both the list (Experiment 1) and item method of directed forgetting (Experiment 2). In Experiment 1, we did not replicate the findings of (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) - that the directed forgetting effect is enhanced when engaging in survival processing. Rather, we demonstrated that making survival ratings and moving ratings yielded a similar cost of directed forgetting for List 1 items. In Experiment 2, survival processing provided an overall memory benefit (but not when recalling to-be-remembered and to-be-forgotten items in separate recall tests) but did not differentially impact to-be-remembered and to-be-forgotten words. Thus, we did not find evidence that survival processing influences directed forgetting.

Surviving with story characters: What do we remember?

Readers simulate story characters' emotions, memories, and perceptual experiences. The current study consists of three experiments that investigated whether survival threat would amplify the mnemonic experience of a narrative. First, a replication study of Nairne et al. (Journal of Experimental Psychology: Learning, Memory, and Cognition, 33 (2), 263-273, 2007) was conducted with minor methodological alternations and yielded improved recall for participants imagining themselves in a survival scenario over a moving scenario (Experiment 1). In Experiments 2 and 3, participants read stories about a character either stranded in the grasslands or moving to a foreign land. Improved recall for objects included in the story (Experiments 2 and 3) and recognition of story details (Experiment 3) was found when the character was in a survival situation. The largest effects were observed when the reader was asked to imagine themselves as the story character (Experiment 3). Overall, readers remembered survival-relevant details as if they were experiencing the story character's plight. These results extend research showing that survival processing enhances memory for word lists (e.g., Nairne et al., Psychological Science, 19 (2), 176-180, 2008).

Is there a survival processing effect in metacognition?

Memory systems serve an adaptive function for the fitness of organisms. A good example of this is the Survival Processing Effect (SPE) which points to increased retention of information when it is processed in a survival context compared to other contexts. Survival processing may also affect metacognitive processes, by increasing confidence judgments as well as increasing metacognitive sensitivity. No previous study, however, has directly examined whether processing information for survival also has an effect on metacognitive processes. Here we ask whether SPE extends to the metacognitive system in terms of both metacognitive sensitivity and confidence bias. In Experiment 1 participants were asked to rate a list of words in terms of relevance in a survival scenario or a moving scenario. In a surprise old/new recognition test, they were given one word at a time and asked to indicate if they have rated the presented word before and state how confident they are in that choice. Surprisingly, the results did not reveal a SPE, which may have been due to high overall performance in the recognition task. In Experiment 2 we increased the level of difficulty of the memory task, which resulted in a robust SPE, but could not find this effect in metacognitive monitoring. Together, these results suggest that survival processing may not affect metacognitive processes in a reliable fashion.

Varying retrieval conditions to study survival processing

The survival processing advantage is a mnemonic benefit resulting from processing items for their relevance to survival. One explanation of the survival processing advantage is the richness-of-encoding hypothesis: Survival processing enhances retention by generating ideas (elaborative and distinctive processing), increasing the number of retrieval cues. Without retrieval, encoding is futile. Hence, the present experiments varied retrieval conditions - via transfer appropriate processing (TAP) tasks - predicting that the survival processing advantage could be reversed. In Experiment 1a, reducing the transfer appropriateness of survival processing caused significantly lower recognition scores after survival processing than after processing of word associates. Experiment 1b replicated a survival processing advantage and found a survival processing disadvantage. In Experiment 2, survival processing was pitted against a gift desirability task and retrieval mode was varied. Survival processing yielded superior memory on a standard free recall test, but the survival processing advantage was eliminated when an unusual retrieval mode was encouraged. Results affirm the importance of context-dependent retrieval.

Effects of survival processing on list method directed forgetting

Two experiments examined the effects of directed (intentional) forgetting on information processed for its survival value. Experiment 1 used the list-method directed forgetting procedure in which items processed for their relevance to survival, moving house or pleasantness were followed by the cue to remember or forget. Following the encoding of a second list, free-recall of both lists showed that survival encoding brought about greater remembering (after the remember cue) and forgetting (after the forget cue). Experiment 2 also used the list-method and manipulated mental context reinstatement prior to recall. Although this manipulation was effective in enhancing memory, more directed forgetting was again shown in the survival condition. In both experiments the effects of survival processing were shown also in free-recall "remember" (vs. "know") responses, indicative of the retrieval of associative or contextual details. The mechanisms that might underpin these were evaluated and considered in relation to future work.

Adaptive Memory: Independent Effects of Survival Processing and Reward Motivation on Memory

Humans preferentially remember information processed for their survival relevance, a memorial benefit known as the survival processing effect. Memory is also biased towards information associated with the prospect of reward. Given the adaptiveness of these effects, they may depend on similar mechanisms. We tested whether motivation drives both effects, with reward incentives that are known to boost extrinsic motivation and survival processing perhaps stimulating intrinsic motivation. Accordingly, we manipulated survival processing and reward incentive independently during an incidental-encoding task in which participants chose between pairs of words concerning their relevance for a scenario, and examined the effects on encoding event-related potentials (ERP) activity and later performance on a surprise recall test. We hypothesized that if survival processing fosters intrinsic motivation, it should reduce the beneficial effects of extrinsic motivation (reward incentive). In contrast to this prediction, we found that reward incentive and survival processing independently improved memory and that the P300, a measure of lower-level cognitive resource allocation, was increased by reward incentive independent of survival processing. Further, survival processing and reward incentive independently increased the frontal slow wave (FSW), a measure of higher-level elaboration. These findings suggest that while survival processing and reward incentive may both increase encoding elaboration, the memory-enhancing effect of survival processing does not depend on increased intrinsic motivation. Additionally, we replicated a recent finding whereby the survival processing effect generalizes to a choice-based encoding task and further showed that the beneficial effect of choice on memory likely does not interact with either survival processing or reward.

Adaptive Memory: Generality of the Parent Processing Effect and Effects of Biological Relatedness on Recall

The adaptive memory framework posits that human memory is an evolved cognitive feature, in which stimuli relevant to fitness are better remembered than neutral stimuli. There is now substantial evidence that processing a neutral stimulus in terms of its relevancy to an imagined ancestral survival scenario enhances recall, although there is still disagreement concerning the proximate mechanisms responsible for this effect. Several other mnemonic biases have recently been discovered that similarly appear to reflect evolutionary pressures, including a bias to remember items relevant to an imagined parenting scenario. We tested the generality of this parent processing effect by varying the biological relatedness of the imagined child. We also varied the biological relatedness of a child during an imagined third-person survival processing scenario. Across four experiments, we found evidence that simply altering the described biological relatedness of a child in the parenting scenario and third-person survival processing scenario can affect recall, such that items are better remembered when made relevant to a biological child compared to an adopted child. How these findings inform the general adaptive memory framework is discussed.

Paired-associate learning, animacy, and imageability effects in the survival advantage

The current study examined animacy and paired-associate learning through a survival-processing paradigm (Nairne et al. in Journal of Experimental Psychology: Learning, Memory, and Cognition, 33(2), 263-273, 2007; Schwartz & Brothers, 2014). English-speaking monolingual participants were asked to learn a set of new word translations to improve their chances of survival or to improve their study abroad experience. Animate and inanimate words were included in this task, to further examine animacy effects in cued recall paradigms (Popp & Serra in Journal of Experimental Psychology: Learning, Memory, and Cognition, 42(2), 186-201, 2016; VanArsdall et al. in Experimental Psychology, 60(3), 172-178, 2013). Across sentence-completion, matching, and picture-naming tasks, learning was facilitated by the survival context, relative to the study abroad context and an intentional learning condition. Scenario ratings indicated this survival advantage could also be a function of higher imageability ratings for the survival context than for the study abroad context. Replicating previous findings with cued recall, inanimate words were overall better remembered than animate words, across all three tasks, though survival processing facilitated language-learning for both animate and inanimate categories. This 'reverse animacy effect' replicated previous findings by Popp and Serra (Journal of Experimental Psychology: Learning, Memory, and Cognition, 42(2), 186-201, 2016), showing animate words can interfere with a participant's ability to create associations with their words, including those in a new language. These results are discussed with regards to the widely-reliable survival and animacy advantages, with a particular emphasis on the role of imageability in this paradigm.

The neurocognitive features in survival processing: An ERP study

Recent behavioral studies used a survival processing task to investigate our memory systems from an evolutionary perspective. These results showed a memory advantage for the words rated for their relevance to a survival scenario compared with the words processed under numerous other tasks. However, the proximate explanations for the survival processing effect were mainly investigated through the subsequent retention data. By using event-related potentials, the present study was aimed to explore the neurocognitive features when we perform the survival-relevance-rating task. We used a pleasantness rating task and a moving processing task as control conditions in Experiments 1 and 2, respectively. Our results showed a larger parietal P600 for the words processed in the survival task compared with those processed in the pleasantness task and the moving task, indicating more elaborative encoding were obtained for the words processed in the survival task. Furthermore, an attenuated N400 was observed for the survival-relevant words in the survival task, indicating the survival scenario could facilitate the retrieval of these survival-relevant words. More importantly, a larger right frontal P600 was also observed for these survival-relevant words. This component might reflect the cognitive processes when we attempt to use the objects at hand to solve the fitness-relevant problems which we are facing. The present study supports the elaborative encoding hypothesis, and found the right frontal cortex plays an important role when we perform the survival task.

Survival Processing in a Novel Choice Procedure

People remember information that has been processed for survival relevance particularly well, perhaps because our memory systems have been tuned by natural selection to retain information pertinent to inclusive fitness. In the standard procedure, people rate the relevance of single words or objects to an imagined survival scenario and then receive a surprise retention test for the rated items. Here we replicate the survival advantage in a novel choice procedure in which people are asked to choose which of two items would be most useful in a survival context or in a “moving” (Experiment 1) or “scavenger hunt” (Experiment 2) control context. Chosen items were remembered better than unchosen items, and the survival processing advantage did not interact with the choice effect. Experiment 2 replicates this pattern using the matched-scenario design first used by Nairne, Pandeirada, Gregory, and VanArsdall (2009). These experiments extend the generality of the survival advantage and provide diagnostic information about its underlying proximate mechanisms.

The Survival Processing Advantage of Face: The Memorization of the (Un)Trustworthy Face Contributes More to Survival Adaptation

Researchers have found that compared with other existing conditions (e.g., pleasantness), information relevant to survival produced a higher rate of retrieval; this effect is known as the survival processing advantage (SPA). Previous experiments have examined that the advantage of memory can be extended to some different types of visual pictorial material, such as pictures and short video clips, but there were some arguments for whether face stimulus could be seen as a boundary condition of SPA. The current work explores whether there is a mnemonic advantage to different trustworthiness of face for human adaptation. In two experiments, we manipulated the facial trustworthiness (untrustworthy, neutral, and trustworthy), which is believed to provide information regarding survival decisions. Participants were asked to predict their avoidance or approach response tendency, when encountering strangers (represented by three classified faces of trustworthiness) in a survival scenario and the control scenario. The final surprise memory tests revealed that it was better to recognize both the trustworthy faces and untrustworthy faces, when the task was related to survival. Experiment 1 demonstrated the existence of a SPA in the bipolarity of facial untrustworthiness and trustworthiness. In Experiment 2, we replicated the SPA of trustworthy and untrustworthy face recognitions using a matched design, where we found this kind of memory benefits only in recognition tasks but not in source memory tasks. These results extend the generality of SPAs to face domain.

Grief and Avoidant Death Attitudes Combine to Predict the Fading Affect Bias

The fading affect bias (FAB) occurs when unpleasant affect fades faster than pleasant affect. To detect mechanisms that influence the FAB in the context of death, we measured neuroticism, depression, anxiety, negative religious coping, death attitudes, and complicated grief as potential predictors of FAB for unpleasant/death and pleasant events at 2 points in time. The FAB was robust across older and newer events, which supported the mobilization-minimization hypothesis. Unexpectedly, complicated grief positively predicted FAB, and death avoidant attitudes moderated this relation, such that the Initial Event Affect by Grief interaction was only significant at the highest 3 quintiles of death avoidant attitudes. These results were likely due to moderate grief ratings, which were, along with avoidant death attitudes, related to healthy outcomes in past research. These results implicate complicated grief and death avoidant attitudes as resiliency mechanisms that are mobilized during bereavement to minimize its unpleasant effects.

Adaptive Memory: Survival Processing and Social Isolation

Social isolation was examined to assess its potential influence on the survival processing effect, which shows that individuals are more likely to remember something when it is processed with regard to their survival. Participants imagined being stranded in the grasslands, going on a space mission, or moving to a foreign land while alone or with a group of friends and rated a list of words for their relevance to the assigned scenario. An incidental memory test showed the typical survival processing effect on recall memory, with a significant interaction showing that the effect occurred in the isolated condition but not in the group condition. A second experiment examined rates of recognition for an isolated and group condition for the grasslands and moving scenarios and found a marginally significant effect of isolation in addition to the typical survival processing effect. Further, in both experiments, the perceived isolation of the isolated and group survival grasslands scenarios was significantly higher than the other conditions. The results are discussed with regard to the self-reference effect and the object-function account of the survival processing effect.

Survival Processing Enhances Visual Search Efficiency

Words rated for their survival relevance are remembered better than when rated using other well-known memory mnemonics. This finding, which is known as the survival advantage effect and has been replicated in many studies, suggests that our memory systems are molded by natural selection pressures. In two experiments, the present study used a visual search task to examine whether there is likewise a survival advantage for our visual systems. Participants rated words for their survival relevance or for their pleasantness before locating that object's picture in a search array with 8 or 16 objects. Although there was no difference in search times among the two rating scenarios when set size was 8, survival processing reduced visual search times when set size was 16. These findings reflect a search efficiency effect and suggest that similar to our memory systems, our visual systems are also tuned toward self-preservation.

Survival processing eliminates collaborative inhibition

The present experiments examined the effect of processing words for their survival value, relevance to moving and pleasantness on participants’ free recall scores in both nominal groups (non-redundant pooled individual scores) and collaborative dyads. Overall, participants recalled more words in the survival processing conditions than in the moving and pleasantness processing conditions. Furthermore, nominal groups in both the pleasantness condition (Experiment 1) and the moving and pleasantness conditions (Experiment 2) recalled more words than collaborative groups, thereby replicating the oft-observed effect of collaborative inhibition. However, processing words for their survival value appeared to eliminate the deleterious effects of collaborative remembering in both Experiments 1 and 2. These results are discussed in the context of the retrieval strategy disruption hypothesis and the effects of both expertise and collaborative skill on group remembering.

Adaptive Memory

A few seconds of survival processing, during which people assess the relevance of information to a survival situation, produces particularly good retention. One interpretation of this benefit is that our memory systems are optimized to process and retain fitness-relevant information. Such a “tuning” may exist, in part, because our memory systems were shaped by natural selection, using a fitness-based criterion. However, recent research suggests that traditional mnemonic processes, such as elaborative processing, may play an important role in producing the empirical benefit. Boundary conditions have been demonstrated as well, leading some to dismiss evolutionary interpretations of the phenomenon. In this article, we discuss the current state of the evolutionary account and provide a general framework for evaluating evolutionary and purportedly nonevolutionary interpretations of mnemonic phenomena. We suggest that survival processing effects are best viewed within the context of a general survival optimization system, designed by nature to help organisms deal with survival challenges. An important component of survival optimization is the ability to simulate activities that help to prevent or escape from future threats which, in turn, depends in an important way on accurate retrospective remembering of survival-relevant information.

Survival Processing and the Stroop Task : Does the Survival Advantage Depend on Deeper Processing During Encoding?

This study was designed to investigate the impact of survival processing with a novel task for this paradigm: the Stroop color-naming task. As the literature is mixed with regard to task generalizability, with survival processing promoting better memory for words, but not better memory for faces or paired associates, these types of task investigations are important to a growing field of research. Using the Stroop task provides a unique contribution, as identifying items by color is an important evolutionary adaptation and not specific to humans as is the case with word recall. Our results indicate that survival processing, with its accompanying survival-relevance rating task, remains the best mnemonic strategy for word memory. However, our results also indicate that presenting the survival passage does not motivate better color-naming performance than color-naming alone. In addition, survival processing led to a larger amount of Stroop interference, though not significantly larger than the other conditions. Together, these findings suggest that considering one's survival when performing memory and attention-based tasks does not enhance cognitive performance generally, although greater allocation of attentional resources to color-incongruent concrete objects could be considered adaptive. These findings support the notion that engaging in deeper processing via survival-relevance ratings may preserve these words across a variety of experimental manipulations.