Survival of the selfish: contrasting self-referential and survival-based encoding

Testing the modulation of self-related automatic and others-related controlled processing by chronotype and time-of-day

We assessed whether self-related automatic and others-related controlled processes are modulated by chronotype and time-of-day. Here, a shape-label matching task composed of three geometrical shapes arbitrarily associated with you, friend, and stranger was used. Twenty Morning-types, and twenty Evening-types performed the task at the optimal and non-optimal times of day (i.e., 8 AM, or 8:30 PM). Morning-types did not exhibit noticeable synchrony effects, thus proving the better adaptation of these participants to non-optimal moments of the day as compared to Evening-types. Contrary to our predictions regarding the absence of automatic-processing modulation and the presence of controlled-processing influences by time-of-day, we found an influence on self-related but not others-related processing only in Evening-type participants. Although brain structures are not directly tackled, we argue that such modulation may be due to the dependence of the activation of the ventromedial prefrontal cortex (VMPFC), an essential component of the self-attention network on circadian rhythms.

The relevance of familiarity in the context of self-related information processing

Humans are inclined to preferentially process self-related content, referred to as the "self-bias." Different paradigms have been used to study this effect. However, not all paradigms included a familiar other condition (but rather an unfamiliar other condition), needed to differentiate self-specific effects from the impact of familiarity. The primary goal of our study was to test the suitability for studying the self-bias of two paradigms that provide robust measures of salience effects-that is, the Repetition Blindness (RB) effect and the Emotional Stroop (ES) interference-while addressing the familiarity confound. We further explored whether self-bias effects were related to autism symptomatology, as a reduced self-bias in autism has been reported in previous research. In an online procedure, 82 adults performed an RB task and an ES task in a counterbalanced order, while being presented with both self- and familiar other-related stimuli. Results of both frequentist and Bayesian analyses did not provide evidence in favour of a specific self-bias on either task: we found no significant modulation of the RB effect, nor of the ES interference, for the own versus a close other's name. Moreover, no link with autism symptomatology was found. Tackling a crucial shortcoming from earlier studies, our investigation raises awareness on the importance of accounting for familiarity when investigating self-related processing.

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.

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.

Conscious awareness of self-relevant information is necessary for an incidental self-memory advantage

Co-presenting an item with self-relevant vs. other-relevant information under a non-self-referential encoding context can produce a memory advantage. The present study examined the relative contributions of conscious vs. unconscious processing of self-cues to this incidental self-memory advantage. During encoding, the participant's own or another person's name was presented supraliminally or subliminally prior to the presentation of each target word. Consistent across two experiments, we found better memory for words preceded by the own name vs. another name but only when the names were presented supraliminally. The masked priming effect produced by the own name in Experiment 2 suggests that the absence of a self-memory advantage following subliminal name presentation was unlikely due to subliminal self-processing being too weak. Our findings suggest that conscious awareness of self-cues is necessary for an incidental self-memory advantage. Potential qualitative differences between conscious vs. unconscious self-processing mediating the impact of self on memory are discussed.

An online paradigm for exploring the self-reference effect

People reliably encode information more effectively when it is related in some way to the self—a phenomenon known as the self-reference effect. This effect has been recognized in psychological research for almost 40 years, and its scope as a tool for investigating the self-concept is still expanding. The self-reference effect has been used within a broad range of psychological research, from cultural to neuroscientific, cognitive to clinical. Traditionally, the self-reference effect has been investigated in a laboratory context, which limits its applicability in non-laboratory samples. This paper introduces an online version of the self-referential encoding paradigm that yields reliable effects in an easy-to-administer procedure. Across four studies (total N = 658), this new online tool reliably replicated the traditional self-reference effect: in all studies self-referentially encoded words were recalled significantly more than semantically encoded words (d = 0.63). Moreover, the effect sizes obtained with this online tool are similar to those obtained in laboratory samples, and are robust to experimental variations in encoding time (Studies 1 and 2) and recall procedure (Studies 3 and 4), and persist independent of primacy and recency effects (all studies).

The Survival Advantage: Underlying Mechanisms and Extant Limitations

Recently, researchers have begun to investigate the function of memory in our evolutionary history. According to Nairne and colleagues (e.g., Nairne, Pandeirada, and Thompson, 2008 ; Nairne, Thompson, and Pandeirada, 2007 ), the best mnemonic strategy for learning lists of unrelated words may be one that addresses the same problems that our Pleistocene ancestors faced: fitness-relevant problems including securing food and water, as well as protecting themselves from predators. Survival processing has been shown to promote better recall and recognition memory than many well-known mnemonic strategies (e.g., pleasantness ratings, imagery, generation, etc.). However, the survival advantage does not extend to all types of stimuli and tasks. The current review presents research that has replicated Nairne et al.'s (2007) original findings, in addition to the research designs that fail to replicate the survival advantage. In other words, there are specific manipulations in which survival processing does not appear to benefit memory any more than other strategies. Potential mechanisms for the survival advantage are described, with an emphasis on those that are the most plausible. These proximate mechanisms outline the memory processes that may contribute to the advantage, although the ultimate mechanism may be the congruity between the survival scenario and Pleistocene problem-solving.

We are more selfish than we think: The endowment effect and reward processing within the human medial-frontal cortex

Perceived ownership has been shown to impact a variety of cognitive processes: attention, memory, and--more recently--reward processing. In the present experiment we examined whether or not perceived ownership would interact with the construct of value-the relative worth of an object. Participants completed a simple gambling game in which they gambled either for themselves or for another while electroencephalographic data were recorded. In a key manipulation, gambles for oneself or for another were for either small or large rewards. We tested the hypothesis that value affects the neural response to self-gamble outcomes, but not other-gamble outcomes. Our experimental data revealed that while participants learned the correct response option for both self and other gambles, the reward positivity evoked by wins was impacted by value only when gambling for oneself. Importantly, our findings provide additional evidence for a self-ownership bias in cognitive processing and further demonstrate the insensitivity of the medial-frontal reward system to gambles for another.

The function of the self-attention network

This commentary links Humphrey and Sui's proposed Self-attention Network (SAN) to the memory advantage associated with self-relevant information (i.e., the self-reference effect). Articulating this link elucidates the functional quality of the SAN in ensuring that information of potential importance to self is not lost. This adaptive system for self-processing mirrors the cognitive response to threat stimuli, which also elicit attentional biases and produce characteristically enhanced, episodic representations in memory. Understanding the link between the SAN and memory is key to comprehending more broadly the operation of the self in cognition.

Multilevel induction of categories: venomous snakes hijack the learning of lower category levels

The induction of categories and concepts from examples-which plays an important role in how people come to organize and understand the world-can happen at multiple levels, but how do competing values at these different levels affect learning? Using perceptually rich images of snakes, we asked participants to attend to either the snakes' specific genus or a broader categorization and then tested induction at both levels. We also varied the intrinsic value of the broader categorization (high value: whether the snake was venomous; low value: whether it was tropical). We found an interaction between study instruction and intrinsic value: Participants in the low-value condition were better able to induce the level they were instructed to attend to (i.e., genus or broader category) than to induce the level they were not instructed to attend to, whereas participants in the high-value condition, regardless of the level of categorization they were instructed to attend to, were significantly better at learning the broad categorization (for them, whether the snake was venomous) than were participants in the low-value condition. Our results suggest that intrinsically valuable features can disrupt the intentional learning of other, task-relevant information, but enhance the incidental learning of the same information.