Adaptive memory: Animacy, threat, and attention in free recall

Agency effects on the binding of event elements in episodic memory

Representing events in episodic memory in a coherent manner requires that their constituent elements are bound together. So far, only few moderators of these binding processes have been identified. Here we investigate whether the presence of an agentic element in an event facilitates binding. The results from six experiments provided no evidence for a facilitating effect of agency on the binding of event elements. In addition, binding effects were only found when event elements were presented simultaneously, but not when they were presented sequentially pairwise, contrary to previous findings. The results suggest that the presence of an agentic element in an event does not, or only to a very limited extent, contribute to the formation of coherent memory representations and that additional processes may be required when binding event elements across temporarily divided encoding episodes. These findings add to a growing body of research regarding moderators and processes relevant for the binding of event elements in episodic memory. Explanations of these findings and directions for future research are discussed.

An exploration of the influence of animal and object categories on recall of item location following an incidental learning task

The current study explores the role of attention in location memory for animals and objects. Participants completed an incidental learning task where they rated animals and objects with regard to either their ease of collection to win a scavenger hunt (Experiments 1a and b) or their distance from the centre of the computer screen (Experiment 2). The images of animals and objects were pseudo-randomly positioned on the screen in both experiments. After completing the incidental learning task (and a reverse counting distractor task), participants were then given a surprise location memory recall task. In the location memory recall task, items were shown in the centre of the screen and participants used the mouse to indicate the position the item had been shown during the incidental encoding task. The results of both experiments show that location memory for objects was more accurate than for animals. While we cannot definitively identify the mechanism responsible for the difference in the location memory of objects and animals, we propose that differences in the influence of object-based attention at encoding affect location memory when tested at recall.

The animacy effect on free recall is equally large in mixed and pure word lists or pairs

The cognitive mechanisms underlying the animacy effect on free recall have as yet to be identified. According to the attentional-prioritization account, animate words are better recalled because they recruit more attention at encoding than inanimate words. The account implies that the animacy effect should be larger when animate words are presented together with inanimate words in mixed lists or pairs than when animate and inanimate words are presented separately in pure lists or pairs. The present series of experiments served to systematically test whether list composition or pair composition modulate the animacy effect. In Experiment 1, the animacy effect was compared between mixed and pure lists. In Experiments 2 and 3, the words were presented in mixed or pure pairs to manipulate the direct competition for attention between animate and inanimate words at encoding. While encoding was intentional in Experiments 1 and 2, it was incidental in Experiment 3. In each experiment, a significant animacy effect was obtained, but the effect was equally large in mixed and pure lists or pairs of animate and inanimate words despite considerable sensitivity of the statistical test of the critical interaction. These findings provide evidence against the attentional-prioritization account of the animacy effect.

A direct replication and extension of Popp and Serra (2016, experiment 1): better free recall and worse cued recall of animal names than object names, accounting for semantic similarity

Introduction

Free recall tends to be better for names of animate concepts such as animals than for names of inanimate objects. In Popp and Serra's 2016 article, the authors replicated this "animacy effect" in free recall but when participants studied words in pairs (animate-animate pairs intermixed with inanimate-inanimate pairs) and were tested with cued recall, performance was better for inanimate-inanimate pairs than for animate-animate pairs ("reverse animacy"). We tested the replicability of this surprising effect and one possible explanation for the effect (semantic similarity).

Methods

Our Experiment 1 was a preregistered direct replication (N = 101) of Popp and Serra's Experiment 1 (mixed-lists condition). In a second preregistered experiment conducted in four different samples (undergraduate N = 153, undergraduate N = 143, online Prolific N = 101, online Prolific/English-as-a-first-language N = 150), we manipulated the within-category semantic similarity of animal and object wordlists.

Results

AIn Experiment 1, just as in Popp and Serra, we observed an animacy effect for free recall and a reverse animacy effect for cued recall. Unlike Popp and Serra, we found that controlling for interference effects rendered the reverse animacy effect non-significant. We took this as evidence that characteristics of the stimulus sets (e.g., category structure, within-category similarity) may play a role in animacy and reverse animacy effects. In Experiment 2, in three out of our four samples, we observed reverse animacy effects when within-category similarity was higher for animals and when within-category similarity was equated for animals and objects.

Discussion

Our results suggest that the reverse animacy effect observed in Popp and Serra's 2016 article is a robust and replicable effect, but that semantic similarity alone cannot explain the effect.

The animacy advantage in memory occurs under self-paced study conditions, but participants' metacognitive beliefs can deter it

Introduction

Animacy distinguishes living (animate) things from non-living (inanimate) things. People tend to devote attention and processing to living over nonliving things, resulting in a privileged status for animate concepts in human cognition. For example, people tend to remember more animate than inanimate items, a phenomenon known as the "animacy effect" or "animacy advantage." To date, however, the exact cause(s) of this effect is unknown.

Methods

We examined the animacy advantage in free-recall performance under computer-paced versus self-paced study conditions and using three different sets of animate and inanimate stimuli (Experiments 1 and 2). We also measured participants' metacognitive beliefs (expectations) about the task before it began (Experiment 2).

Results

We consistently obtained an animacy advantage in free-recall, regardless of whether participants studied the materials under computer-paced or self-paced conditions. Those in self-paced conditions spent less time studying items than did those in computer-paced conditions, but overall levels of recall and the occurrence of the animacy advantage were equivalent by study method. Importantly, participants devoted equivalent study time to animate and inanimate items in self-paced conditions, so the animacy advantage in those conditions cannot be attributed to study time differences. In Experiment 2, participants who believed that inanimate items were more memorable instead showed equivalent recall and study time for animate and inanimate items, suggesting that they engaged in equivalent processing of animate and inanimate items. All three sets of materials reliably produced an animacy advantage, but the effect was consistently larger for one set than the other two, indicating some contribution of item-level properties to the effect.

Discussion

Overall, the results suggest that participants do not purposely allocate greater processing to animate over inanimate items, even when study is self-paced. Rather, animate items seem to naturally trigger greater richness of encoding than do inanimate items and are then better remembered, although under some conditions participants might engage in deeper processing of inanimate items which can reduce or eliminate the animacy advantage. We suggest that researchers might conceptualize mechanisms for the effect as either centering on intrinsic, item-level properties of the items or centering on extrinsic, processing-based differences between animate and inanimate items.

Animacy enhances recollection but not familiarity: Convergent evidence from the remember-know-guess paradigm and the process-dissociation procedure

Words representing living beings are better remembered than words representing nonliving objects, a robust finding called the animacy effect. Considering the postulated evolutionary-adaptive significance of this effect, the animate words' memory advantage should not only affect the quantity but also the quality of remembering. To test this assumption, we compared the quality of recognition memory between animate and inanimate words. The remember-know-guess paradigm (Experiment 1) and the process-dissociation procedure (Experiment 2) were used to assess both subjective and objective aspects of remembering. Based on proximate accounts of the animacy effect that focus on elaborative encoding and attention, animacy is expected to selectively enhance detailed recollection but not the acontextual feeling of familiarity. Multinomial processing-tree models were applied to disentangle recollection, familiarity, and different types of guessing processes. Results obtained from the remember-know-guess paradigm and the process-dissociation procedure convergently show that animacy selectively enhances recollection but does not affect familiarity. In both experiments, guessing processes were unaffected by the words' animacy status. Animacy thus not only enhances the quantity but also affects the quality of remembering: The effect is primarily driven by recollection. The results support the richness-of-encoding account and the attentional account of the animacy effect on memory.

Within-pair factors might explain the inconsistent effects of animacy on paired-associates recall

The tendency for people to have better memory for animate (living) concepts than inanimate (nonliving) concepts in memory tasks involving free recall and recognition suggests that animacy status can be an important predictor of memory. To date, however, the effect of animacy on paired-associates recall has been mixed: Some studies have found an animacy advantage, some have found an animacy disadvantage, and some have found no difference by animacy. We tested the hypothesis that the within-pair relationship of the two words in a pair matters more for cued recall than animacy itself. In two experiments, college students studied animate and inanimate English word pairs for a cued-recall test. We varied whether the pairs involved two typical exemplars from the same category (e.g., SALMON-TROUT; FORK-SPOON), one typical and one atypical exemplar from the same category (e.g., DOCTOR-SCIENTIST; HOUSE-IGLOO), or two unrelated words from different categories (e.g., SERGEANT-COBRA; MAGAZINE-PLIERS). Respectively, these pair types produced an animacy disadvantage, an animacy advantage, and no difference by animacy in both experiments. We then examined several measures of within-pair similarity for the items. All were positively associated with paired-associates recall, but animacy had no effect on cued recall above and beyond the relationship of these measures to recall. These results suggest that the within-pair relationship matters more for cued recall than does animacy. Uneven variation in within-pair relationships for animate versus inanimate pairs-rather than animacy itself-might therefore produce the apparently inconsistent effects of animacy on paired-associates recall.

Thinking of death and remembering living things: mortality salience and the animacy effect

The animacy effect, the finding that animate items are better remembered than inanimate items, provides evidence that human memory prioritizes information that is related to survival. Various proximate mechanisms for this memory effect have been proposed, including mortality salience, that humans are more likely to remember information related to death, and animate items (e.g., shark, tiger) are more likely to elicit thoughts of death than inanimate items (e.g., volleyball, towel). Mortality salience was manipulated in Experiment 1. Animate items were recalled more than inanimate items and threatening items were recalled more than nonthreatening items, but there was no significant effect of mortality salience. For Experiment 2, norming data were collected rating the word stimuli from the previous experiment on the characteristics of arousal, valence, likelihood to capture attention, and likelihood to elicit thoughts of death. These ratings along with threat ratings and animacy status of the items were included in a regression analysis with the frequency of recall of the items in Experiment 1. In addition to animacy, likelihood to capture attention and likelihood to elicit thoughts of death were significant predictors of recall, suggesting that these characteristics could be at least partly responsible for the animacy effect.

Selective remembering and directed forgetting are influenced by similar stimulus properties

Do the properties of to-be-remembered events influence the ability to remember, and also intentionally forget, these events in similar ways? Prior work has examined how the font size, animacy, emotionality, concreteness (the degree to which a word denotes something perceptible), frequency (how often a word appears in language), and length of to-be-remembered words influence memory. However, it was previously unclear whether the forgetting of information is also influenced by these characteristics. In six experiments, we used an item-method directed forgetting task where we presented participants with to-be-remembered and to-be-forgotten words varying in font size (large or small), animacy (animate or inanimate), emotionality (negative or neutral), concreteness (high or low), frequency (high or low), and word length (long or short). Results revealed that animacy, emotionality, concreteness, frequency, and word length (but not font size) influenced both remembering and forgetting. Together, the present findings indicate that the characteristics of presented words can influence remembering as well as directed forgetting, providing further evidence that the remembering and forgetting processes are governed by similar properties.

Analyzing the structure of animacy: Exploring relationships among six new animacy and 15 existing normative dimensions for 1,200 concrete nouns

Animacy is an important word variable (especially for episodic memory), yet no norms exist in the literature. We present a complete, usable normative data set of 1,200 relatively concrete nouns normed on 15 existing dimensions (concreteness, familiarity, imagery, availability, valence, arousal, dominance, age of acquisition, length, orthographic neighborhood, phonographic neighborhood, number of syllables, and subtitle frequency/contextual diversity) and six new animacy dimensions (a general living/non-living scale, ability to think, ability to reproduce, similarity to a person, goal-directedness, and movement likelihood). Principal component analysis of these 21 dimensions revealed that animacy scales were conceptually different from extant word variables. Further, factor analysis of the six new scales revealed these animacy norms may be separable into two dimensions: a "Mental" component related to animates' ability to think and have goals, and a "Physical" component related to animates' general resemblance to living things. These data provide useful theoretical insight into the structure of the animacy dimension, an important factor in many cognitive processes. The norms are accessible at https://osf.io/4t3cu .

Memory for medicinal plants remains in ancient and modern environments suggesting an evolved adaptedness

Adaptive memory is the propensity of human memory to easily store and retrieve important information to deal with challenges related to the Pleistocene. Recent evidence shows that humans have had a multiregional evolution across the African continent, including the rainforests and deciduous forests; however, there is little evidence regarding the implications of these origins and the relevant and recurring challenges of these environments on survival processing advantage in memory. In this study, we conducted an experiment with volunteers to analyze whether adaptive memory operates in the retrieval of important information to solve challenges of using medicinal plants to treat diseases in the ancestral environments of the savanna, rainforests, and deciduous forests compared to the modern environments of desert, tundra, coniferous forest, and urban areas. We used simulated survival environments and asked volunteers (30 per simulated scenario) to imagine themselves sick in one of these environments, and needing to find medicinal plants to treat their disease. The volunteers rated the relevance of 32 words to solve this challenge, followed by a surprise memory test. Our results showed no ancestral priority in recalling relevant information, as both ancestral and modern environments showed a similar recall of relevant information. This suggests that the evolved cognitive apparatus allows human beings to survive and can create survival strategies to face challenges imposed in various environments. We believe that this is only possible if the human mind operates through a flexible cognitive mechanism. This flexibility can reflect, for example, the different environments that the first hominids inhabited and the different dangerous situations that they faced.

Animacy and threat in recognition memory

Animate items are better remembered than inanimate items, suggesting that human memory has evolved to prioritize information related to survival. The proximate mechanisms for the animacy effect are not yet known, but one possibility is that animate items are more likely to capture attention, which then leads to better memory for those items. The first experiment independently manipulated the animacy and perceived threat of studied items and found that both target recognition and false-alarm recognition were higher for animate items compared to inanimate items and for threatening items compared to non-threatening items. The effects were eliminated when d' scores were calculated. The second experiment used a response signal delay (RSD) manipulation where participants were forced to respond after a short (500 ms) or long (2,000 ms) time delay during the recognition test. Similar to the first experiment, the effects of animacy and threat for target recognition and false-alarm recognition persisted and did not interact with the RSD manipulation. Taken together, the results of the studies suggest that the animacy and threat effects in memory are robust and that attention capture might be at least partly responsible for the animacy effect.

Of Beavers and Tables: The Role of Animacy in the Processing of Grammatical Gender Within a Picture-Word Interference Task

Grammatical gender processing during language production has classically been studied using the so-called picture-word interference (PWI) task. In this procedure, participants are presented with pictures they must name using target nouns while ignoring superimposed written distractor nouns. Variations in response times are expected depending on the congruency between the gender values of targets and distractors. However, there have been disparate results in terms of the mandatory character of an agreement context to observe competitive gender effects and the interpretation of the direction of these effects in Romance languages, this probably due to uncontrolled variables such as animacy. In the present study, we conducted two PWI experiments with European Portuguese speakers who were asked to produce bare nouns. The percentage of animate targets within the list was manipulated: 0, 25, 50, and 100%. A gender congruency effect was found restricted to the 0% list (all targets were inanimate). Results support the selection of gender in transparent languages in the absence of an agreement context, as predicted by the Gender Acquisition and Processing (GAP) hypothesis (Sá-Leite et al., 2019), and are interpreted through the attentional mechanisms involved in the PWI paradigm, in which the processing of animate targets would be favored to the detriment of distractors due to biological relevance and semantic prioritization.

Animate and Inanimate Words Demonstrate Equivalent Retrieval Dynamics Despite the Occurrence of the Animacy Advantage

People demonstrate a memory advantage for animate (living) concepts over inanimate (nonliving) concepts in a variety of memory tasks, including free recall, but we do not know the mechanism(s) that produces this effect. We compared the retrieval dynamics (serial-position effects, probability of first recall, output order, categorical clustering, and recall contiguity) of animate and inanimate words in a typical free recall task to help elucidate this effect. Participants were more likely to recall animate than inanimate words, but we found few, if any, differences in retrieval dynamics by word type. The animacy advantage was obtained across serial position, including occurring in both the primacy and recency regions of the lists. Participants were equally likely to recall an animate or inanimate word first on the tests and did not prioritize recalling words of one type earlier in retrieval or demonstrate strong clustering by animacy at recall. Participants showed some greater contiguity of recall for inanimate words, but this outcome ran counter to the animacy effect. Together, the results suggest that the animacy advantage stems from increased item-specific memory strength for animate over inanimate words and is unlikely to stem from intentional or strategic differences in encoding or retrieval by word type, categorical strategies, or differences in temporal organization. Although the present results do not directly support or refute any current explanations for the animacy advantage, we suggest that measures of retrieval dynamics can help to inspire or constrain future accounts for this effect and can be incorporated into relevant hypothesis testing.

Exploring word memorability: How well do different word properties explain item free-recall probability?

What makes some words more memorable than others? Words can vary in many dimensions, and a variety of lexical, semantic, and affective properties have previously been associated with variability in recall performance. Free recall data were used from 147 participants across 20 experimental sessions from the Penn Electrophysiology of Encoding and Retrieval Study (PEERS) data set, across 1,638 words. Here, I consider how well 20 different word properties-across lexical, semantic, and affective dimensions-relate to free recall. Semantic dimensions, particularly animacy (better memory for living), usefulness (with respect to survival; better memory for useful), and size (better memory for larger) demonstrated the strongest relationships with recall probability. These key results were then examined and replicated in the free recall data from Lau, Goh, and Yap (Quarterly Journal of Experimental Psychology, 71, 2207-2222, 2018), which had 532 words and 116 participants. This comprehensive investigation of a variety of word memorability demonstrates that semantic and function-related psycholinguistic properties play an important role in verbal memory processes.

In search of the proximal cause of the animacy effect on memory: Attentional resource allocation and semantic representations

People recall and recognize animate words better than inanimate words, perhaps because memory systems were shaped by evolution to prioritize memory for predators, people, and food sources. Attentional paradigms show an animacy advantage that suggests that the animacy advantage in memory stems from a prioritization of animate items when allocating attentional resources during encoding. According to the attentional prioritization hypothesis, the animacy effect should be even larger when attention is divided during encoding. Alternatively, the animacy effect could be due to more controlled processing during encoding, and so should be reduced when attention is divided during encoding. We tested the attentional prioritization hypothesis and the controlled processing hypothesis by manipulating attention during encoding in free recall (Experiment 1) and recognition (Experiment 2) but failed to find interactions between word type and attentional load in either free recall or recognition, contrary to the predictions from both hypotheses. We then tested whether the semantic representations of animate and inanimate items differ in terms of number of semantic features, using existing recall data from an item-level megastudy by Lau, Goh, and Yap (Quarterly Journal of Experimental Psychology, 71 (10), 2207-2222, 2018). Animate items have more semantic features, which partially mediated the relationship between animacy status and recall.

General and own-species attentional face biases

Humans demonstrate enhanced processing of human faces compared with animal faces, known as own-species bias. This bias is important for identifying people who may cause harm, as well as for recognizing friends and kin. However, growing evidence also indicates a more general face bias. Faces have high evolutionary importance beyond conspecific interactions, as they aid in detecting predators and prey. Few studies have explored the interaction of these biases together. In three experiments, we explored processing of human and animal faces, compared with each other and to nonface objects, which allowed us to examine both own-species and broader face biases. We used a dot-probe paradigm to examine human adults' covert attentional biases for task-irrelevant human faces, animal faces, and objects. We replicated the own-species attentional bias for human faces relative to animal faces. We also found an attentional bias for animal faces relative to objects, consistent with the proposal that faces broadly receive privileged processing. Our findings suggest that humans may be attracted to a broad class of faces. Further, we found that while participants rapidly attended to human faces across all cue display durations, they attended to animal faces only when they had sufficient time to process them. Our findings reveal that the dot-probe paradigm is sensitive for capturing both own-species and more general face biases, and that each has a different attentional signature, possibly reflecting their unique but overlapping evolutionary importance.

Animacy effects extend to working memory: results from serial order recall tasks

Words that represent animate entities (e.g., dog) are recalled from long-term memory more accurately than words representing inanimate entities (e.g., pan). In this research, we examined whether the animacy effect extends to working memory (WM). The potential roles of WM maintenance strategies (rehearsal and directed attention) were also examined. Participants performed serial order recall tasks with sets of 3, 4, 5 or 6 words that were either animate or inanimate. In stage 1 of Experiment 1, participants received no instructions regarding how to maintain the words. In stage 2, participants received either no instructions, sub-vocal rehearsal or directed attention instructions. In all instruction groups and at both stages, significant animacy effects were observed at set sizes of 4, 5 and 6 but not set size 3. The animacy effect was larger at set size 5 than other set sizes. In Experiment 2, participants completed the task with and without articulatory suppression. In both conditions, animacy effects were observed at set sizes 4, 5 and 6, but not at set size 3. The magnitude of the animacy effect declined as set size increased from 4 to 6. Animacy appears to enhance serial recall, but the effect is not dependent on rehearsal.

Adaptive memory: enhanced source memory for animate entities

The animacy effect refers to enhanced memory for animate over inanimate items. In two studies, we examined whether this memory advantage generalises to source memory. A multinomial processing tree model was used to disentangle item recognition, source memory, and guessing processes. In Study 1, animate and inanimate words were presented at different spatial locations on the screen. Animacy was associated with enhanced source memory for the spatial locations of the items. In Study 2, pseudowords were associated with animate and inanimate properties. Replicating previous results, the pseudowords were better remembered when they were associated with animate properties than when they were associated with inanimate properties. What is more, participants had enhanced source memory for the association between the pseudowords and the animate properties. The results strengthen the idea that animate items are associated with richer mnemonic representations than inanimate items.