Event memory and misinformation effects in a gorilla (<Emphasis Type="Italic">Gorilla gorilla gorilla</Emphasis>)

Event memory and misinformation effects were examined in an adult male gorilla ( Gorilla gorilla gorilla). The gorilla witnessed a series of unique events, involving a familiar person engaging in a novel behavior (experiment 1), a novel person engaging in a novel behavior (experiment 2), or the presentation of a novel object (experiment 3). Following a 5- to 10-min retention interval, a tester gave the gorilla three photographs mounted on wooden cards: a photograph depicting the correct person or object and two distractor photographs drawn from the same class. The gorilla responded by returning a photograph. If correct, he was reinforced with food. Across three experiments, the gorilla performed significantly above chance at recognizing the target photograph. In experiment 4, the gorilla showed at-chance performance when the event was followed by misinformation (a class-consistent, but incorrect photograph), but significantly above-chance performance when no misinformation occurred (either correct photograph or no photograph). Although the familiarity can account for these data, they are also consistent with an episodic-memory interpretation.     

Mixed-handedness advantages in episodic memory obtained under conditions of intentional learning extend to incidental learning

The existence of handedness differences in the retrieval of episodic memories is well-documented, but virtually all have been obtained under conditions of intentional learning. Two experiments are reported that extend the presence of such handedness differences to memory retrieval under conditions of incidental learning. Experiment 1 used Craik and Tulving’s (1975) classic levels-of-processing paradigm and obtained handedness differences under incidental and intentional conditions of deep processing, but not under conditions of shallow incidental processing. Experiment 2 looked at incidental memory for distracter items from a recognition memory task and again found a mixed-handed advantage. Results are discussed in terms of the relation between interhemispheric interaction, levels of processing, and episodic memory retrieval.     

The effects of sleep on episodic memory in older and younger adults

Evidence on sleep-dependent benefits for episodic memory remains elusive. Furthermore we know little about age-related changes on the effects of sleep on episodic memory. The study we report is the first to compare the effects of sleep on episodic memories in younger and older adults. Memories of stories and personal events were assessed following a retention interval that included sleep and following an equal duration of wakefulness. Both older and younger adults have superior memory following sleep compared to following wakefulness for both types of material. Amount of forgetting of personal events was less during wakefulness in older adults than in younger adults, possibly due to spontaneous rehearsal. Amount of time spent sleeping correlated highly with sleep benefit in older adults, suggesting that quantity of total sleep, and/or time spent in some stages of sleep, are important contributors to age-related differences in memory consolidation or protection from interference during sleep.     

Autonoetic consciousness: Reconsidering the role of episodic memory in future-oriented self-projection

Following the seminal work of Ingvar (1985. “Memory for the future”: An essay on the temporal organization of conscious awareness. Human Neurobiology, 4, 127–136), Suddendorf (1994. The discovery of the fourth dimension: Mental time travel and human evolution. Master's thesis. University of Waikato, Hamilton, New Zealand), and Tulving (1985. Memory and consciousness. Canadian Psychology/PsychologieCanadienne, 26, 1–12), exploration of the ability to anticipate and prepare for future contingencies that cannot be known with certainty has grown into a thriving research enterprise. A fundamental tenet of this line of inquiry is that future-oriented mental time travel, in most of its presentations, is underwritten by a property or an extension of episodic recollection. However, a careful conceptual analysis of exactly how episodic memory functions in this capacity has yet to be undertaken. In this paper I conduct such an analysis. Based on conceptual, phenomenological, and empirical considerations, I conclude that the autonoetic component of episodic memory, not episodic memory per se, is the causally determinative factor enabling an individual to project him or herself into a personal future.     

Category specificity in normal episodic learning: applications to object recognition and category-specific agnosia

Studies of patients with category-specific agnosia (CSA) have given rise to multiple theories of object recognition, most of which assume the existence of a stable, abstract semantic memory system. We applied an episodic view of memory to questions raised by CSA in a series of studies examining normal observers' recall of newly learned attributes of familiar objects. Subjects first learned to associate arbitrarily assigned colors or textures to objects in a training phase, and then attempted to report the newly learned attribute of each object in a recall task. Our subjects' pattern of recall errors was similar both quantitatively and qualitatively to the identification deficits among patients with CSA for biological objects. Furthermore, errors tended to reflect conceptually and structurally based confusions. We suggest that object identification involves recruitment and integration of information across distributed episodic memories and that this process is susceptible to interference from objects that are structurally similar and conceptually related.     

Parallel interactive retrieval of item and associative information from event memory

Memory contains information about individual events (items) and combinations of events (associations). Despite the fundamental importance of this distinction, it remains unclear exactly how these two kinds of information are stored and whether different processes are used to retrieve them. We use both model-independent qualitative properties of response dynamics and quantitative modeling of individuals to address these issues. Item and associative information are not independent and they are retrieved concurrently via interacting processes. During retrieval, matching item and associative information mutually facilitate one another to yield an amplified holistic signal. Modeling of individuals suggests that this kind of facilitation between item and associative retrieval is a ubiquitous feature of human memory.     

Imitative learning by captive western lowland gorillas (Gorilla gorilla gorilla) in a simulated food-processing task

Although field studies have suggested the existence of cultural transmission of foraging techniques in primates, identification of transmission mechanisms has remained elusive. To test experimentally for evidence of imitation in the current study, we exposed gorillas (Gorilla gorilla gorilla) to an artificial fruit foraging task designed by A. Whiten and D. M. Custance (1996). Gorillas (n=6) watched a human model remove a series of 3 defenses around a fruit. Each of the defenses was removed using 1 of 2 alternative techniques. Subsequent video analysis of gorillas' behavior showed a significant tendency to copy the observed technique on 1 of the individual defenses and the direction of removal on another defense. This is the first statistically reliable evidence of imitation in gorillas. Sequence of defense removal was not replicated. The gorillas' responses were most similar to those of chimpanzees.     

Gender differences in episodic memory and visual working memory including the effects of age

Analysing the relationship between gender and memory, and examining the effects of age on the overall memory-related functioning, are the ongoing goals of psychological research. The present study examined gender and age group differences in episodic memory with respect to the type of task. In addition, these subgroup differences were also analysed in visual working memory. A sample of 366 women and 330 men, aged between 16 and 69 years of age, participated in the current study. Results indicate that women outperformed men on auditory memory tasks, whereas male adolescents and older male adults showed higher level performances on visual episodic and visual working memory measures. However, the size of gender-linked effects varied somewhat across age groups. Furthermore, results partly support a declining performance on episodic memory and visual working memory measures with increasing age. Although age-related losses in episodic memory could not be explained by a decreasing verbal and visuospatial ability with age, women's advantage in auditory episodic memory could be explained by their advantage in verbal ability. Men's higher level visual episodic memory performance was found to result from their advantage in visuospatial ability. Finally, possible methodological, biological, and cognitive explanations for the current findings are discussed.     

The role of the episodic buffer in working memory for language processing

A body of work has accumulated to show that the cognitive process of binding information from different mnemonic and sensory sources as well as in different linguistic modalities can be fractionated from general executive functions in working memory both functionally and neurally. This process has been defined in terms of the episodic buffer (Baddeley in Trends Cogn Sci 4(11):417–423, 2000). This paper considers behavioural, neuropsychological and neuroimaging data that elucidate the role of the episodic buffer in language processing. We argue that the episodic buffer seems to be truly multimodal in function and that while formation of unitary multidimensional representations in the episodic buffer seems to engage posterior neural networks, maintenance of such representations is supported by frontal networks. Although, the episodic buffer is not necessarily supported by executive processes and seems to be supported by different neural networks, it may operate in tandem with the central executive during effortful language processing. There is also evidence to suggest engagement of the phonological loop during buffer processing. The hippocampus seems to play a role in formation but not maintenance of representations in the episodic buffer of working memory.     

Configural learning without reinforcement: Integrated memories for correlates of what,where, and when

In 2 experiments we examined the ability of rats to form configural memories of what auditory stimulus (X or Y) was presented where (Context A or B) and when (morning or afternoon). In both experiments, rats received morning presentations of X in Context A and Y in Context B and afternoon presentations of X in B and Y in A. Subsequently, at midday the rats were exposed to trials where X was paired with footshock whereas Y was not. We then assessed the degree of contextual fear in A and B in the morning and the afternoon. In the morning, rats showed more fear in A than in B, and in the afternoon they showed more fear in B than in A. These results indicate that rats can form configural memories that represent what (X or Y) was presented, where (A or B), and when (morning or afternoon).     

The effects of physical activity timing and complexity on episodic memory: A randomized controlled trial

The role of two types of acute physical activity (PA) bouts were assessed on young adults’ free-recall and recognition memory in two experiments, which differed in the temporal relation of PA and word encoding. Before or following training on the Rey Auditory Verbal Learning Task, participants performed a simple two-step dance, a complex four-step dance, or remained seated. Hypotheses proposed that PA prior to encoding and complex PA would enhance PA’s mnemonic benefits. Memory assessed post-PA, 24 h, and 7 days after training indicated that timing and complexity of PA did not impact free-recall or recognition memory. Findings differ from a previous study showing complex PA benefited motor learning more than simple PA (Tomporowski & Pendleton, 2018). The inconsistency may be due to different working memory processes underlying consolidation and retrieval of procedural or episodic information. Theory-based explanations regarding memory storage and retrieval are proposed to elucidate this selective process.     

Working memory deficits in boys with attention deficit/hyperactivity disorder (ADHD): An examination of orthographic coding and episodic buffer processes

The episodic buffer component of working memory was examined in children with attention deficit/hyperactivity disorder (ADHD) and typically developing peers (TD). Thirty-two children (ADHD = 16, TD = 16) completed three versions of a phonological working memory task that varied with regard to stimulus presentation modality (auditory, visual, or dual auditory and visual), as well as a visuospatial task. Children with ADHD experienced the largest magnitude working memory deficits when phonological stimuli were presented via a unimodal, auditory format. Their performance improved during visual and dual modality conditions but remained significantly below the performance of children in the TD group. In contrast, the TD group did not exhibit performance differences between the auditory- and visual-phonological conditions but recalled significantly more stimuli during the dual-phonological condition. Furthermore, relative to TD children, children with ADHD recalled disproportionately fewer phonological stimuli as set sizes increased, regardless of presentation modality. Finally, an examination of working memory components indicated that the largest magnitude between-group difference was associated with the central executive. Collectively, these findings suggest that ADHD-related working memory deficits reflect a combination of impaired central executive and phonological storage/rehearsal processes, as well as an impaired ability to benefit from bound multimodal information processed by the episodic buffer.     

Orangutans (Pongo abelii) and a gorilla (Gorilla gorilla gorilla) match features in familiar and unfamiliar individuals

Great apes can perceive images as representative of corresponding real-life objects. Coupled with the potential advantages of identifying specific members of one’s species and mounting evidence for individual recognition in other non-humans, it seems likely that great apes would have the ability to identify conspecifics in photographs. The ability of four orangutans and a gorilla to match images of individuals of their own and a closely related but unfamiliar species was examined here for the first time. First, the subjects matched photographs of familiar conspecifics taken at various time points in a delayed matching-to-sample procedure (Experiment 1). Second, they matched different photographs of unfamiliar individuals of a different species (Experiment 2) at above chance levels. These results suggest that the subjects matched photographs by matching physical features, not necessarily by recognizing the identity of the individuals depicted. However, they also quickly learned to select photographs of familiar individuals when these photographs were paired with photographs of unfamiliar individuals of their own species (Experiment 3), and three subjects showed transfer to novel images of familiar and unfamiliar individuals. Thus, the findings support the idea that subjects attended to physical features to identify individuals that they could categorize on the basis of familiarity.     

Mother-infant interactions in western Lowland Gorillas (Gorilla gorilla gorilla): spatial relationships,communication, and opportunities for social learning

This study investigated mother-infant interactions in lowland gorillas (Gorilla gorilla gorilla) with particular focus on the relative role of mothers and infants in creating situations that are potentially conducive to infant social learning. Eleven gorilla mother-infant dyads were focally observed in weekly 1-hr sessions for 12 months. Spatial relationships were affected by age as well as by ambient temperature. Although the youngest infant was encouraged by its mother to walk and climb, mothers showed little or no encouragement in other contexts. In contrast, infants were quite interested in their mothers' activities, on some occasions repeated their mother's behavior, and actively encouraged their mothers to share food, play, or follow them. These findings suggest that gorilla infants are more active than their mothers in creating situations that are potentially conducive to the acquisition of knowledge or skills.     

Modifying memory for a museum tour in older adults: Reactivation-related updating that enhances and distorts memory is reduced in ageing

Memory reactivation, the activation of a latent memory trace when we are reminded of a past experience, strengthens memory but can also contribute to distortions if new information present during reactivation is integrated with existing memory. In a previous study in young adults we found that the quality of memory reactivation, manipulated using the principle of encoding specificity and indexed by recollection ratings, modulated subsequent true and false memories for events experienced during a museum tour. Here in this study, we examined age-related changes in the quality of memory reactivation on subsequent memory. Memories of museum stops in young and older adults were reactivated and then immediately followed by the presentation of a novel lure photo from an alternate tour version (i.e., reactivation plus new information). There was an increase in subsequent true memories for reactivated targets and for subsequent false memories for lures that followed reactivated targets, when compared to baseline target and lure photos. However, the influence of reactivation on subsequent memories was reduced in older adults. These data reveal that ageing alters reactivation-related updating processes that allow memories to be strengthened and updated with new information, consequently reducing memory distortions in older adults compared to young adults.     

Coding of stimuli by animals: Retrospection, prospection, episodic memory and future planning

When animals code stimuli for later retrieval they can either code them in terms of the stimulus presented (as a retrospective memory) or in terms of the response or outcome anticipated (as a prospective memory). Although retrospective memory is typically assumed (as in the form of a memory trace), evidence of prospective coding has been found when response intentions and outcomes are particularly salient. At a more abstract level is the question of whether animals are able figuratively to travel back in time to recover memories of past events (episodic memory) and forward in time to predict future events (future planning). Although what would constitute adequate evidence of episodic memory and future planning is controversial, preliminary evidence suggests that animals may be capable of both forms of subjective time travel.     

Effects of saccadic bilateral eye movements on memory in children and adults: an exploratory study

The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30s of bilateral vs. vertical vs. no eye movements. For studied information, the results for adults replicated previous work; bilateral eye movements were demonstrated to increase the accuracy of memory by increasing the hit rate and reducing the false alarm rate for related and unrelated recognition test lures. The results for children also indicated an improvement in memory accuracy, and like adults, was due to both an increase in the hit rate and a reduction in the false alarm rate. In spite of these similarities, the effects of bilateral eye movements differed between adults and children for critical unstudied words; i.e., those associated with the theme of the list. Only in adults did, bilateral eye movements reduce associative false memories; children did not show a reduction in false memory for critical associates. This produced a dissociation between the effects of eye movements on associative false memory as a function of age. The results are discussed from a developmental perspective in terms of potential mechanisms underlying true and false memory.     

The relationship between theory of mind and episodic memory: evidence for the development of autonoetic consciousness

The study investigated a link between theory of mind and episodic memory involving autonoetic consciousness (). Eighty-nine Japanese 4- to 6-year-olds received two versions of a false belief task, a task of aspectuality or knowledge origins, and four memory tests. After controlling for age, most theory of mind abilities showed no interrelations, and own and other's belief understandings in deceptive appearance tasks were solely related to source memory, but not to free recall, temporal ordering, or working memory. Moreover, even when age and verbal intelligence were controlled, the association between representational change and source memory was highly significant in 6-year-olds but not in 4- and 5-year-olds. Results suggest that during development only a particular kind of theory of mind ability is integrated with episodic memory.     

Age invariance in semantic and episodic metamemory: Both younger and older adults provide accurate feeling-of-knowing for names of faces

Age differences in feeling-of-knowing (FOK) accuracy were examined for both episodic memory and semantic memory. Younger and older adults either viewed pictures of famous faces (semantic memory) or associated non-famous faces and names (episodic memory) and were tested on their memory for the name of the presented face. Participants viewed the faces again and made a FOK prediction about future recognition of the name associated with the presented face. Finally, four-alternative forced-choice recognition memory for the name, cued by the face, was tested and confidence judgments (CJs) were collected for each recognition response. Age differences were not obtained in semantic memory or the resolution of semantic FOKs, defined by within-person correlations of FOKs with recognition memory performance. Although age differences were obtained in level of episodic memory, there were no age differences in the resolution of episodic FOKs. FOKs for correctly recognized items correlated reliably with CJs for both types of materials, and did not differ by age group. The results indicate age invariance in monitoring of retrieval processes for name–face associations.