Evidence for a Weak but Reliable Processing Advantage for False Beliefs Over Similar Nonmental States in Adults.

The ability to understand the mental states of others has sometimes been attributed to a domain-specific mechanism which privileges the processing of these states over similar but nonmental representations. If correct, then others' beliefs should be processed more efficiently than similar information contained within nonmental states. We tested this by examining whether adults would be faster to process others' false beliefs than equivalent "false" photos. Additionally, we tested whether they would be faster to process others' true beliefs about something than their own (matched) personal knowledge about the same event. Across four experiments, we found a small but reliable effect in favor of the first prediction, but no evidence for the second. Results are consistent with accounts positing specialized processes for (false) mental states. The size of the effect does, however, suggest that alternative explanations such as practice effects cannot be ruled out.

Teleporting into walls? The irrelevance of the physical world in embodied perspective-taking.

Embodied theories of Level 2 visual perspective-taking usually assume that we imagine ourselves in other real-world locations to take perspectives. We tested this assertion by giving participants an embodied perspective-taking task in which they were instructed to make manual responses based on imagined perspectives. Importantly, on half of the trials, the location of the alternative perspective was not physically possible (i.e., blocked with a wall). Across two experiments, results showed that participants performed just as well for the physically impossible perspectives as for accessible ones. We interpret these data as evidence that embodied perspective-taking is agnostic to local physical features of our environment.

It's Not You, It's Me: A Review of Individual Differences in Visuospatial Perspective Taking.

Visuospatial perspective taking (VSPT) concerns the ability to understand something about the visual relationship between an agent or observation point on the one hand and a target or scene on the other. Despite its importance to a wide variety of other abilities, from communication to navigation, and decades of research, there is as yet no theory of VSPT. Indeed, the heterogeneity of results from different (and sometimes the same) VSPT tasks point to a complex picture suggestive of multiple VSPT strategies, individual differences in performance, and context-specific factors that together have a bearing on both the efficiency and accuracy of outcomes. In this article, we review the evidence in search of patterns in the data. We found a number of predictors of VSPT performance but also a number of gaps in understanding that suggest useful pathways for future research and, possibly, a theory (or theories) of VSPT. Overall, this review makes the case for understanding VSPT by better understanding the perspective taker rather than the target agents or their perception.

A return of mental imagery: The pictorial theory of visual perspective-taking.

The pictorial theory of mental imagery was a central concern of cognitive science during the latter years of the last century. Proponents of the theory argued that images are reinterpreted by the same processes that act upon perceptual inputs. This idea has recently re-emerged within the context of visual perspective-taking. The perceptual simulation theory argues that an observer not only generates an image of what another individual sees but the image is used by the perceptual system in a bottom-up manner. Based on the assumption of Kosslyn and colleagues, we argue that a minimum requirement of a pictorial theory of visual perspective-taking is that observers must faithfully represent relative distance between different points of a scene as would be viewed from an alternative position. The available evidence does not however support this. We conclude that the latest attempt to give mental imagery causal status in a cognitive process is unwarranted.

Visual perspective taking without visual perspective taking.

What happens when an observer takes an agent's visual perspective of a scene? We conducted a series of experiments designed to measure what proportion of adults take a stimulus-centered rather than agent-centered approach to a visual perspective taking task. Adults were presented with images of an agent looking at a number (69). From the perspective of the viewer, the number appeared upside down. We then asked participants what number the agent saw. An agent-centered approach, that is, one that takes into account the other's visual experience, should produce the correct answer "69". Even an egocentric error (i.e., the participant's own perspective) would provide the same correct response. We were interested in what proportion of participants would give the incorrect answer "96", which is best explained by a stimulus-centered rather than agent-centered strategy, namely "flipping" each digit one at a time from left to right. Crucially, such a strategy ignores the alternative visual perspective. We found that, on average, 12-21% of participants made this error. We discuss this finding in the context of the key questions around representation, content, and Theory of Mind in visual perspective taking. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

'Seeing' proximal representations: Testing attitudes to the relationship between vision and images.

Corrections applied by the visual system, like size constancy, provide us with a coherent and stable perspective from ever-changing retinal images. In the present experiment we investigated how willing adults are to examine their own vision as if it were an uncorrected 2D image, much like a photograph. We showed adult participants two lines on a wall, both of which were the same length but one was closer to the participant and hence appeared visually longer. Despite the instruction to base their judgements on appearance specifically, approximately half of the participants judged the lines to appear the same. When they took a photo of the lines and were asked how long they appeared in the image their responses shifted; now the closer line appeared longer. However, when they were asked again about their own view they reverted to their original response. These results suggest that many adults are resistant to imagining their own vision as if it were a flat image. We also place these results within the context of recent views on visual perspective-taking.

Perirhinal cortex and the recognition of relative familiarity.

Spontaneous object recognition (SOR) is a widely used task of recognition memory in rodents which relies on their propensity to explore novel (or relatively novel) objects. Network models typically define perirhinal cortex as a region required for recognition of previously seen objects largely based on findings that lesions or inactivations of this area produce SOR deficits. However, relatively little is understood about the relationship between the activity of cells in the perirhinal cortex that signal novelty and familiarity and the behavioural responses of animals in the SOR task. Previous studies have used objects that are either highly familiar or absolutely novel, but everyday memory is for objects that sit on a spectrum of familiarity which includes objects that have been seen only a few times, or objects that are similar to objects which have been previously experienced. We present two studies that explore cellular activity (through c-fos imaging) within perirhinal cortex of rats performing SOR where the familiarity of objects has been manipulated. Despite robust recognition memory performance, we show no significant changes in perirhinal activity related to the level of familiarity of the objects. Reasons for this lack of familiarity-related modulation in perirhinal cortex activity are discussed. The current findings support emerging evidence that perirhinal responses to novelty are complex and that task demands are critical to the involvement of perirhinal cortex in the control of object recognition memory.

Visual perspective-taking and image-like representations: We don't see it.

The ability to represent another agent's visual perspective has recently been attributed to a process called "perceptual simulation", whereby we generate an image-like or "quasi-perceptual" representation of another agent's vision. In an extensive series of experiments we tested this notion. Adult observers were presented with pictures of an agent looking at two horizontal lines, one of which was closer to the agent and hence appeared longer from his/her visual perspective. In each case approximately as many participants judged the closer line to appear shorter as longer (to the agent), i.e., failures to take the agent's perspective. This occurred when clear depth cues were added to emphasise the agent's location relative to the stimuli, when the agent was moved closer to the lines, when the lines were oriented vertically, when judgments could be made while viewing the image, and when participants imagined themselves in the agent's place. It also persisted when we asked participants to imagine what a photo taken from the same location as the agent would show, ruling out a misinterpretation of the instructions. Overall, our data suggest that adults attempt to solve visual perspective-taking problems by drawing upon naïve and often erroneous ideas about how vision works.

Impaired episodic simulation in a patient with visual memory deficit amnesia.

For the first time, we assess episodic simulation in a patient with visual memory deficit amnesia, following damage to visual association cortices. Compared to control participants, the patient with visual memory deficit amnesia shows severely restricted responses when asked to simulate different types of future episodic scenarios. Surprisingly, the patient's responses are more limited in cases where the scenarios require less reliance on visual information. We explain this counterintuitive finding through discussing how the severe retrograde amnesia in visual memory deficit amnesia limits the patient's access to episodic memories in which vision has not been a focus of their life. As a result, we argue that the deficits in visual memory deficit amnesia continue to distinguish it from amnesia after direct damage to the hippocampus.

Two independent sources of difficulty in perspective-taking/theory of mind tasks.

Many perspective-taking and theory of mind tasks require participants to pass over the answer that is optimal from the self-perspective. For instance, in the classic change-of-location (false belief) task, participants are required to ignore where they know the object to be, and in the director task participants are required to ignore the best match for the instruction the other, less knowledgeable agent gives them (e.g., 'the top cup'). However, a second but equally critical requirement in such tasks is the ability to select a response which is wrong from the self-perspective; where the object is not, or an object that does not match the instruction (e.g., the middle cup instead of the top cup from one's own perspective). We present the results of an experiment that teases apart these two effects and demonstrate that both contribute independently to the difficulty in taking other perspectives. Reanalyses of data from previous experiments confirm this dual effect. These results suggest a revision of our understanding of egocentricity and difficulty in perspective-taking generally.

Perspective-Taking: In Search of a Theory.

Perspective-taking has been one of the central concerns of work on social attention and developmental psychology for the past 60 years. Despite its prominence, there is no formal description of what it means to represent another's viewpoint. The present article argues that such a description is now required in the form of theory-a theory that should address a number of issues that are central to the notion of assuming another's viewpoint. After suggesting that the mental imagery debate provides a good framework for understanding some of the issues and problems surrounding perspective-taking, we set out nine points that we believe any theory of perspective-taking should consider.

Grammatical gender and linguistic relativity: A systematic review.

Many languages assign nouns to a grammatical gender class, such that "bed" might be assigned masculine gender in one language (e.g., Italian) but feminine gender in another (e.g., Spanish). In the context of research assessing the potential for language to influence thought (the linguistic relativity hypothesis), a number of scholars have investigated whether grammatical gender assignment "rubs off" on concepts themselves, such that Italian speakers might conceptualize beds as more masculine than Spanish speakers do. We systematically reviewed 43 pieces of empirical research examining grammatical gender and thought, which together tested 5,895 participants. We classified the findings in terms of their support for this hypothesis and assessed the results against parameters previously identified as potentially influencing outcomes. Overall, we found that support was strongly task- and context-dependent, and rested heavily on outcomes that have clear and equally viable alternative explanations. We also argue that it remains unclear whether grammatical gender is in fact a useful tool for investigating relativity.

The NMDA receptor antagonist MK-801 fails to impair long-term recognition memory in mice when the state-dependency of memory is controlled.

NMDA receptor-dependent synaptic plasticity has been proposed to be important for encoding of memories. Consistent with this hypothesis, the non-competitive NMDA receptor antagonist, MK-801, has been found to impair performance on tests of memory. Interpretation of some of these findings has, however, been complicated by the fact that the drug-state of animals has differed during encoding and tests of memory. Therefore, it is possible that MK-801 may result in state-dependent retrieval or expression of memory rather than actually impairing encoding itself. We tested this hypothesis in mice using tests of object recognition memory with a 24-hour delay between the encoding and test phase. Mice received injections of either vehicle or MK-801 prior to the encoding phase and the test phase. In Experiment 1, a low dose of MK-801 (0.01 mg/kg) impaired performance when the drug-state (vehicle or MK-801) of mice changed between encoding and test, but there was no significant effect of MK-801 on encoding. In Experiment 2, a higher dose of MK-801 (0.1 mg/kg) failed to impair object recognition memory when mice received the drug prior to both encoding and test compared to mice that received vehicle. MK-801 did not affect object exploration, but it did induce locomotor hyperactivity at the higher dose. These results suggest that some previous demonstrations of MK-801 effects may reflect a failure to express or retrieve memory due to the state-dependency of memory rather than impaired encoding of memory.

Walking through doorways differentially affects recall and familiarity.

Previous research has reported that walking through a doorway to a new location makes memory for objects and events experienced in the previous location less accurate. This effect, termed the location updating effect, has been used to suggest that location changes are used to mark boundaries between events in memory: memories for objects encountered within the current event are more available than those from beyond an event boundary. Within a computer-generated memory task, participants navigated through virtual rooms, walking through doorways, and interacting with objects. The accuracy and their subjective experience of their memory for the objects (remember/know and confidence) were assessed. The findings showed that shifts in location decreased accurate responses associated with the subjective experience of remembering but not those associated with the experience of knowing, even when considering only the most confident responses in each condition. These findings demonstrate that a shift in location selectively impacts recollection and so contributes to our understanding of boundaries in event memory.

Continual Trials Spontaneous Recognition Tasks in Mice: Reducing Animal Numbers and Improving Our Understanding of the Mechanisms Underlying Memory.

Spontaneous recognition tasks are widely used as a laboratory measure of memory in animals but give rise to high levels of behavioral noise leading to a lack of reliability. Previous work has shown that a modification of the procedure to allow continual trials testing (in which many trials are run concurrently in a single session) decreases behavioral noise and thus significantly reduces the numbers of rats required to retain statistical power. Here, we demonstrate for the first time that this improved method of testing extends to mice, increasing the overall power of the approach. Moreover, our results show that the new continual trials approach provides the additional benefits of heightened sensitivity and thus provides greater insight into the mechanisms at play. Standard (c57) and transgenic Alzheimer model (TASTPM) mice were tested both at 7 and 10 months of age in both object recognition (OR) and object-location (OL) spontaneous recognition tasks using the continual trials methodology. Both c57 and TASTPM mice showed age-dependent changes in performance in OR. While c57 mice also showed age-related changes in performance of OL, TASTPM mice were unable to perform OL at either age. Significantly, we demonstrate that differences in OL performance in c57s and TASTPM animals is a result of proactive interference rather than an absolute inability to recognize OL combinations. We argue that these continual trials approaches provide overall improved reliability and better interpretation of the memory ability of mice, as well as providing a significant reduction in overall animal use.

Incidental context information increases recollection.

The current study describes a receiver-operating characteristic (ROC) task for human participants based on the spontaneous recognition memory paradigms typically used with rodents. Recollection was significantly higher when an object was in the same location and background as at encoding, a combination used to assess episodic-like memory in animals, but not when only one of these task-irrelevant cues was present. The results show that incidentally encoded cue information can determine the degree of recollection, and opens up the possibility of assessing recollection across species in a single experimental paradigm, allowing better understanding of the cognitive and biological mechanisms at play.

Self-referential memory in autism spectrum disorder and typical development: Exploring the ownership effect.

Owned objects occupy a privileged cognitive processing status and are viewed almost as extensions of the self. It has been demonstrated that items over which a sense of ownership is felt will be better remembered than other items (an example of the "self-reference effect"). As autism spectrum disorder (ASD) is characterised by an a typical self-concept, people with ASD may not demonstrate this "ownership effect". Two experiments were conducted which replicate and extend Cunningham, Turk, MacDonald, and Macrae (2008). In Experiment 1, neurotypical adults completed a card sorting task and cards belonging to the 'self' were better remembered than cards belonging to another person. In Experiment 2, adults with ASD recalled self- and other owned items equally well. These results shed light both on the relation between sense of self and the ownership effect, and the nature of the self-concept in ASD.

Episodic-like memory is sensitive to both Alzheimer's-like pathological accumulation and normal ageing processes in mice.

Episodic memory depends on the hippocampus and is sensitive to both Alzheimer's disease (AD) pathology and normal ageing. We showed previously that 3xTgAD mice express a specific, episodic-memory deficit at 6 months of age in the What-Where-Which occasion (WWWhich) task (Davis, Easton, Eacott and Gigg, 2013). This task requires the integration of object-location and contextual cues to form an episodic-like memory. Here, we explore the cumulative effect of AD pathology on WWWhich memory by testing very young and middle-aged mice (3 and 12 months old, respectively). For comparison, we included an alternative episodic-like task (What-Where-When; WWWhen) and an object temporal order (Recency) task to explore claims that WWWhen types of memory are open to non-episodic solutions. We found that in contrast to their performance at 6 months, 3-month-old 3xTgAD mice formed WWWhich episodic-like memories; however, their performance at this age was poorer than in matched controls. In contrast, 3xTgAD and control animals aged 12 months were both impaired on the WWWhich task. Finally, 3xTgAD mice with a WWWhich deficit were unimpaired in both Recency and WWWhen tasks. These results support conclusions that: (1) young 3xTgAD mice express episodic-like memory, albeit depressed relative to controls; (2) age-related changes result in a deficit on the hippocampal-dependent WWWhich episodic memory task; and (3) control and 3xTgAD mice can use recency (trace strength) rather than episodic-like memory for tasks that contain a temporal 'When' component. These results, in combination with our previous findings, support an age-related decline in WWWhich episodic-like memory in mice. Furthermore, this decline is accelerated in the 3xTgAD model.

Episodic-like memory for what-where-which occasion is selectively impaired in the 3xTgAD mouse model of Alzheimer's disease.

Episodic memory loss is a defining feature of early-stage Alzheimer's disease (AD). A test of episodic-like memory for the rat, the What-Where-Which occasion task (WWWhich), requires the association of object, location, and contextual information to form an integrated memory for an event. The WWWhich task cannot be solved by use of non-episodic information such as object familiarity and is dependent on hippocampal integrity. Thus, it provides an ideal tool with which to test capacity for episodic-like memory in the 3xTg murine model for AD. As this model captures much of the human AD phenotype, we hypothesized that these mice would show a deficit in the WWWhich episodic-like memory task. To test the specificity of any episodic-like deficit, we also examined whether mice could perform components of the WWWhich task that do not require episodic-like memory. These included object (Novel Object Recognition), location (Object Location Task, What-Where task), and contextual (What-Which) memory, as well as another three-component task that can be solved without reliance on episodic recall (What-Where-When; WWWhen). The results demonstrate for the first time that control 129sv/c57bl6 mice could form WWWhich episodic-like memories, whereas, 3xTgAD mice at 6 months of age were impaired. Importantly, while 3xTgAD mice showed some deficit on spatial component tasks, they were unimpaired in the more complex WWWhen combination task (which includes a spatial component and is open to non-episodic solutions). These results strongly suggest that AD pathology centered on the hippocampal formation mediates a specific deficit for WWWhich episodic-like memory in the 3xTgAD model.

Cholinergic mechanisms of episodic memory: what specific behavioural tasks can tell us about specific neural mechanisms.

Understanding the neural basis of episodic memory is crucial for understanding how to treat memory loss in normal ageing as well as in disorders such as Alzheimer's disease. However, it is only recently that episodic memory has been able to be reliably modelled in animals allowing the biological basis to be fully explored. Here we review studies on the role of the cholinergic basal forebrain on episodic memory, and highlight differences in findings from studies in monkeys and rats. The results highlight the importance of choosing appropriate behavioural models of cognitive processes in order to understand the neural basis of the processes accurately.