Scott A. Guerin

Memory distortion: an adaptive perspective

Memory is prone to distortions that can have serious consequences in everyday life. Here we integrate emerging evidence that several types of memory distortions - imagination inflation, gist-based and associative memory errors, and post-event misinformation - reflect adaptive cognitive processes that contribute to the efficient functioning of memory, but produce distortions as a consequence of doing so. We consider recent cognitive and neuroimaging studies that link these distortions with adaptive processes, including simulation of future events, semantic and contextual encoding, creativity, and memory updating. We also discuss new evidence concerning factors that can influence the occurrence of memory distortions, such as sleep and retrieval conditions, as well as conceptual issues related to the development of an adaptive perspective.

Theory of mind broad and narrow: Reasoning about social exchange engages ToM areas, precautionary reasoning does not

Abstract Baron-Cohen (1995) proposed that the theory of mind (ToM) inference system evolved to promote strategic social interaction. Social exchange—a form of co-operation for mutual benefit—involves strategic social interaction and requires ToM inferences about the contents of other individuals’ mental states, especially their desires, goals, and intentions. There are behavioral and neuropsychological dissociations between reasoning about social exchange and reasoning about equivalent problems tapping other, more general content domains. It has therefore been proposed that social exchange behavior is regulated by social contract algorithms: a domain-specific inference system that is functionally specialized for reasoning about social exchange. We report an fMRI study using the Wason selection task that provides further support for this hypothesis. Precautionary rules share so many properties with social exchange rules—they are conditional, deontic, and involve subjective utilities—that most reasoning theories claim they are processed by the same neurocomputational machinery. Nevertheless, neuroimaging shows that reasoning about social exchange activates brain areas not activated by reasoning about precautionary rules, and vice versa. As predicted, neural correlates of ToM (anterior and posterior temporal cortex) were activated when subjects interpreted social exchange rules, but not precautionary rules (where ToM inferences are unnecessary). We argue that the interaction between ToM and social contract algorithms can be reciprocal: social contract algorithms requires ToM inferences, but their functional logic also allows ToM inferences to be made. By considering interactions between ToM in the narrower sense (belief–desire reasoning) and all the social inference systems that create the logic of human social interaction—ones that enable as well as use inferences about the content of mental states—a broader conception of ToM may emerge: a computational model embodying a Theory of Human Nature (ToHN).

Modulation of neural activity by angle of rotation during imagined spatial transformations

Imagined spatial transformations of objects (e.g., mental rotation) and the self (e.g., perspective taking) are psychologically dissociable. In mental rotation, the viewer transforms the location or orientation of an object relative to stable egocentric and environmental reference frames. In imagined shifts of perspective, the viewers egocentric reference frame is transformed with respect to stable objects and environment. Using fMRI, we showed that during mental transformations of objects the right superior parietal cortex exhibited a positive linear relationship between hemodynamic response and degrees of rotation. By contrast, during imagined transformations of the self, the same regions exhibited a negative linear trend. We interpret this finding in terms of the role of parietal cortex in coding the locations of objects in relation to the body.

Lateralization of the parietal old/new effect: An event-related fMRI study comparing recognition memory for words and faces

Although the parietal cortex is not conventionally thought of as a major component of the neural systems that mediate declarative memory, many fMRI studies of recognition memory have found that correctly identified old items produce greater activation than correctly rejected new items throughout parietal cortex. This effect is usually heavily lateralized to the left. However, the vast majority of previous studies have used verbal materials. Does the left-lateralization of this effect result from the left hemispheres role in language or does it suggest the possibility of a specialized role for the left hemisphere in recognition memory that applies across stimulus domains? To address this question, we directly compared recognition memory for words and faces in two event-related fMRI experiments with a total of 38 subjects. In the second experiment, we included a manipulation of recognition difficulty. Despite extensive material-specific lateralization in terms of the brains overall response to stimuli revealed by a direct comparison of words and faces, the parietal old/new effect did not exhibit material-specific lateralization. Rather, the lateralization of the effect depended on the region of parietal cortex in question. In lateral parietal cortex, the effect was left-lateralized. In medial parietal cortex, the effect was bilateral. These findings indicate that the left-lateralization of the parietal old/new effect is unrelated to the left hemispheres role in language and raises the possibility of a specialized role for the left hemisphere in recognition memory.

Interactions between Visual Attention and Episodic Retrieval: Dissociable Contributions of Parietal Regions during Gist-Based False Recognition

The interaction between episodic retrieval and visual attention is relatively unexplored. Given that systems mediating attention and episodic memory appear to be segregated, and perhaps even in competition, it is unclear how visual attention is recruited during episodic retrieval. We investigated the recruitment of visual attention during the suppression of gist-based false recognition, the tendency to falsely recognize items that are similar to previously encountered items. Recruitment of visual attention was associated with activity in the dorsal attention network. The inferior parietal lobule, often implicated in episodic retrieval, tracked veridical retrieval of perceptual detail and showed reduced activity during the engagement of visual attention, consistent with a competitive relationship with the dorsal attention network. These findings suggest that the contribution of the parietal cortex to interactions between visual attention and episodic retrieval entails distinct systems that contribute to different components of the task while also suppressing each other.

The Strategic Nature of False Recognition in the DRM Paradigm

The false memory effect produced by the Deese/Roediger & McDermott (DRM) paradigm is reportedly impervious to warnings to avoid false alarming to the critical lures (D. A. Gallo, H. L. Roediger III, & K. B. McDermott, 2001). This finding has been used as strong evidence against models that attribute the false alarms to a decision process (e.g., M. B. Miller & G. L. Wolford, 1999). In this report, the authors clarify their earlier article and suggest that subjects establish only 2 underlying criteria for a recognition judgment, a liberal criterion for items that seem to be related to 1 of the study list themes and a conservative criterion for items that do not seem to be related. They demonstrate that warnings designed on the basis of these underlying criteria are effective in significantly suppressing the false recognition effect, suggesting that strategic control of the retrieval response does play a role in the DRM paradigm.

Semantic organization of study materials has opposite effects on recognition and recall

It has been well established for several decades that semantic organization of study materials greatly enhances recall by facilitating access to information during retrieval. However, the effect of organization on recognition, and its relationship to the effect on recall, is in doubt. We report the first direct comparison of the effects of categorically organizing study lists on recognition, cued recall, and free recall. We found that whereas organization improved recall, it impaired recognition. Organization had a larger effect on free recall than on cued recall. Within the categorized lists, recall was superior for items highly associated with the category; the opposite was true of recognition. In recall, organization improved the proportion of categories recalled, but it lowered the proportion of items per category recalled. A simple framework for interpreting the dissociation is offered. Possible mechanisms underlying the detrimental effect of organization on memory and prospects for future research are briefly discussed.

Accurate expectancies diminish perceptual distraction during visual search

The load theory of visual attention proposes that efficient selective perceptual processing of task-relevant information during search is determined automatically by the perceptual demands of the display. If the perceptual demands required to process task-relevant information are not enough to consume all available capacity, then the remaining capacity automatically and exhaustively “spills-over” to task-irrelevant information. The spill-over of perceptual processing capacity increases the likelihood that task-irrelevant information will impair performance. In two visual search experiments, we tested the automaticity of the allocation of perceptual processing resources by measuring the extent to which the processing of task-irrelevant distracting stimuli was modulated by both perceptual load and top-down expectations using behavior, functional magnetic resonance imaging, and electrophysiology. Expectations were generated using a trial-by-trial cue that provided information about the likely load of the upcoming visual search task. When the cues were valid, behavioral interference was eliminated and the influence of load on frontoparietal and visual cortical responses was attenuated relative to when the cues were invalid. In conditions in which task-irrelevant information interfered with performance and modulated visual activity, individual differences in mean blood oxygenation level dependent responses measured from the left intraparietal sulcus were negatively correlated with individual differences in the severity of distraction. These results are consistent with the interpretation that a top-down biasing mechanism interacts with perceptual load to support filtering of task-irrelevant information.

Decoding the temporal structure of perception and reflection.

Perception has a clear temporal structure: each stimulus is preceded and followed by other stimuli. However, we may think about recently encountered stimuli in a temporal order that deviates from the perceptual input. How does the brain generate and maintain distinct representations of temporal structure associated with perception and reflection? In this experiment, we constructed a task that dissociates the temporal structure of perception and reflection. Participants viewed one face and one scene (2 s each) in one of two sequences: Face-Scene or Scene-Face. Following perception, participants were cued to direct their internal attention towards one then the other of the just-seen stimuli (refreshing, Johnson et al., 2005). Participants were instructed to imagine the picture as vividly as possible and answer a question about it (Male/Female or Indoor/Outdoor). Each refresh period lasted 2 s. On half the trials, participants refreshed the pictures in the same order they were perceived. On the other half of trials, participants refreshed the pictures in the reverse order. We applied multi-voxel pattern analysis to decode the temporal structure of perception and reflection. Based on an initial analysis of 12 participants, and consistent with our previous findings, we were able to decode the temporal structure of perception above chance in occipital, ventral temporal, and parietal cortices (all p < .001), with a trend in prefrontal cortex (p = .06). Critically, we were also able to decode the temporal structure of reflection in occipital, ventral temporal, parietal (all p < .01), and prefrontal cortices (p < .05). Consistent with previous studies indicating that perception and reflection share overlapping visual representations, our results indicate that perception and reflection share common neural machinery for the representation of temporal structure. Meeting abstract presented at VSS 2015.