Diego Fernandez-Duque

Attentional Networks in Normal Aging and Alzheimer's Disease

By combining a flanker task and a cuing task into a single paradigm, the authors assessed the effects of orienting and alerting on conflict resolution and explored how normal aging and Alzheimers disease (AD) modulate these attentional functions. Orienting failed to enhance conflict resolution; alerting was most beneficial for trials without conflict, as if acting on response criterion rather than on information processing. Alerting cues were most effective in the older groups--healthy aging and AD. Conflict resolution was impaired only in AD. Orienting remained unchanged across groups. These findings provide evidence of different life span developmental and clinical trajectories for each attentional network.

Impaired recognition of negative facial emotions in patients with frontotemporal dementia

Patients with behavioral variant of frontotemporal dementia (FTD) have difficulties recognizing facial emotions, a deficit that may contribute to their impaired social skills. In three experiments, we investigated the FTD deficit in recognition of facial emotions, by comparing six patients with impaired social conduct, nine Alzheimers patients, and 10 age-matched healthy adults. Experiment 1 revealed that FTD patients were impaired in the recognition of negative facial emotions. Experiment 2 replicated these findings when participants had to determine whether two faces were expressing the same or different emotions. Experiment 3 was a control study in which participants had to discriminate whether two faces were of the same sex. In this non-emotional processing task, both patient groups performed worse than normal participants, but FTD patients performed as well as Alzheimers patients. We conclude that FTD patients are impaired in the recognition of negative facial emotions.

Cognitive Control : Dynamic, Sustained, and Voluntary Influences

The cost of incongruent stimuli is reduced when conflict is expected. This series of experiments tested whether this improved performance is due to repetition priming or to enhanced cognitive control. Using a paradigm in which Word and Number Stroop alternated every trial, Experiment 1 assessed dynamic trial-to-trial changes. Incongruent trials led to task-specific reduction of conflict (trial n + 2) without cross-task modulation (trial n + 1), but this was fully explained by repetition priming. In contrast, an increased ratio of incongruent words did lead to sustained task-specific enhancement, above and beyond repetition priming (Experiment 2). Experiments 3 and 4 assessed the voluntary modulation of cognitive control: A cue predicted the congruency of the incoming trial, allowing participants to establish the correct mindset (Word Stroop in Experiment 3, Flanker task in Experiment 4). Preparing oneself to process an incongruent word (or flanker) enhanced conflict resolution in the subsequent Number Stroop, an example of cross-task modulation. Taken together, these experiments reveal the multifaceted aspects of conflict resolution: Trial-to-trial changes are often due to repetition priming; sustained modulations brought about by task demands are task specific; and voluntary modulations are task general.

False-belief understanding in frontotemporal dementia and Alzheimer's disease

The ability to understand other peoples behavior in terms of mental states, such as beliefs, desires, and intentions, is central to social interaction. It has been argued that the interpersonal problems of patients with behavioral variant of frontotemporal dementia (FTD-b) are due to a dysfunction of that system. We used first- and second-order false-belief tasks to assess theory-of-mind reasoning in a group of patients with FTD-b and a cognitively matched group of patients with Alzheimers disease (AD). Both patient groups were equally impaired relative to a healthy elderly group in the cognitively demanding second-order false-belief tasks, revealing that cognitive demands are an important factor in false-belief task performance. Both patient groups reached ceiling performance in the first-order false-belief tasks with minimal cognitive demands, despite the striking difference in their social graces. These results suggest that a conceptual deficit in theory of mind—as measured by the false-belief task—is not at the core of the differences between FTD-b and AD.

Superfluous neuroscience information makes explanations of psychological phenomena more appealing

Does the presence of irrelevant neuroscience information make explanations of psychological phenomena more appealing? Do fMRI pictures further increase that allure? To help answer these questions, 385 college students in four experiments read brief descriptions of psychological phenomena, each one accompanied by an explanation of varying quality (good vs. circular) and followed by superfluous information of various types. Ancillary measures assessed participants analytical thinking, beliefs on dualism and free will, and admiration for different sciences. In Experiment 1, superfluous neuroscience information increased the judged quality of the argument for both good and bad explanations, whereas accompanying fMRI pictures had no impact above and beyond the neuroscience text, suggesting a bias that is conceptual rather than pictorial. Superfluous neuroscience information was more alluring than social science information (Experiment 2) and more alluring than information from prestigious “hard sciences” (Experiments 3 and 4). Analytical thinking did not protect against the neuroscience bias, nor did a belief in dualism or free will. We conclude that the “allure of neuroscience” bias is conceptual, specific to neuroscience, and not easily accounted for by the prestige of the discipline. It may stem from the lay belief that the brain is the best explanans for mental phenomena.

Empathy in frontotemporal dementia and Alzheimer's disease

Using naturalistic stimuli, we assessed the ability to infer what other people are feeling in three groups of participants: healthy elderly adults, patients suffering from the behavioral variant of frontotemporal dementia (FTD-b), and patients suffering from Alzheimers disease (AD). After watching videotaped interviews of everyday people (nonactors) discussing an emotionally relevant event in their lives, participants answered questions regarding the interviewees feelings. Both patient groups inferred emotions as accurately as the healthy elderly, provided the emotions were displayed unambiguously and consistently across the interview. However, when the displayed emotions became more variable and ambiguous, performance in both patient groups became impaired relative to healthy elderly participants. The similar profile across the two clinical groups despite their differences in social skills suggests that nonsocial cognitive processes affected in dementia may be an important factor in drawing inferences about other peoples feelings.

Selective attention in early Dementia of Alzheimer Type.

This study explored possible deficits in selective attention brought about by Dementia of Alzheimer Type (DAT). In three experiments, we tested patients with early DAT, healthy elderly, and young adults under low memory demands to assess perceptual filtering, conflict resolution, and set switching abilities. We found no evidence of impaired perceptual filtering nor evidence of impaired conflict resolution in early DAT. In contrast, early DAT patients did exhibit a global cost in set switching consistent with an inability to maintain the goals of the task (mental set). We discuss these findings in relation to the DAT literature on executive attention, dual-tasking, and working memory.

Common Sense Beliefs about the Central Self, Moral Character, and the Brain

To assess lay beliefs about self and brain, we probed peoples opinions about the central self, in relation to morality, willful control, and brain relevance. In study 1, 172 participants compared the central self to the peripheral self. The central self, construed at this abstract level, was seen as more brain-based than the peripheral self, less changeable through willful control, and yet more indicative of moral character. In study 2, 210 participants described 18 specific personality traits on 6 dimensions: centrality to self, moral relevance, willful control, brain dependence, temporal stability, and desirability. Consistent with Study 1, centrality to the self, construed at this more concrete level, was positively correlated to brain dependence. Centrality to the self was also correlated to desirability and temporal stability, but not to morality or willful control. We discuss differences and similarities between abstract (Study 1) and concrete (Study 2) levels of construal of the central self, and conclude that in contemporary American society people readily embrace the brain as the underlying substrate of who they truly are.

Lay Theories of the Mind/Brain Relationship and the Allure of Neuroscience

Psychology is in the midst of a neuroscience revolution, with attributes deemed uniquely human—language, free will, moral responsibility, a notion of self—no longer exempt from material exploration. It is anybody’s guess whether this neuroscience endeavor to explain the human mind will succeed. In the meantime, what does seem clear is that neuroscience is everywhere these days, and that people—both expert and ordinary folk—are intrigued by its role in explaining the mind. Why is neuroscience so alluring? To ask this question is to ask about current lay theories of the mind/brain relation. To approximate an answer, I start by describing the allure of neuroscience (brain) explanations for psychological (mind) phenomena. Is the allure due to neuroscience’s status as a ‘real’ science? Or is it due to its reductive appeal? Next, I review the effect of neuroscience on judgments of responsibility and free will. Do ordinary folk shy away from free will and moral condemnation when actions are couched in terms of brain function? The next stop on our tour of uniquely human capacities is the notion of the self. Do ordinary folk believe that their brains are who they truly are? I conclude by exploring possible policy implications of the allure of neuroscience. How might it affect our funding of science, our education policy, and our mental health system?