A MIMIC Model Approach to Research in Geriatric Neuropsychology: The Case of Vascular Dementia

The goal of the current study is to demonstrate a new methodology that can be used in neuropsychological research concerning differential diagnosis research. The multiple indicators, multiple causes (MIMIC) model is a latent variable methodology which can examine group differences on individual tests while controlling group differences in global cognitive impairment. As a demonstration, neuropsychological data from 217 dementia patients were incorporated into a MIMIC model to examine the influence of cerebrovascular disease (CVD) upon (1) dimensions of global cognitive impairment and (2) upon individual tests after controlling for global impairment. The presence of CVD in dementia (i.e., vascular dementia [VaD]) was not significantly related to dimensions of global impairment. In addition, the presence of CVD within dementia did not significantly contribute to impairment on 9 out of 10 neuropsychological tests/subscales examined after controlling global cognitive impairment. These results are discussed in the context of current vascular dementia research, and are focused primarily upon the MIMIC model methodology and suggestions for its use in future research.     

Intact attentional control of working memory encoding in schizophrenia

This study reports evidence that individuals with schizophrenia (SC) demonstrate intact attentional selection for visual working memory (WM) storage. A group of 62 participants with SC and 55 control participants without SC were studied in a series of 5 experiments that examined the ability to use top-down and bottom-up cues to guide WM encoding, as well as the ability to spontaneously select a subset of representations for storage. Participants with SC exhibited a consistent and robust ability to use selective attention in the control of WM in all 5 experiments, demonstrating a remarkable island of preserved functioning given the broad spectrum of impairments of attention and WM that have been widely reported in those with SC. These findings indicate that attention is not globally impaired in SC and make it possible to delineate more precisely the nature of the specific impairment of attention in this disorder.     

Is Moral Responsibility Essentially Interpersonal? A Reply to Zimmerman

According to Michael Zimmerman, no interpretation of the idea that moral responsibility is essentially interpersonal captures a significant truth. He raises several worries about the Strawsonian view that moral responsibility consists in susceptibility to the reactive attitudes and claims that this view at best supports only an etiolated interpretation of the idea that moral responsibility is essentially interpersonal. He outlines three problems. First, the existence of self-reactive attitudes may be incompatible with the interpersonal nature of moral responsibility. Secondly, Zimmerman questions the significance of the interpersonal nature of moral responsibility, according to the Strawsonian view. Thirdly, he argues that that view may be taken to suggest the wrong kind of priority relation between ‘P is morally responsible’ and ‘it is appropriate to adopt some reactive attitude toward P’. I discuss each of these problems in turn and conclude that Strawsonians can respond to all three problems raised by Zimmerman. The Strawsonian view supports a significant interpretation of the idea that moral responsibility is essentially interpersonal.     

Effects of feedback reliability on feedback-related brain activity: A feedback valuation account

Adaptive decision making relies on learning from feedback. Because feedback sometimes can be misleading, optimal learning requires that knowledge about the feedback’s reliability be utilized to adjust feedback processing. Although previous research has shown that feedback reliability indeed influences feedback processing, the underlying mechanisms through which this is accomplished remain unclear. Here we propose that feedback processing is adjusted by the adaptive, top-down valuation of feedback. We assume that unreliable feedback is devalued relative to reliable feedback, thus reducing the reward prediction errors that underlie feedback-related brain activity and learning. A crucial prediction of this account is that the effects of feedback reliability are susceptible to contrast effects. That is, the effects of feedback reliability should be enhanced when both reliable and unreliable feedback are experienced within the same context, as compared to when only one level of feedback reliability is experienced. To evaluate this prediction, we measured the event-related potentials elicited by feedback in two experiments in which feedback reliability was varied either within or between blocks. We found that the fronto-central valence effect, a correlate of reward prediction errors during reinforcement learning, was reduced for unreliable feedback. But this result was obtained only when feedback reliability was varied within blocks, thus indicating a contrast effect. This suggests that the adaptive valuation of feedback is one mechanism underlying the effects of feedback reliability on feedback processing.     

Introspective disputes deflated: the case for phenomenal variation

Sceptics vis-à-vis introspection often base their scepticism on ‘phenomenological disputes’, ‘introspective disagreement’, or ‘introspective disputes’ (ID) (see Kriegel in Phenomenol CognSci 6(1):115–136, 2007; Bayne and Spener in Philos Issues 20(1):1–22, 2010; Schwitzgebel in Perplexities of consciousness, MIT Press, Cambridge, 2011): introspectors massively diverge in their opinions about experiences, and there seems to be no method to resolve these issues. Sceptics take this to show that introspection lacks any epistemic merit. Here, I provide a list of paradigmatic examples, distill necessary and sufficient conditions for IDs, present the sceptical argument encouraged by IDs, and review the two main strategies (resolution and containment) to reject such a scepticism. However, both types of strategies are unsatisfactory. In order to save introspection from the looming sceptical threat, I advocate a deflationary strategy, based on either an ‘Argument from Perceptual Kinship’ or an ‘Argument from Ownership’. In the end, there cannot be any genuine IDs, for nothing can fulfil the reasonable conditions for IDs. What looks like IDs may instead be indicators of phenomenal variation. Debates that look like IDs may then arise even if introspection were a perfect method to know one’s mind. Thus, scepticism vis-à-vis introspection based on IDs rests on shaky grounds.