Updating impairments and the failure to explore new hypotheses following right brain damage

Abstract

We have shown recently that damage to the right hemisphere impairs the ability to update mental models when evidence suggests an old model is no longer appropriate. We argue that this deficit is generic in the sense that it crosses multiple cognitive and perceptual domains. Here, we examined the nature of this updating impairment to determine more precisely the underlying mechanisms. We had right (RBD, N = 12) and left brain damaged (LBD, N = 10) patients perform versions of our picture-morphing task in which pictures gradually morph from one object (e.g., shark) to another (e.g., plane). Performance was contrasted against two groups of healthy older controls, one matched on age (HCO-age-matched, N = 9) and another matched on general level of cognitive ability (HCO-cognitively-matched, N = 9). We replicated our earlier findings showing that RBD patients took longer than LBD patients and HCOs to report seeing the second object in a sequence of morphing images. The groups did not differ when exposed to a morphing sequence a second time, or when responding to ambiguous images outside the morphing context. This indicates that RBD patients have little difficulty alternating between known representations or labeling ambiguous images. Instead, the difficulty lies in generating alternate hypotheses for ambiguous information. Lesion overlay analyses, although speculative given the sample size, are consistent with our fMRI work in healthy individuals in implicating the anterior insular cortex as critical for updating mental models.

The neural systems for perceptual updating

“…These areas were not only active at the time point of change but also immediately before, suggesting a possible causal role of these areas in updating. This finding was consistent with earlier results in patients showing that damage to the anterior insula – especially on the right – resulted in selective updating impairments in both the picture morphing task and in playing a simple competitive game (Danckert et al, 2012; Stöttinger et al, 2014; under revision), indicating a general updating impairment across different cognitive domains.…”

Children struggle beyond preschool-age in a continuous version of the ambiguous figures task

“…There we presented 5-to 6-year-old children 6 with a manual version of this task where we asked them to sort the pictures into a "rabbit" or a "duck" box. Despite a clear reduction in working memory load (i.e., children had to simply compare the picture with the target pictures on the boxes), children still needed significantly more pictures before they reported the second object compared to adult participants reported in Stöttinger, Guay, Danckert and Anderson (2018); [F(1, 115) = 21.50, p < 0.001, η 2 = 0.16]). The exceptionally late shift could potentially reflect a motivation issue, especially in our youngest children.…”

“…Interestingly, this is only the case when the picture is presented in a gradual context compared to when the same picture is presented outside of the morphing context (Egré, Ripley, & Verheyen, 2018;Stöttinger et al 2018;Stöttinger, Sepahvand, Danckert, & Anderson, 2016). This effect is reversed after damage to the right hemisphere: right-brain-damaged patients need significantly more pictures to identify the emerging object when it is presented in the gradual compared to the individual condition (Stöttinger et al, 2018). It is speculated that healthy adult participants use high-level "exploratory" search strategies (e.g., it started out as a duck, but what else could it be?…”