The role of the basal ganglia in learning and memory: insight from Parkinson's disease

It has long been known that memory is not a single process. Rather, there are different kinds of memory that are supported by distinct neural systems. This idea stemmed from early findings of dissociable patterns of memory impairments in patients with selective damage to different brain regions. These studies highlighted the role of the basal ganglia in non-declarative memory, such as procedural or habit learning, contrasting it with the known role of the medial temporal lobes in declarative memory. In recent years, major advances across multiple areas of neuroscience have revealed an important role for the basal ganglia in motivation and decision making. These findings have led to new discoveries about the role of the basal ganglia in learning and highlighted the essential role of dopamine in specific forms of learning. Here we review these recent advances with an emphasis on novel discoveries from studies of learning in patients with Parkinson's disease. We discuss how these findings promote the development of current theories away from accounts that emphasize the verbalizability of the contents of memory and towards a focus on the specific computations carried out by distinct brain regions. Finally, we discuss new challenges that arise in the face of accumulating evidence for dynamic and interconnected memory systems that jointly contribute to learning.     

Actual and non-actual motion: why experientialist semantics needs phenomenology (and vice versa)

Experientialist semantics has contributed to a broader notion of linguistic meaning by emphasizing notions such as construal, perspective, metaphor, and embodiment, but has suffered from an individualist concept of meaning and has conflated experiential motivations with conventional semantics. We argue that these problems can be redressed by methods and concepts from phenomenology, on the basis of a case study of sentences of non-actual motion such as “The mountain range goes all the way from Mexico to Canada.” Through a phenomenological reanalysis of proposals of Talmy, Langacker, and Matlock, we show that non-actual motion is both experientially and linguistically non-unitary. At least three different features of human consciousness—enactive perception, visual scanning, and imagination—constitute experiential motivations for non-actual motion sentences, and each of these could be related to phenomenological analyses of human intentionality. The second problem is addressed by proposing that the experiential motivations of non-actual motion sentences can be viewed as sedimented through “passive” processes of acquisition and social transmission and that this implies an interactive loop between experience and language, yielding losses in terms of original experience, but gains in terms of communal signification. Something that is underestimated by phenomenology is that what is sedimented are not only intentional objects such as states of affairs, but aspects of how they are given, i.e., the original, temporal, bodily experiences themselves. Since cognitive semantics has emphasized such aspects of meaning, we suggest that phenomenology can itself benefit from experientialist semantics, especially when it turns its focus from prepredicative to predicative, linguistic intentionality.     

Notional number agreement in English

To investigate the contested role of notional number in English subject-verb agreement, we used a sentence completion task to examine agreement with minimally different subject noun-phrases, such as the gang on the motorcycles and the gang near the motorcycles. These contrasting phrases biased different notional construals of collective nouns, such as gang, which are normally ambiguous between plural (distributed) and singular (collected) construals. With subjects biased toward spatial distribution, such as gang on motorcycles, more plural verbs occurred in speakers’ sentence completions than in sentence completions with a bias toward spatial collection such as gang near motorcycles. This offers strong evidence regarding both the existence and the magnitude of notional effects on subject-verb number agreement in English.     

Developmental Differences in Metacognition and their Connections with Cognitive Development in Adulthood

This study investigated developmental differences in some metacognitive variables in ill-defined problem solving and their possible connections with cognitive development in adulthood. Participants were 57 individuals of different ages (adolescents, young adults, mature adults and older adults). They solved one well-defined and six ill-defined problems while their thinking-aloud was taped. They then answered a metacognitive statements questionnaire. Differences in performance were statistically significant in all problems: the best results in interpolation and divergent production problems were achieved by the younger adult group and the best performance on most dialectical everyday problems was found in the mature adults' group. We found no significant differences between age groups in the on-line monitoring of the solving process. Accuracy in metacognitive statements was however significantly better in the mature adult and the younger adult groups. Awareness of and reflection on one's own mental processes showed a similar developmental pattern to relativistic/dialectical thought: low expression in adolescence, an increase in early adulthood, a peak in mature adulthood and a minor decline in later years.     

The moderator effect that wasn't there: statistical problems in ambivalence research

Ambivalence researchers often collapse separate measures of positivity and negativity into a single numerical index of ambivalence and refer to it as objective, operative, or potential ambivalence. The authors argue that this univariate approach to ambivalence models undermines the validity of subsequent statistical analyses because it confounds the effects of the index and its components. To remedy this situation, they demonstrate how the assumptions underlying the indices derived from the conflicting reactions model and similarity-intensity model can be tested using a multivariate approach to ambivalence models. On the basis of computer simulations and reanalyses of published moderator effects, the authors show that the frequently reported moderating influence of ambivalence on attitude effects may be a statistical artifact resulting from unmodeled correlations of positivity and negativity with attitude and the dependent variable. On the basis of extensive power analyses, they conclude that it may be extremely difficult to detect moderator effects of ambivalence in observational data. Therefore, they encourage ambivalence researchers to take an experimental approach to study design and a multivariate approach to data analysis.     

A scaling analysis of the snake lightness illusion

Logvinenko and Maloney (2006) measured perceived dissimilarities between achromatic surfaces placed in two scenes illuminated by neutral lights that could differ in intensity. Using a novel scaling method, they found that dissimilarities between light surface pairs could be represented as a weighted linear combination of two dimensions, "surface lightness" (a perceptual correlate of the difference in the logarithm of surface albedo) and "surface brightness" (which corresponded to the differences of the logarithms of light intensity across the scenes). Here we attempt to measure the contributions of these dimensions to a compelling lightness illusion (the "snake illusion"). It is commonly assumed that this illusion is a result of erroneous segmentation of the snake pattern into regions of unequal illumination. We find that the illusory shift in the snake pattern occurs along the surface lightness dimension, with no contribution from surface brightness. Thus, even if an erroneous segmentation of the snake pattern into strips of unequal illumination does happen, it reveals itself, paradoxically, as illusory changes in surface lightness rather than as surface brightness. We conjecture that the illusion strength depends on the balance between two groups of illumination cues signaling the true (uniform) illumination and the pictorial (uneven) illumination.     

Disgust as embodied moral judgment

How, and for whom, does disgust influence moral judgment? In four experiments participants made moral judgments while experiencing extraneous feelings of disgust. Disgust was induced in Experiment 1 by exposure to a bad smell, in Experiment 2 by working in a disgusting room, in Experiment 3 by recalling a physically disgusting experience, and in Experiment 4 through a video induction. In each case, the results showed that disgust can increase the severity of moral judgments relative to controls. Experiment 4 found that disgust had a different effect on moral judgment than did sadness. In addition, Experiments 2-4 showed that the role of disgust in severity of moral judgments depends on participants' sensitivity to their own bodily sensations. Taken together, these data indicate the importance-and specificity-of gut feelings in moral judgments.