Visual similarity is greater for line drawings of nonliving than living things: the importance of musical instruments and body parts

It has been argued that greater intra-category structural similarity for living things, and the subsequent "visual crowding," makes them more difficult to recognize and name for neurologically damaged individuals and normal subjects (Humphreys et al., 1988). Nevertheless, the precise meaning and quantification of structural similarity remains unclear, as does the rationale for why it necessarily should be greater for living things. We derived a new measure of visual overlap from the Snodgrass and Vanderwart corpus of line drawings: the degree of pixel overlap within subcategories (Euclidean distance: ED). Contrary to existing notions of visual crowding and extant measures of contour overlap, within-category ED indicated less within-category visual overlap for living things. Furthermore, musical instruments clustered with living things (having low overlap), while body parts clustered with nonliving things (having high overlap). These counter-intuitive findings accord with patient data and thus, provide evidence for the psychological reality and utility of ED.     

An electrophysiological comparison of visual categorization and recognition memory

Object categorization emphasizes the similarities that bind exemplars into categories, whereas recognition memory emphasizes the specific identification of previously encountered exemplars. Mathematical modeling has highlighted similarities in the computational requirements of these tasks, but neuropsychological research has suggested that categorization and recognition may depend on separate brain systems. Following training with families of novel visual shapes (blobs), event-related brain potentials (ERPs) were recorded during both categorization and recognition tasks. ERPs related to early visual processing (N1, 156–200 msec) were sensitive to category membership. Middle latency ERPs (FN400 effects, 300–500 msec) were sensitive to both category membership and old/new differences. Later ERPs (parietal effects, 400–800 msec) were primarily affected by old/new differences. Thus, there was a temporal transition so that earlier processes were more sensitive to categorical discrimination and later processes were more sensitive to recognition-related discrimination. Aspects of these results are consistent with both mathematical modeling and neuropsychological perspectives.     

ERP evidence for conceptual mappings and comparison processes during the comprehension of conventional and novel metaphors

Cognitive linguists suggest that understanding metaphors requires activation of conceptual mappings between the involved concepts. We tested whether mappings are indeed in use during metaphor comprehension, and what mapping means as a cognitive process with Event-Related Potentials. Participants read literal, conventional metaphorical, novel metaphorical, and anomalous target sentences preceded by primes with related or unrelated mappings. Experiment 1 used sentence-primes to activate related mappings, and Experiment 2 used simile-primes to induce comparison thinking. In the unprimed conditions of both experiments, metaphors elicited N400s more negative than the literals. In Experiment 1, related sentence-primes reduced the metaphor-literal N400 difference in conventional, but not in novel metaphors. In Experiment 2, related simile-primes reduced the metaphor-literal N400 difference in novel, but not clearly in conventional metaphors. We suggest that mapping as a process occurs in metaphors, and the ways in which it can be facilitated by comparison differ between conventional and novel metaphors.     

Cultural values and attitudes towards guidance and counselling services in one secondary school in Malaysia: the role of a school cultural system

This narrative ethnographic study aims to explore students' attitudes towards guidance and counselling services in one secondary school in Malaysia. Semi-structured individual interviews, group interviews and observations were conducted with school students of different racial backgrounds. They were identified as referred clients, self-referred clients, and those not deemed to be involved in counselling. The data were analysed using the constant comparative analysis grounded theory approach. The findings indicate that there were different attitudes among the three groups of participants concerning counselling services. The study highlights the role of a school system in elucidating attitudes towards guidance and counselling services. It poses implications for understanding counselling services within the school system.     

Interindividual–intergroup discontinuity in the prisoner’s dilemma game: How common fate,proximity, and similarity affect intergroup competition

In two experiments with the PDG we manipulated the Campbell (1958), or Wertheimer (1923), indices of entitativity (common fate, proximity, and similarity) to examine when a set of individuals interacts with another set of individuals in the competitive manner that is characteristic of group-on-group interactions. Experiment 1 found that interactions between two 3-person sets were more competitive when participants within each set shared (vs. did not share) common fate. In Experiment 2, the Wertheimer–Campbell indices were manipulated for one 3-person set only (targets). Participants in the other 3-person set were sequestered in separate rooms (observers). Observers as well as targets were more competitive when targets shared (vs. did not share) common fate. Path analyses in both experiments supported the idea that common fate increases competition via increased own-set entitativity and subsequent greed, and via increased other-set entitativity and subsequent fear. We found no consistent evidence for the possible roles of proximity and similarity.     

The relationship between depressive symptoms and error monitoring during response switching

Heightened sensitivity to failure and negative information is thought to be an important maintenance mechanism for symptoms of depression. However, the specific neural and behavioral correlates of the abnormal reactions to errors associated with depression are not yet well understood. The present study was designed to shed new light on this issue by examining how depressive symptoms relate to error monitoring in the context of different task demands. We used a modified flanker task in which the stimulus–response (S–R) mappings were reversed between blocks, differentiating relatively easy nonreversal blocks from the more-demanding S–R reversal blocks. Undergraduates performed this task and then completed a self-report measure of anhedonic depression. The results revealed that depressive symptoms were related to poorer posterror accuracy in the more-difficult S–R reversal blocks, but not in the easier nonreversal blocks. Event-related brain potentials (ERPs) within a subsample of these participants further indicated that depressive symptoms were associated with reduced error positivity (Pe) amplitudes in both block types, suggesting that depressive symptoms were related to reduced attention allocation to errors across the easy and hard blocks. Finally, brain–behavior correlations indicated that highly depressed individuals failed to display a relationship between Pe amplitude and posterror accuracy in the S–R reversal blocks, a relationship that was intact in the low-depression group. Together, these results suggest that task demands play a critical role in the emergence of error-monitoring abnormalities in depression.     

Constraints on decision making: Implications from genetics, personality, and addiction

An influential neurocomputational theory of the biological mechanisms of decision making, the “basal ganglia go/no-go model,” holds that individual variability in decision making is determined by differences in the makeup of a striatal system for approach and avoidance learning. The model has been tested empirically with the probabilistic selection task (PST), which determines whether individuals learn better from positive or negative feedback. In accordance with the model, in the present study we examined whether an individual’s ability to learn from positive and negative reinforcement can be predicted by genetic factors related to the midbrain dopamine system. We also asked whether psychiatric and personality factors related to substance dependence and dopamine affect PST performance. Although we found characteristics that predicted individual differences in approach versus avoidance learning, these observations were qualified by additional findings that appear inconsistent with the predictions of the go/no-go model. These results highlight a need for future research to validate the PST as a measure of basal ganglia reward learning.