From interpretation to segmentation

In visual perception, part segmentation of an object is considered to be guided by image-based properties, such as occurrences of deep concavities in the outer contour. However, object-based properties can also provide information regarding segmentation. In this study, outer contours and interpretations of object configurations were manipulated to examine differences between image-based and object-based segmentation in a visual search task. We found that locating a two-dimensional object configuration with deep concavities in the outer contour depends on the type of outer contour of the surrounding distractors. In addition, locating a three-dimensional object configuration was harder when it was surrounded by object-based-disconnected distractors, as compared with object-based-connected distractors, regardless of image-based connections in these distractors. We conclude that segmentation based on the outer contours of a target facilitates its localization. However, when three-dimensional information is available, segmentation strongly depends on object-based properties, rather than on image-based properties.     

On the mental representation of negative numbers: Context-dependent SNARC effects with comparative judgments

In one condition, positive and negative number pairs were compared in separate blocks of trials. In another condition, the positive and the negative number pairs were intermixed. In the intermixed condition, comparisons involving negative numbers were faster with the left hand than with the right, and comparisons were faster with the right hand than with the left hand with the positive numbers; that is, a spatial numerical association of response codes (SNARC) effect was obtained, in which the mental number line was extended leftward with the negative numbers. On the other hand, in the blocked condition, a reverse SNARC effect was obtained with the negative numbers; that is, negative number pairs have the same underlying spatial representation as the positive numbers in this context. Nongraded semantic congruity effects, obtained in both the blocked and the intermixed conditions, are consistent with the idea that magnitude information is extracted prior to the generation of discrete semantic codes.     

Attention capture is modulated in dual-task situations

Because some features affect the efficiency of visual search even when they are irrelevant to the task, they are thought tocapture attention in a stimulus-driven manner. If such attention shifts are stimulus driven, they should be unaffected by reduced resources. We added a concurrent auditory task to a traditional attention capture paradigm and found that capture by an irrelevant, abruptly appearing stimulus (i.e., an onset) was eliminated. In contrast, prioritization of an irrelevant color singleton—a stimulus that at most receives only mild prioritization in this paradigm—was increased under dual-task conditions. These results challenge the hypothesis that attention capture by irrelevant features is stimulus driven. Instead, prioritization depends on and is modulated by the availability of resources.     

The role of working memory in spatial enumeration: Patterns of selective interference in subitizing and counting

Articulatory suppression (repeatedly pronouncing a syllable or word while carrying out another task) is thought to interfere selectively with the phonological store in working memory (Larsen & Baddeley, 2003). Although suppression interferes with temporal enumeration (enumerating successive light flashes), to date there has been little evidence of such interference in spatial enumeration (enumerating units laid out in space at one time)—a finding with serious ramifications for theories of enumeration. Participants carried out a spatial enumeration task, enumerating 1–8 dots while listening to a metronome (baseline condition) or while carrying out a secondary task to the rhythm of the metronome (dual-task condition). There were four secondary tasks: simple articulation (saying a letter), complex articulation (alternating between two letters), simple tapping (tapping a finger), and complex tapping (alternating between two fingers). Interference varied with number of items, but the pattern differed from that observed with temporal enumeration (Logie & Baddeley, 1987).     

The role of similarity in deductive categorical inference

The category inclusion rule specifies that categories inherit the properties of their superordinates. For example, given thatall metals are pentavalent, it can be concluded thatall iron is pentavalent. Sloman (1998) showed that people do not fully endorse conclusions that follow from the category inclusion rule. He claims that people rely on the similarity between the premise and the conclusion categories (metals andiron), rather than applying the category inclusion rule. By allowing reasoners to rate their certainty for category relations (e.g.,iron is metal), as well as for conclusions, the present study shows that similarity has only an indirect effect on the certainty of conclusions: Reasoners are more certain that similar categories have a category inclusion relation, and this in turn affects the certainty of conclusions based on this relation.     

Coantagonism of glutamate receptors and nicotinic acetylcholinergic receptors disrupts fear conditioning and latent inhibition of fear conditioning

The present study investigated the hypothesis that both nicotinic acetylcholinergic receptors (nAChRs) and glutamate receptors (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPARs) and N-methyl-d-aspartate glutamate receptors (NMDARs)) are involved in fear conditioning, and may modulate similar processes. The effects of the nAChR antagonist mecamylamine administered alone, the AMPAR antagonist NBQX administered alone, and the NMDAR antagonist MK-801 administered alone on cued fear conditioning, contextual fear conditioning, and latent inhibition of cued fear conditioning were examined. In addition, the effects of coadministration of either mecamylamine and NBQX or mecamylamine and MK-801 on these behaviors were examined. Consistent with previous studies, neither mecamylamine nor NBQX administered alone disrupted any of the tasks. However, coadministration of mecamylamine and NBQX disrupted both contextual fear conditioning and latent inhibition of cued fear conditioning. In addition, coadministration of mecamylamine with a dose of MK-801 subthreshold for disrupting either task disrupted both contextual fear conditioning and latent inhibition of cued fear conditioning. Coadministration of mecamylamine and NBQX, and coadministration of mecamylamine with a dose of MK-801 subthreshold for disrupting fear conditioning had little effect on cued fear conditioning. These results suggest that nAChRs and glutamate receptors may support similar processes mediating acquisition of contextual fear conditioning and latent inhibition of fear conditioning.     

Mindfulness and Marital Satisfaction

This study investigated the relationships among mindfulness, marital satisfaction, and perceived spousal similarity. All 95 subjects responded to a questionnaire measuring each of these variables, and an additional series of demographic variables. A significant positive relationship was found between mindfulness and marital satisfaction, with no statistically significant relationship found between perceived spousal similarity and marital satisfaction. There was a stronger correlation between mindfulness and marital satisfaction than the correlation between marital satisfaction and any of the other variables, including similarity. These results carry meaningful implications for the role of mindfulness techniques within the context of building and maintaining happy marital relationships and general well-being.     

Integrating neurobiology and psychopathology into evidence-based treatment of social anxiety disorder

Social anxiety disorder (SAD) is a common, chronic psychiatric disorder characterized by a persistent fear of social or performance situations in which embarrassment can occur. This disorder typically appears during the mid-adolescent years and is unremitting throughout life if not properly treated. SAD presents as two subtypes: the more common and debilitating generalized form, and the nongeneralized form, which consists predominantly of performance anxiety. The majority of patients with SAD have comorbid mental disorders, including mood, anxiety, and substance abuse. No single development theory has been proposed to account for the origins of SAD, although current understanding of the etiology of SAD posits an interaction between psychological and biological factors. Risk factors include environmental and parenting influences and dysfunctional cognitive and conditioning events in early childhood. The neurobiology of SAD appears to involve neurochemical dysfunction, as evidenced by studies of neuroreceptor imaging, neuroendocrine function, and profiles of response to specific medications. Clinical trials have demonstrated that benzodiazepines and antidepressants are effective in the treatment of SAD. The selective serotonin reuptake inhibitors are emerging as the first-line treatment for SAD, based on their proven safety, tolerability, and efficacy. Goals for ongoing future research include development of approaches to achieve remission, to convert nonresponders and partial responders to full responders, and to prevent relapse and maintain long-term efficacy. This monograph explores the epidemiology, clinical presentation, and differential diagnosis of SAD, with a focus on neural circuitry of social relationships and neurochemical dysfunction. The prevalence, rates of recognition and treatment, patterns of comorbidity, quality-of-life issues, and natural history of SAD are discussed as well as pharmacologic and psychosocial treatment strategies for SAD.     

Deletion of the mu opioid receptor results in impaired acquisition of Pavlovian context fear

The mu opioid receptor may constitute a critical component of a negative feedback system that regulates Pavlovian fear conditioning. We investigated context fear conditioning acquisition and expression in mu opioid receptor knockout mice (on an inbred, C57 genetic background). We discovered that the mu receptor knockout results in an unexpected and significant deficit in context fear acquisition. Mice lacking the mu receptor showed normal fear acquisition when subjected to a 1-day fear conditioning protocol but evinced deficient fear learning when acquisition was conducted across 5 days. The knockout mice showed normal reactivity to footshock in both fear conditioning protocols. Finally, we confirmed the effectiveness of the receptor deletion in the C57 strain by subjecting the mice to a test of morphine analgesia in the hot-plate assay. As has been seen with mixed genetic background, the receptor deletion resulted in a complete lack of analgesic response to 10 mg/kg morphine. Surprisingly, mice with a single copy of the mu receptor gene (heterozygous knockouts) showed intact sensitivity to morphine but a significant deficit in Pavlovian fear conditioning. The results indicate that deletion of the mu receptor gene impairs fear conditioning and that the conditioning and analgesia effects of heterozygous deletion are dissociable. The conditioning deficit seen in this line of mice may be related to impairment in hippocampus function.