Neural enhancement and pre-emptive perception: the genesis of attention and the attentional maintenance of the cortical salience map

One of the stable hypotheses in systems neuroscience is the relationship between attention and the enhancement of visual responses when an animal attends to the stimulus in its receptive field (Goldberg and Wurtz, 1972 Journal of Neurophysiology 35 560-574). This was first discovered in the superior colliculus of the monkey: neurons in the superficial layers of the superior colliculus responded more intensely to the onset of a stimulus during blocks of trials in which the monkey had to make a saccade to it than they did during blocks of trials in which the monkey had to continue fixating a central point and not respond to the stimulus. This enhancement has been found in many brain regions, including prefrontal cortex (Boch and Goldberg, 1987 Investigative Ophthalmology 28 Supplement, 124), V4 (Moran and Desimone, 1985 Science 229 782-784), and lateral intraparietal area (Colby et al, 1996 Journal of Neurophysiology 76 2841-2852; Colby and Goldberg, 1999 Annual Review of Neuroscience 22 319-349), and even V1 (Lamme et al, 2000 Vision Research 40 1507-1521). In these studies the assumption has been that the monkey attended to the stimulus because the stimulus evoked an enhanced response. In the experiments described here we show that for abruptly appearing stimuli, attention is not related to the initial response evoked by the stimulus, but by the activity present on the salience map in the parietal cortex when the stimulus appears. Attention to the stimulus may subsequently, by a top down signal, sustain the map, but stimuli can as easily be suppressed by top down features as they can be enhanced.     

Support for lateralization of the Whorf effect beyond the realm of color discrimination

Recent work has shown that Whorf effects of language on color discrimination are stronger in the right visual field than in the left. Here we show that this phenomenon is not limited to color: The perception of animal figures (cats and dogs) was more strongly affected by linguistic categories for stimuli presented to the right visual field than those presented to the left. Moreover, the magnitude of the visual field asymmetry was reduced when demands on verbal working memory were increased by a secondary task. This reduction did not occur when the secondary task imposed demands on spatial working memory. Taken together, these results demonstrate that the lateralized Whorf effect may be quite general, reflecting an interaction of linguistic and perceptual codes primarily in the left hemisphere.     

Extinction in human learning and memory

In two experiments, participants were given extinction training in a human causal learning task. In both experiments, three critical experimental cues were paired with different outcomes in a first phase of training and were then extinguished in a second phase. Three control cues were given the same treatment in the first phase of training, but were not then presented in the second phase. Participants' ability to correctly identify the outcome with which each cue had been paired in the first phase was lower for extinguished than for control cues. Causal attributions to the extinguished cues were also lower than those to the control cues, a difference that correlated with outcome memory. These data are consistent with the idea that extinction in causal judgement is due, at least in part, to a failure to remember the cue-outcome relationship encoded in the first phase of training.     

The role of interdependence and perceived similarity in depressed affect contagion

This study hypothesized that perceived similarity significantly impacts depressed affect contagion only for individuals with highly interdependent self-construals. Baseline self-construal and affect were measured. Then, after reading a vignette about a depressed or nondepressed target, affect and perceived similarity were assessed. Participants reading the depressed vignette reported higher negative affect than participants reading the nondepressed vignette. Positive affect did not differ between the two conditions. For participants exposed to the depressed vignette, the hypothesized interaction between perceived similarity and interdependence significantly predicted positive affect. It appears that participants with more interdependent self-construals were more likely to "catch" the low positive affect displayed by the depressed target only if they perceived themselves as highly similar to the target.     

Visual identity and uncertainty in repetition blindness

Repetition blindness (RB) was investigated in 6 experiments. In the first 3 experiments participants detected vowel targets in 11-letter sequences. When all letters were uppercase, detection was poorer for same (e.g., AA) than for different (e.g., AO) targets. However, when one target was uppercase and the other lowercase, RB was found only for targets visually identical except for size (e.g., Oo), not for visually different pairs (e.g., Aa). Experiment 4 found RB for visually identical versus different consonant-vowel-consonant words. Experiments 5 and 6 replicated Kanwisher's (1987) experiment in which RB was insensitive to word case but revealed these effects to be artifacts of poor recognition of 5-letter words coupled with a biased guessing strategy. Overall, these experiments found RB only at a low level of visual information processing.     

The good-subject effect: investigating participant demand characteristics

Although researchers are often concerned with the presence of participant demand, few have directly examined effects of demand on participant behavior. Before beginning the present study, a confederate informed participants (N = 100) of the study's purported hypothesis. Participants then performed a laboratory task designed to evaluate the extent to which they would respond in ways that may confirm or disconfirm the hypothesis of the study. The authors found that participants tended to respond in ways that confirmed the hypothesis, yet this tendency depended on attitudes toward the experiment or experimenter and other individual differences. In addition, results suggested that suspicion probes may be ineffective in measuring participants' previous knowledge and suspicion. Findings indicate the need for more research and consideration of demand in the design of studies and analysis of data.     

Let your preference be your guide? Preferences and choices are more tightly linked for North Americans than for Indians

Using experimental paradigms from economics and social psychology, the authors examined the cross-cultural applicability of 3 widely held assumptions about preference and choice: People (a) recruit or construct preferences to make choices; (b) choose according to their preferences; and (c) are motivated to express their preferences in their choices. In 6 studies, they compared how middle-class North American and Indian participants choose among consumer products. Participants in both contexts construct nonrandom preferences at similar speeds. Those in Indian contexts, however, are slower to make choices, less likely to choose according to their personal preferences, and less motivated to express their preferences in their choices. The authors infer that the strong link between preferences and choices observed among North Americans is not a universal feature of human nature. Instead, this link reflects the disjoint model of agency, which prescribes that people should choose freely on the basis of their preferences. In contrast, Indian contexts reflect and promote a conjoint model of agency, according to which agency is responsive to the desires and expectations of important others and may require restraining one's preferences. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Interpersonal subtypes within generalized anxiety disorder

In this study, we addressed the heterogeneity in interpersonal problems across patients with generalized anxiety disorder (GAD). We assessed interpersonal problems by the Inventory of Interpersonal Problems (IIP-C; Horowitz, Alden, Wiggins, & Pincus, 2000) in a sample of 78 GAD patients. We used IIP-C profiles describing interpersonal characteristics of the total GAD sample as well as clustered GAD interpersonal subtypes. Although the overall sample was located in the friendly submissive quadrant of the circumplex model, this was true only for the Exploitable cluster, which includes more than 50% of the patients. Importantly, clusters of GAD patients with other locations reporting predominantly Cold, Nonassertive, or Intrusive interpersonal problems were also identified. The 4 clusters did not differ in terms of gender, comorbid disorders, or the severity of depression or anxiety. Thus, the assessment of interpersonal problems provides additional diagnostic information covering the heterogeneity of GAD patients. This information could be used for differential indication and individual case formulation in GAD.     

Brain abnormalities in antisocial individuals: implications for the law

With the increasing popularity in the use of brain imaging on antisocial individuals, an increasing number of brain imaging studies have revealed structural and functional impairments in antisocial, psychopathic, and violent individuals. This review summarizes key findings from brain imaging studies on antisocial/aggressive behavior. Key regions commonly found to be impaired in antisocial populations include the prefrontal cortex (particularly orbitofrontal and dorsolateral prefrontal cortex), superior temporal gyrus, amygdala-hippocampal complex, and anterior cingulate cortex. Key functions of these regions are reviewed to provide a better understanding on how deficits in these regions may predispose to antisocial behavior. Objections to the use of imaging findings in a legal context are outlined, and alternative perspectives raised. It is argued that brain dysfunction is a risk factor for antisocial behavior and that it is likely that imaging will play an increasing (albeit limited) role in legal decision-making.