Aging and the intrusion superiority effect in visuo-spatial working memory

This study investigated the active component of visuo-spatial working memory (VSWM) in younger and older adults testing the hypotheses that elderly individuals have a poorer performance than younger ones and that errors in active VSWM tasks depend, at least partially, on difficulties in avoiding intrusions (i.e., avoiding already activated information). In two experiments, participants were presented with sequences of matrices on which three positions were pointed out sequentially: their task was to process all the positions but indicate only the final position of each sequence. Results showed a poorer performance in the elderly compared to the younger group and a higher number of intrusion (errors due to activated but irrelevant positions) rather than invention (errors consisting of pointing out a position never indicated by the experiementer) errors. The number of errors increased when a concurrent task was introduced (Experiment 1) and it was affected by different patterns of matrices (Experiment 2). In general, results show that elderly people have an impaired VSWM and produce a large number of errors due to inhibition failures. However, both the younger and the older adults' visuo-spatial working memory was affected by the presence of activated irrelevant information, the reduction of the available resources, and task constraints.     

Effect of click trains on duration estimates by people with Parkinson's disease

Patients with a diagnosis of Parkinson's disease and age- and IQ-matched controls estimated the duration of short 500-Hz tones (325-1,225 ms), on trials where the tone was either preceded by 3 s of 5-Hz clicks, or presented without clicks. The click manipulation had been shown in earlier studies with student participants to make verbal estimates longer. Patients were tested both on and off their dopaminergic medication, and controls were also tested in two sessions. Verbal estimates were markedly and significantly longer on trials with clicks than on those without clicks for both the patients and the controls, but there were no significant performance differences between patients or controls, nor between the on and off medication sessions in the patients. The study shows that a manipulation of subjective time, which has had small but consistent effects in student participants, also affects timing in patients and adds to a growing body of evidence that timing in patients with Parkinson's disease may in many cases have the same characteristics as those of neurologically intact control groups.     

Habituation to repeated stress: get used to it

Habituation, as described in the landmark paper by Thompson et al. [Thompson, R. F., & Spencer, W. A. (1966). Habituation: A model phenomenon for the study of neuronal substrates of behavior. Psychological Review, 73(1), 16–43], is a form of simple, nonassociative learning in which the magnitude of the response to a specific stimulus decreases with repeated exposure to that stimulus. A variety of neuronal and behavioral responses have been shown to be subject to habituation based on the criteria presented in that paper. It has been known for several decades that the magnitude of hypothalamic–pituitary–adrenal (HPA) activation occurring in response to a stressor declines with repeated exposure to that same stressor. For some time this decline has been referred to as “habituation” in the stress neurobiology literature. However, how this usage compares to the definition proposed by Thompson and Spencer has not been systematically addressed. For this special issue, we review the stress neurobiology literature and examine the support available for considering declines in HPA response to repeated stress to be response habituation in the sense defined by Thompson and Spencer. We conclude that habituation of HPA activity meets many, but not all, important criteria for response habituation, supporting the use of this term within the context of repeated stress. However, we also propose that response habituation can, at best, only partially explain the phenomenon of HPA habituation, which also involves well-known negative feedback mechanisms, activation of broad stress-related neural circuitry and potentially more complex associative learning mechanisms.     

Right-hemisphere reading in a case of developmental deep dyslexia

The right-hemisphere hypothesis of deep dyslexia has received support from functional imaging studies of acquired deep dyslexia following damage to the left cerebral hemisphere, but no imaging studies of cases of developmental deep dyslexia, in which brain damage is not suspected, have been reported. In this paper, we report the first evidence of right hyperactivation in an adult case of developmental deep dyslexia. Hyperactivation was observed in the right inferior frontal cortex during functional magnetic resonance imaging (fMRI) of the oral reading of imageable content words and nonwords to which imageable lexical responses were frequently made. No evidence of right hyperactivation was observed in the oral reading of function words, nor during the naming of imageable words in response to pictured objects. The results reveal strategic and selective use of right-hemisphere functions for particular types of written stimuli. We propose that children with developmental deep dyslexia compensate for their lack of phonological skills by accessing right-hemisphere imageable associations that provide a mnemonic for linking written forms to spoken names.     

Examining “fat talk” experimentally in a female dyad: How are women influenced by another woman's body presentation style?

Fat talk, the verbal dissatisfaction that women express about their bodies, was studied in a female dyad whereby participants interacted with a female confederate who either self-derogated, self-accepted, or self-aggrandized. A 2 (participant body esteem: high vs. low) ×3 (confederate style of body image presentation) design was used. Results revealed that participants’ public disclosure of their body image varied according to confederate's style. Consistent with a reciprocity effect, participants disclosed the lowest public body image ratings in the self-derogate condition, with moderate ratings in the self-accept condition, and highest ratings in the self-aggrandize condition. Moreover, participants with low compared to high body esteem stated lower public body image. Participants’ judgments of the confederates’ likeability did not vary as a function of the confederate's body presentational style. Findings support the recursive nature of the social psychology of body image such that personal body image dissatisfaction is partially influenced by fat talk social norms.     

In‐group reassurance in a pain setting produces lower levels of physiological arousal: direct support for a self‐categorization analysis of social influence

A large body of research demonstrates a strong social component to people's pain experiences and pain‐related behaviours. We investigate this by examining the impact of social‐influence processes on laboratory‐induced pain responses by manipulating the social‐categorical relationship between the person experiencing pain and another who offers reassurance. We show that physiological arousal associated with laboratory‐induced pain is significantly lower in normal, healthy participants following reassurance about the pain‐inducing activity when that reassurance comes from an in‐group member in contrast to reassurance from an out‐group member and a no reassurance control. These data are consistent with predictions derived from self‐categorization theory, providing convincing empirical support of its analysis of social influence using a non‐reactive measure. These data also represent a clear advance within the pain literature by identifying a possible common process to the social‐psychological component of pain responses. Copyright © 2006 John Wiley & Sons, Ltd.     

The control of food-caching behavior by Western scrub-jays (Aphelocoma californica)

Western scrub-jays (Aphelocoma californica) did not show extinction when caching behavior was never rewarded and they had no choice of where to cache the food. However, when the jays had the choice of caching items in 2 different locations or during 2 successive episodes, and only 1 of each was always rewarded at recovery, they rapidly learned to cache in the rewarded location or episode. When the jays had learned during training trials that their caches were always moved to 1 of 2 locations they did not cache in, then on the test trial they cached in the location that had been previously rewarded. To test whether these jays avoided the location in which their caches had been pilfered or chose the rewarded location, the procedure was repeated to include a 3rd location that was never rewarded. The jays avoided the pilfered location but cached equally in the rewarded and nonrewarded locations.     

Change in affective state assessed by impaired color-naming of threat-related words

This study investigated the effects of mood induction on Stroop color-naming times for threat-related words. The subjects’ task was to color-name sets of threat-related words and affectively neutral matched control words both before and after mood-induction. Subjects were shown a short film about the medical effects of nuclear war (negative affect manipulation), a humorous cartoon, or no film. A significant and highly reliable color-naming decrement of the threat-related words was observed only after the negative affect manipulation. This indicates that the attentional bias towards the processing of threat-related material observed in clinically anxious or high Trait-Anxious subjects can be induced in initially nonanxious subjects. An incidental recall task included in the procedure provided no evidence of mood state dependent recall.