The strategic control of multiple routes in imitation of actions

The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients.     

The picture superiority effect in categorization: visual or semantic?

Two experiments are reported whose aim was to replicate and generalize the results presented by Snodgrass and McCullough (1986) on the effect of visual similarity in the categorization process. For pictures, Snodgrass and McCullough's results were replicated because Ss took longer to discriminate elements from 2 categories when they were visually similar than when they were visually dissimilar. However, unlike Snodgrass and McCullough, an analogous increase was also observed for word stimuli. The pattern of results obtained here can be explained most parsimoniously with reference to the effect of semantic similarity, or semantic and visual relatedness, rather than to visual similarity alone.     

Levels of representation in word processing

Abstract

Four experiments are described examining the effects of words frequency, orthographic structure, and letter spacing on a range of tasks designed to tap different levels of representation in word processing. In Experiment 1, the task was lexical decision. Effects of both frequency (high-frequency words were recognized faster than low-frequency words) and orthographic regularity (illegal non-words were rejected faster than legal non-words) were found. In Experiment 2 subjects had to detect a rotated letter within the letter strings. Effects of orthographic structure emerged, with a marked disadvantage for illegal non-words with respect to the other types of string. No difference was found among high-frequency words, lowfrequency words and legal non-words. In Experiment 3, subjects had to detect a letter elevated above the horizontal plan with respect to the rest of the string. Effects of both spatial arrangement of letters and number of letters were found (spaced strings were responded to less accurately than non-spaced strings and seven-letter extra-spaced strings were responded to slower than the other strings). Neither lexical nor orthograpic variables affected this task. In Experiment 4 subjects had to detect the presence of a bold segment contained in one of the letters in the strings. Performance was unaffected by both lexical and spatial variables. The pattern of results is discussed with reference to a multi-stage model of word recognition in which lexical and spatial variables affect processing at different stages. At a feature map level, in which features are extracted from the discontinuities of light intensities, processing is independent of both spatial and lexical factors. At a letter-shape map level, in which spatial relationships between features are coded, spacing between letters affects encoding. At a graphemic map level, in which letter identities and their relative positions within strings are coded, orthographic variables have an effect. Lexicality and frequency affect only subsequent stages of processing, when stored lexical information is retrieved (e.g. for lexical decision).     

Improving Attitudes Toward Prostate Examinations by Loss-Framed Appeals

One of the main causes of late diagnoses in prostate cancer is the aversive attitude toward prostate examinations. In this study, we analyze the efficacy of an informative pamphlet in changing that attitude. A randomized sample of north Italian men was given different versions of an informative pamphlet, obtained by systematically manipulating the message framing and emotional vividness. After reading the pamphlet, each participant completed an attitude questionnaire. Levels of anxiety and self-reported health status were measured using the STAI-X2 and the SF-36 questionnaires. Results show that loss-framed messages (i.e., messages highlighting the negative consequences of not doing the examinations) had a significant positive effect on attitudes toward the prostate screening, but the effect was rather small.     

Acceptance of a price discount: the role of the semantic relatedness between purchases and the comparative price format

Two studies are reported where people are asked to accept or not a price reduction on a target product. In the high (low) relative saving version, the regular price of the target product is low (high). In both versions, the absolute value of the price reduction is the same as well as the total of regular prices of planned purchases. As first reported by Tversky and Kahneman ( 1981 ), findings show that the majority of people accept the price discount in the high‐relative saving version whereas the minority do it in the low one. In Study 1, findings show that the previous preference reversal disappears when planned purchases are strongly related. Also, a previously unreported preference reversal is found. The majority of people accept the price discount when the products are weakly related whereas the minority accept when the products are strongly related. In Study 2, findings show that the classic preference reversal disappears as a function of the comparative price format. Also, another previously unreported preference reversal is found. When the offered price reduction relates to a low‐priced product, people are more inclined to accept it with a control than a minimal comparative price format. Findings reported in Studies 1 and 2 are interpreted in terms of mental accounting shifts. Copyright © 2002 John Wiley & Sons, Ltd.     

Simple movement imitation: Are kinematic features sufficient to map perceptions into actions?

The aim of this study was to pinpoint the nature of the visual features used in the automatic mapping of perceived movements into similar executed movements, following the direct matching hypothesis. In Experiment 1 subjects imitated the lifting of one of two fingers, presented with different orientations. As predicted, stimuli which were further rotated away from the posture of the executing hand elicited slower reaction times. In Experiment 2, we verified that this orientation effect was not a purely perceptual effect by presenting the same stimuli but asking subjects to respond verbally. No orientation effect was found using a verbal response. In Experiment 3, we replaced the moving fingers by two arbitrary objects moving with the trajectories of the finger tips of Experiment 1. The same orientation effect as in Experiment 1 was observed. We conclude that in this experiment participants are using purely kinematic features to map perceived into executed movements.     

Visual Object Agnosia without Alexia or Prosopagnosia: Arguments for Separate Knowledge Stores

We review the points raised by Farah (this issue) in her discussion of the paper by Rumiati, Humphreys, Riddoch, and Bateman (1994), in which a case study was presented of a patient, Mr W., with visual object agnosia without either prosopagnosia or alexia. We reiterate the argument that Mr W. had impaired stored knowledge about the visual characteristics of objects, and that this was more severe than his deficit at a semantic level. In addition, we summarize supporting evidence from another patient (Humphreys & Rumiati, submitted), who showed the same pattern of breakdown as Mr W. We suggest that stored visual knowledge can be specific to the form of stimulus (words, objects, and faces), that these different forms of knowledge may be represented in distinct neural areas, and that agnosia can result after damage to stimulus-specific sites of knowledge representation.     

Dissociation between the mental rotation of visual images and motor images in unilateral brain-damaged patients

Deficits in the mental rotation of body parts and of external objects can be doubly dissociated (Rumiati, Tomasino, Vorano, Umiltà, & De Luce, 2001; Sirigu & Duhamel, 2001; Tomasino, Rumiati, & Umità, in press). The aim of this study was to replicate this finding and to then investigate the relevance of the specific hemispheres in these deficits. Nine patients with unilateral lesions (five in the Left Hemisphere and four in the Right) and 20 control subjects, performed a single task requiring mental rotation of hands, and two tasks requiring mental rotation of external objects. RH patients were impaired in the rotation of external objects, but showed intact performance on the rotation of hands; the opposite pattern was found for LH patients. These results support the view that the LH contributes to the mental rotation of hands, recruiting processes specific to motor preparation, while the RH is specialized for mental rotation of external objects.     

Visual object agnosia without prosopagnosia or alexia: Evidence for hierarchical theories of visual recognition

Abstract

A single case study is presented of a patient, Mr. W, with a selective deficit in recognizing pictures and real objects, linked to impaired stored visual knowledge about objects. Despite this, Mr. W maintained a preserved ability both to read aloud printed words and to recognize famous faces, when compared with age-matched control subjects. In addition, his access to semantic information from words was superior to that from pictures. The data provide evidence that visual agnosia can occur without alexia or prosopagnosia, contrary to recent proposals (Farah 1990, 1991). This finding is consistent with a hierarchical model of visual object recognition in which agnosia can reflect impaired stored knowledge of objects without accompanying perceptual deficits. The selective recognition deficit for objects further indicates that stored knowledge concerning different classes of visual stimuli (common objects, faces, and words) is separately represented in the brain.     

Are irrational reactions to unfairness truly emotionally-driven? Dissociated behavioural and emotional responses in the Ultimatum Game task

The “irrational” rejections of unfair offers by people playing the Ultimatum Game (UG), a widely used laboratory model of economical decision-making, have traditionally been associated with negative emotions, such as frustration, elicited by unfairness (Sanfey et al., 2003, van’t Wout et al., 2006). We recorded skin conductance responses as a measure of emotional activation while participants performed a modified version of the UG, in which they were asked to play both for themselves and on behalf of a third-party. Our findings show that even unfair offers are rejected when participants’ payoff is not affected (third-party condition); however, they show an increase in the emotional activation specifically when they are rejecting offers directed towards themselves (myself condition). These results suggest that theories emphasizing negative emotions as the critical factor of “irrational” rejections (Pillutla & Murninghan, 1996) should be re-discussed. Psychological mechanisms other than emotions might be better candidates for explaining this behaviour.