305,252 research outputs found
Implicit visual analysis in handedness recognition
No full textIn the present study, we addressed the problem of whether hand representations, derived from the control of hand gesture, are used in handedness recognition. Pictures of hands and fingers, assuming either common or uncommon postures, were presented to right-handed subjects, who were required to judge their handedness. In agreement with previous results (Parsons, 1987, 1994; Gentilucci, Daprati, & Gangitano, 1998), subjects recognized handedness through mental movement of their own hand in order to match the posture of the presented hand. This was proved by a control experiment of physical matching. The new finding was that presentation of common finger postures affected responses differently from presentation of less common finger postures. These effects could be not attributed to mental matching movements nor related to richness in hand-finger cues useful for handedness recognition. The results of the present study are discussed in the context of the notion that implicit visual analysis of the presented hands is performed before mental movement of one's hand takes place (Parsons, 1987; Gentilucci et al., 1998). In this process, hand representation acquired by experience in the control and observation of one's and other people's hand gestures is used. We propose that such an immediate recognition mechanism belongs to the class of mental processes which are grouped under the name of intuition, that is, the processes by which situations or people's intentions are immediately understood, without conscious reasoning
Impaired control of an action after supplementary motor area lesion: A case study
No full textThe kinematics of the action formed by reaching±grasping an object and placing it on a second target was studied in a patient
who su ered from an acute vascular left brain lesion, which a ected the Supplementary Motor Area proper (SMA-proper)
(Matelli M, Luppino G. Thalamic input to mesial and superior area 6 in the macaque monkey. Journal of Comparative
Neurology 1996;372:59±87, Matelli M, Luppino G, Fogassi L, Rizzolatti G. Thalamic input to inferior area 6 and area 4 in the
macaque monkey. Journal of Comparative Neurology 1989;280:468±488), and in ®ve healthy control subjects. The reach kinematics of the controls was a ected by the positions of both the reaching±grasping and the placing targets (Gentilucci M,
Negrotti A, Gangitano M. Planning an action. Experimental Brain Research 1997;115:116±28). In contrast, the reach kinematics
of the patient was a ected only by the position of the reaching±grasping target. By comparing these results with those
previously found in Parkinson's disease patients executing the same action (Gentilucci M, Negrotti A. Planning and executing an
action in Parkinson's disease patients. Movement Disorders 1999;1:69±79, Gentilucci M, Negrotti A. The control of an action in
Parkinson's disease. Experimental Brain Research 1999;129:269±277), we suggest that the anatomical ``motor'' circuit formed by SMA-proper (see above), Basal Ganglia (BG) and Thalamus (Alexander GE, Crutcher MD. Functional architecture of basal ganglia circuits: neural substrates of parallel processing. Trends in the Neurosciences 1990;13:266±271, Hoover JE, Strick PL.
Multiple output channels in the basal ganglia. Nature 1993;259:819±821) may be involved in the control of actions: SMA-proper assembles the sequence of the action, whereas BG updates its parameters and stores them
Visual illusions and the control of children arm movements
No full textThe aim of the present study was to determine whether children like adults (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni
I. Visual illusion and action. Neuropsychologia 1996;34:369–76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position
tunes the contribution of allocentric and egocentric information to target localisation in human goal directed arm movements.
Neurosci Lett 1997;222:123–6) are influenced by visual illusions when they transform visual information in motor command.
Children and adults pointed to a shaft extremity of the Mu ̈ ller-Lyer configurations, as well as to an extremity of a control
configuration. Movements were executed in two experimental conditions. In the vision condition subjects saw both the stimulus
and their hand before and during movement. In the no vision (memory) condition subjects saw the stimulus and their hand before, but not during movement. Movement started 5 s after vision was precluded. The Mu ̈ ller-Lyer illusion affected pointing kinematics of both children and adults. As found previously (Gentilucci M, Chieffi S, Daprati E, Saetti MC, Toni I. Visual illusion and action. Neuropsychologia 1996;34:369–76; Gentilucci M, Daprati E, Gangitano M, Toni I. Eye position tunes the contribution
of allocentric and egocentric information to target localisation in human goal directed arm movements. Neurosci Lett
1997;222:123–6), subjects undershot and overshot the shaft extremity of the closed and of the open configuration, respectively.
The illusion effect was greater in the no vision than in the vision condition. These results show that in children like in adults the
system underlying visual perception in an object-centered frame of reference and that involved in motor control functionally
interact with each other. Although the processes of target localisation were the same, the transformation of target position
information in a sequence of motor patterns was different in children from that in adults. Even if both children and adults
lengthened duration of the deceleration phase in the vision condition, only adults shortened duration of the acceleration phase in order to maintain constant movement time (Viviani P, Schneider R. A developmental study of the relationship between geometry
and kinematics in drawing movements. J Exp Psychol 1991;17:198–218). This result suggests that children are yet unable to co-ordinate temporally acceleration with deceleration phase
Culture femministe e culture lgbtq. punti di convergenza e di contrasto
No full textIn varia misura a seconda dell’epoca e dei luoghi, le culture femministe hanno avversato più forme di discriminazione, oltre a quelle basate sul genere. In tal senso, da un paio di decenni, nell’ambito dei Gender Studies ha assunto rilevanza l’approccio intersezionale. Esso considera l’intreccio di discriminazioni multiple − che si sommano a quelle di genere − legate all’orientamento sessuale, all’etnia, all’età, alla classe sociale .
Però questo percorso di inclusione delle “differenze” è stato accidentato, come testimoniato, ad esempio, dalle critiche mosse dal black feminism al femminismo “bianco”, e recentemente dal dibattito, che ha anche assunto toni conflittuali, tra certi filoni femministi e le culture della comunità lgbtq. Questi contrasti hanno preso l’avvio dalla proposizione del ddl Zan, percepito da alcuni gruppi femministi come una minaccia alla specificità del genere femminile, che sia di origine biologica (la capacità riproduttiva innanzitutto) o culturale.
Tuttavia furono proprio i movimenti delle donne a mettere in luce che i ruoli maschili e femminili vengono costruiti fin dalla prima infanzia. Già nel 1949 ne Il secondo sesso Simone de Beauvoir dichiarava “Donna non si nasce, lo si diventa”. In quel periodo iniziò a diffondersi la “teoria della socializzazione di genere” (Gayle Rubin 1975; Giddens 1989): le differenze tra donne e uomini non sono naturali ma hanno origine culturale. Punti di vista radicali sostengono che anche il sesso è una costruzione sociale (Margaret Mead 1949; Berger e Luckmann 1966).
Tra i filoni femministi contrari a certi aspetti della cultura lgbtq (ad esempio la “fluidità del genere”, la GPA ̶ gestazione per altri, la scelta della prostituzione, denominata sex-work, come affermazione di autodeterminazione), vi sono quello cosiddetto della differenza (Irigaray 1994) tacciato di recente di essere trans-escludente e altri come quello denominato femonazionalista , ma esistono anche posizioni non riconducibili a etichette.
Si ritiene interessante e utile mettere a confronto le culture femministe e quelle della comunità lgbtq per individuare e riflettere sugli aspetti che hanno originato la contrapposizione sopra menzionata, e sulle possibilità di valorizzare i punti di convergenza (ad esempio il contrasto al patriarcato e l’indivisibilità dei diritti) mediante un approccio intersezionale.
Preliminarmente si forniscono brevi cenni sulla storia del femminismo e su quella della comunità lgbtq in Italia. Ci si propone poi di ripercorrere il dibattito innescato dalla proposta del parlamentare Zan mediante l’analisi qualitativa di documenti che lo hanno ospitato: fonti digitalizzate (quotidiani e riviste online) e fonti digitali (siti, blog). Seguiranno poi le voci di esponenti delle culture considerate: i punti critici individuati saranno sottoposti alla loro riflessione mediante interviste non direttive
Haptic information differentially interferes with visual analysis in reaching-grasping control and in perceptual processes
No full textWe used an interference paradigm in order to study integration between haptic and visual information in motor control and in perceptual analysis. Subjects either reached and grasped a visually presented sphere or matched its size with their left hand while manipulating with their right hand another sphere whose size could be smaller or greater. In four experiments haptic analysis of the manipulated sphere could be either automatically incorporated with or explicitly dissociated from visual analysis. In a fifth experiment reaching-grasping and matching were executed with the right hand, whereas manipulation was executed with the left hand. Manipulation with the right hand influenced finger shaping during grasping with the left hand when the sizes of the two objects were different. Interference was observed mainly in those experiments in which haptic analysis could be automatically integrated with visual analysis. In the matching task, no effect was observed. Finally, manipulation with the left hand did not produce any interference effect on reaching-grasping and matching executed by the right hand. The results of the present study suggest that somesthetic information is integrated with visual information only in sensorimotor transformations. In addition, they support the notion that the left hemisphere together with the right hemisphere is involved in the control of left hand reaching-grasping movements
Right-handers and left-handers have different representations of their own hand
No full textThe visual control of our own hand when dealing with an object and the observation of interactions between other people's hand and objects can be involved in the construction of internal representations of our own hand, as well as in hand recognition processes. Therefore, a different effect on handedness recognition is expected when subjects are presented with hands holding objects with either a congruent or an incongruent type of grip. Such an experiment was carried out on right-handed and left-handed subjects. We expected that the different degree of lateralisation in motor activities observed in the two populations [J. Herron, Neuropsychology of left-handedness, Academic Press, New York, 1980.] could account for the construction of different internal hand representations. As previously found [L.M. Parsons, Imaged spatial transformations of one's hands and feet, Cogn. Psychol., 19 (1987) 178-241.], in order to identify handedness, subjects mentally rotated their own hand until it matched with the presented one. This process was confirmatory, being preceded by an implicit visual analysis of the target hand. Presentation of hands holding objects with congruent or incongruent types of grip influenced handedness recognition at different stages in right-handed and left-handed subjects. That is, the mental rotation stage was affected in right-handed subjects, whereas the initial phase of implicit hand analysis was affected in left-handed subjects. We suggest that in handedness recognition, left-handers relied more on a pictorial hand representation, whereas right-handers relied more on a pragmatic hand representation, probably derived from experience in the control of their own movements. The use of different hand representations may be due to differential activation of temporal and premotor areas
Visual distractors differentially interfere with the reaching and grasping components of prehension movements
No full textIn the present study we addressed the issue of how an object is visually isolated from surrounding cues when a reaching-grasping (prehension) movement towards it is planned. Subjects were required to reach and grasp an object presented either alone or with a distractor. In five experiments, different degrees of elaboration of the distractor were induced by varying: (1) the position of the distractor (central or peripheral); (2) the time when the distractor was suppressed (immediately or delayed, with respect to stimulus presentation); and (3) the type of distractor analysis (implicit or explicit). In addition, we tested whether the possible effects of the distractor on reaching-grasping were due to the use of an allocentric reference centered on it. This was obtained by comparing the effects of the distractor with those of a stimulus, the target of a placing movement successive to the reaching-grasping. The results of the five experiments can be summarized as follows. The necessary condition for an interference effect on both the reaching and the grasping components was the central presentation of the distractor. When the information on the distractor could be immediately suppressed, an interference effect was observed only on the grasp component. In the case of delayed suppression, an effect was found on the reaching component. Finally, when an overt analysis of the distractor was required, the interference effect disappeared. Two main conclusions have been drawn from the results of the present study. First, comparison between properties of the target and surrounding cues is performed by two independent processes for reaching and grasping an object. The process for the grasp relies more on allocentric cues than that for the reach. Second, when surrounding stimuli are automatically analyzed during visual search of the target, the process of visuo-motor transformation can incorporate their features into the target. In contrast, overt analysis of surrounding stimuli is performed separately from that of the target. Finally, the data of the present study are discussed in support of the premotor theory of attention
Language and motor control
No full textWe investigated the possible influence of automatic word reading on processes of visuo-motor transformation. Subjects reached and grasped an object on which the following Italian words were printed: "VICINO" (near) or "LONTAN" (far) on an object either near or far from the agent (experiments 1, 2); PICCOLO (small) or "GRANDE" (large) on either a small or a large object (experiment 4); and "ALTO" (high) or "BASSO" (low) on either a high or a low object (experiment 5). The kinematics of the initial phase of reaching-grasping was affected by the meaning of the printed words. Namely, subjects automatically associated the meaning of the word with the corresponding property of the object and activated a reach and/or a grasp motor program influenced by the word. No effect on initial reach kinematics was observed for words related to object properties not directly involved in reach control (experiment 3). Moreover, in all the experiments, the presented words poorly influenced perceptual judgement of object properties. In experiments 5-7, the effects of the Italian adjectives "ALTO" (high) and "BASSO" (low) on reaching-grasping control were compared with those of the Italian adverbs "SOPRA" (up) and "SOTTO" (down). Adjectives influenced visual analysis of target-object properties, whereas adverbs more directly influenced the control of the action. We suggest that these effects resemble the structure of a sentence, where adjectives are commonly referred to nouns, and adverbs to verbs. In other words, class of words and, in a broad sense, grammar influenced motor control. The results of the present study show that cognitive functions such as language can affect visuo-motor transformation. They are discussed according to the notion that a strict relation between language and motor control exists, and that the frontal cortex can be involved in interactions between automatic word reading and visuo-motor transformation
Atteggiamenti omofobici. confronto fra test di completamento di frasi e scala likert
No full textQuesto lavoro è stato concepito per effettuare, tramite uno studio pilota appositamente ideato dall'autrice di questo libro, un confronto fra una tecnica di scaling - la tecnica Likert – e un test proiettivo - il Test di completamento di frasi – per rilevare il livello di uno specifico atteggiamento: l’omofobia. Questo obiettivo di ricerca nasce dall’interesse per le riflessioni teoriche sulla natura delle proprietà indagate nelle scienze psicosociali, e sui limiti nella rilevazione delle stesse
Haptic information differentially interferes with visual analysis in reaching-grasping control and perceptual processes.
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