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L’obiettivo del presente lavoro è stato quello di indagare il ruolo dei processi percettivi (i.e. figural binding) e attentivi coinvolti nella percezione di una figura illusoria di Kanizsa. Nel primo esperimento si è cercato di individuare quali strategie visuo-eplorative vengono messe in atto per selezionare un triangolo illusorio di Kanizsa inserito in un insieme di elementi inducenti (pacman) e se le strategie visuo-esplorative coinvolte nell’individuazione del triangolo illusorio sono le stesse implicate nella selezione di un triangolo reale. Nel secondo esperimento è stato ridotto il numero dei pacman al fine di verificare se la selezione della figura illusoria coinvolge le stesse modalità attentive implicate nella selezione della figura reale. I risultati ottenuti attraverso la registrazione dei movimenti oculari dimostrano che la figura di Kanizsa e la figura reale vengono selezionate per prime e in minor tempo rispetto agli altri elementi presenti nel display e che sia lo stimolo illusorio che lo stimolo non illusorio sono selezionati senza l’intervento di una ricerca seriale dell’attenzione.

This study investigated processing of number and extent in newborns. Using visual preference, we showed that newborns discriminated between small sets of dot collections relying solely on implicit numerical information when non-numerical continuous variables were strictly controlled (Experiment 1), and solely on continuous information when numerical variables were controlled (Experiment 2). When number and extent were pitted against each other (Experiment 3), newborns showed no visual preference, suggesting that the two variables play comparable roles in attracting newborns’ visual attention. In contrast to reports of dominance of continuous variables, these findings suggest that multiple dimensions attract newborns’ attention and guide their visual exploration.

The aim of the present study was to investigate how perceptual binding and selective attention operate during infants' and adults' visual search of an illusory figure. An eye-tracker system was used to test adults and infants in two conditions: illusory and non-illusory (real). In the illusory condition, a Kanizsa triangle was embedded among distractor pacmen which did not generate illusory contours. In the non-illusory condition, a real triangle was included in the same pacmen's display. The results showed that adults detected both the Kanizsa and the real figure automatically and without focal attention (experiment 1). In contrast, 6-month-old infants showed a pop-out effect only for the real figure (experiment 2). The failure of the illusory figure to trigger infants' attention was not due to infants' inability to perceive the illusory figure per se, as infants preferred the illusory figure over a non-illusory control stimulus in a classical preferential-looking task (experiment 3). Overall, these findings indicate that the illusory Kanizsa triangle triggers visual attention in adults, but not in infants, supporting evidence that at 6 months of age the binding processes involved in the perception of a Kanizsa figure do not operate in an adult-like manner.

Many studies have shown that newborns prefer (e.g. Goren, Sarty & Wu, 1975; Valenza, Simion, Macchi Cassia & Umiltà, 1996) and recognize (e.g. Bushnell, Say & Mullin, 1989; Pascalis & de Schonen, 1994) faces. However, it is not known whether, at birth, faces are still preferred and recognized when some of their parts are not visible because hindered by other configurations, that is when faces are partly occluded. Also, it is not known whether newborns’ preference for an upright over an inverted face and newborns’ face recognition are differentially affected depending on the salience of the occluded face features. Seventy-seven newborns (mean age of 43.5 hrs) were tested using the preferential looking (Experiment 1) and the habituation techniques (Experiment 2). Results demonstrated that newborns prefer and recognize occluded faces even if some portions of them are not available, at least when the hindered features are not salient. On the contrary, these abilities are affected by obscuring high salience facial features (i.e. eyes). However, while in the case of face detection, eyes occlusion completely prevented newborns’ face detection, in the case of face recognition an analogous stimulus manipulation heavily impaired, but did not totally preclude, newborns’ recognition performance. The data collected improve our comprehension of newborns’ way of processing and encoding information to detect and recognize faces.

Il volume offre un panorama aggiornato dei modelli teorici che la psicologia ha elaborato per spiegare le cause e i meccanismi che determinano lo sviluppo della mente umana. Dopo aver affrontato nella prima parte le teorie classiche, le autrici passano in rassegna, nella seconda parte, i modelli più recenti relativi allo sviluppo cognitivo, sottolineandone gli aspetti interdisciplinari. È così illustrato con chiarezza il fondamentale ruolo che questo filone di ricerca svolge nell’indagine sull’architettura e sul funzionamento della mente umana.

The present study aimed to investigate whether perceptual completion is available at birth, in the absence of any visual experience. An extremely underspecified kinetic visual display composed of four spatially separated fragments arranged to give rise to an illusory rectangle that occluded a vertical rod (illusory condition) or rotated so as not to elicit perceptual grouping (control condition) was constructed. After newborns’ ability to detect the particular kind of rod-and-box display used in the present study had been probed (Experiment 1), they were habituated to the illusory rod-and-box display (Experiment 2), to the control display that did not contain illusory contours (Experiment 3), and to a standard real rod-and-box display akin to those used in previous infants’ studies (Experiment 4). Newborns perceived the rod as a connected unit either in the illusory condition (Experiment 2) or in the real condition (Experiment 4), as documented by a preference for a broken rod over a complete rod during the test phase, but not when the occluder was absent (Experiment 3). In all experiments newborns showed no preference between the two test stimuli (control condition), avoiding the possibility that newborns have a spontaneous preference for one test display over the other. Overall, the results of the present study provide evidence that the ability to achieve object unity (1)stems from intrinsic properties of the human perceptual system and (2) is operative from birth, given the right conditions.

Past research has shown that top-heaviness is a perceptual property that plays a crucial role in triggering newborns’ preference toward faces. The present study examined the contribution of a second configural property, congruency, to newborns’ face preference. Experiments 1 and 2 demonstrated that, when embedded in non-facelike stimuli, congruency induces a preference of the same strength of that induced by facedness. Experiments 3 and 4 demonstrated that the attentional biases toward facedness and congruency produce a cumulative effect on newborns’ visual preferences according to an additive model. These findings were extended by those of Experiment 5, showing that the additive model holds true when congruency is added to top-heaviness in non-facelike stimuli displaying more elements in the upper portion.

The present chapter deals with the topic of the ontogeny and development of face processing in the first months of life and is organized into two sections concerning face detection and face recognition. The first section focuses on the mechanisms underlying infants' visual preference for faces. Evidence is reviewed supporting the contention that newborns' face preferences is due to a set of non-specific constraints that stem from the general characteristics of the human visuo-perceptual system, rather than to a representational bias for faces. It is shown that infants' response to faces becomes more and more tuned to the face category over the first 3 months of life, revealing a gradual progressive specialization of the face-processing system. The second section sought to determine the properties of face recognition at birth. In particular, a series of experiments are presented to examine whether the inner facial part is processed and encoded when newborns recognize a face, and what kind of information - featural or configural - newborns' face recognition rely on. Overall, results are consistent with the existence of general constraints present at birth that tune the system to become specialized for faces later during development.

Previous research, in which static figures were used, showed that the ability to perceive illusory contours emerges around 7 months of age. However, recently, evidence has suggested that 2–3-month-old infants are able to perceive illusory contours when motion information is available (Johnson & Mason, 2002; Otsuka & Yamaguchi, 2003). The present study was aimed at investigating whether even newborns might perceive kinetic illusory contours when a motion easily detected by the immature newborn’s visual system (i.e. stroboscopic motion) is used. In Experiment 1, using a preference looking technique, newborns’ perception of kinetic illusory contours was explored using a Kanizsa figure in a static and in a kinetic display. The results showed that newborns manifest a preference for the illusory contours only in the kinetic, but not in the static, condition. In Experiment 2, using an habituation technique, newborns were habituated to a moving shape that was matched with the background in terms of random-texture-surface; thus the recovery of the shape was possible relying only on kinetic information. The results showed that infants manifested a novelty preference when presented with luminance-defined familiar and novel shapes. Altogether these findings provide evidence that motion enhances (Experiment 1) and sometimes is sufficient (Experiment 2) to induce newborns’ perception of illusory contours.