New evidence for the perceptual precedence of global information

Two experiments are reported investigating the order in which global and local information of visual forms is processed. Subjects were presented with compound stimuli and were asked to identify the local level, always consisting of small letters. At the global level, the stimuli could be either large letters, consistent or inconsistent with the local level, or meaningless patterns derived from the large letters by modifying the spatial relations among segments. Results showed that inconsistent stimuli were responded to more slowly than both consistent stimuli and meaningless patterns, which did not differ from each other. This was true both when letters and patterns were presented intermixed, as in experiment 1 or separately, as in experiment 2. The pattern obtained accords well with predictions derived from the perceptual precedence hypothesis which states that global information becomes available at a faster rate than local information. No support for the alternative, post-perceptual, hypothesis was found.     

Contingent application of the cancellation editing operation: the role of semantic relatedness between risky outcomes

This article presents findings on the restructuring component of the decision process. Two experiments are described employing hypothetical vacation choice dilemmas. The aim was to explore the conditions under which outcomes common to two risky prospects with the same probabilities of occurrence are or are not cancelled and how consequent decisions are influenced. The design of the options presented to participants was based on pilot work to establish appropriate contexts. The key independent variable was the semantic relatedness between outcomes of the same risky prospect. The main finding was that the participants did not cancel the outcome shared by two prospects when it was semantically related to another outcome within the same prospect. In this case, the prospect with greater risk was chosen significantly more frequently in comparison to when the common outcome was unrelated to other outcomes. An interpretation of the findings is presented in terms of contingent editing processes. Copyright © 2004 John Wiley & Sons, Ltd.     

The role of emotional context in facilitating imitative actions

In two experiments, we explored whether emotional context influences imitative action tendencies. To this end, we examined how emotional pictures, presented as primes, affect imitative tendencies using a compatibility paradigm. In Experiment 1, when seen index finger movements (lifting or tapping) and pre-instructed finger movements (tapping) were the same (tapping–tapping, compatible trials), participants were faster than when they were different (lifting–tapping, incompatible trials). This compatibility effect was enhanced when the seen finger movement was preceded by negative primes compared with positive or neutral primes. In Experiment 2, using only negative and neutral primes, the influence of negative primes on the compatibility effect was replicated with participants performing two types of pre-instructed finger movements (tapping and lifting). This emotional modulation of the compatibility effect was independent of the participants' trait anxiety level. Moreover, the emotional modulation pertained primarily to the compatible conditions, suggesting facilitated imitation due to negatively valent primes rather than increased interference. We speculate that negative stimuli increase imitative tendencies as a natural response in potential flight-or-fight situations.     

The effects of task requirements on the processing of complex stimuli

In the present study the effects of task requirements were investigated using a same-different paradigm with geometric configurations as stimuli. Two conditions were employed: in the first, the instructions required the subjects to focus upon all dimensions of the stimuli; in the second, instead, the instructions required the subjects to attend only to some of the dimensions. The results show that in the first condition the subjects, in order to reach their decision, used a template- matching strategy, while in the second condition an analytic strategy was employed.     

To imitate or not to imitate? How the brain can do it, that is the question!

In this paper the authors discuss the most prominent views addressing the issue of how we imitate actions. It is argued that the existing theories lay along a continuum, with the direct mapping approach at one end (Butterworth, 1990; Gray, Neisser, Shapiro, & Kouns, 1991) the Active Intermodal Matching approach (Melzoff & Moore, 1997) in the middle, and the goal-directed theory (Bekkering, Wohlsh?ger, & Gattis, 2000) and the dual route theory (Rumiati & Tessari, 2002) at the opposite end. Interestingly the latter views can account for behaviors that cannot be explained by invoking the direct mapping or the Active Intermodal Matching approach.     

A kinematic analysis of age-related changes in grasping to use and grasping to move common objects

Grasping is a complex action which requires high-level motor control. Although the impact of aging on grasping has been investigated in some studies, to date little is known as to how the aging process interacts with the purpose of the movement. The aims of the present study were (i) to investigate the effect of aging on grasping movements, and to explore on how this effect is modulated by (ii) the goal of the task, and by (iii) the characteristics of the target such as its location in the visual field, its orientation and its size. Young and elderly adults were asked to grasp to move or to grasp to use objects of different sizes and orientations, presented either in the central or the peripheral visual field. Movement duration did not differ between the two groups. However, elderly participants required a longer approach phase and showed a different grasping strategy, characterized by larger grip aperture and smaller percentage of wrist rotation in comparison to young adults. Elderly adults showed a decrease in accuracy when grasping objects presented in the peripheral, but not in the central visual field. A similar modulation of the kinematic parameters consisting in longer planning and execution phases in the grasp to use in comparison to the grasp to move condition was observed in both groups, suggesting that the effect of aging might be minimized and compensated in more goal-directed tasks.     

Processing of global and local information in memory

The experiments reported in this paper were designed to test how global and local information are processed by the memory system. When subjects are required to match a given letter with either a previously presented large capital letter or the small capital letters comprising it, (1) responses to the global level (i.e. the big letter) are faster than responses to the local level (i.e. the small letters), and (2) responses to the latter level only are affected by the consistency between the large and the small letters (Experiment 2), a pattern similar to that obtained in perception (Experiment 1). Such results obtain when subjects are required to attend to only one level with a short ISI between the first and second stimulus, but not when a longer ISI is used (Experiment 5) or when subjects are required to attend to both levels at the same time (Experiments 3 and 4). The results are discussed in the light of a model that postulates a temporal precedence of the global information over the local one at the perceptual level.