Luisa Lugli

Novelty and emotion: Pupillary and cortical responses during viewing of natural scenes.

Given the remarkable similarities in the antecedent conditions-stimulus motivational relevance and novelty (i.e., probability of occurrence)-that elicit amplitude modulation of the late positive potential (LPP) and the pupillary dilation response, the present study examines whether these two indexes of orienting response reflect common processes that are responsible for modulatory patterns in motivationally relevant contexts. In the present study, the LPP and the pupillary dilation response were co-registered in a free-picture viewing context in which stimulus novelty was manipulated through repeated presentation of the same picture exemplar. More specifically, pictures depicting both emotional and neutral contents could be novel, that is never seen before in the course of the study, or repeated 4-8 times in a row (i.e., massed repetition). Results showed that, despite massed repetitions, the late positive potential amplitude continued to be highly modulated by picture content, whereas affective modulation of pupil dilation decreased with picture repetition. These findings indicate that, although the LPP and pupil dilation are similarly affected by motivational relevance during the viewing of novel pictures, they differ when pictures are highly familiar, possibly reflecting different functional meanings in the context of the orienting response.

Visual versus auditory Simon effect: a behavioural and physiological investigation.

This study investigated whether the visual and auditory Simon effects could be accounted for by the same mechanism. In a single experiment, we performed a detailed comparison of the visual and the auditory Simon effects arising in behavioural responses and in pupil dilation, a psychophysiological measure considered as a marker of the cognitive effort induced by conflict processing. To address our question, we performed sequential and distributional analyses on both reaction times and pupil dilation. Results confirmed that the mechanisms underlying the visual and auditory Simon effects are functionally equivalent in terms of the interaction between unconditional and conditional response processes. The two modalities, however, differ with respect to the strength of their activation and inhibition. Importantly, pupillary data mirrored the pattern observed in behavioural data for both tasks, adding physiological evidence to the current literature on the processing of visual and auditory information in a conflict task.

Action-space coding in social contexts

In two behavioural experiments we tested whether performing a spatial task along with another agent changes space representation by rendering some reference frames more/less salient than others. To this end, we used a Simon task in which stimuli were presented in four horizontal locations thus allowing for spatial coding according to multiple frames of reference. In Experiment 1 participants performed a go/no-go Simon task along another agent, each being in charge of one response. In Experiment 2 they performed a two-choice Simon task along another agent, each being in charge of two responses. Results showed that when participants were in charge of only one response, stimulus position was coded only with reference to the centre of the screen hence suggesting that the co-actor’s response, or the position of the co-actor, was represented and used as a reference for spatial coding. Differently, when participants were in charge of two responses, no effect of the social context emerged and spatial coding relied on multiple frames of reference, similarly to when the Simon task is performed individually. These findings provide insights on the influence played by the interaction between the social context (i.e. the presence of others) and task features on individual performance.

Eyes keep watch over you! Competition enhances joint attention in females.

The present study investigated if the gaze-cuing effect (i.e., the tendency for observers to respond faster to targets in locations that were cued by others gaze direction than to not-cued targets) is modulated by the type of relationship (i.e., cooperative or competitive) established during a previous interaction with a cuing face. In two experiments, participants played a series of single-shot games of a modified version of the two-choice Prisoners Dilemma against eight simulated contenders. They were shown a fictive feedback indicating if the opponents chose to cooperate or compete with them. Opponents faces were then used as stimuli in a standard gaze-cuing task. In Experiment 1 females classified as average in competitiveness were tested, while in Experiment 2 females classified as high and low in competitiveness were tested. We found that only in females classified as low and average in competitiveness the gaze-cuing effect for competitive contenders was greater than for cooperative contenders. These findings suggest that competitive opponents represent a relevant source of information within the social environment and female observers with low and average levels of competition cannot prevent from keeping their eyes over them.

Hitting is male, giving is female: automatic imitation and complementarity during action observation

Is somebody going to hurt us? We draw back. The present study investigates using behavioral measures the interplay between imitative and complementary actions activated while observing female/male hands performing different actions. Female and male participants were required to discriminate the gender of biologically and artificially colored hands that displayed both individual (grasping) and social (giving and punching) actions. Biological hands evoked automatic imitation, while hands of different gender activated complementary mechanisms. Furthermore, responses reflected gender stereotypes: giving actions were more associated to females, punching actions to males. Results have implications for studies on social stereotyping, and for research on action observation, showing that the mirror neuron system resonates in both an imitative and complementary fashion.

Interactive effects between gaze direction and facial expression on attentional resources deployment: the task instruction and context matter

In three experiments, we tested whether the amount of attentional resources needed to process a face displaying neutral/angry/fearful facial expressions with direct or averted gaze depends on task instructions, and face presentation. To this end, we used a Rapid Serial Visual Presentation paradigm in which participants in Experiment 1 were first explicitly asked to discriminate whether the expression of a target face (T1) with direct or averted gaze was angry or neutral, and then to judge the orientation of a landscape (T2). Experiment 2 was identical to Experiment 1 except that participants had to discriminate the gender of the face of T1 and fearful faces were also presented randomly inter-mixed within each block of trials. Experiment 3 differed from Experiment 2 only because angry and fearful faces were never presented within the same block. The findings indicated that the presence of the attentional blink (AB) for face stimuli depends on specific combinations of gaze direction and emotional facial expressions and crucially revealed that the contextual factors (e.g., explicit instruction to process the facial expression and the presence of other emotional faces) can modify and even reverse the AB, suggesting a flexible and more contextualized deployment of attentional resources in face processing.

The Simon Effect With Saccadic Eye Movements

In the Simon effect performance is faster and more accurate when the task-irrelevant spatial dimension of the stimulus corresponds to the location of the response, compared to when they do not correspond. In the prosaccade-antisaccade effect the latencies of saccades away from the stimulus location (i.e., antisaccades) are slower than the latencies of saccades toward the stimulus location (i.e., prosaccades). Because these two effects share a similar basis, the study of the Simon effect with saccadic eye movements needs to be decoupled from the prosaccade-antisaccade effect. A standard Simon task (Experiment 1) and a Simon task in which a distractor stimulus was also presented (Experiment 2) were implemented. In Experiment 1, results showed an effect likely attributable to the sum of the Simon effect and the prosaccade-antisaccade effect. In Experiment 2, in which the difference between the prosaccade and antisaccade was eliminated, only a Simon effect, cognitive in nature, manifested itself.

The Multilevel Modality-Switch Effect: What Happens When We See the Bees Buzzing and Hear the Diamonds Glistening

Previous studies demonstrated that the sequential verification of different sensory modality properties for concepts (e.g., BLENDER-loud; BANANA-yellow) brings about a processing cost, known as the modality-switch effect. We report an experiment designed to assess the influence of the mode of presentation (i.e., visual, aural) of stimuli on the modality-switch effect in a property verification and lexical decision priming paradigm. Participants were required to perform a property verification or a lexical decision task on a target sentence (e.g., “a BEE buzzes”, “a DIAMOND glistens”) presented either visually or aurally after having been presented with a prime sentence (e.g., “the LIGHT is flickering”, “the SOUND is echoing”) that could either share both, one or none of the target’s mode of presentation and content modality. Results show that the mode of presentation of stimuli affects the conceptual modality-switch effect. Furthermore, the depth of processing required by the task modulates the complex interplay of perceptual and semantic information. We conclude that the MSE is a task-related, multilevel effect which can occur on two different levels of information processing (i.e., perceptual and semantic).

Comparing Stroop-like and Simon Effects on Perceptual Features

Stroop-like and Simon tasks produce two sources of interference in human information processing. Despite being logically similar, it is still debated whether the conflicts ensuing from the two tasks are resolved by the same or different mechanisms. In the present study, we compare two accounts of the Stroop-like effect. According to the Perceptual Account, the Stroop-like effect is due to Stimulus-Stimulus congruence. According to the Decisional Account, the Stroop-like effect results from the same mechanisms that produce the Simon effect, that is, Stimulus-Response compatibility. In two experiments we produced Stroop-like and Simon effects by presenting left/right-located stimuli consisting of a colored square surrounded by a frame of the same color as the square or of a different color. Results showed that discriminating either the color of the square (Experiment 1) or that of the frame (Experiment 2) yielded additive Stroop-like and Simon effects. In addition, the patterns of temporal distributions of the two effects were different. These results support the Perceptual Account of the Stroop-like effect and the notion that the Stroop-like effect and the Simon effect occur at different processing stages and are attributable to different mechanisms.

The Role of Visual Distractors in the Simon Effect

The Simon effect lies on the automatic generation of a stimulus spatial code, which, however, is not relevant for performing the task. Results typically show faster performance when stimulus and response locations correspond, rather than when they do not. Considering reaction time distributions, two types of Simon effect have been individuated, which are thought to depend on different mechanisms: visuomotor activation versus cognitive translation of spatial codes. The present study aimed to investigate whether the presence of a distractor, which affects the allocation of attentional resources and, thus, the time needed to generate the spatial code, changes the nature of the Simon effect. In four experiments, we manipulated the presence and the characteristics of the distractor. Findings extend previous evidence regarding the distinction between visuomotor activation and cognitive translation of spatial stimulus codes in a Simon task. They are discussed with reference to the attentional model of the Simon effect.