Cristina Iani

Simon-like and functional affordance effects with tools: The effects of object perceptual discrimination and object action state

In the present study two separate stimulus–response compatibility effects (functional affordance and Simon-like effects) were investigated with centrally presented pictures of an object tool (a torch) characterized by a structural separation between the graspable portion and the goal-directed portion. In Experiment 1, participants were required to decide whether the torch was red or blue, while in Experiment 2 they were required to decide whether the torch was upright or inverted. Our results showed that with the same stimulus two types of compatibility effect emerged: one based on the direction signalled by the goal-directed portion of the tool (a Simon-like effect as observed in Experiment 1), and the other based on the actions associated with an object (a functional affordance effect as observed in Experiment 2). Both effects emerged independently of the persons intention to act on the stimulus, but depended on the stimulus properties that were processed in order to perform the task.

The role of group membership on the modulation of joint action

Two experiments were conducted to assess whether the emergence of shared representations, as indexed by the joint Simon effect, is modulated by perceived group membership. In both experiments, participants were required to perform a Simon task along another person who was perceived as belonging either to the same group or to a different group. In Experiment 1, ingroup–outgroup discrimination was obtained by dividing participants into two groups based on a superficial criterion; in Experiment 2, it was obtained by manipulating the interdependence experienced by the two acting individuals. The mere social categorization of co-acting participants into groups did not modulate the joint Simon effect which was observed even when participants believed to perform the task along with an individual belonging to a different social group (Experiment 1). On the contrary, the effect was modulated by perceived interdependence, with a null effect when participants experienced negative interdependence (Experiment 2). These results suggest that when acting in a social context, by default, individuals may perceive positive interdependence with co-acting individuals, even when cooperation is not explicitly requested.

Shared learning shapes human performance: Transfer effects in task sharing

We investigated whether performing a task with a co-actor shapes the way a subsequent task is performed. In four experiments participants were administered a Simon task after practicing a spatial compatibility task with an incompatible S-R mapping. In Experiment 1 they performed both tasks alongside another person; in Experiment 2 they performed the spatial compatibility task alone, responding to only one stimulus position, and the Simon task with another person; in Experiment 3, they performed the spatial compatibility task with another person and the Simon task alone; finally, in Experiment 4, they performed the spatial compatibility task alone and the Simon task with another person. The incompatible practice eliminated the Simon effect in Experiments 1 and 4. These results indicate that when a task is distributed between two participants with each one performing a different part of it, they tend to represent the whole task rather than their own part of it. This experience can influence the way a subsequent task is performed, as long as this latter occurs in a social context.

Co-occurrence of sequential and practice effects in the Simon task: Evidence for two independent mechanisms affecting response selection

The Simon effect refers to the observation that responses to a relevant stimulus dimension are faster and more accurate when the stimulus and response spatially correspond than when they do not, even though stimulus position is irrelevant. Recent findings have suggested that the Simon effect can be strongly modulated by prior practice with a spatially incompatible mapping and by correspondence sequence. Although practice is thought to influence conditional stimulus —response (S-R) processing, leaving response priming through the unconditional route unaffected, sequential effects are thought to represent trial-by-trial adaptations that selectively involve unconditional S —R processing. In the present study, we tested this assumption by assessing the effects of correspondence sequence both when the Simon task alone was performed and when it was preceded by a spatial compatibility task with either incompatible (Experiments 1-2) or compatible (Experiment 2) instructions. The observation that practice and correspondence sequence co-occur and exert additive effects strongly demonstrates that the two factors affect different processing routes.

Hypnotic Suggestion Modulates Cognitive Conflict The Case of the Flanker Compatibility Effect

The present work was aimed at investigating whether the flanker compatibility effect can be eliminated by means of a posthypnotic suggestion influencing attentional focusing. In Experiment 1, participants who scored high and low on hypnotic susceptibility performed the flanker compatibility task when naturally awake and when under a posthypnotic suggestion aimed at increasing the targets discriminability from the flankers. Results showed that the posthypnotic suggestion effectively eliminated the flanker compatibility effect in highly susceptible participants, whereas low-susceptibility participants did not show any reduction in the effect. In Experiment 2, highly susceptible participants performed the task after receiving a suggestion but without the induction of hypnosis. Results showed that the suggestion alone was not sufficient to reduce the flanker compatibility effect. These results support the view that in highly susceptible participants, hypnotic suggestion can influence the ability to focus on relevant information.

On the relationship between affordance and Simon effects: Are the effects really independent?

The aim of the present study was to investigate the relationship between the affordance effect (i.e., the advantage for responses corresponding spatially with the location of an objects graspable part) and the Simon effect (i.e., the advantage for responses corresponding spatially with stimulus location) and to assess whether they both occur at the response selection stage. In two experiments participants were required to respond according to the vertical orientation (upward or inverted) of photographs of graspable objects, located to the left or right of fixation, with their handles oriented to the right or left. In Experiment 1 the response was a buttonpress; in Experiment 2 was a reaching movement. Our results showed that both Simon and affordance effects emerged in response times but not in movement times. In Experiment 1, the two effects did not interact, whereas a clear interaction emerged in Experiment 2. These results seem to suggest that the interaction between Simon and affordance effects may depend on the type of required action.

Attention control and susceptibility to hypnosis

The present work aimed at assessing whether the interference exerted by task-irrelevant spatial information is comparable in high- and low-susceptible individuals and whether it may be eliminated by means of a specific posthypnotic suggestion. To this purpose high- and low-susceptible participants were tested using a Simon-like interference task after the administration of a suggestion aimed at preventing the processing of the irrelevant spatial information conveyed by the stimuli. The suggestion could be administered either in the absence or following a standard hypnotic induction. We showed that, outside from the hypnotic context, the Simon effect was similar in high and low-susceptible participants and it was significantly reduced following the posthypnotic suggestion in high-susceptible participants only. These results show that a specific posthypnotic suggestion can alter information processing in high-susceptible individuals and reduce the interfering effect exerted by arrow stimuli.

Contextual determinants of the social-transfer-of-learning effect

A recent study (Milanese et al. in Cogn 116(1):15–22, 2010) showed that performing a spatial compatibility task with incompatible S–R links (i.e., the practice task) alongside a co-actor eliminates the Simon effect in a subsequent joint Simon task (i.e., the transfer task). In the present study, we conducted three experiments to individuate which elements of the practice task need to remain constant for this social-transfer-of-learning to occur. In Experiment 1, participants performed the practice task alongside a co-actor and the Simon task with a different co-actor; in Experiment 2, they performed the practice task alongside a co-actor and the Simon task with the same co-actor after exchanging their seats. Results showed a modulation of the joint Simon effect in Experiment 1 only. In Experiment 2, we found a regular joint Simon effect. These results indicate that, while co-actor identity is not crucial, other elements of the context, such as keeping the same position across tasks, are necessary for the social-transfer-of-learning to occur. On the whole, our data suggest that the social-transfer-of-learning effect is not tuned to a specific co-actor and depends on spatial parameters of the practice and transfer tasks.

Shifting attention between objects

Experiment 1 used a modified spatial cueing paradigm that was introduced by Egly et al. [J. Exp. Psychol. Gen. 123 (1994) 161] to investigate the cost incurred in shifting attention within an object as opposed to shifting attention between objects. Subjects were presented with two outline rectangles and had to detect a target (a luminance increment) that could appear in the cued location (valid trials), in an uncued location inside the cued rectangle (inside-invalid trials), or in an uncued location inside the uncued rectangle (outside-invalid trials). Valid trials were faster than invalid trials, and inside-invalid trials were faster than outside-invalid trials. In Experiment 2, the two rectangles were joined to form a unitary object. Here, no difference was found between outside-invalid trials and inside-invalid trials. Experiment 3 showed that the delayed response on outside-invalid trials in Experiment 1 was not due to attention needing to cross the figural borders in order to re-orient to the uncued rectangle. The results were interpreted as showing that an extra cost is incurred for shifting attention between different objects.

Facilitation and interference components in the joint Simon task

Two experiments were conducted to assess whether the joint Simon effect is composed of facilitation and interference and whether facilitation is increased by a joint spatially compatible practice performed before performing the joint Simon task. In both experiments, participants were required to perform a Simon task along another person. Trials could be corresponding, non-corresponding, and neutral. In Experiment 1, participants performed only the Simon task. In Experiment 2, participants first practiced on a joint spatial compatibility task with a compatible mapping and, after a 5-min delay, transferred to a joint Simon task. Results indicated that the joint Simon effect consisted primarily of interference, which was significantly increased by a spatially compatible practice performed jointly. These results allow us to better define in what ways the presence of the other influences performance, in showing that when participants perform a task along with another individual, they display a disadvantage (i.e., slower RTs) when they have to respond to stimuli appearing on the other agent’s side.