Cognitive representations of obligation and prohibition signs when they provide the same amount of semantic information

Esta investigación pretende investigar si existe una dificultad inherente en la comprensión de las señales de prohibición respecto a las señales de obligación. En este estudio los participantes decidían si las maniobras realizadas por un vehículo esquemático, presentando en una pantalla de ordenador, estaban permitidas o no de acuerdo con las señales mostradas. Se utilizaron diversas escenas, tales como intersección en T. En estas situaciones, una señal de "obligación a la izquierda" indica también que girar a la derecha no está permitido, es decir, es equivalente a la señalización "no girar a la derecha". Ambas señalizaciones aunque diferentes, determinan igualmente que una de las carreteras está "permitida" y la otra no. Sin embargo, los estudios de razonamiento sugieren diferencias comportamentales ante ambas situaciones. Investigaciones previas mostraron ventaja global para las señales de obligación. En este estudio se controló el número de carreteras alternativas referidas por cada tipo de señal, usando distintos tipos de intersecciones de carreteras. En estas condiciones particulares, los resultados no mostraron ventaja global para las señales de obligación o prohibición, sino que dependió de la maniobra. Las respuestas más rápidas se dieron con maniobra permitida ante señales de obligación y con maniobra no permitida ante señales de prohibición. Estos resultados, usando situaciones esquemáticas, son consistentes con las predicciones de teorías como la de los modelos mentales sobre razonamiento con proposiciones deónticas(AU)

The aim of this research was to test whether there is an inherent difficulty in understanding prohibition signs rather than obligation signs. In the experiment conducted, participants decided whether simple car movements presented on a computer screen were allowed or not according to either obligation or prohibition traffic signs. The information provided by obligation and prohibition signs at a T-junction can be understood as messages in the form: A "mandatory left turn" sign indicates that turning right is not allowed, the same as a "no right turn" sign. Both statements mark each of the relevant roads as "allowed" and "not-allowed" in exactly the same way. However, reasoning studies suggest dramatic differences in behaviour. Previous research showed a general advantage for obligation signs. In this study, the number of alternative roads indicated by these two kinds of traffic sign was controlled using different crossroad junctions. In those particular conditions, our results showed that there is no overall advantage for either obligation or prohibition signs. It depends on the manoeuvre performed by the vehicle. Obligation signs produce faster responses when the manoeuvre is allowed, whereas prohibition signs show faster reaction times when the manoeuvre is not allowed. Those results obtained with diagrammatic information are consistent with some cognitive theories, such as the mental model theory about reasoning with deontic propositions(AU)

Spotlight failure effect in exogenous orienting.

Many experimental results about spatial attention have been explained by assuming the existence of an attentional "spotlight" which can move from one location in visual space to another. Such an account has been recently challenged by findings which show the influence of nonspatial factors in spatial attention. In particular, the so-called "spotlight failure" effect refers to the influence of the probability of occurrence of different stimuli. However, such an effect has only been reported in the case of endogenous (or central) orientation, rather than on exogenous (or peripheral) orienting. We present evidence showing that the spotlight failure effect can be obtained with exogenous orienting, even at a short SOA (100 ms). Besides, experimental instructions can modulate the effect, which agrees with theoretical accounts proposing that top-down factors can influence attentional capture.

A more complete task-set reconfiguration in random than in predictable task switch.

Three experiments are presented that compare the cost found when switching from one task to another in two different conditions. In one of them, the tasks switch in predictable sequences. In the other condition, the tasks alternate at random. A smaller time cost is found in the random-switch condition when enough preparation time is allowed. Such an effect is due to the random-switch cost continuing to decrease with preparation time after the predictable-switch cost has reached an asymptote. Although the relationship between number of repetitions of one task and time cost is different in the random- and the predictable-switch conditions, only the latter shows the presence of an "exogenous" component of cost. The implications of this finding are discussed in relationship with the usual distinction between an endogenous component of switch cost that is affected by preparation time and another exogenous, residual component (e.g., Rogers & Monsell, 1995). It is proposed that a different kind of task-set preparation is at work when tasks alternate at random.

Does IOR occur in discrimination tasks? Yes, it does, but later.

When a stimulus appears in a previously cued location several hundred milliseconds after the cue, the time required to detect that stimulus is greater than when it appears in an uncued location. This increase in detection time is known as inhibition of return (IOR). It has been suggested that IOR reflects the action of a general attentional mechanism that prevents attention from returning to previously explored loci. At the same time, the robustness of IOR has been recently disputed, given several failures to obtain the effect in tasks requiring discrimination rather than detection. In a series of eight experiments, we evaluated the differences between detection and discrimination tasks with regard to IOR. We found that IOR was consistently obtained with both tasks, although the temporal parameters required to observe IOR were different in detection and discrimination tasks. In our detection task, the effect appeared after a 400-msec delay between cue and target, and was still present after 1,300 msec. In our discrimination task, the effect appeared later and disappeared sooner. The implications of these data for theoretical accounts of IOR are discussed.