Modal completion: critical variables in apparent transparency

Conditions for perceptual modal completion are investigated using a stimulation pattern consisting of a figure moving behind a black opaque strip. This configuration leads, depending on conditions, either to the amodal Michotte tunnel effect, or to modal completion, ie the apparent transparency phenomenon. Four experiments are reported in which an attempt was made to define the critical variables of this latter effect. The results show that modal completion is not typically related to luminance interactions, ie to assimilation, but depends on the figural dominance of the filled-in object, this being determined by structural factors such as figure-ground relationship and stimulation change. The effect also depends strongly on the complexity of the spatiotemporal integration needed to maintain phenomenal identity of the object. No significant effect was found for the two other variables investigated, ie formal complexity of the figure and depth between the figure and the strip. The data are discussed in relation to those on moving visual phantoms.     

One‐year‐old infants use teleological representations of actions productively

Two experiments investigated whether infants represent goal‐directed actions of others in a way that allows them to draw inferences to unobserved states of affairs (such as unseen goal states or occluded obstacles). We measured looking times to assess violation of infants' expectations upon perceiving either a change in the actions of computer‐animated figures or in the context of such actions. The first experiment tested whether infants would attribute a goal to an action that they had not seen completed. The second experiment tested whether infants would infer from an observed action the presence of an occluded object that functions as an obstacle. The looking time patterns of 12‐month‐olds indicated that they were able to make both types of inferences, while 9‐month‐olds failed in both tasks. These results demonstrate that, by the end of the first year of life, infants use the principle of rational action not only for the interpretation and prediction of goal‐directed actions, but also for making productive inferences about unseen aspects of their context. We discuss the underlying mechanisms that may be involved in the developmental change from 9 to 12 months of age in the ability to infer hypothetical (unseen) states of affairs in teleological action representations.     

Strategic associative priming in the lexical decision task

Two experiments explore the nature of prelexical expectancy processes in the lexical decision task. The strength of the prime-target relationship and the size of the associative set defined by the prime were manipulated in both experiments. In Experiment 1, the proportion of strong relative to weak primes induced subjects to include strong and weak candidate words in their expectancy set, whereas in Experiment 2 that proportion attempted to induce subjects to include mainly strongly related words. Results showed that priming depended on whether the primes were included in the set. Thus, in Experiment 1 facilitation was obtained for both strong and weak primes, whereas in Experiment 2 the facilitation of weak primes depended on the size of the associative set defined by the prime. Results are discussed within a theoretical framework that includes prelexical expectancy processes in the lexical decision task.     

The sign effect,systematic devaluations and zero discounting

The sign effect is the steeper discounting of gains compared to losses. However, we see a greater sign effect on an individual level compared to an aggregate level. In this experiment, we compare discounting of gains and losses on an individual and aggregate level, to explore further details about when and to what extent human adults discount. Thirty-one participants went through a computer-based choice-task procedure of hypothetical monetary gains and losses. The results show clear qualitative differences between discounting of gains and losses, adding empirical data to support the sign effect. The results also support previous findings that show that aggregate and individual results do not always correspond. Further, the within-subject details showing zero discounting or nonsystematic changes concerning losses, replicate earlier studies suggesting that discounting of gains and losses involve different reinforcing contingencies. The present study expands on this research area by including verbal reports, supplementing details about the unobserved reinforcing contingencies. Implications of research on discounting may indicate how to deal with decision-making challenges and might shed light on why predictions about complex decision making sometimes fail.