Clarification of the dual task dilemma: Lateralized effects for perfunctory and purposeful tasks in left- and right-handed males

The hypothesis that behavioral asymmetries with the dual task paradigm represent manual dominance was investigated with right- and left-handed males performing verbal and spatial tasks ordered by complexity. Lateralization was assessed for nonideational (perfunctory) and ideational (purposeful) components of tasks with multivariate and ANCOVA procedures. The outcomes of prerequisite tests showed the assumptions for conducting ANCOVA procedures were not satisfied with different handedness groups in the same design. However, results of the multivariate analyses suggest lateralized effects are more likely to represent the cognitive task when interference is high and may represent manual dominance when interference is low.     

The orientation of a parallel-line texture between the verticals can modify the strength of the Poggendorff illusion

In the present experiments, we attempted to evaluate the modification of the strength of the Poggendorff illusion as a function of the different orientation of a parallel-line texture filling the space between the vertical lines. In Experiment 1, the standard version of the Poggendorff configuration was tested against four different parallel-line textures oriented at 0°, 45°,90°, and 135° with respect to the obliques. The results showed that the illusory effect was a linear function of the progressive discrepancy between the angle of the lines of the texture and that of the obliques. In Experiment 2, we tested the same textures used in Experiment 1 after the elimination of the two vertical lines. The data obtained approximated a linear function, as in the previous experiment, but the alignment errors were consistently lower. The statistical analysis performed on the data of all eight experimental conditions shows that both factors—texture and presence/absence of verticals—were significant, but most of the effect was due to the texture factor. The results may be interpreted through the “perceptual compromise hypothesis,” originally proposed for the bisection forms of the Poggendorff illusion, but with important modifications. The data are also discussed in terms of their implications for other theories proposed for the Poggendorff illusion.     

Observing responses and uncertainty reduction. II The effect of varying the probability of reinforcement

The observing response paradigm was used to assess the reinforcing properties of discriminative stimuli by allowing animals either to work for food in the presence of a neutral stimulus or to first make an observing response by pressing a lever. On a progressive ratio schedule this resulted in the appearance of easily discriminable stimuli which marked positive and negative trials. The uncertainty associated with the imposed neutral stimulus was varied by manipulating the proportion of positive and negative trials in the session. The animals switched most often when the probability of reinforcement was low, less often when it was intermediate, and least often when it was high. This was not consistent with an uncertainty reduction hypothesis but could be explained if the uncertainty had to do with response rather than outcome.     

An analysis of some conditions for representingN state Markov processes as general all or none models

Recently Markov learning models with two unidentifiable presolution success states, an error state, and an absorbing learned state, have been suggested to handle certain aspects of data better than the three state Markov models of the General All or None model type. In attempting to interpret psychologically, and evaluate statistically the adequacy of various classes of Markov models, a knowledge of the relationship between the classes of models would be helpful. This paper considers some aspects of the relationship between the class of General All or None models and the class of Stationary Absorbing Markov models withN error states, andM presolution success states.     

A Rational Way of Playing: Revision Theory for Strategic Interaction

Gupta (2011) has proposed a definition of strategic rationality cast in the framework of his revision theory of truth. His analysis, relative to a class of normal form games in which all players have a strict best reply to all other players’ strategy profiles, shows that game-theoretic concepts (e.g. Nash equilibrium) have revision-theoretic counterparts. We extend Gupta’s approach to deal with normal form games in which players’ may have weak best replies. We do so by adapting intuitions relative to Nash equilibrium refinements (in particular, trembling-hand perfection and properness) to the revision-theoretic framework. We prove that there is a precise equivalence between trembling-hand perfect equilibria in two-player normal games and a revision-theoretic property. We then introduce lexicographic choice of action as a way to represent players’ expectations, which allows our analysis to reach full generality. Finally, we provide an example of the versatility of revision theory as applied to strategic interaction by formalizing a risk-and-compensation procedure of strategic choice in the revision-theoretic framework.     

Exploring the mechanism of dishabituation

In this study we explored elicitation and habituation of the orienting reflex (OR) in the context of indifferent and significant stimuli, particularly aiming to clarify the mechanism driving dishabituation. An in-depth analysis of the mechanisms of electrodermal habituation and dishabituation was conducted, focusing on the role of state measures as determinants of the phasic response profile. Twenty-four young adult participants completed an auditory dishabituation task while electrodermal activity was recorded. Participants listened to a series of 10 innocuous tones of the same frequency (standards), followed by a deviant tone of a different frequency, and succeeded by 2-4 tones of the same frequency as the initial 10 stimuli. All stimuli had a random stimulus onset asynchrony of 5-7 s. Participants completed an indifferent condition in which there was no task in relation to the stimuli, and a significant condition where instruction was given to count the stimuli silently; order was counterbalanced between participants. As predicted, both skin conductance responses (SCRs) and skin conductance levels (SCLs) were larger for the significant than the indifferent condition. The initial phasic ORs were dependent on pre-stimulus arousal level, and there were significant decreases in both SCR and SCL over the first 10 standards in both conditions. Phasic response recovery was apparent to the deviant stimulus, and dishabituation to the following standard stimulus; both effects were enhanced in the significant condition. Sensitisation was apparent in SCL following the initial and deviant stimuli, but the extent of this was confounded with incomplete resolution of the preceding phasic OR in the significant condition. In the indifferent condition, dishabituation was independent of deviant-related sensitisation; this could not be tested in the significant condition. These findings suggest that dishabituation is not a process of sensitisation, but rather, a disruption of the habituation process.