Strategic influences on implementing instructions for future actions

Temporal and strategic factors that might influence the transformation of verbal task rules into functional stimulus–response associations were investigated in three experiments. In a dual task paradigm of the ABBA type participants were presented new S–R instructions for the A-task at the beginning of each trial. On varying proportions of trials No-go signals rendered the instructed A-task mappings irrelevant before instruction implementation was assessed during performance of an unrelated B-task. Our results indicate that participants refrain from implementing the mappings during instruction presentation when No-go signals appear frequently and late (Exp. 2), and that they can interrupt implementing instructed S–R mappings when frequent No-go signals appear early enough during implementation (Exp. 3). When No-go signals are rare and late, however (Exp. 1), the instructed stimulus features always activate their associated responses during performance of the embedded B-task in an automatic manner. Together, these findings suggest that participants strategically control whether or not they implement verbal instructions. Once implemented, however, instructed S–R associations influence behaviour even when the instructed mappings are no longer task relevant.

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Top-down influences on attentional capture by color changes

Previous studies have shown that a change in an existing object is not as effective in capturing attention as the appearance of a new object. This view was recently challenged by Lu and Zhou (Psychonomic Bulletin and Review 12:567–572, 2005), who found strong capture effects for an object changing its color. We suspected that this finding critically depends on a procedural particularity in Lu and Zhou’s study, namely that the color of the unique item and the color of the no-unique items randomly switched between trials. In the current study we replicate Lu and Zhou’s capture effect (Experiment 1) and show that no capture occurs when the color-to-stimuli assignment is fixed (Experiment 2). Two further experiments suggest that the capture effect in Experiment 1 is not because the unique item switched color (Experiment 3), but because all the no-unique items switched color (Experiment 4). The results are discussed considering top-down modulation and inter-trial priming effects.

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Saccadic eye movement programming: sensory and attentional factors

The relationship between attention and eye movements is explored by consideration of the variety of ways attention may affect saccade programming. Four forms of attention are distinguished: one exogenous and three endogenous through either locations or objects or features. Each of these can control or influence the saccadic generation process. Visual onsets generate a rapid transient signal with low resolution that travels from the visual system to the oculomotor system. Generation of an eye movement is associated with an attentional signal, probably also with low resolution, travelling from the oculomotor system to the visual system. A high-resolution attentional signal, which appears to require voluntary effort, can also select saccadic targets.     

Counting distinctions: on the conceptual foundations of Shannon’s information theory

Categorical logic has shown that modern logic is essentially the logic of subsets (or “subobjects”). In “subset logic,” predicates are modeled as subsets of a universe and a predicate applies to an individual if the individual is in the subset. Partitions are dual to subsets so there is a dual logic of partitions where a “distinction” [an ordered pair of distinct elements (u, u′) from the universe U] is dual to an “element”. A predicate modeled by a partition π on U would apply to a distinction if the pair of elements was distinguished by the partition π, i.e., if u and u′ were in different blocks of π. Subset logic leads to finite probability theory by taking the (Laplacian) probability as the normalized size of each subset-event of a finite universe. The analogous step in the logic of partitions is to assign to a partition the number of distinctions made by a partition normalized by the total number of ordered |U|² pairs from the finite universe. That yields a notion of “logical entropy” for partitions and a “logical information theory.” The logical theory directly counts the (normalized) number of distinctions in a partition while Shannon’s theory gives the average number of binary partitions needed to make those same distinctions. Thus the logical theory is seen as providing a conceptual underpinning for Shannon’s theory based on the logical notion of “distinctions.” This paper is dedicated to the memory of Gian-Carlo Rota—mathematician, philosopher, mentor, and friend.     

Indeterminacy,identity and counterparts: Evans reconsidered

In this paper I argue that Gareth Evans’ famous proof of the impossibility of de re indeterminate identity fails on a counterpart-theoretic interpretation of the determinacy operators. I attempt to motivate a counterpart-theoretic reading of the determinacy operators and then show that, understood counterpart-theoretically, Evans’ argument is straightforwardly invalid.     

Goal congruency without stimulus congruency in bimanual coordination

Two experiments explored the role of stimulus congruency and goal congruency for the generation of object-oriented actions with two hands. Participants had to place two objects into either parallel or opposite orientations by carrying out either symmetrical or asymmetrical forearm rotations. Performance was superior when the required object orientations were identical rather than different, almost independent of the symmetry of the required arm movements. In extending previous research, goal congruency effects ensued even under conditions in which congruency of imperative response signals could not have contributed to goal congruency effects, either because only a single stimulus was used to indicate the required goals in an individual trial (Experiment 1) or such stimuli were absent at all (Experiment 2). The results thus confirm the importance of goal codes for the reconcilableness of bimanual actions, and rule out accounts in terms of stimulus-related processes.     

Simulation à la Goldman: pretend and collapse

Theories of mind draw on processes that represent mental states and their computational connections; simulation, in addition, draws on processes that replicate (Heal 1986) a sequence of mental states. Moreover, mental simulation can be triggered by input from imagination instead of real perceptions. To avoid confusion between mental states concerning reality and those created in simulation, imagined contents must be quarantined. Goldman bypasses this problem by giving pretend states a special role to play in simulation (Goldman 2006). We argue that this path leads to the resurgence of the threat of collapse (Davies 1994), diluting the principled distinction between simulation and theory use. Exploration of a related method of real-mental states operating in a pretend mode leads to a factually untenable model. Our main goal here is to raise this problem as a challenge for Goldman’s reconfigured simulation theory. Only at the end we will briefly sketch a possible alternative way of quarantine that preserves the replicative element of simulation and avoids collapse. Figure 1 provides a guide to our argument. Fig. 1 Structure of argument

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Structural equations and causation: six counterexamples

Hall [(2007), Philosophical Studies, 132, 109–136] offers a critique of structural equations accounts of actual causation, and then offers a new theory of his own. In this paper, I respond to Hall’s critique, and present some counterexamples to his new theory. These counterexamples are then diagnosed.

How Do Trait Dimensions Map onto ADHD Symptom Domains?

Theories of Attention-Deficit/Hyperactivity Disorder (ADHD) implicate dysfunctional regulation mechanisms that have been conceptually grouped into “top-down” control and “bottom-up” affective/reactive processes. This dual-process account can be invoked in relation to temperament or personality traits and may clarify how traits relate to ADHD. Two samples were examined to illuminate developmental effects. The younger sample was 179 youngsters aged 7 to 12 years (113 boys; 107 with ADHD). The older sample was 184 adolescents (109 boys; 87 with ADHD) aged 13 to 18 years. Structural equation models included parent-rated traits, teacher-rated ADHD symptoms, and laboratory-obtained executive functions. A control or “top-down” factor included cognitive control and conscientiousness/effortful control. A second factor labeled affective or “bottom-up” included neuroticism/negative emotionality, agreeableness, and reactive control. In the younger sample, these two factors were differentially and specifically related to inattention and hyperactivity, respectively. However, in the older sample, the first factor was related to inattention and hyperactivity, whereas the second factor was related to hyperactivity. Personality traits appear to map onto ADHD symptoms in a meaningful manner consistent with a dual-process model of temperament and ADHD. This research was supported by NIH National Institute of Mental Health Grant R01-MH63146, MH59105, and MH70542 to Joel Nigg. Martel was supported by NIH F31 MH075533. We are indebted to the families and staff who made this study possible.