The subject of “We intend”

This paper examines and compares the ways in which intentions of the singular kind (“I intend”) and the plural kind (“we intend”) are subjective. Are intentions of the plural kind ours in the same way intentions of the singular kind are mine? Starting with the singular case, it is argued that “I intend” is subjective in virtue of self-knowledge. Self-knowledge is special in that it is self-identifying, self-validating, self-committing, and self-authorizing. Moving to the plural form, it is argued that in spite of apparent differences, attitudes of the form “we intend” are subjective in the same way. The self-knowledge at work here is plural rather than singular. This supports a plural subject account of collective intentionality. It is argued that the worries sometimes raised in the literature against the metaphysical “spookiness” of plural subjects are due to a fundamental misconception of the way in which attitudes of either kind –singular and plural – are subjective.     

Beyond the leftward limit of the perceptual span: Parafoveal processing to the left of fixation in Chinese reading

During reading, Chinese readers have been found to obtain useful visual information from one character to the left to three characters to the right of fixation. The perceptual span is asymmetrical, and its leftward extent seems to be limited compared with the rightward extent. We conducted an experiment to investigate whether Chinese readers could process written information beyond the leftward extent of the perceptual span. We did this by using a variation of the gaze-contingent display change paradigm (Rayner, Cognitive Psychology, 81, 65–81, 1975) in order to manipulate the parafoveal “postview” that was available to the left of where readers were fixating. Each sentence contained an invisible boundary. Once the readers’ eyes crossed the boundary, all of the characters to the left of the boundary except for one, two, or three characters directly to the left of the boundary were replaced with visually similar characters. The change lasted for only one single fixation, resulting in four different “postview” conditions including a control condition (n ? 1, n ? 2, n ? 3, control). The results showed that, compared with the control condition, there were more regressions to the display change area immediately after readers’ eyes crossed the boundary in the n ? 1, n ? 2, and n ? 3 conditions, demonstrating that readers can acquire information from the three characters to the left of fixation at least.     

The relationship between feature binding and consciousness: evidence from asynchronous multi-modal stimuli

Processing the various features from different feature maps and modalities in coherent ways requires a dedicated integration mechanism (“the binding problem”). Many authors have related feature binding to conscious awareness but little is known about how tight this relationship really is. We presented subjects with asynchronous audiovisual stimuli and tested whether the two features were integrated. The results show that binding took place up to 350 ms feature-onset asynchronies, suggesting that integration covers a relatively wide temporal window. We also asked subjects to explicitly judge whether the two features would belong to the same or to the different events. Unsurprisingly, synchrony judgments decreased with increasing asynchrony. Most importantly, feature binding was entirely unaffected by conscious experience: features were bound whether they were experienced as occurring together or as belonging to a separate events, suggesting that the conscious experience of unity is not a prerequisite for, or a direct consequence of binding.     

Action-induced effects on perception depend neither on element-level nor on set-level similarity between stimulus and response sets

As was shown by Wykowska, Schubö, and Hommel (Journal of Experimental Psychology, Human Perception and Performance, 35, 1755–1769, 2009), action control can affect rather early perceptual processes in visual search: Although size pop-outs are detected faster when having prepared for a manual grasping action, luminance pop-outs benefit from preparing for a pointing action. In the present study, we demonstrate that this effect of action–target congruency does not rely on, or vary with, set-level similarity or element-level similarity between perception and action—two factors that play crucial roles in standard stimulus–response interactions and in models accounting for these interactions. This result suggests that action control biases perceptual processes in specific ways that go beyond standard stimulus–response compatibility effects and supports the idea that action–target congruency taps into a fundamental characteristic of human action control.     

Action-feature integration blinds to feature-overlapping perceptual events: Evidence from manual and vocal actions

Previous studies showed that the identification of a left- or right-pointing arrowhead is impaired when it appears while planning and executing a spatially compatible left or right keypress (Müsseler & Hommel, 1997a). We attribute this effect to stimulus processing and action control operating on the same feature codes so that, once a code is integrated in an action plan, it is less available for perceptual processing. In three pairs of experiments we tested the generality of this account by using stimulus–response combinations other than arrows and manual keypresses. Planning manual left–right keypressing actions impaired the identification of spatially corresponding arrows but not of words with congruent meaning. On the contrary, planning to say “left” or “right” impaired the identification of corresponding spatial words but not of congruent arrows. Thus, as the feature-integration approach suggests, stimulus identification is impaired only with overlap of perceptual or perceptually derived stimulus and response features while mere semantic congruence is insufficient.     

A behavioral and genetic dissection of two forms of olfactory plasticity in Caenorhabditis elegans: adaptation and habituation

Continuous presentation of an olfactory stimulus causes a decrement of the chemotaxis response in the nematode Caenorhabditis elegans. However, the differences between the learning process of habituation (a readily reversible decrease in behavioral response) and other types of olfactory plasticity such as adaptation (a decrement in response due to sensory fatigue, which cannot be dishabituated) have not been addressed. The volatile odorant diacetyl (DA) was used within a single paradigm to assess the distinct processes of olfactory adaptation and habituation. Preexposing and testing worms to 100% DA vapors caused a chemotaxis decrement that was not reversible despite the presentation of potentially dishabituating stimuli. This DA adaptation was abolished in worms with an odr-10 mutation (encoding a high-affinity DA receptor on the AWA neuron), even though naive chemotaxis remained unaffected. Conversely, DA adaptation remained intact in odr-1 mutants (defective in AWC neuron-mediated olfactory behavior), even though naive chemotaxis to DA decreased. Surprisingly, exposure to vapors of intermediate concentrations of DA (0.01% and 25%) did not cause worms to exhibit any response decrement. In contrast to preexposure to high DA concentrations, preexposure to low DA concentrations (0.001%) produced habituation of the chemotaxis response (a dishabituating stimulus could reverse the response decrement back to baseline levels). The distinct behavioral effects produced by DA preexposure highlight a concentration-dependent dissociation between two decremental olfactory processes: adaptation at high DA concentrations versus habituation at low DA concentrations.     

Intelligence and cognitive flexibility: Fluid intelligence correlates with feature “unbinding” across perception and action

People integrate the features of perceived events and of action plans, as well as of episodic stimulus—response relations, intoevent files. We investigated whether the management of event files, and particularly the speed of updating the binding between the task-relevant stimulus feature and the response, correlates with fluid intelligence. Indeed, the performance of participants scoring high on Raven’s Standard Progressive Matrices test was less impaired by a mismatch between the stimulus—response relation in the current and the previous trial. This result suggests that high intelligence is accompanied by a higher degree of flexibility in handling event files—that is, by higher efficiency in updating episodic representations.