The effects of syntactic structure on letter detection in adjacent function words

In the present study, we examined letter detection in very frequent function-word sequences. It has been claimed that such sequences are processed in a unitized manner, thus preempting access to their constituent letters. In contrast, we showed that letter detection in the words for and the (1) was no more difficult when the words appeared in adjacent locations in a sentence (familiar) than when they appeared apart (less familiar sequence) and (2) was contingent upon the words' syntactic roles within the phrase. Thus, letter detection in for was easier when the sequence was separated by a clause boundary than when the words were part of the same clause. The advantage derived from clause separation was strongest when a comma divided clauses. These results challenge the unitization account of the "missing-letter" effect in common phrases and support a position where this phenomenon is seen to reflect the extraction of phrase structure during reading.     

A logic of intentions and beliefs

Intentions are an important concept in Artificial Intelligence and Cognitive Science. We present a formal theory of intentions and beliefs based on Discourse Representation Theory that captures many of their important logical properties. Unlike possible worlds approaches, this theory does not assume that agents are perfect reasoners, and gives a realistic view of their internal architecture; unlike most representational approaches, it has anobjective semantics, and does not rely on anad hoc labeling of the internal states of agents. We describe a minimal logic for intentions and beliefs that is sound and complete relative to our semantics. We discuss several additional axioms, and the constraints on the models that validate them.     

Encoding information for future action: Memory for to-be-performed tasks versus memory for to-be-recalled tasks

What is the nature of the representation underlying memory for future tasks such as calling the doctor or buying milk? If this representation consists of a verbal instruction that is translated into action at the time of retrieval, then memory should be better when tested via verbatim recall of the instruction than when tested via actual performance. Three experiments rejected this possibility, indicating better memory for a perform mode of report than for a recall mode of report. This was true in Experiment 1 in which subjects saw a series of verbal instructions (e.g., “move the eraser,” “lift the cup,” “touch the ashtray”), with advance information regarding the mode of report required during testing. In Experiment 2, the advance cue was valid only in 75% of the trials. Memory depended more heavily on the expected mode of report thanon the actual mode ofreport, suggesting that the perform superiority is due to processes that occur during encoding. In Experiment 3, subjects learned 20 phrases depicting minitasks were remembered by subjects tested via performance than by subjects tested via verbatim recall. A second part of Experiment 3 also indicated superior memory when a perform test was expected, regardless of which mode of report was actually required. The results were compared with the finding that subject-performed tasks are better remembered thanare their verbal instructions, which suggeststhat the representation underlying memory for future assignments-may-take advantage of the imaginal-enactive properties ofthe envisagedacts. Other possible differences between memory for to-be-recalled tasks and memory for to-be-performed tasks are discussed.     

Learning spatial sequences in unilateral neglect

Brain-damaged patients with unilateral spatial neglect ignore aspects of the world located on the side opposite their lesion. In the present study we examined the performance of unilateral neglect patients (UN) on an SRT task in which a hybrid repeating sequence (21313) was used. We analyzed the patients' performance for each location separately as a function of the target's location in the trial preceding the response. The UN patients were severely limited in their learning of the sequence when compared to normal controls. In particular, they appeared to learn unique associations (21 and 13) but not ambiguous ones (31 and 32). We discuss two possible explanations for this phenomenon. The first is that UN patients show a deficit similar to that of normal subjects in dual task situations. The second is that the learning deficit is unique to spatial processing impairments of UN patients and is not directly related to research with normal population. We outline future research that may distinguish between these two explanations.     

Prima facie obligation

This paper presents a nonmonotonic deontic logic based on commonsense entailment. It establishes criteria a successful account of obligation should satisfy, and develops a theory that satisfies them. The theory includes two conditional notions of prima facie obligation. One is constitutive; the other is epistemic, and follows nonmonotonically from the constitutive notion. The paper defines unconditional notions of prima facie obligation in terms of the conditional notions.     

Semantic facilitation in lexical decision as a function of prime-target association

Using a lexical decision task, the relationship between magnitude of semantic facilitation and degree of prime-target relatedness was examined as a function of amount of attention allocated to the prime and the prime-target interval. In none of the conditions studied did amount of facilitation vary with prime-target relatedness, a finding which was seen as inconsistent with the spread of activation account of the association effect in lexical decision. Both forward (prime to target) and backward (target to prime) associations were effective in producing semantic facilitation. Backward associates, however, were effective only during earlier stages of the experiment and forward associations only during later stages. The implications of these findings for the processes underlying the association effect was discussed.     

The contextualization of input and output events in memory

Summary Several observations from everyday life suggest that people are deficient in monitoring their own actions, often forgetting that they have already performed a planned act, or experiencing doubt as to whether they have done so. These observations appear inconsistent with the many laboratory studies that indicate that people are quite efficient in monitoring their own actions. Towards the resolution of this discrepancy we proposed that: (a) output monitoring in real life often requires the retrieval of a specific, contextually framed episode rather than mere familiarity with an event, and (b) output events are less strongly integrated with their environmental contexts than input events are. Therefore, despite the output advantage that is frequently reported in occurrence memory, context memory should be relatively less efficient for output than for input events. This hypothesis received some support in Experiment 1, in which generated verbal responses were remembered better than read responses, but the difference was significantly smaller for context than for occurrence memory. Experiment 2 employed a task simulating a two-person interaction. While occurrence memory was superior for self-performed tasks to that for other-performed tasks, context memory was in fact inferior for the former tasks. These results were seen to suggest that self-initiated actions tend to undergo a weaker contextual integration than events that originate from a source external to the person.     

The recovery of incidentally acquired information

The psychoanalytically derived hypothesis that marginal registrations are best recovered indirectly, under conditions minimizing the active-selective intention to remember, was examined using associative priming as an index of indirect recovery. A list of words was presented under intentional or incidental-and-distraction conditions and its memory was tested under free recall, recognition or priming conditions. About ten times as many words were recalled and five times as many recognized in the intentional than in the incedental condition. Although significant, the extent of the priming effect did not differ under the two conditions. The results are discussed in terms of Craik and Lockhart's levels of processing approach and Posner's distinction between conscious and automatic activation processes.     

Action-based and vision-based selection of input: Two sources of control

In the first part of this paper we review evidence suggesting that there exists a mechanism that selects input on the basis of its similarity to the required action. This response-based input selection differs from the more established space- and object-based input selection in that it is not constrained by the structure of the input. Our evidence suggests that the two-choice Stroop effect is caused by this response-based selection mechanism. By contrast, it is known that the flanker effect is determined by the space- and object- based selection mechanisms. We explore whether the conflict resolution of the Stroop and flanker tasks is different as well by embedding these two tasks in a PRP (Psychological Refractory Period) paradigm. We show that the Stroop and the PRP effects are additive whereas the flanker and the PRP effects are underadditive, suggesting that the processes in charge of the conflict resolution in the Stroop and the flanker tasks are indeed different. We discuss possible reasons for this difference, and discuss possible ways in which the response-based mechanism can be implemented in information processing models.     

Visual attention and coactivation of response decisions for features from different dimensions

The role of visual attention in task performance has been extensively debated. On the basis of the dimensional-action model, we hypothesized that a major role of attention is to transfer response decisions from targets on which it is focused to high-level centers dealing with response execution. This hypothesis predicts that response decisions for two targets will interact only when attention is focused on both targets, and only when the response to the targets is defined by different dimensions. Three experiments, using the redundancy-gain paradigm, tested and confirmed this prediction. Experiment 1 showed that coactivation of two cross-dimensional targets occurred only when the targets were positioned in the same location, not when they were in separate locations. Experiment 2 manipulated the focus of attention and showed that coactivation can occur even for targets positioned in different locations if they are both within the attentional focus. Experiment 3 showed that this attention-induced coactivation does not occur for targets from the same dimensional module. These results suggest that a major role of attention is postperceptual and involves gating of selected responses to executive functions.