Luis J. Fuentes

The impact of bilingualism on the executive control and orienting networks of attention

The main objective of this article is to provide new evidence regarding the impact of bilingualism on the attentional system. We approach this goal by assessing the effects of bilingualism on the executive and orienting networks of attention. In Experiment 1, we compared young bilingual and monolingual adults in a numerical version of the Stroop task, which allowed the assessment of the executive control network. We observed more efficient performance in the former group, which showed both reduced Stroop Interference and larger Stroop Facilitation Effects relative to the latter. Conversely, Experiment 2, conducted with a visual cueing task in order to assess the orienting network, revealed similar Cueing Facilitation and Inhibition (Inhibition of Return – IOR) Effects for both groups of speakers. The implications of the results of these two experiments for the origin and boundaries of the bilingual impact on the attentional system are discussed.

Induced Cross-Modal Synaesthetic Experience Without Abnormal Neuronal Connections

Are the kinds of abnormal cross-modal interactions seen in synaesthesia or following brain damage due to hyperconnectivity between or within brain areas, or are they a result of lack of inhibition? This question is highly contested. Here we show that posthypnotic suggestion induces abnormal cross-modal experience similar to that observed in congenital grapheme-color synaesthesia. Given the short time frame of the experiment, it is unlikely that new cortical connections were established, so we conclude that synaesthesia can result from disinhibition between brain areas.

Semantic Processing of Foveally and Parafoveally Presented Words in a Lexical Decision Task

Using a lexical decision task in which two primes appeared simultaneously in the visual field for 150 msec followed by a target word, two experiments examined semantic priming from attended and unattended primes as a function of both the separation between the primes in the visual field and the prime-target stimulus-onset asynchrony (SOA). In the first experiment significant priming effects were found for both the attended and unattended prime words, though the effect was much greater for the attended words. In addition, and also for both attention conditions, priming showed a tendency to increase with increasing eccentricity (2.3°, 3.3°, and 4.3°) between the prime words in the visual field at the long (550 and 850 msec) but not at the short (250 msec) prime-target SOA. In the second experiment the prime stimuli were either two words (W-W) or one word and five Xs (W-X). We manipulated the degree of eccentricity (2° and 3.6°) between the prime stimuli and used a prime-target SOA of 850 msec. Again significant priming was found for both the attended and unattended words but only the W-W condition showed a decrement in priming as a function of the separation between the primes; this decrement came to produce negative priming for the unattended word at the narrow (2°) separation. These results are discussed in relation to the semantic processing of parafoveal words and the inhibitory effects of focused attention.

Inhibitory Tagging of Stimulus Properties in Inhibition of Return: Effects on Semantic Priming and Flanker Interference

In this study we examine the level at which inhibition of return (IOR) affects the processing of visual stimuli. Experiments 1 and 2 examined the effect of IOR on semantic priming. Experiments 3 and 4 examined the effect on flanker interference. In both cases IOR could reverse the standard effects. We suggest that when attention is drawn away from a location, there is temporary inhibitory tagging of stimuli that are presented there. This tagging extends to the semantic and response-relevant properties of stimuli, helping to bias attention away from old and towards new events. Due to inhibitory tagging, responses to new targets can be slowed down when targets are semantically related (Experiments 1 and 2) or require the same response (Experiments 3 and 4) as inhibited primes.

Temperament and attention in the self-regulation of 7-year-old children

Abstract The present work assessed the implications of the posterior orienting and the anterior executive attentional networks on self-regulation abilities in children through studying the relations of 7-year-old children’s temperament characteristics to different forms of attentional control. Children were classified in terms of their temperament traits measured through the Children’s Behavior Questionnaire. Children carried out two Stroop tasks, with and without distracting stimuli, and flanker and Stroop interference effects were calculated as measures of the orienting and the executive attentional networks, respectively. Results indicated that children scoring high in Anger, Discomfort, Sadness (only girls) and Approach-Anticipation (only girls) showed a stronger flanker interference effect, exhibiting greater difficulty to filter out the non relevant information than children scoring low did. On the other hand, children scoring high in Activity Level and Impulsivity (only girls), and low in Inhibitory Control, showed a stronger Stroop interference effect, indicating less ability to suppress prepotent behaviors under instructions. Also, patterns of interactions between some pairs of scales revealed that negative emotionality and self-regulatory aspects of temperament predicted both Stroop and flanker interference performance.

The role of the anterior attention system in semantic processing of both foveal and parafoveal words

This research takes advantage of combined cognitive and anatomical studies to ask whether attention is necessary for high-level word processing to occur. In Experiment 1 we used a lexical decision task in which two prime words, one in the fovea and the other in the parafovea, appeared simultaneously for 150 msec, followed by a foveal target (word/nonword). Target words were semantically related either to the foveal or to the parafoveal word, or unrelated to them. In one block of trials subjects were also required to perform an auditory shadowing task. From PET studies we know that shadowing activates the anterior cingulate cortex, involved in selective attention. If the anterior attention system is always involved in semantic processing, shadowing should reduce semantic priming obtained from both foveal and parafoveal words. In contrast, if semantic priming by parafoveal words is independent of activation in that attention area, priming will not be affected by shadowing. Our results supported the latter hypothesis. A large priming effect arose from foveal primes, which was reduced by shadowing. For parafoveal primes a smaller priming effect arose, which was not affected by shadowing. In Experiment 2 prime words were masked. Semantic priming was reliable for both foveal and parafoveal words but there were then no differences between them. Most important, the size of priming was similar to that obtained from parafoveal words in Experiment 1. We conclude that the anterior attention system increases the potency of processing of consciously perceived stimuli, but there is a component of semantic priming that occurs without both focusing of attention and awareness, involving different cerebral areas to those involved in attention to language.

Acquisition and generalization of action effects

Three experiments studied the acquisition of action-contingent events (action effects). In a first, acquisition phase participants performed free-choice reactions with each keypress leading to the presentation of either a particular category word (e.g., animal or furniture) or an exemplar word (e.g., dog or chair). In the test phase, choice responses were made to category or exemplar words by using a word-key mapping that was either compatible or incompatible with the key-word mapping during acquisition. Compatible mapping produced better performance than incompatible mapping if the words in the practice and the test phase were the same (e.g., animal M animal), if they had a subordinate-superordinate relationship (e.g., dog M animal), belonged to the same category (e.g., dog M cat), or referred to visually related concepts (e.g., orange M circle). The findings support the assumption that action effects are acquired and integrated with the accompanying action automatically, so that perceiving the effect leads to the priming of the associated response. And, most importantly, they demonstrate that effect acquisition generalizes to other, feature-overlapping events.

Inhibition of return in aging and Alzheimer's disease: performance as a function of task demands and stimulus timing.

Inhibition of return (IOR) is a phenomenon of spatial attention that biases attention toward novel events in the environment. Recent evidence suggests that the magnitude and timing of IOR varies as a function of task conditions (e.g., detection vs. discrimination tasks, short vs. long cue-target intervals, intrinsic vs. extrinsic cues). Although IOR appears relatively preserved with both normal aging and Alzheimers disease (AD), it has been tested under relatively simple task conditions. To test whether IOR is resistant to age and/or AD when cognitive demands are increased, we employed a double-cue IOR paradigm that required categorization as well as detection responses. The stimulus onset asynchrony (SOA) between the cue and target events was varied to determine whether group differences existed in IOR effects over time. Younger normal adults and older normal adults exhibited significant IOR effects on both the detection task and the categorization task at a short cue-target SOA (950 ms). In contrast, AD patients exhibited significant IOR effects at the short SOA on the detection task but not on the categorization task. From the short to the long SOA (3500 ms), IOR effects exhibited by younger normal adults declined significantly during both the detection and the categorization tasks, suggesting that inhibition resolved over time. In contrast, neither older normal adults nor AD patients exhibited SOA-related IOR reductions on the detection task. These results suggest that IOR may show differential age- and AD-related vulnerabilities depending on task conditions and timing characteristics.

Spatial and semantic inhibitory processing in schizophrenia.

Two experiments assessed inhibitory mechanisms associated with the posterior and anterior attention networks in schizophrenia. Experiment 1 assessed the inhibition of return effect of the posterior network. Both healthy adults and schizophrenic adults showed inhibition of return, suggesting that this inhibitory mechanism of visual orienting is preserved in schizophrenia. Experiment 2 assessed semantic inhibition, which supposedly taps the anterior network, in a lexical-decision task. Healthy adults showed semantic inhibition effects in both visual fields. Schizophrenic adults showed semantic inhibition effects when targets were presented to the left visual field, involving the right hemisphere. However, semantic facilitation rather than inhibition was observed when targets were presented to the right visual field, involving the left hemisphere. These results reflect left hemisphere dysfunction associated with deficits in attentional control in schizophrenia.

Semantic priming in the prime task effect: Evidence of automatic semantic processing of distractors

The automaticity of the semantic processing of words has been questioned because of the reduction of semantic priming when the prime word is processed nonsemantically—for example, in letter search (the prime task effect). In two experiments, prime distractor words produced semantic priming in a subsequent lexical decision task, but with the direction of priming (positive or negative) depending on the prime task. Lexico-semantic tasks produced negative semantic priming, whereas letter search produced positive semantic priming. These results are discussed in terms of task-based inhibition. We argue that, given the results from the distractors, the absence of semantic priming does not indicate an absence of semantic activation but reflects the action of control processes on prepotent responses when less practiced responses are needed.