Isolating Unconscious Influences: The Neutral Parameter Procedure

Earlier demonstrations of unconscious learning have been regularly challenged. In this paper, we suggest that earlier demonstrations were not compelling due to certain properties of the experimental situations, and notably that conscious exploitation of explicit knowledge, if present, would coincide or conflict with the results of unconscious processing. We designed a method consisting of inducing a neutral behavioural change in the way subjects drew geometric figures. Two experiments showed that important and long-lasting modifications of drawing behaviour were obtained following specially devised practice, although these modifications could not be expected from deliberate adaptive strategies. In addition, we showed that subjects were unaware of the manipulation to which they had been exposed. The study provides striking evidence for unconscious learning and offers insights for the design of suitable new tools to investigate unconscious cognition.     

The emergence of explicit knowledge during the early phase of learning in sequential reaction time tasks

Five experiments investigated the formation of explicit knowledge of a repeating sequence in a sequential reaction time task. Reliable explicit knowledge was obtained even though various conditions prevented the selective improvement of RTs (Exps. 1–4). This knowledge emerged early during training. Participants were able to recognize segments of the sequence (Exps. 3 and 4) or correctly assess the probabilities of transition of the target between successive locations (Exp. 5) after only two blocks of training trials. These findings rule out an interpretation of sequence learning that posits that explicit knowledge emerges from implicit knowledge during the course of training. Although these findings are compatible with a framework centered around the notion of dissociation between implicit and explicit knowledge, they are also consonant with a questioning of the usefulness of the concept of implicit knowledge.     

Stereotyping and action tendencies attribution as a function of available emotional information

In three experiments, we addressed the role of stereotypes in the attribution of action tendencies in intergroup contexts. We hypothesized that stereotyping would affect the attribution of action tendencies to out‐group members. Participants were presented with a facial expression displayed by either an in‐group or an out‐group member, followed by the presentation of a label describing an action tendency. They were then asked whether the label corresponded to the feeling state of the expresser. Study 1 tested whether stereotypes influence the attribution of action tendencies to out‐group members. Study 2 tested whether stereotype application varies as a function of the emotional information contained in the facial stimuli (i.e. neutral vs. emotional). Finally, Study 3 tested whether stereotype activation is indirectly determined by a difference in morphology between in‐group and out‐group members or directly determined by the expresser's group membership. As predicted, an increase in attribution of stereotypic action tendencies was observed for out‐group expressers. The application of stereotypes was specifically observed when facial expressions were neutral as compared to emotional and was independent of morphological differences between in‐group and out‐group faces. Such biases in interpreting out‐group members feeling states may play a crucial role in the maintenance of intergroup prejudice. Copyright © 2005 John Wiley & Sons, Ltd.     

Two-month-old infants of depressed mothers show mild, delayed and persistent change in emotional state after non-contingent interaction

The aim of this study was to explore how early infants show different responses to non-contingent maternal behavior according to their past history of relations with their mother. Two groups of 2-month-olds interacted with their mother who was assessed as depressed (group 1) or non-depressed (group 2). Although they received a continuous image and voice of their mothers, the infants were presented either a 30-s contingent maternal communication (live episode 1) or a thirty second non-contingent episode (replay of prior maternal communication), or again a 30-s contingent live episode (live2). The lower percentage of negative facial expressions displayed during replay by infants of depressed mothers suggests on one hand that they are less sensitive to a non-contingent maternal behavior than infants of non-depressed mothers. However, within group comparisons demonstrate a notable difference: while infants of non-depressed mothers show a U curve of smile, infants of depressed mothers show decreasing smile throughout the three episodes. Taken together, these results plead in favour of an other profile of sensitivity displayed by infants of depressed mothers. Instead of the strong but short-term reaction of infants of non-depressed mothers, the response of infants of depressed mothers appeared to be a mild, delayed and more persistent change in emotional state. These findings are discussed in the light of possible cognitive and social incidence of passive avoidance of stressful events in infants of depressed mothers.     

Development of children's mental representations: effects of age, sex, and school experience

In the present study mental representations in drawings by 158 young children, ages 2 1/2 to 6 yr. old were analysed. The aim was to investigate whether the accuracy of mental representations increased with age and how this development progressed. Also tested were whether the inferred mental representations differed for boys and girls and whether preschool experience affected the drawings. As expected, mental representation increased in complexity with age as measured by Goodenough's score, and girls' mental representations (drawings) were significantly more elaborate than boys. Moreover, attending school early seemed to affect mental representations of the 3-yr.-olds but not the 4-yr.-olds. Results are discussed in terms of internal and external factors in mental representation in drawing a man.     

A role for backward transitional probabilities in word segmentation?

A number of studies have shown that people exploit transitional probabilities between successive syllables to segment a stream of artificial continuous speech into words. It is often assumed that what is actually exploited are the forward transitional probabilities (given XY, the probability that X will be followed by Y), even though the backward transitional probabilities (the probability that Y has been preceded by X) were equally informative about word structure in the languages involved in those studies. In two experiments, we showed that participants were able to learn the words from an artificial speech stream when the only available cues were the backward transitional probabilities. Learning is as good under those conditions as when the only available cues are the forward transitional probabilities. Implications for some current models of word segmentation, particularly the simple recurrent networks and PARSER models, are discussed.     

Perceptual processing of partially and fully assimilated words in French

Models of speech perception attribute a different role to contextual information in the processing of assimilated speech. This study concerned perceptual processing of regressive voice assimilation in French. This phonological variation is asymmetric in that assimilation is partial for voiced stops and nearly complete for voiceless stops. Two auditory-visual cross-modal form priming experiments were used to examine perceptual compensation for assimilation in French words with voiceless versus voiced stop offsets. The results show that, for the former segments, assimilating context enhances underlying form recovery, whereas it does not for the latter. These results suggest that two sources of information -- contextual information and bottom-up information from the assimilated forms themselves -- are complementary and both come into play during the processing of fully or partially assimilated word forms.     

The scope and limits of enactive approaches to visual experience

I pursue here three related aims. First, I criticise some of the metaphysical claims made on behalf of the so-called 'enactive' approach to visual experience. Secondly, I explain why the enactive view of visual experience is hard to square with the evidence in favour of the two-visual-systems model of human vision. Finally, I explore one possible way to develop the 'pre-emptive perception' framework and explain why, contrary to first appearances, some of the fundamental discoveries of brain mechanisms, whose function might be to underlie pre-emptive perception, do not really support the enactive approach to visual experience.