Evaluative learning in human Pavlovian conditioning: Extinct, but still there?

Previous studies of human affective learning, the acquisition of likes and dislikes, provided evidence that extinction training does not affect changes in conditional stimulus (CS) valence as indexed by paper/pencil ratings. Experiment 1 (N = 32) investigated whether this is an artifact of the CS valence assessment, which is taken in test sessions before and after training. Pleasantness ratings were collected in pre/post training tests and, for half of the participants, on-line during training. Rated unpleasantness of the CS that preceded the aversive US (CS+) increased during acquisition and decreased during extinction back to neutral. However, as in previous studies, post extinction paper/pencil ratings revealed the maintenance of rated CS+ unpleasantness. Experiment 2 (N = 34) replicated this finding for two measures of CS valence, paper/pencil and the continuous measure used during training. The present results indicate that previous reports of failures to find extinction of affective learning may reflect renewal rather than maintenance of acquired CS valence across extinction training. (C) 2003 Elsevier Science (USA). All rights reserved.

Highlighting hybridity: A critical discourse analysis of teacher talk in science classrooms

There is evidence that alienation from science is linked to the dominant discourse practices of science classrooms (cf. Lemke, J. L. (1990). Talking Science: Language, Learning, and Values. Norwood, NJ: Ablex). Yet, in secondary science education it is particularly hard to find evidence of curriculum reform that includes explicit changes in pedagogic discourses to accommodate the needs of students from a wide range of backgrounds. However, such evidence does exist and needs to be highlighted wherever it is found to help address social justice concerns in science education. In this article, I show how critical discourse analysis can be used to explore a way of challenging the dominant discourse in teacher-student interactions in science classrooms. My findings suggest a new way of moving toward more socially just science curricula in middle years and secondary classrooms by using hybrid discourses that can serve emancipatory purposes. © 2005 Wiley Periodicals. Inc.

Evidence for retarded extinction of aversive learning in anxious children

The habituation to intense acoustic stimuli and the acquisition of differentially conditioned fear were assessed in 53 clinically anxious and 30 non-anxious control children and young adolescents. Anxious children tended to show larger electrodermal responses during habituation, but did not differ in blink startle latency or magnitude. After acquisition training, non-anxious children rated the CS + as more fear provoking and arousing than the CS- whereas the ratings of anxious children did not differ. However, anxious children rated the CS + as more fear provoking after extinction, a difference that was absent in non-anxious children. During extinction training, anxious children displayed larger blink magnitude facilitation during CS + and a trend towards larger electrodermal responses, a tendency not seen in nonanxious children. These data suggest that extinction of fear learning is retarded in anxious children. (c) 2005 Elsevier Ltd. All rights reserved.