Three-concept monte: Explanation,implementation and systematicity

Fodor and Pylyshyn (1988), Fodor and McLaughlin (1990) and McLaughlin (1993) challenge connectionists to explain systematicity without simply implementing a classical architecture. In this paper I argue that what makes the challenge difficult for connectionists to meet has less to do with what is to be explained than with what is to count as an explanation. Fodor et al. are prepared to admit as explanatory, accounts of a sort that only classical models can provide. If connectionists are to meet the challenge, they are going to have to insist on the propriety of changing what counts as an explanation of systematicity. Once that is done, there would seem to be as yet no reason to suppose that connectionists are unable to explain systematicity.Shorter versions of this paper were presented at the 1993 annual meetings of both the Southern Society for Philosophy and Psychology and the Society for Philosophy and Psychology. The paper has benefited from the comments and criticisms of Frances Egan, David Chalmers, Terry Horgan, Brian McLaughlin, Tim van Gelder and Ted Warfield.     

Scheffler Revisited on the Role of History and Philosophy of Science in Science Teacher Education

Twenty-five years ago Israel Scheffler argued for the inclusion of philosophy of science in the preparation of science teachers. It was part of his wider argument for the inclusion of courses in the philosophy of the discipline in programmes that are preparing people to teach that discipline. For the most part Scheffler's suggestion, at least as far as science education is concerned, went unheeded. Pleasingly, in recent times there has been some rapprochement between these fields. This paper will restate parts of Scheffler's argument, it will develop some additional considerations pertaining to it, and it will set the discussion in the context of contemporary debate about science, science education and teacher training. With changed time and circumstances, Scheffler' arguments might find more adherents than when they were initially proposed. My revision of Scheffler's argument has two planks: first pedagogical, second professional.     

Velocity-dependent improvements in single-dot direction discrimination

Thirty-six Brown University students participated in three experiments designed to address perceptual learning. In each experiment, visual discrimination thresholds were tracked over 4,200 trials. Results from Experiment 1 suggest that the pattern of threshold reduction on a single-dot motion-direction discrimination task was stimulus-direction specific and matched (in a velocity-dependent manner) the threshold reduction pattern previously reported for a line-orientation discrimination task. In Experiment 2, it was determined that the stationary-line-orientation—specific practice effects originally reported by Vogels and Orban (1985) could be replicated but were contingent on line length. Similarly, the results from Experiment 3 suggest that practice effects originally reported by Ball and Sekuler (1987) could be replicated but were contingent on stimulus velocity. Implications for the mechanisms underlying direction and orientation discrimination are considered.     

Selective sensitivity of schedule-induced activity to an operant suppression contingency.

The sensitivity of pigeons' schedule-induced activity to operant consequences was studied in two experiments. During a 30-s interval between food presentations, a keylight stimulus brightened incrementally. Stable terminal key pecking and interim locomotor activity developed. An operant "setback" contingency was applied to activity. The contingency arranged for locomotor movements (detected by a nine-panel floorboard) to be followed by a resetting of the keylight brightness to a dimmer value and a 1-s delay of reinforcement (for individual responses). Experiment 1 showed that activity patterns were highly sensitive to their operant consequences. Accompanying key-peck rates were only transiently affected. In Experiment 2, the setback contingency was imposed during restricted portions of the trial, and differential operant control of activity was demonstrated. However, birds in this study produced higher rates of key pecking as activity rates were reduced. These results suggest that although schedule-induced activity arises in response to the temporal arrangement of stimulus events, this behavior may retain considerable sensitivity to response-consequence relations.     

Repetition of Lexicalization Across Languages: A Further Test of the Locus of Priming

Wheeldon and Monsell (this issue) found that production of a word in response to a definition had a large and long-lasting facilitatory effect on latency for later production of the same word to name a pictured object, and that this priming effect was not due to repeated production of the phonological word-form per se. This paper reports a further test of the locus of the effect. Welsh-English bilinguals named pictured objects in Welsh. Half the words were primed either by their earlier production in Welsh in response to Welsh definitions or by production of their equivalents in English in response to English definitions. Substantial facilitation resulted from prior production in the same language, none from prior production in the other language—provided that the equivalents differed in phonological form. Given that priming results neither from repeated activation of a meaning when different phonological forms are produced, nor from repetition of the same phonological form in response to different meanings, the priming effect must be localized in the connection between a word's meaning and its phonological form. We also put forward an account of bilingual lexicalization that accommodates this result together with some evidence indicating that production of words in one language is not wholly insulated from the “availability” of words in the other.     

"Turning back the clock" on serial-stimulus sign tracking.

Two experiments examined the effects of a negative (setback) response contingency on key pecking engendered by a changing light-intensity stimulus clock (ramp stimulus) signaling fixed-time 30-s food deliveries. The response contingency specified that responses would immediately decrease the light-intensity value, and, because food was delivered only after the highest intensity value was presented, would delay food delivery by 1 s for each response. The first experiment examined the acquisition and maintenance of responding for a group trained with the contingency in effect and for a group trained on a response-independent schedule with the ramp stimulus prior to introduction of the contingency. The first group acquired low rates of key pecking, and, after considerable exposure to the contingency, those rates were reduced to low levels. The rates of responding for the second group were reduced very rapidly (within four to five trials) after introduction of the setback contingency. For both groups, rates of responding increased for all but 1 bird when the contingency was removed. A second experiment compared the separate effects of each part of the response contingency. One group was exposed only to the stimulus setback (stimulus only), and a second group was exposed only to the delay of the reinforcer (delay only). The stimulus-only group's rates of responding were immediately reduced to moderate levels, but for most of the birds, these rates recovered quickly when the contingency was removed. The delay-only groups's rates decreased after several trials, to very low levels, and recovery of responding took several sessions once the contingency was removed. The results suggest that (a) sign-tracking behavior elicited by an added clock stimulus may be reduced rapidly and persistently when a setback contingency is imposed, and (b) the success of the contingency is due both to response-dependent stimulus change and response-dependent alterations in the frequency of food delivery. The operation of the contingency is compared with the effects of secondary reinforcement and punishment procedures.     

Stress reactivity and exercise training in premenopausal and postmenopausal women.

Examined the influence of ovarian function on psychophysiological stress responses and determined if aerobic exercise reduced stress reactivity. Fifty premenopausal and postmenopausal women initially were subjected to a public speaking task and an ice-on-the-forehead procedure, during which time their blood pressure and heart rate were monitored and continuous blood samples were obtained. Subjects also underwent aerobic fitness evaluations with a maximum-exercise treadmill test. Subjects were then randomly assigned to a 12-week exercise program of either aerobic exercise (e.g., walking and jogging at a prescribed exercise intensity) or non-aerobic strength and flexibility training and were then reevaluated. Results indicated that postmenopausal women exhibited lower resting epinephrine levels but greater epinephrine reactivity to the speaking task compared to the premenopausal women. There were no differences between premenopausal and postmenopausal women with respect to cardiovascular or catecholamine responses during the cold challenge. Premenopausal and postmenopausal women also achieved comparable improvements in aerobic fitness. However, results of the mental stress testing were complex and provided only partial support for the role of aerobic exercise in reducing stress responses.     

Sex-role perception,portrayal, and preference in the fantasy play of young children

The naturalistic observation of role-taking behavior in 90 spontaneously occurring (i.e., unelicited) fantasy play episodes of 16 4-year-old children in same-sex paired interaction revealed (1) a differential perception of male, female, parental, and conjugal roles, particularly in terms of competence; (2) the accuracy, depth, and breadth of their sex-role portrayals; and (3) a preference for same-sex role-play. The assimilative and accommodative functions of roleplay in the early acquisition of sex role are discussed, as well as the degree of decentration required for the roleplay activities to occur.The research reported here was carried out at Cornell University. It was part of a doctoral dissertation on the nature of fantasy in the spontaneous play of young children, which was in turn part of a larger study of peer interaction conducted by Lee C. Lee. It was supported by a research grant from the College of Human Ecology, State University of New York. This article was originally presented as a paper at the meeting of the Society for Research in Child Development, New Orleans, March 1977.     

Further investigation of Coleman's Level Hypothesis

Volunteers (16 male and 17 female) from introductory psychology courses were used to investigate Coleman's rationale in support of the Levels Hypothesis. Projective stimuli from parts of the Rorschach, TAT, and Sentence Completion techniques were presented, and subjects asked to rate how much the stimuli and their responses said something about themselves, their fathers, or mothers, to determine their awareness of the personal relevance of the stimuli and responses. Results indicated that both the stimulus and response ratings varied as expected at the .01 level of significance, thus supporting Coleman's rationale.