Psychology at Indiana University: A Centennial Review and Compendium

Preface -- The legacy of the Laboratory (1888-1988): a history of the Department of Psychology at Indiana University / by James H. Capshew --Appendices A: Psychology Faculty, 1885-1988 -- B. Department Chairs, 1885-1988 -- C. Psychological Clinic Directors, 1922-1988 -- D. Graduate Degrees, 1886-1987 -- E. Bibliography of William Lowe Bryan -- Index to Appendices A-C -- The faculty in 1988

Delayed alternation in the pigeon

Pigeons were studied in a delayed-response task requiring alternation of key pecks on two response keys. Blackouts of from 1 to 10 sec intervened between successive choices on the two keys. The following results were obtained: (1) Birds performed at well above chance accuracy on all the delays tested. Accuracy was generally lowest at 1- and 10-sec delays. (2) Overt postural orientations during the delay interval appeared to mediate accurate key-pecking behavior. (3) The shape of the delay vs. accuracy function was discussed in terms of the possibly confounding influences of (a) stimulus “trace” variables, and (b) aversive effects of the time outs produced by incorrect responding

Contrast and stimulus generalization following prolonged discrimination training

Different groups of pigeons received discrimination training in which the reinforcement-associated and extinction-associated stimuli were respectively either (a) a line tilt vs a blank key, (b) a blank key vs a line tilt, or (c) two different line tilts. The high response rates that developed to the positive stimulus in all groups during discrimination learning were maintained over 64 sessions of training. After these sessions, all subjects were tested for stimulus generalization along the line-tilt dimension. Gradients of relative (per cent) generalization around the stimulus associated with reinforcement (so-called excitatory gradients) and around the stimulus associated with extinction (so-called inhibitory gradients) were as steep as they typically are after much briefer training periods. These results do not support several of Terrace's predictions on the basis of the hypothesis that emotional responses develop to the stimulus associated with extinction during discrimination learning with errors, but eventually dissipate after extended training

Inhibitory control and errorless discrimination learning

Pigeons learned to discriminate between a positive stimulus (white key) and a negative stimulus (red or green key, depending on the subject) via Terrace's fading procedure. Generalization tests, conducted with intermittent reinforcement for key pecking at various wavelengths, yielded minima at the value of the negative stimulus in most “errorless” birds. Terrace's contrary finding of flat gradients in errorless subjects probably resulted from a floor-effect (i.e., virtually zero responding) produced by his extinction-test procedure. The present and other findings do not support Terrace's conclusions that the negative stimulus of an errorless discrimination is behaviorally neutral; inhibition apparently develops to the nonreinforced stimulus even during errorless discrimination learning. A negative correlation between stimulus and reinforcer seems the crucial factor in producing an inhibitory stimulus

Search, Recognition, and Visualization in Chess: Rebuttal to Gobet’s Critique of Chabris & Hearst (2003)

computer analysis of errors in grandmaster games to measure the effects of additional thinking time and the ability to see the board on decision quality in expert-level chess. By comparing games played by the same players at rapid (R) and slower “classical ” (C) time limits, we concluded that additional thinking time substantially increases the quality of moves played. By comparing rapid games to blindfold (B) games between the same opponents, we concluded that the benefit of being able to see the chessboard and pieces during the game was surprisingly small. We discussed the implications of these results for theoretical claims about the relative values of pattern recognition and forward search in chess expertise, especially a claim by Gobet and Simon (1996a; hereafter G&S) that pattern recognition is the more important process. Here we respond to comments made in an unpublished critique of our work by Gobet (2003). 1 We have great respect for Gobet’s large body of work on chess expertise, and for his own expertise as an international master of chess. However, we believe his critique suffers from several deficiencies. Besides being vague in an empirical sense, it merely repeats many of the points that C&H brought up and that others have said before, seems to be inconsistent with Gobet’s previous statements by trying to make it appear that our results present no problems fo