The effects of eye position and expectation on sound localization

Ss who are exposed to a sound coming from straight ahead, but who turn their eyes 20 deg to the side toward a visible speaker during the exposure period and expect to hear the sound coming from the visible source, show a shift in localization of the sound up to a maximum of about 9 deg. Ss who only turn their eyes 20 deg to the side during the exposure period show a smaller but significant shift in sound localization, while Ss who do not turn their eyes, but are led to expect that the sound will appear to come from a visible loudspeaker 20 deg to the side, show no significant shift. Comparison of test results before and after the exposure period, with eyes directed straight ahead and no visible speaker present, shows the presence of a localization aftereffect for those experimental groups that showed a significant localization shift during the exposure period. Sounds are localized a few degrees to the side of their physical location in the same direction as the shift in localization during the exposure period. Further experiments show that part, but not all, of the shift in localization during the exposure period can be understood in terms of a shift in perceived head direction. The localization aftereffects are shown not to be due to change in physical or perceived eye or head position.     

An analysis of some conditions for representingN state Markov processes as general all or none models

Recently Markov learning models with two unidentifiable presolution success states, an error state, and an absorbing learned state, have been suggested to handle certain aspects of data better than the three state Markov models of the General All or None model type. In attempting to interpret psychologically, and evaluate statistically the adequacy of various classes of Markov models, a knowledge of the relationship between the classes of models would be helpful. This paper considers some aspects of the relationship between the class of General All or None models and the class of Stationary Absorbing Markov models withN error states, andM presolution success states.     

College Student Personnel and Academic Freedom for Students

The issue of academic freedom for students is frequently a source of heated controversy. In the emotionally charged atmosphere that surrounds this question the true nature and purpose of academic freedom are too often obscured. This discussion focuses attention on the philosophical and educational premises that underlie this concept and attempts to examine it from several frames of reference. A brief summary tracing the historical evolution of academic freedom for students to the present is developed and 8 common points of emphasis as interpreted from several current statements on the subject are outlined. An additional concern of some moment involving the relationship and responsibility of the college student personnel worker to these 8 significant points of common emphasis is noted.     

Effect of prior Pavlovian discrimination training upon learning an operant discrimination

The effect of Pavlovian discrimination training with two stimuli upon subsequent learning of an operant discrimination involving those stimuli was studied. After preliminary lever press training, the lever was removed and thirsty rats received noncontingent pairings between S₁ (a tone or a clicker) and water reinforcements, whereas S₂ (a clicker or a tone) occurred always without reinforcement. This procedure presumably established S₁ as a positive CS for respondent behavior, whereas S₂ was established as an inhibitory CS. Following this training, the lever was reintroduced and the rats were trained on an operant (lever pressing) discrimination involving S₁ and S₂. For the Consistent Ss, S₁ was the S^D and S₂ the S^Δ in the operant discrimination; for the Reversed Ss, S₂ served as S^D and S₁ as S^Δ. The Consistent Ss learned the operant discrimination significantly faster than did the Reversed Ss. The result emphasizes the importance of respondents, conditioned to S^D and S^Δ, which modulate operant performance to these stimuli.     

Verbal versus manual reaction time in schizophrenic and normal subjects

On the assumption that schizophrenia involves a disturbance in interpersonal relations it is predicted that the verbal reaction time responses of schizophrenic subjects should have disproportionately longer latencies than manual reaction time responses as compared to normal subjects. Using data presented in this Journal by Venables and O'Connor (1959). the prediction is confirmed for patients whose reaction time level is relatively fast, but not in those with relatively slow reaction times. Several possible mechanisms are postulated to account for the results, including differential reinforcement, amount of practice, and complexity of verbal responses, and degree of pathology of the patients.     

Deferred decision in human signal detection: A preliminary experiment

In the detection task characterized by deferred decision, the observer is allowed to determine how many observations he will make before deciding whether or not a signal is present, and he is called upon to balance the goals of maximizing accuracy and conserving time. The human observer appears capable of using the optimal process of cumulating sensory information over successive observations, but certain common training procedures lead him to use a less efficient process. Though he displays a consistent decision bias, his performance is also in good agreement with the optimal model of the process of terminating a sequence of observations.