Memory of a speaker's voice: Reaction time to same- or different-voiced letters

Subjects were presented with a sequence of two letters, each letter spoken in either a male or female voice. On each trial, the subject was required to indicate, as quickly as possible, whether the two letters had the same name. Reaction times (RTs) were faster for letters spoken in the same voice for both “same” and “different” responses, even when letters were separated by 8 s. These results are incompatible with the notion of physical and name codes in auditory memory since a “different” response should always be based on a comparison of letter names and should not be influenced by voice quality. It was also found that RTs were not influenced by the phonemic distinctive feature similarity of the letters.     

The phantom in the phoneme: Invariant cues for stop consonants

The stop consonants /b, d, g, p, t, k/were recorded before/i/,/a/,/u/. The energy spectrum for each stop consonant was removed from its original vowel and spliced onto a different steady-state vowel. Results of a recognition test revealed that consonants were accurately recognized in all cases except when /k/ or/g[ was spliced from/i/to/u/. Further demonstrations suggested that/k/ and /g/ do have invariant characteristics before/i/, /a/, and /u/. These results support the general notion that stop consonants may be recognized before different vowels in normal speech in terms of invariant acoustic features.     

Response rate under varying frequency of non-contingent reinforcement

Two White Carneaux hen pigeons were exposed to a 60-sec random-interval baseline procedure. Six different exteroceptive stimuli were successively correlated, within a single session, with blocks of 10 reinforcement presentations. Following this training, a non-contingent reinforcement procedure was instated with inter-reinforcement intervals of 5, 15, 30, 60, 120, and 240 sec. Within a single session, each non-contingent frequency was correlated with one of the previously presented discriminative stimuli. After an initial increase in the rate of responding as the result of a high density of non-contingent reinforcements, the rate declined as exposure to each non-contingent frequency was prolonged.     

Mechanisms of aural encoding: I. Distinctive features for consonants

To examine the importance of distinctive features that are used to encode consonants (following Wickelgren’s analysis) in an immediate recall task, sequences of 5 consonants, all paired with the vowel /a/ were constructed and presented aurally for recall. The middle three items in each sequence all had either the same place of articulation (front, middle, or back of the vocal apparatus), orthe same manner of articulation (voiced, unvoiced, or nasal), or were unrelated in either place or manner (control). It was shown that, in comparison with the control sequences, consonants imbedded among others articulated similarly were recalled less accurately, suggesting that these distinctive features are important in encoding and memory maintenance. A comparison of the 3 manner and 3 place features showed that the greatest difficulty in recall occurred for the similar manner sequences (especially voiced and unvoiced, implicating manner of articulation as the critical distinctive feature in aural encoding. Some discussion is also presented of a distinction between articulation and acoustic factors in encoding processes.     

Success Rates in the Vocational Rehabilitation Of Mental Patients

The post-treatment work adjustment of mental patients receiving rehabilitation services is extremely difficult to evaluate. A follow-up study of 223 patients referred for vocational rehabilitation to the Mental Health and Manpower project from the Fort Logan Health Center revealed percentages of patients successfully employed or in training which appear to be slightly higher than those usually reported. There were marked differences in post-rehabilitation adjustment between alcoholic and psychiatric referrals. These differences in success rates appeared to be partly a function of type of placement (i.e., direct job placement, on-the-job placement, or institutional training placement).