Learning to search: From weak methods to domain-specific heuristics

Learning from experience involves three distinct components—generating behavior, assigning credit, and modifying behavior. We discuss these components in the context of learning search heuristics, along with the types of learning that can occur. We then focus on SAGE, a system that improves its search strategies with practice. The program is implemented as a production system, and learns by creating and strengthening rules for proposing moves. SAGE incorporates five different heuristics for assigning credit and blame, and employs a discrimination process to direct its search through the space of rules. The system has shown its generality by learning heuristics for directing search in six different task domains. In addition to improving its search behavior on practice problems, SAGE is able to transfer its expertise to scaled-up versions of a task, and in one case, transfers its acquired search strategy to problems with different initial and goal states.     

Learning to pause: Fidelity of and biases in the developmental acquisition of gaps in the communicative signals of a songbird

The temporal organization of sounds used in social contexts can provide information about signal function and evoke varying responses in listeners (receivers). For example, music is a universal and learned human behavior that is characterized by different rhythms and tempos that can evoke disparate responses in listeners. Similarly, birdsong is a social behavior in songbirds that is learned during critical periods in development and used to evoke physiological and behavioral responses in receivers. Recent investigations have begun to reveal the breadth of universal patterns in birdsong and their similarities to common patterns in speech and music, but relatively little is known about the degree to which biological predispositions and developmental experiences interact to shape the temporal patterning of birdsong. Here, we investigated how biological predispositions modulate the acquisition and production of an important temporal feature of birdsong, namely the duration of silent pauses (“gaps”) between vocal elements (“syllables”). Through analyses of semi-naturally raised and experimentally tutored zebra finches, we observed that juvenile zebra finches imitate the durations of the silent gaps in their tutor's song. Further, when juveniles were experimentally tutored with stimuli containing a wide range of gap durations, we observed biases in the prevalence and stereotypy of gap durations. Together, these studies demonstrate how biological predispositions and developmental experiences differently affect distinct temporal features of birdsong and highlight similarities in developmental plasticity across birdsong, speech, and music.

Research Highlights

• The temporal organization of learned acoustic patterns can be similar across human cultures and across species, suggesting biological predispositions in acquisition.
• We studied how biological predispositions and developmental experiences affect an important temporal feature of birdsong, namely the duration of silent intervals between vocal elements (“gaps”).
• Semi-naturally and experimentally tutored zebra finches imitated the durations of gaps in their tutor's song and displayed some biases in the learning and production of gap durations and in gap variability.
• These findings in the zebra finch provide parallels with the acquisition of temporal features of speech and music in humans.

     

EARLY AND CURRENT READING AND SPELLING PRACTICES OF GIFTED SPELLERS

This study continued investigating the early reading and spelling experiences as well as the spelling practices of the finalists in the Scripps Howard National Spelling Bee, specifically the 1987 spellers who were considered gifted spellers. Two open-ended questionnaires were used: one for the parents of the spellers and one for the spellers. A follow-up telephone interview was conducted with a random sample of respondents. Results indicated that gifted spellers showed an early interest in language arts activities with 86% of the parents reporting that their children could read prior to formal schooling. The spellers considered themselves avid readers and indicated sophisticated metacognitive awareness whether reading or spelling. Results that suggested the spellers passed through developmental spelling stages far earlier than average children and relied on visual memory strategies, word meanings, and saying/writing words to master the orthography replicated findings from an earlier study.     

Mary Cover Jones: Feminine as Asset

Mary Cover Jones has played many roles during her career as a psychologist—researcher, professor, wife of the eminent psychologist Harold E. Jones, and friend to some of the great names in the field such as Erik Erikson and Nevitt Sanford. Included in the paper is a discussion of three of her primary areas of research—the case study of Peter which provided a preview of behavior modification, evidence from longitudinal studies regarding the problems of early and late maturing, and work on personality antecedents in problem drinkers. In addition, her part in the establishment of the major longitudinal studies at the University of California is reported. Finally, her successful application of traditionally feminine strengths to these many professional undertakings is discussed.     

The Relationship of Sex, Sex Role, and Mental Health

Mental health differences due to sex, sex-role identification, and sex-role attitudes were investigated using 109 undergraduate students. Females reported higher levels of depression and anxiety. Both males and females with more liberal scores on the Attitudes Toward Women Scale scored higher on the Well-Being Scale of the California Psychological Inventory. No differences due to androgyny were found.