Time window and unit capacity: dual constraints on the acquisition of serial information in songbirds

✍ Scribed by Henrike Hultsch

• Publisher: Springer
• Year: 1992
• Tongue: English
• Weight: 715 KB
• Volume: 170
• Category: Article
• ISSN: 0340-7594
• DOI: 10.1007/bf00191415

✦ Synopsis

Hand raised nightingales (Luscinia megarhynchos) perform imitations of song-types that were serial neighbours in a string of master song-types sequentially associated as "packages" of limited size. This study examines whether such "chunking" of auditorily perceived serial information can be influenced by the presentation rate of stimuli. Subjects (n = 8 males) were exposed to 3 different tutoring regimes, designed to offer either a "normal", or a "dense", or a "spaced" distribution of information (measure: number of songs per unit time): The duration of silent intervals separating subsequent songs in a string of master song-types was 4 s ("normal"), 1 s ("dense") or 10 s ("spaced"). The analysis of packages of acquired song-types revealed the following results:

1. Packages developed from the "dense" programmes were not larger in size (number of song-types, X___ SD: 3.9 + 1.2) than those developed from the "normal", programmes (X___ SD: 4.5 ___ 1.6). This suggests capacity constraints on data processing to account for package formation.

2. Packages developed from the "spaced" programmes, on the other hand, were significantly smaller (number of song-types, X + SD : 2.5 + 0.7), suggesting that the parsing is controlled by time factors.

3. This was supported by analyzing the duration of master string segments from which packages had been developed: The duration was not different for both the "normal" programmes (X+SD: 32.1• Max: 56.4 s), and the "spaced" programmes (X • SD : 32.8• Max: 54.1 s). The results confirm an earlier hypothesis predicting that the formation of song-type packages is mediated by a process which parses strings of auditorily perceived information upon exposure to serial stimuli. In addition, the results suggest that the parsing of a song-type string is controlled by two components: a unit (or information) based capacity buffer (evidence: constraints during "dense"), and a time window based gating mechanism (evidence: constraints during "spaced").