---
title: "Focus of Attention in the Hearsay-II Speech Understanding System"
authors:
  - "Frederick Hayes-Roth"
  - "Victor R. Lesser"
doi: ""
url: "https://ijcai.org/proceedings/1977/7"
pdf: "https://ijcai.org/proceedings/1977/0007.pdf"
venue: "Proceedings of the Fifth International Joint Conference on Artificial Intelligence"
year: 1977
pages: "27-34"
track: "Natural Language"
keywords:
---

# Focus of Attention in the Hearsay-II Speech Understanding System

Frederick Hayes-Roth, Victor R. Lesser

*Proceedings of the Fifth International Joint Conference on Artificial Intelligence*, pages 27-34.

## Abstract

Using the concepts of stimulus and response frames of scheduled knowledge source instantiations, competition among alternative responses, goals, and the desirability of a knowledge source instantiation, a general aUentlonal control mechanism is developed. This general focusing mechanism facilitates the experimental evaluation of a variety of specific attentional control policies (such as best-first, bottom-:-up, and top-down search strategies) and allows the modular addition of specialized heuristics for the speech understanding task . Empirical results demonstrate the effectiveness of the focusing prin.ciples, and possible directions for future research are considered.