The roles of instructions and examples in learning a second language from an instructional text: A computational model.

Abstract

Many second language instructional texts are written in a format in which the learner is presented with an instruction followed by a set of examples. This thesis discusses the roles played by both instruction and examples in learning from such a text and gives functional reasons of why both forms of input are necessary. A computer model of second language learning, called ANT, was built to investigate these roles. Input to the system is similar to what is found in an instructional text. ANT's learning with this input is compared to two alternatives: learning from only examples and learning from only instructions. I discuss why, from a functional or processing standpoint, learning from a mixed input is more effective than either of the alternatives. An empirical comparison was done of ANT's performance on input containing instructions and examples versus performance of the system when given instructions only or examples only. The results of the comparison support the hypothesis as to the utility of mixed input. In addition, a psychological experiment was done with human subjects, the results of which justified the hypotheses of the ANT model. Through the study it was found that the roles instructions play are that they: (1) focus the learner's attention on the nature of the difference between the native and second language; (2) focus the learner's attention on features in the examples relevant to those changes; (3) tell the learner how far the rule can be generalized; (4) allow the learner to alter expectations about the second language input; and (5) tell the learner to which rules the change applies. The roles examples play are that they: (1) help to identify relevant previous knowledge; (2) help to form the new rules; and (3) provide details essential to the rule which are omitted in the instruction. The study also discusses constraints which language learning puts on knowledge representation.