Final answer:
David Denby indicates that grit, characterized by determination and perseverance, is crucial for academic success, as it outperforms talent or IQ as a predictor of achievement.
Step-by-step explanation:
Based on the study referenced, David Denby’s argument regarding grit implies that it is essential for success. The research indicates that characteristics like grit and perseverance have a significant impact on academic success, challenging the traditional emphasis on natural talent or IQ as prime indicators of achievement. Grit involves the determination to work through challenges and maintain effort over a long period, which this study has shown to be a crucial factor in attaining one's goals academically and presumably in other areas of life too.