| Categories | Message variables | Output variables | Key references |
| Surprise | Conflict | Interest/liking | Berlyn, 1960, 1974; Nunnally & Lemond, 1973 |
| Incongruity | Interest/liking | Hunt, 1963, 1965; Mandler, 1982 | |
| Structural anomaly | Interest/liking | Lepper, 1988 | |
| Surprise | Interest/liking | Hidi & Baird, 1986; Iran-Nejad, 1987 | |
| Unexpectedness | Interest/liking | Schank, 1979; Wade et al., 1999 | |
| Novelty | Interest/liking | Anderson et al., 1987; Wade et al., 1999; Silvia, 2005 | |
| Question | Mystery | Interest/liking | Cialdini, 2005; Kruglanski & Webster, 1996 |
| Information gap | Interest/liking | Loewenstein, 1994 | |
| Question | Interest/liking | Berlyn, 1960; Loewenstein, 1994 | |
| Recall | Slamecka & Graf, 1978; Pressley et al., 1987; Mulligan & Lozito, 2004 | ||
| Visualization | Imagery | Interest/liking | Wade et al., 1999; |
| Comprehension | Clark and Paivio, 1991 | ||
| Recall | Clark and Paivio, 1991 | ||
| Vivid detail | Interest/liking | Schraw et al., 1995 | |
| Concreteness | Recall | Wharton, 1980; Sadoski et al., 1993; Sadoski et al., 2000 | |
| Pictures | Attention | Delp & Jones, 1996; | |
| Comprehension | Michielutte et al., 1992; Austin et al., 1995; Morrow et al., 1998; Mansoor & Dowse, 2003 | ||
| Recall | Patel et al., 1990; Delp & Jones, 1996; Sojourner & Wogalter; 1998 | ||
| Decision making | Roter et al., 1987; Delp & Jones, 1996; Whatley et al., 2002 | ||
| Metaphor/analogy | Comprehension | Mio, 1996; Gentner & Markman, 1997 | |
| Emotional appeal | Emotional arousing | Attention | Yiend, 2010;Carretié, 2014. |
| Interest/liking | Schank,1979; Kintsch, 1980 | ||
| Recall | Sadoski & Quast, 1990; Schmolck et al., 2000; Hamann, 2001; Buchanan & Adolphs, 2002 |