The predicted interference by depressotypic cognitions on the lexical decision task resembles a phenomenon labeled ``rumination'' by other researchers. Theorists such as Morrow and Nolen-Hoeksema (1990) suggest that depression involves a trait-like feature called rumination by which attention is focused on an individual's depressive symptoms. Nolen-Hoeksema has shown in a series of experiments that individuals possessing a ruminative cognitive style tend to focus on their symptoms of depression at the expense of other tasks which they are given to do (e.g., Nolen-Hoeksema, Parker, & Larson, 1994; Nolen-Hoeksema & Morrow, 1993), and that this rumination appears to worsen their mood (e.g., Nolen-Hoeksema, Morrow, & Fredrickson, 1993). Rumination on symptoms may thus be equated to Ingram's (1984) notion of feedback loops between affective and semantic nodes in which recurrent activation serves to propagate the activation of the strongest connected pathways, in this case those reflecting a person's own symptomatology. Nolen-Hoeksema's theory might predict relatively few facilitative effects on a lexical decision task in which subjects are queried about negative words which do not necessarily reflect their own symptoms. It might, in fact, predict delays on negative words on this task, if the task is presumed to activate such ``ruminative'' processes. Thus, when examining results of future lexical decision tasks, the amount of rumination in which people engage may be an important variable to account for.
Similar reasoning may be used to integrate Stip et al.'s (1994) theory of affective stress with the preceding explanation. Stip et al. (1994) suggest that psychomotor retardation in depression involves being so overcome with stress that one is unable to respond to cognitively demanding tasks. They state that depressed people will be most overcome with stress upon seeing a negative stimulus, and will therefore be especially delayed in responding to the stimulus. They thus predict, and find, that depressed people are delayed in responding to negative words with respect to positive or neutral words on an affective lexical decision task.
Stip et al.'s (1994) conjectures regarding affective stress may also be interpreted as reflecting cognitive over-arousal with respect to negative stimuli. The activation of multiple negative constructs brought on by spreading activation from a negative stimulus may be thought of as invoking stress associated with negative affect (e.g., as proposed by Ingram, 1984). Thus, feedback within an affective-semantic network could be seen alternately as causing ambiguity between the semantic content of the stimulus and a personal depressotypic cognition, rumination which prevents quick reactions to negative stimuli, or, in Stip's conception, stress which prevents a response to a negative stimulus.
An earlier article by Stip and Le Cours (1992) presents a theory predicting delays on the affective lexical decision task which even more closely resembles the affective interference theory. They suggest that limited attentional resources are available to a depressed or nondepressed person. They further hypothesize that many of the depressed person's resources are devoted specifically to attending to negative internally generated cognitions. The affective interference theory may be viewed as extending this hypothesis by stating to exactly which negative cognitions the depressed person is hypothesized to attend. Specifically the affective interference theory predicts the depressed person will be prompted to generate negative cognitions semantically related to the stimulus, but also related to his or her depressotypic cognitions in response to the stimulus. Their efforts to disambiguate the semantic representation of the stimulus from those representing their negative cognitions may be seen as ``attending to negative cognitions'' as predicted by Stip and Le Cours (1992).