This investigation is concerned with the control and organization of the "psychological present," or primary memory, and specifically with the implications of such control and organization for the suffix effect. The suffix effect arises when a nominally irrelevant speech item, or "suffix," is appended to a spoken sequence of items, and it consists of an impairment in the recall of the most recent items in the sequence, especially the last item (e.g., Crowder, 1967; Dallett, 1965). The dominant explanation of the suffix effect has been in terms of "bottom-up" masking in general (e.g., Nairne, 1990) and precategorical acoustic masking in particular (e.g., Crowder & Morton, 1969; Crowder, 1978, 1983; Greene & Crowder, 1984). The current version of this explanation is "two-component" theory, wherein the precategorical masking explanation is confined to the terminal component of the suffix effect (i.e., at the last position of the sequence), with the preterminal component being open to influences of top-down or conceptually-based interpretation and strategy (see Greene, 1992 for a review). Reported here are 12 experiments, each of which provides evidence inconsistent with two-component theory. Experiments 1--4 failed to replicate the principal findings proffered in support of the theory; Experiments 5--11 extended some of the findings of the first four experiments by showing additional evidence of postcategorical influences on the terminal suffix effect; and Experiment 12 demonstrated a suffix effect with static visual presentation. These findings, and indeed those in the suffix effect literature in general, are interpreted along the lines of the now largely ignored perceptual grouping account proposed by Kahneman (1973; Kahneman & Henik, 1981).