An important difference between the present study and the work of Adcock et al. (2006) and Spaniol et al. (2013) is that these studies used a 24 h delay between the study and test phases. In the present study, there was only a 5 min filled delay between the end of the study phase and the beginning of the recognition test. With longer delays, there may have been a more robust effect on familiarity-based memory. Many items that would be initially recollected may be merely familiar after a long delay, as episodic detail memory fades (Dudukovic & Knowlton, 2006). It has also been hypothesized that dopamine release due to presenta- tion of cues indicating high value will enhance consolida- tion processes, with effects apparent in retention over a long delay (Murayama & Kitagami, 2014). Specifically, research suggests that this dopaminergic enhancement of memory is not apparent 30 min or even 9 h after study, and often takes approximately 12–24 h to manifest (Bethus, Tse, & Morris, 2010; Rossato, Bevilaqua, Izquierdo, Medina, & Cammarota, 2009). In previous stud- ies, the effect of value on recognition at short delays may not have been as robust if performance in these previous studies was primarily based on familiarity.
The present results demonstrate that the benefits of value on recognition are also apparent after a short delay, and that these are primarily driven by increased recollec- tion. Although recollection is often associated with signifi- cant memory for contextual details, recollection of valuable items appears to be less likely to be accompanied by memory for these details. High-value items may have been encoded at a deeper, more elaborative and semantic level than low-value items that were recollected. Thus, value may promote encoding that results in a qualitatively