Manipulating the depth of processing reveals the relevance of second eye fixations for recollection but not familiarity

It is well known that memory affects eye movements. However, the role of individual eye fixations for recognition memory processes has hardly been investigated. Recent findings show that second fixations are especially relevant for recollection, a process associated with the retrieval of context information, but less for recognition based solely on item familiarity. The aim of the present study was to overcome limitations of a previous study (Schwedes and Wentura in Memory, 2019. https://​doi.​org/​10.​1080/​09658211.​2019.​1567789) and to provide further evidence that second fixations are especially relevant for recollection-based recognition. Whereas recollection- and familiarity-based recognition was an unconstrained quasi-experimental variable in a previous study, here we manipulated the depth of stimulus processing in the encoding phase to experimentally manipulate the probability of subsequent item recollection. In the old/new recognition memory test, presentation of test probes was terminated after one or two stimulus fixations. “Old” responses in the recognition test were followed by a remember/know/guess procedure to assess recollection-based versus familiarity-based recognition. We found the expected depth of processing effect, with better recognition and more recollection-based responses after deep encoding. This effect, however, was significantly larger if two fixations instead of just one were allowed. There were no corresponding effects for familiarity-based recognition. Thus, a second fixation seems to play an important role only for recollection-based recognition.