Age of acquisition affects object recognition and naming in patients with Alzheimer's disease.

Twenty-two patients with a diagnosis of dementia of the Alzheimer type (DAT) and a comparison group of 22 age-matched individuals took part in an object decision and picture naming task. The age of acquisition (AoA) of the picture names was manipulated (25 early, 25 late). The comparison group identified significantly more objects as real than the patients. While the comparison group made very few errors in object decision, DAT patients failed to classify significantly more late than early acquired objects as real. The patients also named significantly fewer pictures than the comparison group, showing a differential impairment in naming late acquired objects. Late acquired objects induced proportionately more visual errors in the patients than did early acquired objects. The results are discussed in terms of current theories of age of acquisition and of the impact of Alzheimer's disease on lexical and semantic processing.

Measuring the speed of the conscious components of recognition memory: remembering is faster than knowing.

Three experiments investigated response times (RTs) for remember and know responses in recognition memory. RTs to remember responses were faster than RTs to know responses, regardless of whether the remember-know decision was preceded by an old/new decision (two-step procedure) or was made without a preceding old/new decision (one-step procedure). The finding of faster RTs for R responses was also found when remember-know decisions were made retrospectively. These findings are inconsistent with dual-process models of recognition memory, which predict that recollection is slower and more effortful than familiarity. Word frequency did not influence RTs, but remember responses were faster for words than for nonwords. We argue that the difference in RTs to remember and know responses reflects the time taken to make old/new decisions on the basis of the type of information activated at test.