INTRODUCTION

1. FREQUENCY EFFECTS IN RECOGNITION MEMORY:EVIDENCE FOR A MULTIPROCESS DETECTION MODEL David G. Smith University of Toronto Marty W. Niewiadomski University of Toronto at Scarborough INTRODUCTION DISCUSSION In a recognition test, participants typically make more hits and fewer false alarms on low-frequency words compared to high frequency words (A pattern of results known as the mirror effect, Glanzer & Adams, 1985). In most of these experiments high and low frequency words are mixed at both study and test. Experiments 1 and 2 show that the hit-rate component of the mirror effect is eliminated when participants study a pure list of either low or high frequency list. The pattern of false alarms also changes depending on the type of list. We suggest that our current pattern of results as well as previous results can be understood if one assumes that there are two-dimensions of information available for recognition decisions: one that is used primarily for recognition of low-frequency words and another that is used for the recognition of high-frequency words. One way to understand these results is to assume that the kind of information one uses for recognition decisions is based on the characteristics of the study items. Our results are consistent with the idea that when one studies an HF study list, recognition decisions are based on familiarity (hence the frequency effects). When one studies a list of LF words ones decisions are based on another internal variable not based on familiarity (e.g. Recollection) which eliminates frequency effects.* Figures 3a,b,&c demonstrate how a two-dimensional model could accommodate the results. When one studies only HF words recognition is based entirely on familiarity. When one studies LF words recognition is based on the second dimension (which we call Strength Of Recollection). When one studies a mixed list of words recognition is based on a combination of both dimensions. *Banks (2000) used a similar approach to model source memory. EXPERIMENT 1 • Method: • One group studied a list of 80 low frequency words and another group studied a list of 80 high-frequency words. At test all studied items were presented as probes along with 40 HF lures and 40 LF lures. • Results: • Contrary to the standard within subjects mirror effect the Hit rate was not significantly different for HF (M=0.78) and LF (M=0.83) targets. For a list of LF study items false alarms for HF (M=0.13) and LF lures (M=0.13) did not differ. For a list of HF study items there were more FA’s to HF lures (M=0.34) than LF lures (M=0.02). Legend LL=LF Lure LT=LF Target HL=HF Lure HT=HF Target Figure 3a. LF Study Figure 3b. HF Study Figure 3c. Mixed Study EXPERIMENT 2 • Method: • Same method as Experiment 1 except that Lure type (HF or LF) was blocked. Half the participants had HF lures in the first block and the other half had HF lures in the second. • Results: • Like Experiment 1 Hit rate was the same for HF (M=0.77) and LF targets (M=0.75). For a list of LF study items False alarms for HF (M=0.24) and LF lures (M=0.20) did not differ. For list of HF study items there were more False alarms to HF lures (M=0.39) than LF lures (M=0.09). • Hit rate depended on the type of lure for HF but not LF study items. • When subjects studied HF items and were tested in a context of LF lures the Hit rate was higher (M=0.81) then for HF lure context (M=0.73). • However, when subjects studied LF items, the Hit rates in the different contexts were the same (M=0.75) SOR GENERAL METHOD SOF • Study list: • 80 words were presented, one at a time, on the computer screen. • Words were either high frequency (mean kf = 156.0 ) or low frequency (mean kf = 2.4 ) depending on group assignment. • Recognition test: • 160 words were presented on the computer screen, one at a time. • Test word frequencies varied across experiments. • Half of the words appeared in the study list (old), and half did not (new). • Subjects were asked to decide whether the words are old or new, as well as provide confidence judgments ranging from 3 to 1 (3 = sure, 2 = moderately sure, 1 = unsure). • ACKNOWLEDGEMENTS • The authors would like to thank Bill Hockley and Ben Murdock for the use of their laboratory facilities, as well as their insightful comments and Steve Joordens for his helpful suggestions. REFERENCES Banks, W. P. (2000). Recognition and source memory as multivariate decision processes. Psychological Science, 11, 267-273. Glanzer, M. & Adams, J. K. (1985). The mirror effect in recognition memory. Memory & Cognition, 13, 8-20. For additional information please contact David Smith at smith@psych.utoronto.ca or Marty Niewiadomski at martin@psych.utoronto.ca This research was supported by an NSERC operating grant