Encoding, storage and judgment of experienced frequency and duration

Judgment and Decision Making, Vol. 5, No. 5, August 2010, pp. 347–364 Encoding, storage and judgment of experienced frequency and duration Tilmann Betsch,∗ Madlen Glauer, Frank Renkewitz University of Erfurt, Germany Isabell Winkler, Peter Sedlmeier Chemnitz University of Technology, Germany Abstract This paper examines conditions that do or do not lead to accurate judgments of frequency (JOF) and judgments of duration (JOD). In three experiments, duration and frequency of visually presented stimuli are varied orthogonally in a within-subjects design. Experiment 1 reveals an asymmetric judgment pattern. JOFs reflected actual presentation frequency quite accurately and were unbiased by exposure duration. Conversely, JODs were almost insensitive to actual exposure duration and were systematically biased by presentation frequency. We show, however, that a tendency towards a symmetric judgment pattern can be obtained by manipulating encoding conditions. Sustaining attention during encoding (Experiment 2) or enhancing richness of the encoded stimuli (Experiment 3) increases judgment sensitivity in JOD and yields biases in both directions (JOF biased by exposure duration, JOD biased by presentation frequency). The implications of these findings for underlying memory mechanisms are discussed. Keywords: frequency processing, time perception, quantitative judgment, long-term memory. 1 Introduction Event frequency and duration are of fundamental importance in behavioral adaptation (Gallistel, 1989; Schwartz & Reisberg, 1991). Predators, for instance, increase their chances of survival if they approach areas where the prey resides more frequently and for longer periods of time. Conversely, prey should strive to avoid areas where predators roam frequently and consistently. Consider an individual who must decide where to go hunting: the probability of maximizing the individual’s yield is a function of the frequency and length of time (duration) prey lingers in a certain area. Assume the individual is an experienced hunter who has often visited different areas in the past and observed the behavior of the prey animals. Further assume that the observations made would represent a valid sample of the prey animals’ migrations. In order to properly adapt his own behavior to the environment, the hunter should use frequentistic and temporal information in his subsequent choice (Attneave, 1953; ∗ This research was supported by grants from the German Science Foundation (Deutsche Forschungsgemeinschaft) to Tilmann Betsch (BE 2012/5–1) and Peter Sedlmeier (SE 686/8–1). We thank two anonymous reviewers for valuable comments. We are grateful to Judith Bernauer, Stefanie Häusig, Marei Krüger, Justus Julius Wolfgang Kunz, Frank Lindow and Nicola Schindler for running the experiments. Address: Tilmann Betsch, Department of Psychology, University of Erfurt, PO Box 900 221, D-99105 Erfurt, Germany. Email: . Herrnstein, 1961). This requires two abilities: first, the individual must be capable of discriminating differences in frequency and duration; second, representations of frequency and duration must be stored in memory so that they can be used later for judgment and decision making. Psychologists from various fields have studied processing of duration and frequency extensively. Their approaches, however, differ. Research in animal cognition and neuropsychology focuses primarily on discrimination and short term storage (e.g., Meck, 2003). Cognitive psychologists are often interested in memory processes (e.g., Lewis & Miall, 2006; Zacks & Hasher, 2002), whereas JDM researchers mainly consider judgmental heuristics (e.g. Kahneman, Slovic & Tversky, 1982). These fields host different theoretical perspectives, apply different research paradigms and arrive at diverging interpretations of the phenomena. Consider, for example, the case of frequency judgment. Cognitive psychologists normally employ learning procedures to induce frequency knowledge in the laboratory and usually find that participants subsequently make quite accurate judgments. They explain their findings with reference to general models of memory (e.g., Hintzman, 1988; Hasher & Zacks, 1984). Conversely, JDM researchers often investigate factors that cause changes in judgment accuracy and explain their results with reference to judgmental heuristics (see Sedlmeier, Betsch & Renkewitz, 2002, for a discussion). 347 Judgment and Decision Making, Vol. 5, No. 5, August 2010 The separation between research fields has been often lamented, but there is an increasing number of researchers striving towards integration both on the methodological and the theoretical level (e.g., Dougherty, Gettys & Ogden, 1999; Fiedler, 2002, Thomas, Dougherty, Sprenger & Harbison, 2008; Weber, Goldstein & Barlas, 1995; Weber, Johnson, Milch, Chang, Brodscholl & Goldstein, 2007) In this paper, we report studies using a research paradigm from cognitive psychology to induce knowledge about frequency and duration. We compare judgments in two related domains, judgments of duration (JOD) and judgments of frequency (JOF). We manipulate conditions of encoding and assess their effects on judgmental patterns. Specifically, we compare JOD and JOF regarding differences in their retrospective sensitivity and differences in their susceptibility for biases. With this approach, we seek to increase our knowledge of fundamental memory processes. Such knowledge may help to achieve a better understanding of variations in judgment. In the remainder of the introduction, we give a brief overview of the state of research on processing of frequency and duration and arrive at a working hypothesis regarding storage of these entities in memory. Ample evidence indicates that organisms are remarkably good at discriminating differences in frequency and duration (e.g., Gallistel, 1989). Like animals (Meck & Church, 1983), adult humans (Hasher & Zacks, 1984; Whalen & Gallistel, 1999; Zacks & Hasher, 2002) and even young children (Droit-Volet & Wearden, 2001) are capable of effectively discriminating low range frequencies (n < 10). Similarly, humans, like many other species, are able to discriminate temporal information across a wide range of intervals — from circadian timing to the timing of seconds and even milliseconds (Buhusi & Meck, 2005). The discrimination of very short durations in the millisecond range, in particular, seems to be very accurate (Lewis & Miall, 2006; Rammsayer, 2003). All together, research findings suggest that a common mental mechanism drives discrimination of both stimulus dimensions — frequency and duration (Walsh, 2003; but see Dormal et al., 2006). Granting the findings on discrimination, one may be tempted to assume that frequency and duration would also affect storage in memory in a similar fashion. According to such a common-path hypothesis (Figure 1), frequency and duration would have commensurate effects on a stimulus’ representation (RS ) and subsequent judgm (...truncated)