Peter Juslin Department of Psychology Umeå University Linnea Karlsson Department of Psychology Umeå University Henrik O

1. Peter Juslin Department of Psychology Umeå University Linnea Karlsson Department of Psychology Umeå University Henrik Olsson Department of Psychology Uppsala University This research was supported by the Swedish Tercentenary Bank Foundation

2. AGENDA • Multiple-cue judgment, • Two cognitive processes in multiple cue judgment: • Cue abstraction with intuitive cue integration, • Exemplar memory. • -- a generalized model of the judgment process: • Multiple representational systems with adaptive changes between representations. • Structural properties of cue-criterion relations predicts what representations dominate the judgments. • Additive or multiplicative cue-criterion relations,

3. Exemplar (instance) memory Categorization Features Category Probe C1 Criterion C2 Inference Cj Judgment Cues Cue abstraction with intuitive cue integration Multiple-Cue Judgment MULTIPLE CUE JUDGMENT • A physician relying on symptoms to make a diagnosis, • A meteorologist estimating the risk of precipitation from weather indices, • A stock broker estimating stock value of a company based on economic indices

4. Cue Abstraction Exemplar Memory Fever is typical of pneumonia, swollen glands is not, but coughing is typical of pneumonia, so... This patient looks like the patient last week with pneumonia,... COGNITIVE PROCESSES IN HUMAN MULTIPLE CUE JUDGMENT Intuitive (unaided) judgment

5. Deep-lying structural properties of the cue-criterions relations determine the representational mode SOME CHARACTERISTIC PROPERTIES

6. Adjustment implied by the aspect considered at n Adustment weight for the aspect considered at n -- POINT OF DEPARTURE • Belief adjustment model (Hogarth & Einhorn, 1992): • Sequential and iterative adjustment of estimate that is held active in working memory, • Linear and additive cognitive processing as a function of architectural constraints of the mind, • Hogarth and Einhorn (1992) addressed order effects in the presentation of information. Process Eq. New estimateat time n Previous estimate at n-1

7. -- GENERALIZATION AND ADAPTATION • Multiple representations: The representations fed to the judgment process derive from multiple representations: • Abstracted cue-criterion relations, • Exemplar memory. • Adaptive: The representational input is selected to be appropriate to the computational demands made by the task. • Flexible: A stopping rule that is flexible allowing both “fast and frugal judgment” as well as life-long reflection.

8. Time n-2 Time n-1 Time n Fever is typical of pneumonia, swollen glands is not, but coughing is typical of pneumonia, so... CUE ABSTRACTION WITH Sequential consideration of explicitly abstracted cue-criterion relations, the impact of which are intuitively integrated

9. Adustment: towards the highest possible value (max) for positive cue values; towards lowest possible value (min) for negative cue values. Equivalent to the linear additive model (linear multiple regression) Adjustment weight: Cue weight or importance of the cue currently considered, relative to weight of cues considered thus far. Structural Eq. CUE ABSTRACTION WITH Process Eq. Representations: Abstracted cue-criterion relations with cue-weights

10. Time n-2 Time n-1 Time n This looks like patient X who suffered from Pneumonia…., On the other hand, patient Y , also with similar Symptoms did not suffer from pneumonia… , so... EXEMPLAR MEMORY WITH Sequential consideration of previously encountered exemplars, the impact of which are intuitively integrated

11. Adustment: towards the value implied by the exemplar that is considered at time n. Equivalent to the context model of classification (e.g., Medin & Schaffer, 1978; Nosofsky, 1984; Nosofsky & Johansen, 2000). Adjustment weight: Similarity between the judgment probe and the retrieved exemplar at n, relative to the similarity of the exemplars retrieved thus far. Structural Eq. EXEMPLAR MEMORY WITH Process Eq. Representations: Previously encountered concrete exemplars.

12. Probability of cue retrieval at time n Consideration of concrete exemplars Consideration of abstracted cues QUASI-RATIONALITY WITH Structural Eq. The input to changes from moment to moment in real time, where is the probability of sampling an abstracted cue-criterion relation rather than an exemplar at time t.

13. Can represent non-linear and non-additive cue-criterion relations EXEMPLAR MEMORY Exemplars [1, 1, 0, 0]  57 [1, 0, 1, 0]  56 [0, 0, 0, 1]  51 [1, 1, 1, 0]  59 Similarity s2 = .01 s2 = .01 s3 = .001 s = .1 Judgment process Experience Exemplar Cues Criterion 4 1 1 0 0 57 6 1 0 1 0 56 15 0 0 0 1 51 2 1 1 1 0 59 58.5 Probe p [1, 1, 1, 1,]  ? 60 EXPLICIT CUE ABSTRACTION Can only represent linear, additive cue-criterion relations Cue weight Intercept = 50 Cue i 1 2 3 4 Weight 4 3 2 1 Judgment process PREDICTED ADAPTABILITY Additive combination of exemplars Additive combination of cues

14. Environment Stimuli Long green legs Patterned green buttock Short darkblue nose Green foreback with two red spots Basic design Training Training with outcome feedback for 11 or 13 “training exemplars” Test All 16 exemplars, including those that require extrapolation and interpolation. JUDGMENT TASK

15. JUDGMENT TASK Withheld in training

16. EXAMPLE WITH TWO PARTICIPANTSJuslin, H. Olsson, & A-C. Olsson (2003). JEP: G Participant relying on explicit cue abstraction Participant relying on exemplar retrieval

17. + + + × × × ADDITIVE OR MULTIPLICATIVE TASK ENVIRONMENTJuslin, Karlsson, & H. Olsson (in preparation) Environment where the cues combine by addition [0, 0, 0, 1]  51 [1, 1, 1, 0]  59 Environment where the cues combine by multiplication or

18. Training range 51-59 • Re = .9 (probabilistic) Continuous task What is the toxicity of this bug? Long green legs Patterned green buttock Short darkblue nose Green foreback with two red spots Feedback: e.g., “This bughas toxicity 57%” EXPERIMENT 1Juslin, Karlsson, & H. Olsson (in preparation)

19. 240 trials Training ”How poisonous is this subspecies?” ”This subspecies has toxicity 57 ppm” 54? (no feed-back) 32 trials Test ”How poisonous is this subspecies?” 57? JUDGMENT TASK

20. Ability to extrapolate QUANTITATIVE PREDICTIONS Additive task Multiplicative task Cue-Abstraction Model (additive) Exemplar-Based Model

21. Results from Experiment 1 Juslin, Karlsson, & H. Olsson (in preparation) Interpretation: A multiplicative environment hinders effective abstraction of explicit cue-criterion relations and forces the participants to shift to exemplar memory

22. Interpretation: Also in a deterministic multiplicative task are people forced to rely on exemplars EXPERIMENT 2Juslin, Karlsson, & H. Olsson (in preparation) • Training range 51-59, but with equal mean and variance as in the additive condition • Re = 1.0 (deterministic)

23. Long green legs Patterned green buttock Short darkblue nose Green foreback with two red spots Cue 1 = 1 add 629 Cue 2 = 1 add 472 Cue 3 = 1 add 315 Cue 4 = 1 add 157 Cue 1 = 1 multiply with 55 Cue 2 = 1 multiply with 20 Cue 3 = 1 multiply with 7 Cue 4 = 1 multiply with 3 EXPERIMENT 3Juslin, Karlsson, & H. Olsson (in preparation) If the pp are trained to aquire the representations relevant to cue abstraction – thecue weights and the integration rule – are they equally able to do this in an additive and a multiplicative task

24. Long green legs Patterned green buttock Long green legs Patterned green buttock Long green legs Patterned green buttock 240 trials with pairs of cues Training ”These features contribute 629 µg poison.” ”How much poison is contributed by these two features?” 472? Long green legs Patterned green buttock Short darkblue nose Green foreback with two red spots Long green legs Patterned green buttock Short darkblue nose Green foreback with two red spots 32 trials with full exemplars (no feedback) Test ”How poisonuous is this subspecies?” 787? Study 3Juslin, Karlsson, & H. Olsson (in preparation)

25. Interpretation: If specifically trained to acquire the representations needed to implement cue abstraction with intuitive cue integration, pps can do this but only if the cognitive representations involve additive cur-criterion relations – as indeed implied by Experiment 3Juslin, Karlsson, & H. Olsson (in preparation)

26. GENERAL CONCLUSIONS • Two cognitive processes in multiple cue judgment: • Cue abstraction with intuitive cue integration, • Exemplar memory. • -- a generalized model of the judgment process: • Multiple representational systems with adaptive changes between representations. • Structural properties of cue-criterion relations predicts what representations dominate the judgments. • Additive or multiplicative cue-criterion relations,