Detecting Violations In Real- And Counterfactual- World Contexts: Eye-movements And ERP Analysis Heather J Ferguson, Anthony J Sanford & Hartmut Leuthold Department of Psychology, University of Glasgow GLASGOW LANGUAGE PROCESSING

Comprehending counterfactuals and the beliefs of others (ToM) Main aims

Counterfactuals Counterfactual thinking: –Valid reasoning arising from premises that are true in a hypothetical model, but false in actuality “If Ruth had gone to the shops then she would have bought sweets”

Counterfactuals in cognitive science Fauconnier (1994; 2002) –Forced incompatibility between two mental spaces: reality & hypothetical Leslie (1987) –Counterfactual thinking is a special case of theory of mind Kahneman & Miller (1986) –Modifying past experiences manipulates expected norms

Anomaly detection in reading Semantic anomalies & eye-movements (Ni et al, 1998; Braze et al, 2002): –generate longer reading times prior to a gradual increase in regressive eye-movements Semantic anomalies & ERP (Kutas & Hillyard, 1980): –N400 effect to pragmatic violations Discourse-dependent context anomalies & ERP (Van Berkum, Hagoort & Brown, 1999): –elicit a large N400 effect

Experiment 1 Is the same disruption of the reading process elicited for RW violations when it is consistent within a pre-specified counterfactual context? 36 participants 24 experimental items SRI Dual-purkinje eye-tracker Within subjects 3-factor design

Experimental items [1] CW- consistent If cats were vegetarians they would be cheaper for owners to look after. Families could feed their cat a bowl of carrots and it would gobble it down happily. [2] RW- inconsistent If cats are hungry they usually pester their owners until they get fed. Families could feed their cat a bowl of carrots and it would gobble it down happily. [3] RW- consistent If cats are hungry they usually pester their owners until they get fed. Families could feed their cat a bowl of fish and it would gobble it down happily.

Methods of analysis 6 regions: |If cats were vegetarians they would be cheaper for owners to look after. 1 | Families could 2 | feed their cat a bowl of 3 | carrots and 4 | it would gobble it down happily. 5 | Cats are loving pets when you look after them well. 6 | Critical region 4 contained inconsistent/ consistent word Corresponding regions contained approximately the same number of words in all three versions Specifically, critical region was matched across conditions for length and word frequency

Results Total RT & Number of fixations ** *** **

Results Regressions ***

Results First-pass RT ***

Experiment 1: Summary Is the same disruption of the reading process elicited for RW violations when it is consistent within a pre-specified counterfactual context? RW violations were treated as acceptable in a pre- specified CW context Effect on early processing for RW violations regardless of prior context

Experiment 2 Does a disruption of the reading process emerge for RW congruent information when it is inconsistent within a pre-specified counterfactual context? 36 participants 36 experimental items SRI Dual Purkinje eye-tracker Within subjects 2 (count/ non-count) x 2 (inconsistent/ consistent) design

Materials & Methods of analysis [4] CW- inconsistent If cats were vegetarians they would be cheaper for owners to look after. Families could feed their cat a bowl of fish and it would gobble it down happily. Divided into the same regions for analysis as experiment 1

Results Total RT * ** *

Results Number of fixations *

Results Regressions *** * *

No differences in first-pass RT at critical region Critical region now region 5 |If cats were vegetarians they would be cheaper for owners to look after. 1 | Families could 2 | feed their cat a 3 | bowl of 4 | carrots 5 | and 6 | it would gobble it down happily. 7 | Cats are loving pets when you look after them well. 8 | Results First-pass RT

Results First-pass RT Families could 2 | feed their cat a 3 | bowl of 4 | carrots 5 | and 6 | it would gobble it down happily. 7 |

Experiment 2: Summary Does a disruption of the reading process emerge for RW congruent information when it is inconsistent within a pre-specified counterfactual context? RW congruent items were processed as anomalous in a CW context –prior context is rapidly utilised RW inconsistencies are detected faster than CW inconsistencies –effects for a RW inconsistency are detected in the first- pass RT

Can we distinguish between CW and RW inconsistencies in the ERP components? 160 experimental items displayed in a fixed random order alongside filler items 19 native English speakers Within-subjects 2 (CW/ RW) x 2 (consistent/ inconsistent) design Experiment 3

Visually presented: (1) If margarine contained a detergent it would have many domestic uses. (2) Mum could use margarine in her hair/ baking and impress her friends and family. EEG continuously recorded from 72 scalp electrodes and averaged time- locked to onset of consistent/ inconsistent critical word Method

Results N400 effect: RW & CW inconsistent more negative than consistent

Results N400 effect: Larger negativity for RW than CW RW inconsistent effect begins later than CW inconsistent - Might be due to overlap with earlier larger positivity for CW than RW Time-frequency analysis of ERP data

Both eye-movements and ERPs are sensitive to RW and CW inconsistencies EM data suggests an initial processing strategy using RW knowledge But, incoming words are very rapidly integrated to the semantics of the wider context –Longer reading times & increased regressions –N400 effect EM suggest RW inconsistencies are more ‘powerful’ and are detected faster than CW inconsistencies Conclusions

GLASGOW LANGUAGE PROCESSING Thank you

EM: Contextually constrained words are fixated for less time than words not constrained by the semantic context –Altarriba, Kroll, Sholl & Rayner, 1996; Rayner & Well, 1996; Schustack, Ehrlich & Rayner, 1987 Semantic context effects

[5] & [6] RW- inconsistent & RW- consistent Evolution dictates that cats are carnivores and cows are vegetarians. Experiment 4