Systematic biases in perception and memory – harnassing for good Glyn Humphreys

Everyday slips of action Who has ever……? Picked up the wrong thing or poured into the wrong container when doing two things at once Taken the more familiar route when you meant to be going the other way Everyday slips of action

Utilisation behaviour (Lhermitte, 1983)

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How can we understand these problems?

There are many cues that we face throughout everyday life, and we have: A system that responds to the cues in an automatic and fast-acting way (b) A system that is more under conscious control but involves mental effort and is slower in action Kahneman (2011) Thinking, fast and slow: System 1 (fast automatic) System 2 (slow, effortful)

Kahneman argues that the operations of ‘system 1’ pervade many aspects of thinking A bat and ball costs £1.10. The bat costs £1 more than the ball. How much does the ball cost? Especially when under time pressure, 10p comes to mind BUT if the ball is 10p and the bat is £1 more – then how much would the bat cost ? £1.10, making it all £1.20 Correct answer: £5p June 23, 2018

Proposal – the fast system jumps to the answer based on the availability of ‘10’ and the rapid segmentation of £1.10 into £1 [bat] and 10p [ball] Fast system is ‘intuitive’ but can come to the wrong conclusion Fast system works on association and ‘priming’ Left half of the room think about lunch Right half of the room think about having a shower Complete the word SO_P as fast as you can

We can be primed unconsiously - do people put money into an honesty box when paying for coffee (Bateson et al., 2006)? June 23, 2018

June 23, 2018

These biases also vary according to whether the stimuli are related to ourselves or not There is considerable work showing that humans show a bias towards information related to themselves Memory (Conway et al., 1996) Trait evaluation (Klein et al., 1989) Face recognition (Keenan et al., 1999)

Just as in Kahneman’s examples, these biases can be harmful +

These biases pervade even very simple tasks Draw a triangle and label each corner : stranger, you, best friend Draw a line: position your best friend, you, stranger labels along the line Now write which name you put first on the page You to the left and first

You Friend Stranger

You

Stranger

You

Friend

Stranger

Stranger

Is there a difference in matching the different shape-label combinations (Sui, He & Humphreys, 2012, JEP:HPP)?

Massive self-advantage Gained within 15 learning trials

Trait-like measures -Reliable across test sessions

Effect on perception: change the contrast of the shape Effects of social association modulates effects of stimulus contrast on perceptual sensitivity Evidence for a perceptual locus

Involvement of a specific brain circuit Participants performed the self-association match task in the scanner How do brain states change to generate the effect (Sui, Rotshtein & Humphreys, 2013, PNAS)?

vmPFC classically associated with self processing LpSTS linked to the ventral attentional network Linking of self to socially salient signal

Dynamic causal model: Stronger intrinsic connectivity from vmPFC  LpSTS, the more efficient performance for matching self trials

Activity in the classic dorsal attention control network Self bias not modulated by the ‘slow’ attention system

Self-matching affected by a neural circuit connecting self representations (vmPFC)  attentional responses to sensory signals (LpSTS) Strength of connections within this circuit determine the efficiency of behaviour to self-associated stimuli

Can these effects be usefully harnessed – e. g Can these effects be usefully harnessed – e.g., to improve performance? Example – using self reference in memory

GA – patient who suffered herpes simplex encephalitis – severe amnesia We assessed if his amnesia could be reduced by having him make personal associations with stimuli – objects assigned as belonging to him or sister

25% improvement from linking to the self

GA asked to evaluate if he liked the object, or if his sister Improvement certainly in source memory after relating to the self

Conclusions Human cognition is systematically biased in various ways – fast vs. slow decisions Self-biases are pervasive, consistent and fast Such biases can be used though to improve cognition and may provide a useful scaffold for learning Good teachers make learning relevant to the individual June 23, 2018

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