An Eye Tracking StudyShannon Fitzhugh, Thomas F Shipley, Nora Newcombe,

Dominique DumayTemple University

June 14, 2008

Individual Differences in Mental Rotation of Real World Shepard-

Metzler Figures

OverviewBrief Review of Individual Differences

literatureIdentification of “new” group (Geisler,

Lehmann, & Eid 2006)Eye Movements in Mental Rotation

Just & Carpenter (1976) 3-dimensional stimuliMethodsResultsDiscussionQuestions????

Individual differencesFocus on Gender differences

Biological mechanismsHormones (Hausmann et al.)Different areas of activation in the brain (Hugdahl et

al., 2006)

Experience mediatesComputer experience (Terlecki & Newcombe,

2005)Training (Sorby & Baartmans, 1996;

Wiedenbauer et al., 2007; Hand & Uttal, in prep)

Introducing….Non-rotatorsLatent class analysis of MRT-A (Geisler et

al., 2006)5 “groups” of rotators

Two “low” – poor MRT-A performanceThree “high” – good MRT-A performance

High groups – only differ in speedResponse probabilities drop off after 12 (no drop

off), 8, & 4 Low groups

Poor mental rotators – low solution probabilities for all items

Non – rotators Identified by response patterns on the MRT-AQualitative differences between target and

distracter

Examples

Eye Movements and Mental RotationJust & Carpenter (1976)

Number of fixations increased for low ability rotators

Number of times switched between figures increased monotonically

Search, Transform, CompareOur Expansions

Greater number of subjects (them=8; us=33)Three groups of rotators (high, low, non)Statistical analysis

3-Dimensional StimuliMRT research uses 2-Dimensional

perspective drawings3D-like virtual items (Wohlschlager &

Wohlschlager, 1998)Manual training using Virtual Reality stimuli

(Ruddle & Jones, 2001)Non-rotators

Create stimuli amenable to their strategy to keep them above floor

Application to STEM disciplinesGeology, Engineering, Chemistry, Biology,

Imaging

Then There Were …Real World Stimuli

Methods Vandenberg MRT (1988)

Why not MRT-A? Did not have it Same items for non-rotator identification

present in both testsReal World MRT

3 rotations – 0,45, and 90 degrees 2 axis rotation catch trials30 cm viewing distance – each cube 2.5o

visual angleApplied Science Laboratories MobileEye

0.5o error, 60hz Eye Response Technologies - GazeTracker

Data Analysis Software

Dependent Variables Reaction Time

Predict Linear functionNumber of Fixations

Figure switching number of times participants switch

consecutive fixations between the left and right figures

Fixation Duration

Intra-object v. inter-object fixations

Results – Getting Away from the Descriptive

Time course of intra-object to inter-object fixationsChanges over time?No differences between highs/lows

Search, Transform, CompareInitially defined Transform – others by defaultSome preliminary evidence – although

pattern a bit differentDetermining ways to quantify so statistical

analysis can be preformed

SummaryReplicate traditional MR functions with real

world stimuliLinear RT function Better overall performance

Replicate Just & Carpenter – with non-rotatorsgreater number of fixations for low abilityMonotonic function switching between

figures for high/lowNon-rotators trending toward doubling this

Longer fixation duration for non-rotatorsHigher proportion of intra-object to inter-

object fixations for high and low ability

DiscussionReal World 3D stimuli behave similarly to 2D

Linear reaction timeMonotonic switching between figures for high/low

abilitySimilar eye movement patterns for high/low

ability Including non-rotators in low groups may have

masked these similaritiesSimilar strategies or differing strategies resulting

in similar eye movements?Non-rotators

Pattern of eye movements consistent with feature comparison strategy

Longer fixation durations indicative of increase processing timeCounting strategies

Future DirectionsTraining study – Don’t Sleep In!!

The Effects of Working Memory Training versus Spatial Visualization training on spatial skills

Gesture studyEye movements, verbal report, and

spontaneous gesture (Levine & Goldin-Meadow)

This research was supported by a National Science Foundation grant to support the Spatial Intelligence and Learning Center (No. SBE0541957).

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