Figure 18. Relative magnitude of the longest IRT of Garbo (rhesus macaque) at each position on four 6-item lists.  For each trial, the IRT's at each position were divided by the longest latency on that trial (excluding the latency to A).  The longest latency is represented as X, and the other items correspond to their ordinal distance from X (X-4 to X+4).  The range of the number of correct trials used to calculate each of the data points for positions B-F was 6-34.  See text for additional details.