bool should的算法规则变了吗？

POST /blogs/_search

{

    "query": {

        "bool": {

            "should": [

                { "match": { "title": "Brown fox" }},

                { "match": { "body":  "Brown fox" }}

            ]

        }

    }

    , "explain": true

}

 "_explanation" : {

          "value" : 0.9251295,

          "description" : "sum of:",